Add bc7enc source

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 <stdlib.h>
+#include <stdint.h>
+
+#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