From 68264fcf877f6ed9c3977698d0001e3b9c23917e Mon Sep 17 00:00:00 2001 From: mid <> Date: Sat, 10 May 2025 18:16:07 +0300 Subject: [PATCH] Add bc7enc source --- src/compr/bc7enc.c | 2215 ++++++++++++++++++++++++++++++++++++++++++++ src/compr/bc7enc.h | 82 ++ 2 files changed, 2297 insertions(+) create mode 100644 src/compr/bc7enc.c create mode 100644 src/compr/bc7enc.h diff --git a/src/compr/bc7enc.c b/src/compr/bc7enc.c new file mode 100644 index 0000000..f8a561d --- /dev/null +++ b/src/compr/bc7enc.c @@ -0,0 +1,2215 @@ +// File: bc7enc.c - Richard Geldreich, Jr. 3/31/2020 - MIT license or public domain (see end of file) +// Currently supports modes 1, 6 for RGB blocks, and modes 5, 6, 7 for RGBA blocks. +// NOTE: This module is still a work in progress as of 3/31/2020. It needs to support more modes for RGB content. +#include "bc7enc.h" +#include +#include +#include +#include +#include + +// Helpers +static inline int32_t clampi(int32_t value, int32_t low, int32_t high) { if (value < low) value = low; else if (value > high) value = high; return value; } +static inline float clampf(float value, float low, float high) { if (value < low) value = low; else if (value > high) value = high; return value; } +static inline float saturate(float value) { return clampf(value, 0, 1.0f); } +static inline uint8_t minimumub(uint8_t a, uint8_t b) { return (a < b) ? a : b; } +static inline uint32_t minimumu(uint32_t a, uint32_t b) { return (a < b) ? a : b; } +static inline float minimumf(float a, float b) { return (a < b) ? a : b; } +static inline uint8_t maximumub(uint8_t a, uint8_t b) { return (a > b) ? a : b; } +static inline uint32_t maximumu(uint32_t a, uint32_t b) { return (a > b) ? a : b; } +static inline float maximumf(float a, float b) { return (a > b) ? a : b; } +static inline int squarei(int i) { return i * i; } +static inline float squaref(float i) { return i * i; } + +static inline int32_t iabs32(int32_t v) { uint32_t msk = v >> 31; return (v ^ msk) - msk; } +static inline void swapub(uint8_t* a, uint8_t* b) { uint8_t t = *a; *a = *b; *b = t; } +static inline void swapu(uint32_t* a, uint32_t* b) { uint32_t t = *a; *a = *b; *b = t; } +static inline void swapf(float* a, float* b) { float t = *a; *a = *b; *b = t; } + +typedef struct { uint8_t m_c[4]; } color_quad_u8; +typedef struct { float m_c[4]; } vec4F; + +static inline color_quad_u8 *color_quad_u8_set_clamped(color_quad_u8 *pRes, int32_t r, int32_t g, int32_t b, int32_t a) { pRes->m_c[0] = (uint8_t)clampi(r, 0, 255); pRes->m_c[1] = (uint8_t)clampi(g, 0, 255); pRes->m_c[2] = (uint8_t)clampi(b, 0, 255); pRes->m_c[3] = (uint8_t)clampi(a, 0, 255); return pRes; } +static inline color_quad_u8 *color_quad_u8_set(color_quad_u8 *pRes, int32_t r, int32_t g, int32_t b, int32_t a) { assert((uint32_t)(r | g | b | a) <= 255); pRes->m_c[0] = (uint8_t)r; pRes->m_c[1] = (uint8_t)g; pRes->m_c[2] = (uint8_t)b; pRes->m_c[3] = (uint8_t)a; return pRes; } +static inline bc7enc_bool color_quad_u8_notequals(const color_quad_u8 *pLHS, const color_quad_u8 *pRHS) { return (pLHS->m_c[0] != pRHS->m_c[0]) || (pLHS->m_c[1] != pRHS->m_c[1]) || (pLHS->m_c[2] != pRHS->m_c[2]) || (pLHS->m_c[3] != pRHS->m_c[3]); } +static inline vec4F *vec4F_set_scalar(vec4F *pV, float x) { pV->m_c[0] = x; pV->m_c[1] = x; pV->m_c[2] = x; pV->m_c[3] = x; return pV; } +static inline vec4F *vec4F_set(vec4F *pV, float x, float y, float z, float w) { pV->m_c[0] = x; pV->m_c[1] = y; pV->m_c[2] = z; pV->m_c[3] = w; return pV; } +static inline vec4F *vec4F_saturate_in_place(vec4F *pV) { pV->m_c[0] = saturate(pV->m_c[0]); pV->m_c[1] = saturate(pV->m_c[1]); pV->m_c[2] = saturate(pV->m_c[2]); pV->m_c[3] = saturate(pV->m_c[3]); return pV; } +static inline vec4F vec4F_saturate(const vec4F *pV) { vec4F res; res.m_c[0] = saturate(pV->m_c[0]); res.m_c[1] = saturate(pV->m_c[1]); res.m_c[2] = saturate(pV->m_c[2]); res.m_c[3] = saturate(pV->m_c[3]); return res; } +static inline vec4F vec4F_from_color(const color_quad_u8 *pC) { vec4F res; vec4F_set(&res, pC->m_c[0], pC->m_c[1], pC->m_c[2], pC->m_c[3]); return res; } +static inline vec4F vec4F_add(const vec4F *pLHS, const vec4F *pRHS) { vec4F res; vec4F_set(&res, pLHS->m_c[0] + pRHS->m_c[0], pLHS->m_c[1] + pRHS->m_c[1], pLHS->m_c[2] + pRHS->m_c[2], pLHS->m_c[3] + pRHS->m_c[3]); return res; } +static inline vec4F vec4F_sub(const vec4F *pLHS, const vec4F *pRHS) { vec4F res; vec4F_set(&res, pLHS->m_c[0] - pRHS->m_c[0], pLHS->m_c[1] - pRHS->m_c[1], pLHS->m_c[2] - pRHS->m_c[2], pLHS->m_c[3] - pRHS->m_c[3]); return res; } +static inline float vec4F_dot(const vec4F *pLHS, const vec4F *pRHS) { return pLHS->m_c[0] * pRHS->m_c[0] + pLHS->m_c[1] * pRHS->m_c[1] + pLHS->m_c[2] * pRHS->m_c[2] + pLHS->m_c[3] * pRHS->m_c[3]; } +static inline vec4F vec4F_mul(const vec4F *pLHS, float s) { vec4F res; vec4F_set(&res, pLHS->m_c[0] * s, pLHS->m_c[1] * s, pLHS->m_c[2] * s, pLHS->m_c[3] * s); return res; } +static inline vec4F *vec4F_normalize_in_place(vec4F *pV) { float s = pV->m_c[0] * pV->m_c[0] + pV->m_c[1] * pV->m_c[1] + pV->m_c[2] * pV->m_c[2] + pV->m_c[3] * pV->m_c[3]; if (s != 0.0f) { s = 1.0f / sqrtf(s); pV->m_c[0] *= s; pV->m_c[1] *= s; pV->m_c[2] *= s; pV->m_c[3] *= s; } return pV; } + +// Various BC7 tables +static const uint32_t g_bc7_weights2[4] = { 0, 21, 43, 64 }; +static const uint32_t g_bc7_weights3[8] = { 0, 9, 18, 27, 37, 46, 55, 64 }; +static const uint32_t g_bc7_weights4[16] = { 0, 4, 9, 13, 17, 21, 26, 30, 34, 38, 43, 47, 51, 55, 60, 64 }; +// Precomputed weight constants used during least fit determination. For each entry in g_bc7_weights[]: w * w, (1.0f - w) * w, (1.0f - w) * (1.0f - w), w +static const float g_bc7_weights2x[4 * 4] = { 0.000000f, 0.000000f, 1.000000f, 0.000000f, 0.107666f, 0.220459f, 0.451416f, 0.328125f, 0.451416f, 0.220459f, 0.107666f, 0.671875f, 1.000000f, 0.000000f, 0.000000f, 1.000000f }; +static const float g_bc7_weights3x[8 * 4] = { 0.000000f, 0.000000f, 1.000000f, 0.000000f, 0.019775f, 0.120850f, 0.738525f, 0.140625f, 0.079102f, 0.202148f, 0.516602f, 0.281250f, 0.177979f, 0.243896f, 0.334229f, 0.421875f, 0.334229f, 0.243896f, 0.177979f, 0.578125f, 0.516602f, 0.202148f, + 0.079102f, 0.718750f, 0.738525f, 0.120850f, 0.019775f, 0.859375f, 1.000000f, 0.000000f, 0.000000f, 1.000000f }; +static const float g_bc7_weights4x[16 * 4] = { 0.000000f, 0.000000f, 1.000000f, 0.000000f, 0.003906f, 0.058594f, 0.878906f, 0.062500f, 0.019775f, 0.120850f, 0.738525f, 0.140625f, 0.041260f, 0.161865f, 0.635010f, 0.203125f, 0.070557f, 0.195068f, 0.539307f, 0.265625f, 0.107666f, 0.220459f, + 0.451416f, 0.328125f, 0.165039f, 0.241211f, 0.352539f, 0.406250f, 0.219727f, 0.249023f, 0.282227f, 0.468750f, 0.282227f, 0.249023f, 0.219727f, 0.531250f, 0.352539f, 0.241211f, 0.165039f, 0.593750f, 0.451416f, 0.220459f, 0.107666f, 0.671875f, 0.539307f, 0.195068f, 0.070557f, 0.734375f, + 0.635010f, 0.161865f, 0.041260f, 0.796875f, 0.738525f, 0.120850f, 0.019775f, 0.859375f, 0.878906f, 0.058594f, 0.003906f, 0.937500f, 1.000000f, 0.000000f, 0.000000f, 1.000000f }; + +static const uint8_t g_bc7_partition1[16] = { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 }; +static const uint8_t g_bc7_partition2[64 * 16] = +{ + 0,0,1,1,0,0,1,1,0,0,1,1,0,0,1,1, 0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1, 0,1,1,1,0,1,1,1,0,1,1,1,0,1,1,1, 0,0,0,1,0,0,1,1,0,0,1,1,0,1,1,1, 0,0,0,0,0,0,0,1,0,0,0,1,0,0,1,1, 0,0,1,1,0,1,1,1,0,1,1,1,1,1,1,1, 0,0,0,1,0,0,1,1,0,1,1,1,1,1,1,1, 0,0,0,0,0,0,0,1,0,0,1,1,0,1,1,1, + 0,0,0,0,0,0,0,0,0,0,0,1,0,0,1,1, 0,0,1,1,0,1,1,1,1,1,1,1,1,1,1,1, 0,0,0,0,0,0,0,1,0,1,1,1,1,1,1,1, 0,0,0,0,0,0,0,0,0,0,0,1,0,1,1,1, 0,0,0,1,0,1,1,1,1,1,1,1,1,1,1,1, 0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1, 0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,1, 0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1, + 0,0,0,0,1,0,0,0,1,1,1,0,1,1,1,1, 0,1,1,1,0,0,0,1,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,1,0,0,0,1,1,1,0, 0,1,1,1,0,0,1,1,0,0,0,1,0,0,0,0, 0,0,1,1,0,0,0,1,0,0,0,0,0,0,0,0, 0,0,0,0,1,0,0,0,1,1,0,0,1,1,1,0, 0,0,0,0,0,0,0,0,1,0,0,0,1,1,0,0, 0,1,1,1,0,0,1,1,0,0,1,1,0,0,0,1, + 0,0,1,1,0,0,0,1,0,0,0,1,0,0,0,0, 0,0,0,0,1,0,0,0,1,0,0,0,1,1,0,0, 0,1,1,0,0,1,1,0,0,1,1,0,0,1,1,0, 0,0,1,1,0,1,1,0,0,1,1,0,1,1,0,0, 0,0,0,1,0,1,1,1,1,1,1,0,1,0,0,0, 0,0,0,0,1,1,1,1,1,1,1,1,0,0,0,0, 0,1,1,1,0,0,0,1,1,0,0,0,1,1,1,0, 0,0,1,1,1,0,0,1,1,0,0,1,1,1,0,0, + 0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1, 0,0,0,0,1,1,1,1,0,0,0,0,1,1,1,1, 0,1,0,1,1,0,1,0,0,1,0,1,1,0,1,0, 0,0,1,1,0,0,1,1,1,1,0,0,1,1,0,0, 0,0,1,1,1,1,0,0,0,0,1,1,1,1,0,0, 0,1,0,1,0,1,0,1,1,0,1,0,1,0,1,0, 0,1,1,0,1,0,0,1,0,1,1,0,1,0,0,1, 0,1,0,1,1,0,1,0,1,0,1,0,0,1,0,1, + 0,1,1,1,0,0,1,1,1,1,0,0,1,1,1,0, 0,0,0,1,0,0,1,1,1,1,0,0,1,0,0,0, 0,0,1,1,0,0,1,0,0,1,0,0,1,1,0,0, 0,0,1,1,1,0,1,1,1,1,0,1,1,1,0,0, 0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0, 0,0,1,1,1,1,0,0,1,1,0,0,0,0,1,1, 0,1,1,0,0,1,1,0,1,0,0,1,1,0,0,1, 0,0,0,0,0,1,1,0,0,1,1,0,0,0,0,0, + 0,1,0,0,1,1,1,0,0,1,0,0,0,0,0,0, 0,0,1,0,0,1,1,1,0,0,1,0,0,0,0,0, 0,0,0,0,0,0,1,0,0,1,1,1,0,0,1,0, 0,0,0,0,0,1,0,0,1,1,1,0,0,1,0,0, 0,1,1,0,1,1,0,0,1,0,0,1,0,0,1,1, 0,0,1,1,0,1,1,0,1,1,0,0,1,0,0,1, 0,1,1,0,0,0,1,1,1,0,0,1,1,1,0,0, 0,0,1,1,1,0,0,1,1,1,0,0,0,1,1,0, + 0,1,1,0,1,1,0,0,1,1,0,0,1,0,0,1, 0,1,1,0,0,0,1,1,0,0,1,1,1,0,0,1, 0,1,1,1,1,1,1,0,1,0,0,0,0,0,0,1, 0,0,0,1,1,0,0,0,1,1,1,0,0,1,1,1, 0,0,0,0,1,1,1,1,0,0,1,1,0,0,1,1, 0,0,1,1,0,0,1,1,1,1,1,1,0,0,0,0, 0,0,1,0,0,0,1,0,1,1,1,0,1,1,1,0, 0,1,0,0,0,1,0,0,0,1,1,1,0,1,1,1 +}; + +static const uint8_t g_bc7_partition3[64 * 16] = +{ + 0,0,1,1,0,0,1,1,0,2,2,1,2,2,2,2, 0,0,0,1,0,0,1,1,2,2,1,1,2,2,2,1, 0,0,0,0,2,0,0,1,2,2,1,1,2,2,1,1, 0,2,2,2,0,0,2,2,0,0,1,1,0,1,1,1, 0,0,0,0,0,0,0,0,1,1,2,2,1,1,2,2, 0,0,1,1,0,0,1,1,0,0,2,2,0,0,2,2, 0,0,2,2,0,0,2,2,1,1,1,1,1,1,1,1, 0,0,1,1,0,0,1,1,2,2,1,1,2,2,1,1, + 0,0,0,0,0,0,0,0,1,1,1,1,2,2,2,2, 0,0,0,0,1,1,1,1,1,1,1,1,2,2,2,2, 0,0,0,0,1,1,1,1,2,2,2,2,2,2,2,2, 0,0,1,2,0,0,1,2,0,0,1,2,0,0,1,2, 0,1,1,2,0,1,1,2,0,1,1,2,0,1,1,2, 0,1,2,2,0,1,2,2,0,1,2,2,0,1,2,2, 0,0,1,1,0,1,1,2,1,1,2,2,1,2,2,2, 0,0,1,1,2,0,0,1,2,2,0,0,2,2,2,0, + 0,0,0,1,0,0,1,1,0,1,1,2,1,1,2,2, 0,1,1,1,0,0,1,1,2,0,0,1,2,2,0,0, 0,0,0,0,1,1,2,2,1,1,2,2,1,1,2,2, 0,0,2,2,0,0,2,2,0,0,2,2,1,1,1,1, 0,1,1,1,0,1,1,1,0,2,2,2,0,2,2,2, 0,0,0,1,0,0,0,1,2,2,2,1,2,2,2,1, 0,0,0,0,0,0,1,1,0,1,2,2,0,1,2,2, 0,0,0,0,1,1,0,0,2,2,1,0,2,2,1,0, + 0,1,2,2,0,1,2,2,0,0,1,1,0,0,0,0, 0,0,1,2,0,0,1,2,1,1,2,2,2,2,2,2, 0,1,1,0,1,2,2,1,1,2,2,1,0,1,1,0, 0,0,0,0,0,1,1,0,1,2,2,1,1,2,2,1, 0,0,2,2,1,1,0,2,1,1,0,2,0,0,2,2, 0,1,1,0,0,1,1,0,2,0,0,2,2,2,2,2, 0,0,1,1,0,1,2,2,0,1,2,2,0,0,1,1, 0,0,0,0,2,0,0,0,2,2,1,1,2,2,2,1, + 0,0,0,0,0,0,0,2,1,1,2,2,1,2,2,2, 0,2,2,2,0,0,2,2,0,0,1,2,0,0,1,1, 0,0,1,1,0,0,1,2,0,0,2,2,0,2,2,2, 0,1,2,0,0,1,2,0,0,1,2,0,0,1,2,0, 0,0,0,0,1,1,1,1,2,2,2,2,0,0,0,0, 0,1,2,0,1,2,0,1,2,0,1,2,0,1,2,0, 0,1,2,0,2,0,1,2,1,2,0,1,0,1,2,0, 0,0,1,1,2,2,0,0,1,1,2,2,0,0,1,1, + 0,0,1,1,1,1,2,2,2,2,0,0,0,0,1,1, 0,1,0,1,0,1,0,1,2,2,2,2,2,2,2,2, 0,0,0,0,0,0,0,0,2,1,2,1,2,1,2,1, 0,0,2,2,1,1,2,2,0,0,2,2,1,1,2,2, 0,0,2,2,0,0,1,1,0,0,2,2,0,0,1,1, 0,2,2,0,1,2,2,1,0,2,2,0,1,2,2,1, 0,1,0,1,2,2,2,2,2,2,2,2,0,1,0,1, 0,0,0,0,2,1,2,1,2,1,2,1,2,1,2,1, + 0,1,0,1,0,1,0,1,0,1,0,1,2,2,2,2, 0,2,2,2,0,1,1,1,0,2,2,2,0,1,1,1, 0,0,0,2,1,1,1,2,0,0,0,2,1,1,1,2, 0,0,0,0,2,1,1,2,2,1,1,2,2,1,1,2, 0,2,2,2,0,1,1,1,0,1,1,1,0,2,2,2, 0,0,0,2,1,1,1,2,1,1,1,2,0,0,0,2, 0,1,1,0,0,1,1,0,0,1,1,0,2,2,2,2, 0,0,0,0,0,0,0,0,2,1,1,2,2,1,1,2, + 0,1,1,0,0,1,1,0,2,2,2,2,2,2,2,2, 0,0,2,2,0,0,1,1,0,0,1,1,0,0,2,2, 0,0,2,2,1,1,2,2,1,1,2,2,0,0,2,2, 0,0,0,0,0,0,0,0,0,0,0,0,2,1,1,2, 0,0,0,2,0,0,0,1,0,0,0,2,0,0,0,1, 0,2,2,2,1,2,2,2,0,2,2,2,1,2,2,2, 0,1,0,1,2,2,2,2,2,2,2,2,2,2,2,2, 0,1,1,1,2,0,1,1,2,2,0,1,2,2,2,0, +}; + +static const uint8_t g_bc7_table_anchor_index_third_subset_1[64] = +{ + 3, 3,15,15, 8, 3,15,15, 8, 8, 6, 6, 6, 5, 3, 3, 3, 3, 8,15, 3, 3, 6,10, 5, 8, 8, 6, 8, 5,15,15, 8,15, 3, 5, 6,10, 8,15, 15, 3,15, 5,15,15,15,15, 3,15, 5, 5, 5, 8, 5,10, 5,10, 8,13,15,12, 3, 3 +}; + +static const uint8_t g_bc7_table_anchor_index_third_subset_2[64] = +{ + 15, 8, 8, 3,15,15, 3, 8, 15,15,15,15,15,15,15, 8, 15, 8,15, 3,15, 8,15, 8, 3,15, 6,10,15,15,10, 8, 15, 3,15,10,10, 8, 9,10, 6,15, 8,15, 3, 6, 6, 8, 15, 3,15,15,15,15,15,15, 15,15,15,15, 3,15,15, 8 +}; + +static const uint8_t g_bc7_table_anchor_index_second_subset[64] = { 15,15,15,15,15,15,15,15, 15,15,15,15,15,15,15,15, 15, 2, 8, 2, 2, 8, 8,15, 2, 8, 2, 2, 8, 8, 2, 2, 15,15, 6, 8, 2, 8,15,15, 2, 8, 2, 2, 2,15,15, 6, 6, 2, 6, 8,15,15, 2, 2, 15,15,15,15,15, 2, 2,15 }; +static const uint8_t g_bc7_num_subsets[8] = { 3, 2, 3, 2, 1, 1, 1, 2 }; +static const uint8_t g_bc7_partition_bits[8] = { 4, 6, 6, 6, 0, 0, 0, 6 }; +static const uint8_t g_bc7_color_index_bitcount[8] = { 3, 3, 2, 2, 2, 2, 4, 2 }; +static int get_bc7_color_index_size(int mode, int index_selection_bit) { return g_bc7_color_index_bitcount[mode] + index_selection_bit; } +static uint8_t g_bc7_alpha_index_bitcount[8] = { 0, 0, 0, 0, 3, 2, 4, 2 }; +static int get_bc7_alpha_index_size(int mode, int index_selection_bit) { return g_bc7_alpha_index_bitcount[mode] - index_selection_bit; } +static const uint8_t g_bc7_mode_has_p_bits[8] = { 1, 1, 0, 1, 0, 0, 1, 1 }; +static const uint8_t g_bc7_mode_has_shared_p_bits[8] = { 0, 1, 0, 0, 0, 0, 0, 0 }; +static const uint8_t g_bc7_color_precision_table[8] = { 4, 6, 5, 7, 5, 7, 7, 5 }; +static const int8_t g_bc7_alpha_precision_table[8] = { 0, 0, 0, 0, 6, 8, 7, 5 }; +static bc7enc_bool get_bc7_mode_has_seperate_alpha_selectors(int mode) { return (mode == 4) || (mode == 5); } + +typedef struct { uint16_t m_error; uint8_t m_lo; uint8_t m_hi; } endpoint_err; + +static endpoint_err g_bc7_mode_1_optimal_endpoints[256][2]; // [c][pbit] +static const uint32_t BC7ENC_MODE_1_OPTIMAL_INDEX = 2; + +static endpoint_err g_bc7_mode_7_optimal_endpoints[256][2][2]; // [c][pbit][hp][lp] +const uint32_t BC7E_MODE_7_OPTIMAL_INDEX = 1; + +// Initialize the lookup table used for optimal single color compression in mode 1. Must be called before encoding. +void bc7enc_compress_block_init() +{ + for (int c = 0; c < 256; c++) + { + for (uint32_t lp = 0; lp < 2; lp++) + { + endpoint_err best; + best.m_error = (uint16_t)UINT16_MAX; + for (uint32_t l = 0; l < 64; l++) + { + uint32_t low = ((l << 1) | lp) << 1; + low |= (low >> 7); + for (uint32_t h = 0; h < 64; h++) + { + uint32_t high = ((h << 1) | lp) << 1; + high |= (high >> 7); + const int k = (low * (64 - g_bc7_weights3[BC7ENC_MODE_1_OPTIMAL_INDEX]) + high * g_bc7_weights3[BC7ENC_MODE_1_OPTIMAL_INDEX] + 32) >> 6; + const int err = (k - c) * (k - c); + if (err < best.m_error) + { + best.m_error = (uint16_t)err; + best.m_lo = (uint8_t)l; + best.m_hi = (uint8_t)h; + } + } // h + } // l + g_bc7_mode_1_optimal_endpoints[c][lp] = best; + } // lp + } // c + + // Mode 7: 555.1 2-bit indices + for (int c = 0; c < 256; c++) + { + for (uint32_t hp = 0; hp < 2; hp++) + { + for (uint32_t lp = 0; lp < 2; lp++) + { + endpoint_err best; + best.m_error = (uint16_t)UINT16_MAX; + best.m_lo = 0; + best.m_hi = 0; + + for (uint32_t l = 0; l < 32; l++) + { + uint32_t low = ((l << 1) | lp) << 2; + low |= (low >> 6); + + for (uint32_t h = 0; h < 32; h++) + { + uint32_t high = ((h << 1) | hp) << 2; + high |= (high >> 6); + + const int k = (low * (64 - g_bc7_weights2[BC7E_MODE_7_OPTIMAL_INDEX]) + high * g_bc7_weights2[BC7E_MODE_7_OPTIMAL_INDEX] + 32) >> 6; + + const int err = (k - c) * (k - c); + if (err < best.m_error) + { + best.m_error = (uint16_t)err; + best.m_lo = (uint8_t)l; + best.m_hi = (uint8_t)h; + } + } // h + } // l + + g_bc7_mode_7_optimal_endpoints[c][hp][lp] = best; + + } // hp + + } // lp + + } // c +} + +static void compute_least_squares_endpoints_rgba(uint32_t N, const uint8_t *pSelectors, const vec4F *pSelector_weights, vec4F *pXl, vec4F *pXh, const color_quad_u8 *pColors) +{ + // Least squares using normal equations: http://www.cs.cornell.edu/~bindel/class/cs3220-s12/notes/lec10.pdf + // I did this in matrix form first, expanded out all the ops, then optimized it a bit. + float z00 = 0.0f, z01 = 0.0f, z10 = 0.0f, z11 = 0.0f; + float q00_r = 0.0f, q10_r = 0.0f, t_r = 0.0f; + float q00_g = 0.0f, q10_g = 0.0f, t_g = 0.0f; + float q00_b = 0.0f, q10_b = 0.0f, t_b = 0.0f; + float q00_a = 0.0f, q10_a = 0.0f, t_a = 0.0f; + for (uint32_t i = 0; i < N; i++) + { + const uint32_t sel = pSelectors[i]; + z00 += pSelector_weights[sel].m_c[0]; + z10 += pSelector_weights[sel].m_c[1]; + z11 += pSelector_weights[sel].m_c[2]; + float w = pSelector_weights[sel].m_c[3]; + q00_r += w * pColors[i].m_c[0]; t_r += pColors[i].m_c[0]; + q00_g += w * pColors[i].m_c[1]; t_g += pColors[i].m_c[1]; + q00_b += w * pColors[i].m_c[2]; t_b += pColors[i].m_c[2]; + q00_a += w * pColors[i].m_c[3]; t_a += pColors[i].m_c[3]; + } + + q10_r = t_r - q00_r; + q10_g = t_g - q00_g; + q10_b = t_b - q00_b; + q10_a = t_a - q00_a; + + z01 = z10; + + float det = z00 * z11 - z01 * z10; + if (det != 0.0f) + det = 1.0f / det; + + float iz00, iz01, iz10, iz11; + iz00 = z11 * det; + iz01 = -z01 * det; + iz10 = -z10 * det; + iz11 = z00 * det; + + pXl->m_c[0] = (float)(iz00 * q00_r + iz01 * q10_r); pXh->m_c[0] = (float)(iz10 * q00_r + iz11 * q10_r); + pXl->m_c[1] = (float)(iz00 * q00_g + iz01 * q10_g); pXh->m_c[1] = (float)(iz10 * q00_g + iz11 * q10_g); + pXl->m_c[2] = (float)(iz00 * q00_b + iz01 * q10_b); pXh->m_c[2] = (float)(iz10 * q00_b + iz11 * q10_b); + pXl->m_c[3] = (float)(iz00 * q00_a + iz01 * q10_a); pXh->m_c[3] = (float)(iz10 * q00_a + iz11 * q10_a); + + for (uint32_t c = 0; c < 4; c++) + { + if ((pXl->m_c[c] < 0.0f) || (pXh->m_c[c] > 255.0f)) + { + uint32_t lo_v = UINT32_MAX, hi_v = 0; + for (uint32_t i = 0; i < N; i++) + { + lo_v = minimumu(lo_v, pColors[i].m_c[c]); + hi_v = maximumu(hi_v, pColors[i].m_c[c]); + } + + if (lo_v == hi_v) + { + pXl->m_c[c] = (float)lo_v; + pXh->m_c[c] = (float)hi_v; + } + } + } +} + +static void compute_least_squares_endpoints_rgb(uint32_t N, const uint8_t *pSelectors, const vec4F *pSelector_weights, vec4F *pXl, vec4F *pXh, const color_quad_u8 *pColors) +{ + float z00 = 0.0f, z01 = 0.0f, z10 = 0.0f, z11 = 0.0f; + float q00_r = 0.0f, q10_r = 0.0f, t_r = 0.0f; + float q00_g = 0.0f, q10_g = 0.0f, t_g = 0.0f; + float q00_b = 0.0f, q10_b = 0.0f, t_b = 0.0f; + for (uint32_t i = 0; i < N; i++) + { + const uint32_t sel = pSelectors[i]; + z00 += pSelector_weights[sel].m_c[0]; + z10 += pSelector_weights[sel].m_c[1]; + z11 += pSelector_weights[sel].m_c[2]; + float w = pSelector_weights[sel].m_c[3]; + q00_r += w * pColors[i].m_c[0]; t_r += pColors[i].m_c[0]; + q00_g += w * pColors[i].m_c[1]; t_g += pColors[i].m_c[1]; + q00_b += w * pColors[i].m_c[2]; t_b += pColors[i].m_c[2]; + } + + q10_r = t_r - q00_r; + q10_g = t_g - q00_g; + q10_b = t_b - q00_b; + + z01 = z10; + + float det = z00 * z11 - z01 * z10; + if (det != 0.0f) + det = 1.0f / det; + + float iz00, iz01, iz10, iz11; + iz00 = z11 * det; + iz01 = -z01 * det; + iz10 = -z10 * det; + iz11 = z00 * det; + + pXl->m_c[0] = (float)(iz00 * q00_r + iz01 * q10_r); pXh->m_c[0] = (float)(iz10 * q00_r + iz11 * q10_r); + pXl->m_c[1] = (float)(iz00 * q00_g + iz01 * q10_g); pXh->m_c[1] = (float)(iz10 * q00_g + iz11 * q10_g); + pXl->m_c[2] = (float)(iz00 * q00_b + iz01 * q10_b); pXh->m_c[2] = (float)(iz10 * q00_b + iz11 * q10_b); + pXl->m_c[3] = 255.0f; pXh->m_c[3] = 255.0f; + + for (uint32_t c = 0; c < 3; c++) + { + if ((pXl->m_c[c] < 0.0f) || (pXh->m_c[c] > 255.0f)) + { + uint32_t lo_v = UINT32_MAX, hi_v = 0; + for (uint32_t i = 0; i < N; i++) + { + lo_v = minimumu(lo_v, pColors[i].m_c[c]); + hi_v = maximumu(hi_v, pColors[i].m_c[c]); + } + + if (lo_v == hi_v) + { + pXl->m_c[c] = (float)lo_v; + pXh->m_c[c] = (float)hi_v; + } + } + } +} + +static void compute_least_squares_endpoints_a(uint32_t N, const uint8_t* pSelectors, const vec4F* pSelector_weights, float* pXl, float* pXh, const color_quad_u8* pColors) +{ + // Least squares using normal equations: http://www.cs.cornell.edu/~bindel/class/cs3220-s12/notes/lec10.pdf + // I did this in matrix form first, expanded out all the ops, then optimized it a bit. + float z00 = 0.0f, z01 = 0.0f, z10 = 0.0f, z11 = 0.0f; + float q00_a = 0.0f, q10_a = 0.0f, t_a = 0.0f; + for (uint32_t i = 0; i < N; i++) + { + const uint32_t sel = pSelectors[i]; + + z00 += pSelector_weights[sel].m_c[0]; + z10 += pSelector_weights[sel].m_c[1]; + z11 += pSelector_weights[sel].m_c[2]; + + float w = pSelector_weights[sel].m_c[3]; + + q00_a += w * pColors[i].m_c[3]; t_a += pColors[i].m_c[3]; + } + + q10_a = t_a - q00_a; + + z01 = z10; + + float det = z00 * z11 - z01 * z10; + if (det != 0.0f) + det = 1.0f / det; + + float iz00, iz01, iz10, iz11; + iz00 = z11 * det; + iz01 = -z01 * det; + iz10 = -z10 * det; + iz11 = z00 * det; + + *pXl = (float)(iz00 * q00_a + iz01 * q10_a); *pXh = (float)(iz10 * q00_a + iz11 * q10_a); + + if ((*pXl < 0.0f) || (*pXh > 255.0f)) + { + uint32_t lo_v = UINT32_MAX, hi_v = 0; + for (uint32_t i = 0; i < N; i++) + { + lo_v = minimumu(lo_v, pColors[i].m_c[3]); + hi_v = maximumu(hi_v, pColors[i].m_c[3]); + } + + if (lo_v == hi_v) + { + *pXl = (float)lo_v; + *pXh = (float)hi_v; + } + } +} + +typedef struct +{ + uint32_t m_num_pixels; + const color_quad_u8 *m_pPixels; + uint32_t m_num_selector_weights; + const uint32_t *m_pSelector_weights; + const vec4F *m_pSelector_weightsx; + uint32_t m_comp_bits; + uint32_t m_weights[4]; + bc7enc_bool m_has_alpha; + bc7enc_bool m_has_pbits; + bc7enc_bool m_endpoints_share_pbit; + bc7enc_bool m_perceptual; +} color_cell_compressor_params; + +typedef struct +{ + uint64_t m_best_overall_err; + color_quad_u8 m_low_endpoint; + color_quad_u8 m_high_endpoint; + uint32_t m_pbits[2]; + uint8_t *m_pSelectors; + uint8_t *m_pSelectors_temp; +} color_cell_compressor_results; + +static inline color_quad_u8 scale_color(const color_quad_u8 *pC, const color_cell_compressor_params *pParams) +{ + color_quad_u8 results; + + const uint32_t n = pParams->m_comp_bits + (pParams->m_has_pbits ? 1 : 0); + assert((n >= 4) && (n <= 8)); + + for (uint32_t i = 0; i < 4; i++) + { + uint32_t v = pC->m_c[i] << (8 - n); + v |= (v >> n); + assert(v <= 255); + results.m_c[i] = (uint8_t)(v); + } + + return results; +} + +static inline uint64_t compute_color_distance_rgb(const color_quad_u8 *pE1, const color_quad_u8 *pE2, bc7enc_bool perceptual, const uint32_t weights[4]) +{ + int dr, dg, db; + + if (perceptual) + { + const int l1 = pE1->m_c[0] * 109 + pE1->m_c[1] * 366 + pE1->m_c[2] * 37; + const int cr1 = ((int)pE1->m_c[0] << 9) - l1; + const int cb1 = ((int)pE1->m_c[2] << 9) - l1; + const int l2 = pE2->m_c[0] * 109 + pE2->m_c[1] * 366 + pE2->m_c[2] * 37; + const int cr2 = ((int)pE2->m_c[0] << 9) - l2; + const int cb2 = ((int)pE2->m_c[2] << 9) - l2; + dr = (l1 - l2) >> 8; + dg = (cr1 - cr2) >> 8; + db = (cb1 - cb2) >> 8; + } + else + { + dr = (int)pE1->m_c[0] - (int)pE2->m_c[0]; + dg = (int)pE1->m_c[1] - (int)pE2->m_c[1]; + db = (int)pE1->m_c[2] - (int)pE2->m_c[2]; + } + + return weights[0] * (uint32_t)(dr * dr) + weights[1] * (uint32_t)(dg * dg) + weights[2] * (uint32_t)(db * db); +} + +static inline uint64_t compute_color_distance_rgba(const color_quad_u8 *pE1, const color_quad_u8 *pE2, bc7enc_bool perceptual, const uint32_t weights[4]) +{ + int da = (int)pE1->m_c[3] - (int)pE2->m_c[3]; + return compute_color_distance_rgb(pE1, pE2, perceptual, weights) + (weights[3] * (uint32_t)(da * da)); +} + +static uint64_t pack_mode1_to_one_color(const color_cell_compressor_params *pParams, color_cell_compressor_results *pResults, uint32_t r, uint32_t g, uint32_t b, uint8_t *pSelectors) +{ + uint32_t best_err = UINT_MAX; + uint32_t best_p = 0; + + for (uint32_t p = 0; p < 2; p++) + { + uint32_t err = g_bc7_mode_1_optimal_endpoints[r][p].m_error + g_bc7_mode_1_optimal_endpoints[g][p].m_error + g_bc7_mode_1_optimal_endpoints[b][p].m_error; + if (err < best_err) + { + best_err = err; + best_p = p; + if (!best_err) + break; + } + } + + const endpoint_err *pEr = &g_bc7_mode_1_optimal_endpoints[r][best_p]; + const endpoint_err *pEg = &g_bc7_mode_1_optimal_endpoints[g][best_p]; + const endpoint_err *pEb = &g_bc7_mode_1_optimal_endpoints[b][best_p]; + + color_quad_u8_set(&pResults->m_low_endpoint, pEr->m_lo, pEg->m_lo, pEb->m_lo, 0); + color_quad_u8_set(&pResults->m_high_endpoint, pEr->m_hi, pEg->m_hi, pEb->m_hi, 0); + pResults->m_pbits[0] = best_p; + pResults->m_pbits[1] = 0; + + memset(pSelectors, BC7ENC_MODE_1_OPTIMAL_INDEX, pParams->m_num_pixels); + + color_quad_u8 p; + for (uint32_t i = 0; i < 3; i++) + { + uint32_t low = ((pResults->m_low_endpoint.m_c[i] << 1) | pResults->m_pbits[0]) << 1; + low |= (low >> 7); + + uint32_t high = ((pResults->m_high_endpoint.m_c[i] << 1) | pResults->m_pbits[0]) << 1; + high |= (high >> 7); + + p.m_c[i] = (uint8_t)((low * (64 - g_bc7_weights3[BC7ENC_MODE_1_OPTIMAL_INDEX]) + high * g_bc7_weights3[BC7ENC_MODE_1_OPTIMAL_INDEX] + 32) >> 6); + } + p.m_c[3] = 255; + + uint64_t total_err = 0; + for (uint32_t i = 0; i < pParams->m_num_pixels; i++) + total_err += compute_color_distance_rgb(&p, &pParams->m_pPixels[i], pParams->m_perceptual, pParams->m_weights); + + pResults->m_best_overall_err = total_err; + + return total_err; +} + +static uint64_t pack_mode7_to_one_color(const color_cell_compressor_params* pParams, color_cell_compressor_results* pResults, uint32_t r, uint32_t g, uint32_t b, uint32_t a, + uint8_t* pSelectors, uint32_t num_pixels, const color_quad_u8* pPixels) +{ + uint32_t best_err = UINT_MAX; + uint32_t best_p = 0; + + for (uint32_t p = 0; p < 4; p++) + { + uint32_t hi_p = p >> 1; + uint32_t lo_p = p & 1; + uint32_t err = g_bc7_mode_7_optimal_endpoints[r][hi_p][lo_p].m_error + g_bc7_mode_7_optimal_endpoints[g][hi_p][lo_p].m_error + g_bc7_mode_7_optimal_endpoints[b][hi_p][lo_p].m_error + g_bc7_mode_7_optimal_endpoints[a][hi_p][lo_p].m_error; + if (err < best_err) + { + best_err = err; + best_p = p; + if (!best_err) + break; + } + } + + uint32_t best_hi_p = best_p >> 1; + uint32_t best_lo_p = best_p & 1; + + const endpoint_err* pEr = &g_bc7_mode_7_optimal_endpoints[r][best_hi_p][best_lo_p]; + const endpoint_err* pEg = &g_bc7_mode_7_optimal_endpoints[g][best_hi_p][best_lo_p]; + const endpoint_err* pEb = &g_bc7_mode_7_optimal_endpoints[b][best_hi_p][best_lo_p]; + const endpoint_err* pEa = &g_bc7_mode_7_optimal_endpoints[a][best_hi_p][best_lo_p]; + + color_quad_u8_set(&pResults->m_low_endpoint, pEr->m_lo, pEg->m_lo, pEb->m_lo, pEa->m_lo); + color_quad_u8_set(&pResults->m_high_endpoint, pEr->m_hi, pEg->m_hi, pEb->m_hi, pEa->m_hi); + pResults->m_pbits[0] = best_lo_p; + pResults->m_pbits[1] = best_hi_p; + + for (uint32_t i = 0; i < num_pixels; i++) + pSelectors[i] = BC7E_MODE_7_OPTIMAL_INDEX; + + color_quad_u8 p; + + for (uint32_t i = 0; i < 4; i++) + { + uint32_t low = (pResults->m_low_endpoint.m_c[i] << 1) | pResults->m_pbits[0]; + uint32_t high = (pResults->m_high_endpoint.m_c[i] << 1) | pResults->m_pbits[1]; + + low = (low << 2) | (low >> 6); + high = (high << 2) | (high >> 6); + + p.m_c[i] = (low * (64 - g_bc7_weights2[BC7E_MODE_7_OPTIMAL_INDEX]) + high * g_bc7_weights2[BC7E_MODE_7_OPTIMAL_INDEX] + 32) >> 6; + } + + uint64_t total_err = 0; + for (uint32_t i = 0; i < num_pixels; i++) + total_err += compute_color_distance_rgba(&p, &pPixels[i], pParams->m_perceptual, pParams->m_weights); + + pResults->m_best_overall_err = total_err; + + return total_err; +} + +static uint64_t evaluate_solution(const color_quad_u8 *pLow, const color_quad_u8 *pHigh, const uint32_t pbits[2], const color_cell_compressor_params *pParams, color_cell_compressor_results *pResults) +{ + color_quad_u8 quantMinColor = *pLow; + color_quad_u8 quantMaxColor = *pHigh; + + if (pParams->m_has_pbits) + { + uint32_t minPBit, maxPBit; + + if (pParams->m_endpoints_share_pbit) + maxPBit = minPBit = pbits[0]; + else + { + minPBit = pbits[0]; + maxPBit = pbits[1]; + } + + quantMinColor.m_c[0] = (uint8_t)((pLow->m_c[0] << 1) | minPBit); + quantMinColor.m_c[1] = (uint8_t)((pLow->m_c[1] << 1) | minPBit); + quantMinColor.m_c[2] = (uint8_t)((pLow->m_c[2] << 1) | minPBit); + quantMinColor.m_c[3] = (uint8_t)((pLow->m_c[3] << 1) | minPBit); + + quantMaxColor.m_c[0] = (uint8_t)((pHigh->m_c[0] << 1) | maxPBit); + quantMaxColor.m_c[1] = (uint8_t)((pHigh->m_c[1] << 1) | maxPBit); + quantMaxColor.m_c[2] = (uint8_t)((pHigh->m_c[2] << 1) | maxPBit); + quantMaxColor.m_c[3] = (uint8_t)((pHigh->m_c[3] << 1) | maxPBit); + } + + color_quad_u8 actualMinColor = scale_color(&quantMinColor, pParams); + color_quad_u8 actualMaxColor = scale_color(&quantMaxColor, pParams); + + const uint32_t N = pParams->m_num_selector_weights; + + color_quad_u8 weightedColors[16]; + weightedColors[0] = actualMinColor; + weightedColors[N - 1] = actualMaxColor; + + const uint32_t nc = pParams->m_has_alpha ? 4 : 3; + for (uint32_t i = 1; i < (N - 1); i++) + for (uint32_t j = 0; j < nc; j++) + weightedColors[i].m_c[j] = (uint8_t)((actualMinColor.m_c[j] * (64 - pParams->m_pSelector_weights[i]) + actualMaxColor.m_c[j] * pParams->m_pSelector_weights[i] + 32) >> 6); + + const int lr = actualMinColor.m_c[0]; + const int lg = actualMinColor.m_c[1]; + const int lb = actualMinColor.m_c[2]; + const int dr = actualMaxColor.m_c[0] - lr; + const int dg = actualMaxColor.m_c[1] - lg; + const int db = actualMaxColor.m_c[2] - lb; + + uint64_t total_err = 0; + + if (!pParams->m_perceptual) + { + if (pParams->m_has_alpha) + { + const int la = actualMinColor.m_c[3]; + const int da = actualMaxColor.m_c[3] - la; + + const float f = N / (float)(squarei(dr) + squarei(dg) + squarei(db) + squarei(da) + .00000125f); + + for (uint32_t i = 0; i < pParams->m_num_pixels; i++) + { + const color_quad_u8 *pC = &pParams->m_pPixels[i]; + int r = pC->m_c[0]; + int g = pC->m_c[1]; + int b = pC->m_c[2]; + int a = pC->m_c[3]; + + int best_sel = (int)((float)((r - lr) * dr + (g - lg) * dg + (b - lb) * db + (a - la) * da) * f + .5f); + best_sel = clampi(best_sel, 1, N - 1); + + uint64_t err0 = compute_color_distance_rgba(&weightedColors[best_sel - 1], pC, BC7ENC_FALSE, pParams->m_weights); + uint64_t err1 = compute_color_distance_rgba(&weightedColors[best_sel], pC, BC7ENC_FALSE, pParams->m_weights); + + if (err1 > err0) + { + err1 = err0; + --best_sel; + } + total_err += err1; + + pResults->m_pSelectors_temp[i] = (uint8_t)best_sel; + } + } + else + { + const float f = N / (float)(squarei(dr) + squarei(dg) + squarei(db) + .00000125f); + + for (uint32_t i = 0; i < pParams->m_num_pixels; i++) + { + const color_quad_u8 *pC = &pParams->m_pPixels[i]; + int r = pC->m_c[0]; + int g = pC->m_c[1]; + int b = pC->m_c[2]; + + int sel = (int)((float)((r - lr) * dr + (g - lg) * dg + (b - lb) * db) * f + .5f); + sel = clampi(sel, 1, N - 1); + + uint64_t err0 = compute_color_distance_rgb(&weightedColors[sel - 1], pC, BC7ENC_FALSE, pParams->m_weights); + uint64_t err1 = compute_color_distance_rgb(&weightedColors[sel], pC, BC7ENC_FALSE, pParams->m_weights); + + int best_sel = sel; + uint64_t best_err = err1; + if (err0 < best_err) + { + best_err = err0; + best_sel = sel - 1; + } + + total_err += best_err; + + pResults->m_pSelectors_temp[i] = (uint8_t)best_sel; + } + } + } + else + { + // TODO: This could be improved. + for (uint32_t i = 0; i < pParams->m_num_pixels; i++) + { + uint64_t best_err = UINT64_MAX; + uint32_t best_sel = 0; + + if (pParams->m_has_alpha) + { + for (uint32_t j = 0; j < N; j++) + { + uint64_t err = compute_color_distance_rgba(&weightedColors[j], &pParams->m_pPixels[i], BC7ENC_TRUE, pParams->m_weights); + if (err < best_err) + { + best_err = err; + best_sel = j; + } + } + } + else + { + for (uint32_t j = 0; j < N; j++) + { + uint64_t err = compute_color_distance_rgb(&weightedColors[j], &pParams->m_pPixels[i], BC7ENC_TRUE, pParams->m_weights); + if (err < best_err) + { + best_err = err; + best_sel = j; + } + } + } + + total_err += best_err; + + pResults->m_pSelectors_temp[i] = (uint8_t)best_sel; + } + } + + if (total_err < pResults->m_best_overall_err) + { + pResults->m_best_overall_err = total_err; + + pResults->m_low_endpoint = *pLow; + pResults->m_high_endpoint = *pHigh; + + pResults->m_pbits[0] = pbits[0]; + pResults->m_pbits[1] = pbits[1]; + + memcpy(pResults->m_pSelectors, pResults->m_pSelectors_temp, sizeof(pResults->m_pSelectors[0]) * pParams->m_num_pixels); + } + + return total_err; +} + +static void fixDegenerateEndpoints(uint32_t mode, color_quad_u8 *pTrialMinColor, color_quad_u8 *pTrialMaxColor, const vec4F *pXl, const vec4F *pXh, uint32_t iscale) +{ + //if ((mode == 1) || (mode == 7)) + if (mode == 1) + { + // fix degenerate case where the input collapses to a single colorspace voxel, and we loose all freedom (test with grayscale ramps) + for (uint32_t i = 0; i < 3; i++) + { + if (pTrialMinColor->m_c[i] == pTrialMaxColor->m_c[i]) + { + if (fabs(pXl->m_c[i] - pXh->m_c[i]) > 0.0f) + { + if (pTrialMinColor->m_c[i] > (iscale >> 1)) + { + if (pTrialMinColor->m_c[i] > 0) + pTrialMinColor->m_c[i]--; + else + if (pTrialMaxColor->m_c[i] < iscale) + pTrialMaxColor->m_c[i]++; + } + else + { + if (pTrialMaxColor->m_c[i] < iscale) + pTrialMaxColor->m_c[i]++; + else if (pTrialMinColor->m_c[i] > 0) + pTrialMinColor->m_c[i]--; + } + } + } + } + } +} + +static uint64_t find_optimal_solution(uint32_t mode, vec4F xl, vec4F xh, const color_cell_compressor_params *pParams, color_cell_compressor_results *pResults) +{ + vec4F_saturate_in_place(&xl); vec4F_saturate_in_place(&xh); + + if (pParams->m_has_pbits) + { + const int iscalep = (1 << (pParams->m_comp_bits + 1)) - 1; + const float scalep = (float)iscalep; + + const int32_t totalComps = pParams->m_has_alpha ? 4 : 3; + + uint32_t best_pbits[2]; + color_quad_u8 bestMinColor, bestMaxColor; + + if (!pParams->m_endpoints_share_pbit) + { + float best_err0 = 1e+9; + float best_err1 = 1e+9; + + for (int p = 0; p < 2; p++) + { + color_quad_u8 xMinColor, xMaxColor; + + // Notes: The pbit controls which quantization intervals are selected. + // total_levels=2^(comp_bits+1), where comp_bits=4 for mode 0, etc. + // pbit 0: v=(b*2)/(total_levels-1), pbit 1: v=(b*2+1)/(total_levels-1) where b is the component bin from [0,total_levels/2-1] and v is the [0,1] component value + // rearranging you get for pbit 0: b=floor(v*(total_levels-1)/2+.5) + // rearranging you get for pbit 1: b=floor((v*(total_levels-1)-1)/2+.5) + for (uint32_t c = 0; c < 4; c++) + { + xMinColor.m_c[c] = (uint8_t)(clampi(((int)((xl.m_c[c] * scalep - p) / 2.0f + .5f)) * 2 + p, p, iscalep - 1 + p)); + xMaxColor.m_c[c] = (uint8_t)(clampi(((int)((xh.m_c[c] * scalep - p) / 2.0f + .5f)) * 2 + p, p, iscalep - 1 + p)); + } + + color_quad_u8 scaledLow = scale_color(&xMinColor, pParams); + color_quad_u8 scaledHigh = scale_color(&xMaxColor, pParams); + + float err0 = 0, err1 = 0; + for (int i = 0; i < totalComps; i++) + { + err0 += squaref(scaledLow.m_c[i] - xl.m_c[i] * 255.0f); + err1 += squaref(scaledHigh.m_c[i] - xh.m_c[i] * 255.0f); + } + + if (err0 < best_err0) + { + best_err0 = err0; + best_pbits[0] = p; + + bestMinColor.m_c[0] = xMinColor.m_c[0] >> 1; + bestMinColor.m_c[1] = xMinColor.m_c[1] >> 1; + bestMinColor.m_c[2] = xMinColor.m_c[2] >> 1; + bestMinColor.m_c[3] = xMinColor.m_c[3] >> 1; + } + + if (err1 < best_err1) + { + best_err1 = err1; + best_pbits[1] = p; + + bestMaxColor.m_c[0] = xMaxColor.m_c[0] >> 1; + bestMaxColor.m_c[1] = xMaxColor.m_c[1] >> 1; + bestMaxColor.m_c[2] = xMaxColor.m_c[2] >> 1; + bestMaxColor.m_c[3] = xMaxColor.m_c[3] >> 1; + } + } + } + else + { + // Endpoints share pbits + float best_err = 1e+9; + + for (int p = 0; p < 2; p++) + { + color_quad_u8 xMinColor, xMaxColor; + for (uint32_t c = 0; c < 4; c++) + { + xMinColor.m_c[c] = (uint8_t)(clampi(((int)((xl.m_c[c] * scalep - p) / 2.0f + .5f)) * 2 + p, p, iscalep - 1 + p)); + xMaxColor.m_c[c] = (uint8_t)(clampi(((int)((xh.m_c[c] * scalep - p) / 2.0f + .5f)) * 2 + p, p, iscalep - 1 + p)); + } + + color_quad_u8 scaledLow = scale_color(&xMinColor, pParams); + color_quad_u8 scaledHigh = scale_color(&xMaxColor, pParams); + + float err = 0; + for (int i = 0; i < totalComps; i++) + err += squaref((scaledLow.m_c[i] / 255.0f) - xl.m_c[i]) + squaref((scaledHigh.m_c[i] / 255.0f) - xh.m_c[i]); + + if (err < best_err) + { + best_err = err; + best_pbits[0] = p; + best_pbits[1] = p; + for (uint32_t j = 0; j < 4; j++) + { + bestMinColor.m_c[j] = xMinColor.m_c[j] >> 1; + bestMaxColor.m_c[j] = xMaxColor.m_c[j] >> 1; + } + } + } + } + + fixDegenerateEndpoints(mode, &bestMinColor, &bestMaxColor, &xl, &xh, iscalep >> 1); + + if ((pResults->m_best_overall_err == UINT64_MAX) || color_quad_u8_notequals(&bestMinColor, &pResults->m_low_endpoint) || color_quad_u8_notequals(&bestMaxColor, &pResults->m_high_endpoint) || (best_pbits[0] != pResults->m_pbits[0]) || (best_pbits[1] != pResults->m_pbits[1])) + evaluate_solution(&bestMinColor, &bestMaxColor, best_pbits, pParams, pResults); + } + else + { + const int iscale = (1 << pParams->m_comp_bits) - 1; + const float scale = (float)iscale; + + color_quad_u8 trialMinColor, trialMaxColor; + color_quad_u8_set_clamped(&trialMinColor, (int)(xl.m_c[0] * scale + .5f), (int)(xl.m_c[1] * scale + .5f), (int)(xl.m_c[2] * scale + .5f), (int)(xl.m_c[3] * scale + .5f)); + color_quad_u8_set_clamped(&trialMaxColor, (int)(xh.m_c[0] * scale + .5f), (int)(xh.m_c[1] * scale + .5f), (int)(xh.m_c[2] * scale + .5f), (int)(xh.m_c[3] * scale + .5f)); + + fixDegenerateEndpoints(mode, &trialMinColor, &trialMaxColor, &xl, &xh, iscale); + + if ((pResults->m_best_overall_err == UINT64_MAX) || color_quad_u8_notequals(&trialMinColor, &pResults->m_low_endpoint) || color_quad_u8_notequals(&trialMaxColor, &pResults->m_high_endpoint)) + evaluate_solution(&trialMinColor, &trialMaxColor, pResults->m_pbits, pParams, pResults); + } + + return pResults->m_best_overall_err; +} + +static uint64_t color_cell_compression(uint32_t mode, const color_cell_compressor_params *pParams, color_cell_compressor_results *pResults, const bc7enc_compress_block_params *pComp_params) +{ + assert((mode == 6) || (mode == 7) || (!pParams->m_has_alpha)); + + pResults->m_best_overall_err = UINT64_MAX; + + // If the partition's colors are all the same in mode 1, then just pack them as a single color. + if (mode == 1) + { + const uint32_t cr = pParams->m_pPixels[0].m_c[0], cg = pParams->m_pPixels[0].m_c[1], cb = pParams->m_pPixels[0].m_c[2]; + + bc7enc_bool allSame = BC7ENC_TRUE; + for (uint32_t i = 1; i < pParams->m_num_pixels; i++) + { + if ((cr != pParams->m_pPixels[i].m_c[0]) || (cg != pParams->m_pPixels[i].m_c[1]) || (cb != pParams->m_pPixels[i].m_c[2])) + { + allSame = BC7ENC_FALSE; + break; + } + } + + if (allSame) + return pack_mode1_to_one_color(pParams, pResults, cr, cg, cb, pResults->m_pSelectors); + } + else if (mode == 7) + { + const uint32_t cr = pParams->m_pPixels[0].m_c[0], cg = pParams->m_pPixels[0].m_c[1], cb = pParams->m_pPixels[0].m_c[2], ca = pParams->m_pPixels[0].m_c[3]; + + bc7enc_bool allSame = BC7ENC_TRUE; + for (uint32_t i = 1; i < pParams->m_num_pixels; i++) + { + if ((cr != pParams->m_pPixels[i].m_c[0]) || (cg != pParams->m_pPixels[i].m_c[1]) || (cb != pParams->m_pPixels[i].m_c[2]) || (ca != pParams->m_pPixels[i].m_c[3])) + { + allSame = BC7ENC_FALSE; + break; + } + } + + if (allSame) + return pack_mode7_to_one_color(pParams, pResults, cr, cg, cb, ca, pResults->m_pSelectors, pParams->m_num_pixels, pParams->m_pPixels); + } + + // Compute partition's mean color and principle axis. + vec4F meanColor, axis; + vec4F_set_scalar(&meanColor, 0.0f); + + for (uint32_t i = 0; i < pParams->m_num_pixels; i++) + { + vec4F color = vec4F_from_color(&pParams->m_pPixels[i]); + meanColor = vec4F_add(&meanColor, &color); + } + + vec4F meanColorScaled = vec4F_mul(&meanColor, 1.0f / (float)(pParams->m_num_pixels)); + + meanColor = vec4F_mul(&meanColor, 1.0f / (float)(pParams->m_num_pixels * 255.0f)); + vec4F_saturate_in_place(&meanColor); + + if (pParams->m_has_alpha) + { + // Use incremental PCA for RGBA PCA, because it's simple. + vec4F_set_scalar(&axis, 0.0f); + for (uint32_t i = 0; i < pParams->m_num_pixels; i++) + { + vec4F color = vec4F_from_color(&pParams->m_pPixels[i]); + color = vec4F_sub(&color, &meanColorScaled); + vec4F a = vec4F_mul(&color, color.m_c[0]); + vec4F b = vec4F_mul(&color, color.m_c[1]); + vec4F c = vec4F_mul(&color, color.m_c[2]); + vec4F d = vec4F_mul(&color, color.m_c[3]); + vec4F n = i ? axis : color; + vec4F_normalize_in_place(&n); + axis.m_c[0] += vec4F_dot(&a, &n); + axis.m_c[1] += vec4F_dot(&b, &n); + axis.m_c[2] += vec4F_dot(&c, &n); + axis.m_c[3] += vec4F_dot(&d, &n); + } + vec4F_normalize_in_place(&axis); + } + else + { + // Use covar technique for RGB PCA, because it doesn't require per-pixel normalization. + float cov[6] = { 0, 0, 0, 0, 0, 0 }; + + for (uint32_t i = 0; i < pParams->m_num_pixels; i++) + { + const color_quad_u8 *pV = &pParams->m_pPixels[i]; + float r = pV->m_c[0] - meanColorScaled.m_c[0]; + float g = pV->m_c[1] - meanColorScaled.m_c[1]; + float b = pV->m_c[2] - meanColorScaled.m_c[2]; + cov[0] += r*r; cov[1] += r*g; cov[2] += r*b; cov[3] += g*g; cov[4] += g*b; cov[5] += b*b; + } + + float vfr = .9f, vfg = 1.0f, vfb = .7f; + for (uint32_t iter = 0; iter < 3; iter++) + { + float r = vfr*cov[0] + vfg*cov[1] + vfb*cov[2]; + float g = vfr*cov[1] + vfg*cov[3] + vfb*cov[4]; + float b = vfr*cov[2] + vfg*cov[4] + vfb*cov[5]; + + float m = maximumf(maximumf(fabsf(r), fabsf(g)), fabsf(b)); + if (m > 1e-10f) + { + m = 1.0f / m; + r *= m; g *= m; b *= m; + } + + vfr = r; vfg = g; vfb = b; + } + + float len = vfr*vfr + vfg*vfg + vfb*vfb; + if (len < 1e-10f) + vec4F_set_scalar(&axis, 0.0f); + else + { + len = 1.0f / sqrtf(len); + vfr *= len; vfg *= len; vfb *= len; + vec4F_set(&axis, vfr, vfg, vfb, 0); + } + } + + // TODO: Try picking the 2 colors with the largest projection onto the axis, instead of computing new colors along the axis. + + if (vec4F_dot(&axis, &axis) < .5f) + { + if (pParams->m_perceptual) + vec4F_set(&axis, .213f, .715f, .072f, pParams->m_has_alpha ? .715f : 0); + else + vec4F_set(&axis, 1.0f, 1.0f, 1.0f, pParams->m_has_alpha ? 1.0f : 0); + vec4F_normalize_in_place(&axis); + } + + float l = 1e+9f, h = -1e+9f; + + for (uint32_t i = 0; i < pParams->m_num_pixels; i++) + { + vec4F color = vec4F_from_color(&pParams->m_pPixels[i]); + + vec4F q = vec4F_sub(&color, &meanColorScaled); + float d = vec4F_dot(&q, &axis); + + l = minimumf(l, d); + h = maximumf(h, d); + } + + l *= (1.0f / 255.0f); + h *= (1.0f / 255.0f); + + vec4F b0 = vec4F_mul(&axis, l); + vec4F b1 = vec4F_mul(&axis, h); + vec4F c0 = vec4F_add(&meanColor, &b0); + vec4F c1 = vec4F_add(&meanColor, &b1); + vec4F minColor = vec4F_saturate(&c0); + vec4F maxColor = vec4F_saturate(&c1); + + vec4F whiteVec; + vec4F_set_scalar(&whiteVec, 1.0f); + + if (vec4F_dot(&minColor, &whiteVec) > vec4F_dot(&maxColor, &whiteVec)) + { +#if 0 + // Don't compile correctly with VC 2019 in release. + vec4F temp = minColor; + minColor = maxColor; + maxColor = temp; +#else + float a = minColor.m_c[0], b = minColor.m_c[1], c = minColor.m_c[2], d = minColor.m_c[3]; + minColor.m_c[0] = maxColor.m_c[0]; + minColor.m_c[1] = maxColor.m_c[1]; + minColor.m_c[2] = maxColor.m_c[2]; + minColor.m_c[3] = maxColor.m_c[3]; + maxColor.m_c[0] = a; + maxColor.m_c[1] = b; + maxColor.m_c[2] = c; + maxColor.m_c[3] = d; +#endif + } + + // First find a solution using the block's PCA. + if (!find_optimal_solution(mode, minColor, maxColor, pParams, pResults)) + return 0; + + if (pComp_params->m_try_least_squares) + { + // Now try to refine the solution using least squares by computing the optimal endpoints from the current selectors. + vec4F xl, xh; + vec4F_set_scalar(&xl, 0.0f); + vec4F_set_scalar(&xh, 0.0f); + if (pParams->m_has_alpha) + compute_least_squares_endpoints_rgba(pParams->m_num_pixels, pResults->m_pSelectors, pParams->m_pSelector_weightsx, &xl, &xh, pParams->m_pPixels); + else + compute_least_squares_endpoints_rgb(pParams->m_num_pixels, pResults->m_pSelectors, pParams->m_pSelector_weightsx, &xl, &xh, pParams->m_pPixels); + + xl = vec4F_mul(&xl, (1.0f / 255.0f)); + xh = vec4F_mul(&xh, (1.0f / 255.0f)); + + if (!find_optimal_solution(mode, xl, xh, pParams, pResults)) + return 0; + } + + if (pComp_params->m_uber_level > 0) + { + // In uber level 1, try varying the selectors a little, somewhat like cluster fit would. First try incrementing the minimum selectors, + // then try decrementing the selectrors, then try both. + uint8_t selectors_temp[16], selectors_temp1[16]; + memcpy(selectors_temp, pResults->m_pSelectors, pParams->m_num_pixels); + + const int max_selector = pParams->m_num_selector_weights - 1; + + uint32_t min_sel = 16; + uint32_t max_sel = 0; + for (uint32_t i = 0; i < pParams->m_num_pixels; i++) + { + uint32_t sel = selectors_temp[i]; + min_sel = minimumu(min_sel, sel); + max_sel = maximumu(max_sel, sel); + } + + for (uint32_t i = 0; i < pParams->m_num_pixels; i++) + { + uint32_t sel = selectors_temp[i]; + if ((sel == min_sel) && (sel < (pParams->m_num_selector_weights - 1))) + sel++; + selectors_temp1[i] = (uint8_t)sel; + } + + vec4F xl, xh; + vec4F_set_scalar(&xl, 0.0f); + vec4F_set_scalar(&xh, 0.0f); + if (pParams->m_has_alpha) + compute_least_squares_endpoints_rgba(pParams->m_num_pixels, selectors_temp1, pParams->m_pSelector_weightsx, &xl, &xh, pParams->m_pPixels); + else + compute_least_squares_endpoints_rgb(pParams->m_num_pixels, selectors_temp1, pParams->m_pSelector_weightsx, &xl, &xh, pParams->m_pPixels); + + xl = vec4F_mul(&xl, (1.0f / 255.0f)); + xh = vec4F_mul(&xh, (1.0f / 255.0f)); + + if (!find_optimal_solution(mode, xl, xh, pParams, pResults)) + return 0; + + for (uint32_t i = 0; i < pParams->m_num_pixels; i++) + { + uint32_t sel = selectors_temp[i]; + if ((sel == max_sel) && (sel > 0)) + sel--; + selectors_temp1[i] = (uint8_t)sel; + } + + if (pParams->m_has_alpha) + compute_least_squares_endpoints_rgba(pParams->m_num_pixels, selectors_temp1, pParams->m_pSelector_weightsx, &xl, &xh, pParams->m_pPixels); + else + compute_least_squares_endpoints_rgb(pParams->m_num_pixels, selectors_temp1, pParams->m_pSelector_weightsx, &xl, &xh, pParams->m_pPixels); + + xl = vec4F_mul(&xl, (1.0f / 255.0f)); + xh = vec4F_mul(&xh, (1.0f / 255.0f)); + + if (!find_optimal_solution(mode, xl, xh, pParams, pResults)) + return 0; + + for (uint32_t i = 0; i < pParams->m_num_pixels; i++) + { + uint32_t sel = selectors_temp[i]; + if ((sel == min_sel) && (sel < (pParams->m_num_selector_weights - 1))) + sel++; + else if ((sel == max_sel) && (sel > 0)) + sel--; + selectors_temp1[i] = (uint8_t)sel; + } + + if (pParams->m_has_alpha) + compute_least_squares_endpoints_rgba(pParams->m_num_pixels, selectors_temp1, pParams->m_pSelector_weightsx, &xl, &xh, pParams->m_pPixels); + else + compute_least_squares_endpoints_rgb(pParams->m_num_pixels, selectors_temp1, pParams->m_pSelector_weightsx, &xl, &xh, pParams->m_pPixels); + + xl = vec4F_mul(&xl, (1.0f / 255.0f)); + xh = vec4F_mul(&xh, (1.0f / 255.0f)); + + if (!find_optimal_solution(mode, xl, xh, pParams, pResults)) + return 0; + + // In uber levels 2+, try taking more advantage of endpoint extrapolation by scaling the selectors in one direction or another. + const uint32_t uber_err_thresh = (pParams->m_num_pixels * 56) >> 4; + if ((pComp_params->m_uber_level >= 2) && (pResults->m_best_overall_err > uber_err_thresh)) + { + const int Q = (pComp_params->m_uber_level >= 4) ? (pComp_params->m_uber_level - 2) : 1; + for (int ly = -Q; ly <= 1; ly++) + { + for (int hy = max_selector - 1; hy <= (max_selector + Q); hy++) + { + if ((ly == 0) && (hy == max_selector)) + continue; + + for (uint32_t i = 0; i < pParams->m_num_pixels; i++) + selectors_temp1[i] = (uint8_t)clampf(floorf((float)max_selector * ((float)selectors_temp[i] - (float)ly) / ((float)hy - (float)ly) + .5f), 0, (float)max_selector); + + //vec4F xl, xh; + vec4F_set_scalar(&xl, 0.0f); + vec4F_set_scalar(&xh, 0.0f); + if (pParams->m_has_alpha) + compute_least_squares_endpoints_rgba(pParams->m_num_pixels, selectors_temp1, pParams->m_pSelector_weightsx, &xl, &xh, pParams->m_pPixels); + else + compute_least_squares_endpoints_rgb(pParams->m_num_pixels, selectors_temp1, pParams->m_pSelector_weightsx, &xl, &xh, pParams->m_pPixels); + + xl = vec4F_mul(&xl, (1.0f / 255.0f)); + xh = vec4F_mul(&xh, (1.0f / 255.0f)); + + if (!find_optimal_solution(mode, xl, xh, pParams, pResults)) + return 0; + } + } + } + } + + if (mode == 1) + { + // Try encoding the partition as a single color by using the optimal singe colors tables to encode the block to its mean. + color_cell_compressor_results avg_results = *pResults; + const uint32_t r = (int)(.5f + meanColor.m_c[0] * 255.0f), g = (int)(.5f + meanColor.m_c[1] * 255.0f), b = (int)(.5f + meanColor.m_c[2] * 255.0f); + uint64_t avg_err = pack_mode1_to_one_color(pParams, &avg_results, r, g, b, pResults->m_pSelectors_temp); + if (avg_err < pResults->m_best_overall_err) + { + *pResults = avg_results; + memcpy(pResults->m_pSelectors, pResults->m_pSelectors_temp, sizeof(pResults->m_pSelectors[0]) * pParams->m_num_pixels); + pResults->m_best_overall_err = avg_err; + } + } + else if (mode == 7) + { + // Try encoding the partition as a single color by using the optimal singe colors tables to encode the block to its mean. + color_cell_compressor_results avg_results = *pResults; + const uint32_t r = (int)(.5f + meanColor.m_c[0] * 255.0f), g = (int)(.5f + meanColor.m_c[1] * 255.0f), b = (int)(.5f + meanColor.m_c[2] * 255.0f), a = (int)(.5f + meanColor.m_c[3] * 255.0f); + uint64_t avg_err = pack_mode7_to_one_color(pParams, &avg_results, r, g, b, a, pResults->m_pSelectors_temp, pParams->m_num_pixels, pParams->m_pPixels); + if (avg_err < pResults->m_best_overall_err) + { + *pResults = avg_results; + memcpy(pResults->m_pSelectors, pResults->m_pSelectors_temp, sizeof(pResults->m_pSelectors[0]) * pParams->m_num_pixels); + pResults->m_best_overall_err = avg_err; + } + } + + return pResults->m_best_overall_err; +} + +static uint64_t color_cell_compression_est_mode1(uint32_t num_pixels, const color_quad_u8 *pPixels, bc7enc_bool perceptual, uint32_t pweights[4], uint64_t best_err_so_far) +{ + // Find RGB bounds as an approximation of the block's principle axis + uint32_t lr = 255, lg = 255, lb = 255; + uint32_t hr = 0, hg = 0, hb = 0; + for (uint32_t i = 0; i < num_pixels; i++) + { + const color_quad_u8 *pC = &pPixels[i]; + if (pC->m_c[0] < lr) lr = pC->m_c[0]; + if (pC->m_c[1] < lg) lg = pC->m_c[1]; + if (pC->m_c[2] < lb) lb = pC->m_c[2]; + if (pC->m_c[0] > hr) hr = pC->m_c[0]; + if (pC->m_c[1] > hg) hg = pC->m_c[1]; + if (pC->m_c[2] > hb) hb = pC->m_c[2]; + } + + color_quad_u8 lowColor; color_quad_u8_set(&lowColor, lr, lg, lb, 0); + color_quad_u8 highColor; color_quad_u8_set(&highColor, hr, hg, hb, 0); + + // Place endpoints at bbox diagonals and compute interpolated colors + const uint32_t N = 8; + color_quad_u8 weightedColors[8]; + + weightedColors[0] = lowColor; + weightedColors[N - 1] = highColor; + for (uint32_t i = 1; i < (N - 1); i++) + { + weightedColors[i].m_c[0] = (uint8_t)((lowColor.m_c[0] * (64 - g_bc7_weights3[i]) + highColor.m_c[0] * g_bc7_weights3[i] + 32) >> 6); + weightedColors[i].m_c[1] = (uint8_t)((lowColor.m_c[1] * (64 - g_bc7_weights3[i]) + highColor.m_c[1] * g_bc7_weights3[i] + 32) >> 6); + weightedColors[i].m_c[2] = (uint8_t)((lowColor.m_c[2] * (64 - g_bc7_weights3[i]) + highColor.m_c[2] * g_bc7_weights3[i] + 32) >> 6); + } + + // Compute dots and thresholds + const int ar = highColor.m_c[0] - lowColor.m_c[0]; + const int ag = highColor.m_c[1] - lowColor.m_c[1]; + const int ab = highColor.m_c[2] - lowColor.m_c[2]; + + int dots[8]; + for (uint32_t i = 0; i < N; i++) + dots[i] = weightedColors[i].m_c[0] * ar + weightedColors[i].m_c[1] * ag + weightedColors[i].m_c[2] * ab; + + int thresh[8 - 1]; + for (uint32_t i = 0; i < (N - 1); i++) + thresh[i] = (dots[i] + dots[i + 1] + 1) >> 1; + + uint64_t total_err = 0; + if (perceptual) + { + // Transform block's interpolated colors to YCbCr + int l1[8], cr1[8], cb1[8]; + for (int j = 0; j < 8; j++) + { + const color_quad_u8 *pE1 = &weightedColors[j]; + l1[j] = pE1->m_c[0] * 109 + pE1->m_c[1] * 366 + pE1->m_c[2] * 37; + cr1[j] = ((int)pE1->m_c[0] << 9) - l1[j]; + cb1[j] = ((int)pE1->m_c[2] << 9) - l1[j]; + } + + for (uint32_t i = 0; i < num_pixels; i++) + { + const color_quad_u8 *pC = &pPixels[i]; + + int d = ar * pC->m_c[0] + ag * pC->m_c[1] + ab * pC->m_c[2]; + + // Find approximate selector + uint32_t s = 0; + if (d >= thresh[6]) + s = 7; + else if (d >= thresh[5]) + s = 6; + else if (d >= thresh[4]) + s = 5; + else if (d >= thresh[3]) + s = 4; + else if (d >= thresh[2]) + s = 3; + else if (d >= thresh[1]) + s = 2; + else if (d >= thresh[0]) + s = 1; + + // Compute error + const int l2 = pC->m_c[0] * 109 + pC->m_c[1] * 366 + pC->m_c[2] * 37; + const int cr2 = ((int)pC->m_c[0] << 9) - l2; + const int cb2 = ((int)pC->m_c[2] << 9) - l2; + + const int dl = (l1[s] - l2) >> 8; + const int dcr = (cr1[s] - cr2) >> 8; + const int dcb = (cb1[s] - cb2) >> 8; + + int ie = (pweights[0] * dl * dl) + (pweights[1] * dcr * dcr) + (pweights[2] * dcb * dcb); + + total_err += ie; + if (total_err > best_err_so_far) + break; + } + } + else + { + for (uint32_t i = 0; i < num_pixels; i++) + { + const color_quad_u8 *pC = &pPixels[i]; + + int d = ar * pC->m_c[0] + ag * pC->m_c[1] + ab * pC->m_c[2]; + + // Find approximate selector + uint32_t s = 0; + if (d >= thresh[6]) + s = 7; + else if (d >= thresh[5]) + s = 6; + else if (d >= thresh[4]) + s = 5; + else if (d >= thresh[3]) + s = 4; + else if (d >= thresh[2]) + s = 3; + else if (d >= thresh[1]) + s = 2; + else if (d >= thresh[0]) + s = 1; + + // Compute error + const color_quad_u8 *pE1 = &weightedColors[s]; + + int dr = (int)pE1->m_c[0] - (int)pC->m_c[0]; + int dg = (int)pE1->m_c[1] - (int)pC->m_c[1]; + int db = (int)pE1->m_c[2] - (int)pC->m_c[2]; + + total_err += pweights[0] * (dr * dr) + pweights[1] * (dg * dg) + pweights[2] * (db * db); + if (total_err > best_err_so_far) + break; + } + } + + return total_err; +} + +static uint64_t color_cell_compression_est_mode7(uint32_t num_pixels, const color_quad_u8* pPixels, bc7enc_bool perceptual, uint32_t pweights[4], uint64_t best_err_so_far) +{ + // Find RGB bounds as an approximation of the block's principle axis + uint32_t lr = 255, lg = 255, lb = 255, la = 255; + uint32_t hr = 0, hg = 0, hb = 0, ha = 0; + for (uint32_t i = 0; i < num_pixels; i++) + { + const color_quad_u8* pC = &pPixels[i]; + if (pC->m_c[0] < lr) lr = pC->m_c[0]; + if (pC->m_c[1] < lg) lg = pC->m_c[1]; + if (pC->m_c[2] < lb) lb = pC->m_c[2]; + if (pC->m_c[3] < la) la = pC->m_c[3]; + + if (pC->m_c[0] > hr) hr = pC->m_c[0]; + if (pC->m_c[1] > hg) hg = pC->m_c[1]; + if (pC->m_c[2] > hb) hb = pC->m_c[2]; + if (pC->m_c[3] > ha) ha = pC->m_c[3]; + } + + color_quad_u8 lowColor; color_quad_u8_set(&lowColor, lr, lg, lb, la); + color_quad_u8 highColor; color_quad_u8_set(&highColor, hr, hg, hb, ha); + + // Place endpoints at bbox diagonals and compute interpolated colors + const uint32_t N = 4; + color_quad_u8 weightedColors[4]; + + weightedColors[0] = lowColor; + weightedColors[N - 1] = highColor; + for (uint32_t i = 1; i < (N - 1); i++) + { + weightedColors[i].m_c[0] = (uint8_t)((lowColor.m_c[0] * (64 - g_bc7_weights2[i]) + highColor.m_c[0] * g_bc7_weights2[i] + 32) >> 6); + weightedColors[i].m_c[1] = (uint8_t)((lowColor.m_c[1] * (64 - g_bc7_weights2[i]) + highColor.m_c[1] * g_bc7_weights2[i] + 32) >> 6); + weightedColors[i].m_c[2] = (uint8_t)((lowColor.m_c[2] * (64 - g_bc7_weights2[i]) + highColor.m_c[2] * g_bc7_weights2[i] + 32) >> 6); + weightedColors[i].m_c[3] = (uint8_t)((lowColor.m_c[3] * (64 - g_bc7_weights2[i]) + highColor.m_c[3] * g_bc7_weights2[i] + 32) >> 6); + } + + // Compute dots and thresholds + const int ar = highColor.m_c[0] - lowColor.m_c[0]; + const int ag = highColor.m_c[1] - lowColor.m_c[1]; + const int ab = highColor.m_c[2] - lowColor.m_c[2]; + const int aa = highColor.m_c[3] - lowColor.m_c[3]; + + int dots[4]; + for (uint32_t i = 0; i < N; i++) + dots[i] = weightedColors[i].m_c[0] * ar + weightedColors[i].m_c[1] * ag + weightedColors[i].m_c[2] * ab + weightedColors[i].m_c[3] * aa; + + int thresh[4 - 1]; + for (uint32_t i = 0; i < (N - 1); i++) + thresh[i] = (dots[i] + dots[i + 1] + 1) >> 1; + + uint64_t total_err = 0; + if (perceptual) + { + // Transform block's interpolated colors to YCbCr + int l1[4], cr1[4], cb1[4]; + for (int j = 0; j < 4; j++) + { + const color_quad_u8* pE1 = &weightedColors[j]; + l1[j] = pE1->m_c[0] * 109 + pE1->m_c[1] * 366 + pE1->m_c[2] * 37; + cr1[j] = ((int)pE1->m_c[0] << 9) - l1[j]; + cb1[j] = ((int)pE1->m_c[2] << 9) - l1[j]; + } + + for (uint32_t i = 0; i < num_pixels; i++) + { + const color_quad_u8* pC = &pPixels[i]; + + int d = ar * pC->m_c[0] + ag * pC->m_c[1] + ab * pC->m_c[2] + aa * pC->m_c[3]; + + // Find approximate selector + uint32_t s = 0; + if (d >= thresh[2]) + s = 3; + else if (d >= thresh[1]) + s = 2; + else if (d >= thresh[0]) + s = 1; + + // Compute error + const int l2 = pC->m_c[0] * 109 + pC->m_c[1] * 366 + pC->m_c[2] * 37; + const int cr2 = ((int)pC->m_c[0] << 9) - l2; + const int cb2 = ((int)pC->m_c[2] << 9) - l2; + + const int dl = (l1[s] - l2) >> 8; + const int dcr = (cr1[s] - cr2) >> 8; + const int dcb = (cb1[s] - cb2) >> 8; + + const int dca = (int)pC->m_c[3] - (int)weightedColors[s].m_c[3]; + + int ie = (pweights[0] * dl * dl) + (pweights[1] * dcr * dcr) + (pweights[2] * dcb * dcb) + (pweights[3] * dca * dca); + + total_err += ie; + if (total_err > best_err_so_far) + break; + } + } + else + { + for (uint32_t i = 0; i < num_pixels; i++) + { + const color_quad_u8* pC = &pPixels[i]; + + int d = ar * pC->m_c[0] + ag * pC->m_c[1] + ab * pC->m_c[2] + aa * pC->m_c[3]; + + // Find approximate selector + uint32_t s = 0; + if (d >= thresh[2]) + s = 3; + else if (d >= thresh[1]) + s = 2; + else if (d >= thresh[0]) + s = 1; + + // Compute error + const color_quad_u8* pE1 = &weightedColors[s]; + + int dr = (int)pE1->m_c[0] - (int)pC->m_c[0]; + int dg = (int)pE1->m_c[1] - (int)pC->m_c[1]; + int db = (int)pE1->m_c[2] - (int)pC->m_c[2]; + int da = (int)pE1->m_c[3] - (int)pC->m_c[3]; + + total_err += pweights[0] * (dr * dr) + pweights[1] * (dg * dg) + pweights[2] * (db * db) + pweights[3] * (da * da); + if (total_err > best_err_so_far) + break; + } + } + + return total_err; +} + +// This table contains bitmasks indicating which "key" partitions must be best ranked before this partition is worth evaluating. +// We first rank the best/most used 14 partitions (sorted by usefulness), record the best one found as the key partition, then use +// that to control the other partitions to evaluate. The quality loss is ~.08 dB RGB PSNR, the perf gain is up to ~11% (at uber level 0). +static const uint32_t g_partition_predictors[35] = +{ + UINT32_MAX, + UINT32_MAX, + UINT32_MAX, + UINT32_MAX, + UINT32_MAX, + (1 << 1) | (1 << 2) | (1 << 8), + (1 << 1) | (1 << 3) | (1 << 7), + UINT32_MAX, + UINT32_MAX, + (1 << 2) | (1 << 8) | (1 << 16), + (1 << 7) | (1 << 3) | (1 << 15), + UINT32_MAX, + (1 << 8) | (1 << 14) | (1 << 16), + (1 << 7) | (1 << 14) | (1 << 15), + UINT32_MAX, + UINT32_MAX, + UINT32_MAX, + UINT32_MAX, + (1 << 14) | (1 << 15), + (1 << 16) | (1 << 22) | (1 << 14), + (1 << 17) | (1 << 24) | (1 << 14), + (1 << 2) | (1 << 14) | (1 << 15) | (1 << 1), + UINT32_MAX, + (1 << 1) | (1 << 3) | (1 << 14) | (1 << 16) | (1 << 22), + UINT32_MAX, + (1 << 1) | (1 << 2) | (1 << 15) | (1 << 17) | (1 << 24), + (1 << 1) | (1 << 3) | (1 << 22), + UINT32_MAX, + UINT32_MAX, + UINT32_MAX, + (1 << 14) | (1 << 15) | (1 << 16) | (1 << 17), + UINT32_MAX, + UINT32_MAX, + (1 << 1) | (1 << 2) | (1 << 3) | (1 << 27) | (1 << 4) | (1 << 24), + (1 << 14) | (1 << 15) | (1 << 16) | (1 << 11) | (1 << 17) | (1 << 27) +}; + +// Estimate the partition used by modes 1/7. This scans through each partition and computes an approximate error for each. +static uint32_t estimate_partition(const color_quad_u8 *pPixels, const bc7enc_compress_block_params *pComp_params, uint32_t pweights[4], uint32_t mode) +{ + const uint32_t total_partitions = minimumu(pComp_params->m_max_partitions_mode, BC7ENC_MAX_PARTITIONS1); + if (total_partitions <= 1) + return 0; + + uint64_t best_err = UINT64_MAX; + uint32_t best_partition = 0; + + // Partition order sorted by usage frequency across a large test corpus. Pattern 34 (checkerboard) must appear in slot 34. + // Using a sorted order allows the user to decrease the # of partitions to scan with minimal loss in quality. + static const uint8_t s_sorted_partition_order[64] = + { + 1 - 1, 14 - 1, 2 - 1, 3 - 1, 16 - 1, 15 - 1, 11 - 1, 17 - 1, + 4 - 1, 24 - 1, 27 - 1, 7 - 1, 8 - 1, 22 - 1, 20 - 1, 30 - 1, + 9 - 1, 5 - 1, 10 - 1, 21 - 1, 6 - 1, 32 - 1, 23 - 1, 18 - 1, + 19 - 1, 12 - 1, 13 - 1, 31 - 1, 25 - 1, 26 - 1, 29 - 1, 28 - 1, + 33 - 1, 34 - 1, 35 - 1, 46 - 1, 47 - 1, 52 - 1, 50 - 1, 51 - 1, + 49 - 1, 39 - 1, 40 - 1, 38 - 1, 54 - 1, 53 - 1, 55 - 1, 37 - 1, + 58 - 1, 59 - 1, 56 - 1, 42 - 1, 41 - 1, 43 - 1, 44 - 1, 60 - 1, + 45 - 1, 57 - 1, 48 - 1, 36 - 1, 61 - 1, 64 - 1, 63 - 1, 62 - 1 + }; + + assert(s_sorted_partition_order[34] == 34); + + int best_key_partition = 0; + + for (uint32_t partition_iter = 0; (partition_iter < total_partitions) && (best_err > 0); partition_iter++) + { + const uint32_t partition = s_sorted_partition_order[partition_iter]; + + // Check to see if we should bother evaluating this partition at all, depending on the best partition found from the first 14. + if (pComp_params->m_mode_partition_estimation_filterbank) + { + if ((partition_iter >= 14) && (partition_iter <= 34)) + { + const uint32_t best_key_partition_bitmask = 1 << (best_key_partition + 1); + if ((g_partition_predictors[partition] & best_key_partition_bitmask) == 0) + { + if (partition_iter == 34) + break; + + continue; + } + } + } + + const uint8_t *pPartition = &g_bc7_partition2[partition * 16]; + + color_quad_u8 subset_colors[2][16]; + uint32_t subset_total_colors[2] = { 0, 0 }; + for (uint32_t index = 0; index < 16; index++) + subset_colors[pPartition[index]][subset_total_colors[pPartition[index]]++] = pPixels[index]; + + uint64_t total_subset_err = 0; + for (uint32_t subset = 0; (subset < 2) && (total_subset_err < best_err); subset++) + { + if (mode == 7) + total_subset_err += color_cell_compression_est_mode7(subset_total_colors[subset], &subset_colors[subset][0], pComp_params->m_perceptual, pweights, best_err); + else + total_subset_err += color_cell_compression_est_mode1(subset_total_colors[subset], &subset_colors[subset][0], pComp_params->m_perceptual, pweights, best_err); + } + + if (total_subset_err < best_err) + { + best_err = total_subset_err; + best_partition = partition; + } + + // If the checkerboard pattern doesn't get the highest ranking vs. the previous (lower frequency) patterns, then just stop now because statistically the subsequent patterns won't do well either. + if ((partition == 34) && (best_partition != 34)) + break; + + if (partition_iter == 13) + best_key_partition = best_partition; + + } // partition + + return best_partition; +} + +static void set_block_bits(uint8_t *pBytes, uint32_t val, uint32_t num_bits, uint32_t *pCur_ofs) +{ + assert((num_bits <= 32) && (val < (1ULL << num_bits))); + while (num_bits) + { + const uint32_t n = minimumu(8 - (*pCur_ofs & 7), num_bits); + pBytes[*pCur_ofs >> 3] |= (uint8_t)(val << (*pCur_ofs & 7)); + val >>= n; + num_bits -= n; + *pCur_ofs += n; + } + assert(*pCur_ofs <= 128); +} + +typedef struct +{ + uint32_t m_mode; + uint32_t m_partition; + uint8_t m_selectors[16]; + uint8_t m_alpha_selectors[16]; + color_quad_u8 m_low[3]; + color_quad_u8 m_high[3]; + uint32_t m_pbits[3][2]; + uint32_t m_rotation; + uint32_t m_index_selector; +} bc7_optimization_results; + +static void encode_bc7_block(void* pBlock, const bc7_optimization_results* pResults) +{ + assert(pResults->m_index_selector <= 1); + assert(pResults->m_rotation <= 3); + + const uint32_t best_mode = pResults->m_mode; + + const uint32_t total_subsets = g_bc7_num_subsets[best_mode]; + const uint32_t total_partitions = 1 << g_bc7_partition_bits[best_mode]; + //const uint32_t num_rotations = 1 << g_bc7_rotation_bits[best_mode]; + //const uint32_t num_index_selectors = (best_mode == 4) ? 2 : 1; + + const uint8_t* pPartition; + if (total_subsets == 1) + pPartition = &g_bc7_partition1[0]; + else if (total_subsets == 2) + pPartition = &g_bc7_partition2[pResults->m_partition * 16]; + else + pPartition = &g_bc7_partition3[pResults->m_partition * 16]; + + uint8_t color_selectors[16]; + memcpy(color_selectors, pResults->m_selectors, 16); + + uint8_t alpha_selectors[16]; + memcpy(alpha_selectors, pResults->m_alpha_selectors, 16); + + color_quad_u8 low[3], high[3]; + memcpy(low, pResults->m_low, sizeof(low)); + memcpy(high, pResults->m_high, sizeof(high)); + + uint32_t pbits[3][2]; + memcpy(pbits, pResults->m_pbits, sizeof(pbits)); + + int anchor[3] = { -1, -1, -1 }; + + for (uint32_t k = 0; k < total_subsets; k++) + { + uint32_t anchor_index = 0; + if (k) + { + if ((total_subsets == 3) && (k == 1)) + anchor_index = g_bc7_table_anchor_index_third_subset_1[pResults->m_partition]; + else if ((total_subsets == 3) && (k == 2)) + anchor_index = g_bc7_table_anchor_index_third_subset_2[pResults->m_partition]; + else + anchor_index = g_bc7_table_anchor_index_second_subset[pResults->m_partition]; + } + + anchor[k] = anchor_index; + + const uint32_t color_index_bits = get_bc7_color_index_size(best_mode, pResults->m_index_selector); + const uint32_t num_color_indices = 1 << color_index_bits; + + if (color_selectors[anchor_index] & (num_color_indices >> 1)) + { + for (uint32_t i = 0; i < 16; i++) + if (pPartition[i] == k) + color_selectors[i] = (uint8_t)((num_color_indices - 1) - color_selectors[i]); + + if (get_bc7_mode_has_seperate_alpha_selectors(best_mode)) + { + for (uint32_t q = 0; q < 3; q++) + { + uint8_t t = low[k].m_c[q]; + low[k].m_c[q] = high[k].m_c[q]; + high[k].m_c[q] = t; + } + } + else + { + color_quad_u8 tmp = low[k]; + low[k] = high[k]; + high[k] = tmp; + } + + if (!g_bc7_mode_has_shared_p_bits[best_mode]) + { + uint32_t t = pbits[k][0]; + pbits[k][0] = pbits[k][1]; + pbits[k][1] = t; + } + } + + if (get_bc7_mode_has_seperate_alpha_selectors(best_mode)) + { + const uint32_t alpha_index_bits = get_bc7_alpha_index_size(best_mode, pResults->m_index_selector); + const uint32_t num_alpha_indices = 1 << alpha_index_bits; + + if (alpha_selectors[anchor_index] & (num_alpha_indices >> 1)) + { + for (uint32_t i = 0; i < 16; i++) + if (pPartition[i] == k) + alpha_selectors[i] = (uint8_t)((num_alpha_indices - 1) - alpha_selectors[i]); + + uint8_t t = low[k].m_c[3]; + low[k].m_c[3] = high[k].m_c[3]; + high[k].m_c[3] = t; + } + } + } + + uint8_t* pBlock_bytes = (uint8_t*)(pBlock); + memset(pBlock_bytes, 0, BC7ENC_BLOCK_SIZE); + + uint32_t cur_bit_ofs = 0; + set_block_bits(pBlock_bytes, 1 << best_mode, best_mode + 1, &cur_bit_ofs); + + if ((best_mode == 4) || (best_mode == 5)) + set_block_bits(pBlock_bytes, pResults->m_rotation, 2, &cur_bit_ofs); + + if (best_mode == 4) + set_block_bits(pBlock_bytes, pResults->m_index_selector, 1, &cur_bit_ofs); + + if (total_partitions > 1) + set_block_bits(pBlock_bytes, pResults->m_partition, (total_partitions == 64) ? 6 : 4, &cur_bit_ofs); + + const uint32_t total_comps = (best_mode >= 4) ? 4 : 3; + for (uint32_t comp = 0; comp < total_comps; comp++) + { + for (uint32_t subset = 0; subset < total_subsets; subset++) + { + set_block_bits(pBlock_bytes, low[subset].m_c[comp], (comp == 3) ? g_bc7_alpha_precision_table[best_mode] : g_bc7_color_precision_table[best_mode], &cur_bit_ofs); + set_block_bits(pBlock_bytes, high[subset].m_c[comp], (comp == 3) ? g_bc7_alpha_precision_table[best_mode] : g_bc7_color_precision_table[best_mode], &cur_bit_ofs); + } + } + + if (g_bc7_mode_has_p_bits[best_mode]) + { + for (uint32_t subset = 0; subset < total_subsets; subset++) + { + set_block_bits(pBlock_bytes, pbits[subset][0], 1, &cur_bit_ofs); + if (!g_bc7_mode_has_shared_p_bits[best_mode]) + set_block_bits(pBlock_bytes, pbits[subset][1], 1, &cur_bit_ofs); + } + } + + for (uint32_t y = 0; y < 4; y++) + { + for (uint32_t x = 0; x < 4; x++) + { + int idx = x + y * 4; + + uint32_t n = pResults->m_index_selector ? get_bc7_alpha_index_size(best_mode, pResults->m_index_selector) : get_bc7_color_index_size(best_mode, pResults->m_index_selector); + + if ((idx == anchor[0]) || (idx == anchor[1]) || (idx == anchor[2])) + n--; + + set_block_bits(pBlock_bytes, pResults->m_index_selector ? alpha_selectors[idx] : color_selectors[idx], n, &cur_bit_ofs); + } + } + + if (get_bc7_mode_has_seperate_alpha_selectors(best_mode)) + { + for (uint32_t y = 0; y < 4; y++) + { + for (uint32_t x = 0; x < 4; x++) + { + int idx = x + y * 4; + + uint32_t n = pResults->m_index_selector ? get_bc7_color_index_size(best_mode, pResults->m_index_selector) : get_bc7_alpha_index_size(best_mode, pResults->m_index_selector); + + if ((idx == anchor[0]) || (idx == anchor[1]) || (idx == anchor[2])) + n--; + + set_block_bits(pBlock_bytes, pResults->m_index_selector ? color_selectors[idx] : alpha_selectors[idx], n, &cur_bit_ofs); + } + } + } + + assert(cur_bit_ofs == 128); +} + +static void handle_alpha_block_mode5(const color_quad_u8* pPixels, const bc7enc_compress_block_params* pComp_params, color_cell_compressor_params* pParams, uint32_t lo_a, uint32_t hi_a, bc7_optimization_results* pOpt_results5, uint64_t* pMode5_err, uint64_t* pMode5_alpha_err) +{ + pParams->m_pSelector_weights = g_bc7_weights2; + pParams->m_pSelector_weightsx = (const vec4F*)g_bc7_weights2x; + pParams->m_num_selector_weights = 4; + + pParams->m_comp_bits = 7; + pParams->m_has_pbits = BC7ENC_FALSE; + pParams->m_endpoints_share_pbit = BC7ENC_FALSE; + pParams->m_has_alpha = BC7ENC_FALSE; + + pParams->m_perceptual = pComp_params->m_perceptual; + + pParams->m_num_pixels = 16; + pParams->m_pPixels = pPixels; + + color_cell_compressor_results results5; + results5.m_pSelectors = pOpt_results5->m_selectors; + + uint8_t selectors_temp[16]; + results5.m_pSelectors_temp = selectors_temp; + + *pMode5_err = color_cell_compression(5, pParams, &results5, pComp_params); + assert(*pMode5_err == results5.m_best_overall_err); + + pOpt_results5->m_low[0] = results5.m_low_endpoint; + pOpt_results5->m_high[0] = results5.m_high_endpoint; + + if (lo_a == hi_a) + { + *pMode5_alpha_err = 0; + pOpt_results5->m_low[0].m_c[3] = (uint8_t)lo_a; + pOpt_results5->m_high[0].m_c[3] = (uint8_t)hi_a; + memset(pOpt_results5->m_alpha_selectors, 0, sizeof(pOpt_results5->m_alpha_selectors)); + } + else + { + *pMode5_alpha_err = UINT64_MAX; + + const uint32_t total_passes = (pComp_params->m_uber_level >= 1) ? 3 : 2; + for (uint32_t pass = 0; pass < total_passes; pass++) + { + int32_t vals[4]; + vals[0] = lo_a; + vals[3] = hi_a; + + const int32_t w_s1 = 21, w_s2 = 43; + vals[1] = (vals[0] * (64 - w_s1) + vals[3] * w_s1 + 32) >> 6; + vals[2] = (vals[0] * (64 - w_s2) + vals[3] * w_s2 + 32) >> 6; + + uint8_t trial_alpha_selectors[16]; + + uint64_t trial_alpha_err = 0; + for (uint32_t i = 0; i < 16; i++) + { + const int32_t a = pParams->m_pPixels[i].m_c[3]; + + int s = 0; + int32_t be = iabs32(a - vals[0]); + int e = iabs32(a - vals[1]); if (e < be) { be = e; s = 1; } + e = iabs32(a - vals[2]); if (e < be) { be = e; s = 2; } + e = iabs32(a - vals[3]); if (e < be) { be = e; s = 3; } + + trial_alpha_selectors[i] = (uint8_t)s; + + uint32_t a_err = (uint32_t)(be * be) * pParams->m_weights[3]; + + trial_alpha_err += a_err; + } + + if (trial_alpha_err < *pMode5_alpha_err) + { + *pMode5_alpha_err = trial_alpha_err; + pOpt_results5->m_low[0].m_c[3] = (uint8_t)lo_a; + pOpt_results5->m_high[0].m_c[3] = (uint8_t)hi_a; + memcpy(pOpt_results5->m_alpha_selectors, trial_alpha_selectors, sizeof(pOpt_results5->m_alpha_selectors)); + } + + if (pass != (total_passes - 1U)) + { + float xl, xh; + compute_least_squares_endpoints_a(16, trial_alpha_selectors, (const vec4F*)g_bc7_weights2x, &xl, &xh, pParams->m_pPixels); + + uint32_t new_lo_a = clampi((int)floor(xl + .5f), 0, 255); + uint32_t new_hi_a = clampi((int)floor(xh + .5f), 0, 255); + if (new_lo_a > new_hi_a) + swapu(&new_lo_a, &new_hi_a); + + if ((new_lo_a == lo_a) && (new_hi_a == hi_a)) + break; + + lo_a = new_lo_a; + hi_a = new_hi_a; + } + } + + *pMode5_err += *pMode5_alpha_err; + } +} + +static void handle_alpha_block(void *pBlock, const color_quad_u8 *pPixels, const bc7enc_compress_block_params *pComp_params, color_cell_compressor_params *pParams) +{ + pParams->m_pSelector_weights = g_bc7_weights4; + pParams->m_pSelector_weightsx = (const vec4F *)g_bc7_weights4x; + pParams->m_num_selector_weights = 16; + pParams->m_comp_bits = 7; + pParams->m_has_pbits = BC7ENC_TRUE; + pParams->m_endpoints_share_pbit = BC7ENC_FALSE; + pParams->m_has_alpha = BC7ENC_TRUE; + pParams->m_perceptual = pComp_params->m_perceptual; + pParams->m_num_pixels = 16; + pParams->m_pPixels = pPixels; + + bc7_optimization_results opt_results6, opt_results5, opt_results7; + + color_cell_compressor_results results6; + results6.m_pSelectors = opt_results6.m_selectors; + uint8_t selectors_temp[16]; + results6.m_pSelectors_temp = selectors_temp; + + uint64_t best_err = color_cell_compression(6, pParams, &results6, pComp_params); + uint32_t best_mode = 6; + + if ((best_err > 0) && (pComp_params->m_use_mode5_for_alpha)) + { + uint32_t lo_a = 255, hi_a = 0; + for (uint32_t i = 0; i < 16; i++) + { + uint32_t a = pPixels[i].m_c[3]; + lo_a = minimumu(lo_a, a); + hi_a = maximumu(hi_a, a); + } + + uint64_t mode5_err, mode5_alpha_err; + handle_alpha_block_mode5(pPixels, pComp_params, pParams, lo_a, hi_a, &opt_results5, &mode5_err, &mode5_alpha_err); + + if (mode5_err < best_err) + { + best_err = mode5_err; + best_mode = 5; + } + } + + if ((best_err > 0) && (pComp_params->m_use_mode7_for_alpha)) + { + const uint32_t trial_partition = estimate_partition(pPixels, pComp_params, pParams->m_weights, 7); + + pParams->m_pSelector_weights = g_bc7_weights2; + pParams->m_pSelector_weightsx = (const vec4F*)g_bc7_weights2x; + pParams->m_num_selector_weights = 4; + pParams->m_comp_bits = 5; + pParams->m_has_pbits = BC7ENC_TRUE; + pParams->m_endpoints_share_pbit = BC7ENC_FALSE; + pParams->m_has_alpha = BC7ENC_TRUE; + + const uint8_t* pPartition = &g_bc7_partition2[trial_partition * 16]; + + color_quad_u8 subset_colors[2][16]; + + uint32_t subset_total_colors7[2] = { 0, 0 }; + + uint8_t subset_pixel_index7[2][16]; + uint8_t subset_selectors7[2][16]; + color_cell_compressor_results subset_results7[2]; + + for (uint32_t idx = 0; idx < 16; idx++) + { + const uint32_t p = pPartition[idx]; + subset_colors[p][subset_total_colors7[p]] = pPixels[idx]; + subset_pixel_index7[p][subset_total_colors7[p]] = (uint8_t)idx; + subset_total_colors7[p]++; + } + + uint64_t trial_err = 0; + for (uint32_t subset = 0; subset < 2; subset++) + { + pParams->m_num_pixels = subset_total_colors7[subset]; + pParams->m_pPixels = &subset_colors[subset][0]; + + color_cell_compressor_results* pResults = &subset_results7[subset]; + pResults->m_pSelectors = &subset_selectors7[subset][0]; + pResults->m_pSelectors_temp = selectors_temp; + uint64_t err = color_cell_compression(7, pParams, pResults, pComp_params); + trial_err += err; + if (trial_err > best_err) + break; + + } // subset + + if (trial_err < best_err) + { + best_err = trial_err; + best_mode = 7; + opt_results7.m_mode = 7; + opt_results7.m_partition = trial_partition; + opt_results7.m_index_selector = 0; + opt_results7.m_rotation = 0; + for (uint32_t subset = 0; subset < 2; subset++) + { + for (uint32_t i = 0; i < subset_total_colors7[subset]; i++) + opt_results7.m_selectors[subset_pixel_index7[subset][i]] = subset_selectors7[subset][i]; + opt_results7.m_low[subset] = subset_results7[subset].m_low_endpoint; + opt_results7.m_high[subset] = subset_results7[subset].m_high_endpoint; + opt_results7.m_pbits[subset][0] = subset_results7[subset].m_pbits[0]; + opt_results7.m_pbits[subset][1] = subset_results7[subset].m_pbits[1]; + } + } + } + + if (best_mode == 7) + { + encode_bc7_block(pBlock, &opt_results7); + } + else if (best_mode == 5) + { + opt_results5.m_mode = 5; + opt_results5.m_partition = 0; + opt_results5.m_rotation = 0; + opt_results5.m_index_selector = 0; + + encode_bc7_block(pBlock, &opt_results5); + } + else if (best_mode == 6) + { + opt_results6.m_mode = 6; + opt_results6.m_partition = 0; + opt_results6.m_low[0] = results6.m_low_endpoint; + opt_results6.m_high[0] = results6.m_high_endpoint; + opt_results6.m_pbits[0][0] = results6.m_pbits[0]; + opt_results6.m_pbits[0][1] = results6.m_pbits[1]; + opt_results6.m_rotation = 0; + opt_results6.m_index_selector = 0; + + encode_bc7_block(pBlock, &opt_results6); + } +} + +static void handle_opaque_block(void *pBlock, const color_quad_u8 *pPixels, const bc7enc_compress_block_params *pComp_params, color_cell_compressor_params *pParams) +{ + uint8_t selectors_temp[16]; + + // Mode 6 + bc7_optimization_results opt_results; + + pParams->m_pSelector_weights = g_bc7_weights4; + pParams->m_pSelector_weightsx = (const vec4F *)g_bc7_weights4x; + pParams->m_num_selector_weights = 16; + pParams->m_comp_bits = 7; + pParams->m_has_pbits = BC7ENC_TRUE; + pParams->m_endpoints_share_pbit = BC7ENC_FALSE; + pParams->m_perceptual = pComp_params->m_perceptual; + pParams->m_num_pixels = 16; + pParams->m_pPixels = pPixels; + pParams->m_has_alpha = BC7ENC_FALSE; + + color_cell_compressor_results results6; + results6.m_pSelectors = opt_results.m_selectors; + results6.m_pSelectors_temp = selectors_temp; + + uint64_t best_err = color_cell_compression(6, pParams, &results6, pComp_params); + + opt_results.m_mode = 6; + opt_results.m_partition = 0; + opt_results.m_low[0] = results6.m_low_endpoint; + opt_results.m_high[0] = results6.m_high_endpoint; + opt_results.m_pbits[0][0] = results6.m_pbits[0]; + opt_results.m_pbits[0][1] = results6.m_pbits[1]; + opt_results.m_index_selector = 0; + opt_results.m_rotation = 0; + + // Mode 1 + if ((best_err > 0) && (pComp_params->m_max_partitions_mode > 0)) + { + const uint32_t trial_partition = estimate_partition(pPixels, pComp_params, pParams->m_weights, 1); + + pParams->m_pSelector_weights = g_bc7_weights3; + pParams->m_pSelector_weightsx = (const vec4F *)g_bc7_weights3x; + pParams->m_num_selector_weights = 8; + pParams->m_comp_bits = 6; + pParams->m_has_pbits = BC7ENC_TRUE; + pParams->m_endpoints_share_pbit = BC7ENC_TRUE; + + const uint8_t *pPartition = &g_bc7_partition2[trial_partition * 16]; + + color_quad_u8 subset_colors[2][16]; + + uint32_t subset_total_colors1[2] = { 0, 0 }; + + uint8_t subset_pixel_index1[2][16]; + uint8_t subset_selectors1[2][16]; + color_cell_compressor_results subset_results1[2]; + + for (uint32_t idx = 0; idx < 16; idx++) + { + const uint32_t p = pPartition[idx]; + subset_colors[p][subset_total_colors1[p]] = pPixels[idx]; + subset_pixel_index1[p][subset_total_colors1[p]] = (uint8_t)idx; + subset_total_colors1[p]++; + } + + uint64_t trial_err = 0; + for (uint32_t subset = 0; subset < 2; subset++) + { + pParams->m_num_pixels = subset_total_colors1[subset]; + pParams->m_pPixels = &subset_colors[subset][0]; + + color_cell_compressor_results *pResults = &subset_results1[subset]; + pResults->m_pSelectors = &subset_selectors1[subset][0]; + pResults->m_pSelectors_temp = selectors_temp; + uint64_t err = color_cell_compression(1, pParams, pResults, pComp_params); + + trial_err += err; + if (trial_err > best_err) + break; + + } // subset + + if (trial_err < best_err) + { + best_err = trial_err; + opt_results.m_mode = 1; + opt_results.m_partition = trial_partition; + for (uint32_t subset = 0; subset < 2; subset++) + { + for (uint32_t i = 0; i < subset_total_colors1[subset]; i++) + opt_results.m_selectors[subset_pixel_index1[subset][i]] = subset_selectors1[subset][i]; + opt_results.m_low[subset] = subset_results1[subset].m_low_endpoint; + opt_results.m_high[subset] = subset_results1[subset].m_high_endpoint; + opt_results.m_pbits[subset][0] = subset_results1[subset].m_pbits[0]; + } + } + } + + encode_bc7_block(pBlock, &opt_results); +} + +bc7enc_bool bc7enc_compress_block(void *pBlock, const void *pPixelsRGBA, const bc7enc_compress_block_params *pComp_params) +{ + assert(g_bc7_mode_1_optimal_endpoints[255][0].m_hi != 0); + + const color_quad_u8 *pPixels = (const color_quad_u8 *)(pPixelsRGBA); + + color_cell_compressor_params params; + if (pComp_params->m_perceptual) + { + // https://en.wikipedia.org/wiki/YCbCr#ITU-R_BT.709_conversion + const float pr_weight = (.5f / (1.0f - .2126f)) * (.5f / (1.0f - .2126f)); + const float pb_weight = (.5f / (1.0f - .0722f)) * (.5f / (1.0f - .0722f)); + params.m_weights[0] = (int)(pComp_params->m_weights[0] * 4.0f); + params.m_weights[1] = (int)(pComp_params->m_weights[1] * 4.0f * pr_weight); + params.m_weights[2] = (int)(pComp_params->m_weights[2] * 4.0f * pb_weight); + params.m_weights[3] = pComp_params->m_weights[3] * 4; + } + else + memcpy(params.m_weights, pComp_params->m_weights, sizeof(params.m_weights)); + + for (uint32_t i = 0; i < 16; i++) + { + if (pPixels[i].m_c[3] < 255) + { + handle_alpha_block(pBlock, pPixels, pComp_params, ¶ms); + return BC7ENC_TRUE; + } + } + handle_opaque_block(pBlock, pPixels, pComp_params, ¶ms); + return BC7ENC_FALSE; +} + +/* +------------------------------------------------------------------------------ +This software is available under 2 licenses -- choose whichever you prefer. +------------------------------------------------------------------------------ +ALTERNATIVE A - MIT License +Copyright(c) 2020 Richard Geldreich, Jr. +Permission is hereby granted, free of charge, to any person obtaining a copy of +this software and associated documentation files(the "Software"), to deal in +the Software without restriction, including without limitation the rights to +use, copy, modify, merge, publish, distribute, sublicense, and / or sell copies +of the Software, and to permit persons to whom the Software is furnished to do +so, subject to the following conditions : +The above copyright notice and this permission notice shall be included in all +copies or substantial portions of the Software. +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE +AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE +SOFTWARE. +------------------------------------------------------------------------------ +ALTERNATIVE B - Public Domain(www.unlicense.org) +This is free and unencumbered software released into the public domain. +Anyone is free to copy, modify, publish, use, compile, sell, or distribute this +software, either in source code form or as a compiled binary, for any purpose, +commercial or non - commercial, and by any means. +In jurisdictions that recognize copyright laws, the author or authors of this +software dedicate any and all copyright interest in the software to the public +domain.We make this dedication for the benefit of the public at large and to +the detriment of our heirs and successors.We intend this dedication to be an +overt act of relinquishment in perpetuity of all present and future rights to +this software under copyright law. +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE +AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN +ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION +WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. +------------------------------------------------------------------------------ +*/ diff --git a/src/compr/bc7enc.h b/src/compr/bc7enc.h new file mode 100644 index 0000000..4a12fc3 --- /dev/null +++ b/src/compr/bc7enc.h @@ -0,0 +1,82 @@ +// File: bc7enc.h - Richard Geldreich, Jr. - MIT license or public domain (see end of bc7enc.c) +#include +#include + +#ifdef __cplusplus +extern "C" { +#endif + +#define BC7ENC_BLOCK_SIZE (16) +#define BC7ENC_MAX_PARTITIONS1 (64) +#define BC7ENC_MAX_UBER_LEVEL (4) + +typedef uint8_t bc7enc_bool; +#define BC7ENC_TRUE (1) +#define BC7ENC_FALSE (0) + +typedef struct +{ + // m_max_partitions_mode may range from 0 (disables mode 1) to BC7ENC_MAX_PARTITIONS1. The higher this value, the slower the compressor, but the higher the quality. + uint32_t m_max_partitions_mode; + + // Relative RGBA or YCbCrA weights. + uint32_t m_weights[4]; + + // m_uber_level may range from 0 to BC7ENC_MAX_UBER_LEVEL. The higher this value, the slower the compressor, but the higher the quality. + uint32_t m_uber_level; + + // If m_perceptual is true, colorspace error is computed in YCbCr space, otherwise RGB. + bc7enc_bool m_perceptual; + + // Set m_try_least_squares to false for slightly faster/lower quality compression. + bc7enc_bool m_try_least_squares; + + // When m_mode_partition_estimation_filterbank, the mode1 partition estimator skips lesser used partition patterns unless they are strongly predicted to be potentially useful. + // There's a slight loss in quality with this enabled (around .08 dB RGB PSNR or .05 dB Y PSNR), but up to a 11% gain in speed depending on the other settings. + bc7enc_bool m_mode_partition_estimation_filterbank; + + bc7enc_bool m_use_mode5_for_alpha; + bc7enc_bool m_use_mode7_for_alpha; + +} bc7enc_compress_block_params; + +inline static void bc7enc_compress_block_params_init_linear_weights(bc7enc_compress_block_params *p) +{ + p->m_perceptual = BC7ENC_FALSE; + p->m_weights[0] = 1; + p->m_weights[1] = 1; + p->m_weights[2] = 1; + p->m_weights[3] = 1; +} + +inline static void bc7enc_compress_block_params_init_perceptual_weights(bc7enc_compress_block_params *p) +{ + p->m_perceptual = BC7ENC_TRUE; + p->m_weights[0] = 128; + p->m_weights[1] = 64; + p->m_weights[2] = 16; + p->m_weights[3] = 32; +} + +inline static void bc7enc_compress_block_params_init(bc7enc_compress_block_params *p) +{ + p->m_max_partitions_mode = BC7ENC_MAX_PARTITIONS1; + p->m_try_least_squares = BC7ENC_TRUE; + p->m_mode_partition_estimation_filterbank = BC7ENC_TRUE; + p->m_uber_level = 0; + p->m_use_mode5_for_alpha = BC7ENC_TRUE; + p->m_use_mode7_for_alpha = BC7ENC_TRUE; + bc7enc_compress_block_params_init_perceptual_weights(p); +} + +// bc7enc_compress_block_init() MUST be called before calling bc7enc_compress_block() (or you'll get artifacts). +void bc7enc_compress_block_init(); + +// Packs a single block of 16x16 RGBA pixels (R first in memory) to 128-bit BC7 block pBlock, using either mode 1 and/or 6. +// Alpha blocks will always use mode 6, and by default opaque blocks will use either modes 1 or 6. +// Returns BC7ENC_TRUE if the block had any pixels with alpha < 255, otherwise it return BC7ENC_FALSE. (This is not an error code - a block is always encoded.) +bc7enc_bool bc7enc_compress_block(void *pBlock, const void *pPixelsRGBA, const bc7enc_compress_block_params *pComp_params); + +#ifdef __cplusplus +} +#endif