#include"k3bloom.h"

#include<stddef.h>
#include"k3.h"
#include<assert.h>
#include"gl.h"

static struct k3GLSLP *tonemapper;

static struct k3GLSLP *minibloom1;
static struct k3GLSLP *minibloom2;

int make_mb1() {
	struct k3GLSLV *v = !k3IsCore ? k3ShaderGLSLV(
		"uniform vec2 u_sz;"							"\n"
		"varying vec2 v_uv;"							"\n"
		"void main() {"									"\n"
		"	v_uv = gl_Vertex.xy * (1.0 + 1.0 / u_sz) * 0.5 + 0.5;""\n"
		"	gl_Position = vec4(gl_Vertex.xy, 0, 1);"	"\n"
		"}"												"\n"
	, NULL) : k3ShaderGLSLV(
		"#version 330\n"
		"uniform vec2 u_sz;"							"\n"
		"const vec4 positions[3] = vec4[3] (vec4(-1, -1, 0, 1), vec4(3, -1, 0, 1), vec4(-1, 3, 0, 1));\n"
		"out vec2 v_uv;"								"\n"
		"void main() {"									"\n"
		"	v_uv = positions[gl_VertexID].xy * (1.0 + 1.0 / u_sz) * 0.5 + 0.5;""\n"
		"	gl_Position = positions[gl_VertexID];"		"\n"
		"}"												"\n"
	, NULL);
	
	if(!v) return 0;
	
	struct k3GLSLF *f = !k3IsCore ? k3ShaderGLSLF(
		"#define THRESHOLD 0.6"														"\n"
		"#define FACTOR 0.07"														"\n"
		"uniform sampler2D u_tex;"													"\n"
		"varying vec2 v_uv;"														"\n"
		"vec3 get_col(vec2 uv) {"													"\n"
		"	vec3 col = texture2D(u_tex, uv).rgb;"									"\n"
		"	float luminance = col.r * 0.3086 + col.g * 0.6094 + col.b * 0.0820;"	"\n"
		"	if(luminance < THRESHOLD) col = vec3(0);"								"\n"
		"	return col * FACTOR;"													"\n"
		"}"																			"\n"
		"void main() {"																"\n"
		"	vec3 c = vec3(0);"														"\n"
		"	c += 0.0020 * get_col(v_uv + vec2(-4.0 / 512.0, 0));"					"\n"
		"	c += 0.0060 * get_col(v_uv + vec2(-3.0 / 512.0, 0));"					"\n"
		"	c += 0.0606 * get_col(v_uv + vec2(-2.0 / 512.0, 0));"					"\n"
		"	c += 0.2417 * get_col(v_uv + vec2(-1.0 / 512.0, 0));"					"\n"
		"	c += 0.3829 * get_col(v_uv + vec2(+0.0 / 512.0, 0));"					"\n"
		"	c += 0.2417 * get_col(v_uv + vec2(+1.0 / 512.0, 0));"					"\n"
		"	c += 0.0606 * get_col(v_uv + vec2(+2.0 / 512.0, 0));"					"\n"
		"	c += 0.0060 * get_col(v_uv + vec2(+3.0 / 512.0, 0));"					"\n"
		"	c += 0.0020 * get_col(v_uv + vec2(+4.0 / 512.0, 0));"					"\n"
		"	gl_FragColor = vec4(c, 1);"												"\n"
		"}"																			"\n"
	, NULL) : k3ShaderGLSLF(
		"#version 330\n"
		"#define THRESHOLD 0.6"														"\n"
		"#define FACTOR 0.07"														"\n"
		"uniform sampler2D u_tex;"													"\n"
		"in vec2 v_uv;"																"\n"
		"out vec4 fragcolor;"														"\n"
		"vec3 get_col(vec2 uv) {"													"\n"
		"	vec3 col = texture2D(u_tex, uv).rgb;"									"\n"
		"	float luminance = col.r * 0.3086 + col.g * 0.6094 + col.b * 0.0820;"	"\n"
		"	if(luminance < THRESHOLD) col = vec3(0);"								"\n"
		"	return col * FACTOR;"													"\n"
		"}"																			"\n"
		"void main() {"																"\n"
		"	vec3 c = vec3(0);"														"\n"
		"	c += 0.0020 * get_col(v_uv + vec2(-4.0 / 512.0, 0));"					"\n"
		"	c += 0.0060 * get_col(v_uv + vec2(-3.0 / 512.0, 0));"					"\n"
		"	c += 0.0606 * get_col(v_uv + vec2(-2.0 / 512.0, 0));"					"\n"
		"	c += 0.2417 * get_col(v_uv + vec2(-1.0 / 512.0, 0));"					"\n"
		"	c += 0.3829 * get_col(v_uv + vec2(+0.0 / 512.0, 0));"					"\n"
		"	c += 0.2417 * get_col(v_uv + vec2(+1.0 / 512.0, 0));"					"\n"
		"	c += 0.0606 * get_col(v_uv + vec2(+2.0 / 512.0, 0));"					"\n"
		"	c += 0.0060 * get_col(v_uv + vec2(+3.0 / 512.0, 0));"					"\n"
		"	c += 0.0020 * get_col(v_uv + vec2(+4.0 / 512.0, 0));"					"\n"
		"	fragcolor = vec4(c, 1);"												"\n"
		"}"																			"\n"
	, NULL);
	
	if(!f) return 0;
	
	minibloom1 = k3ProgramGLSL(v, f, NULL);
	
	if(!minibloom1) return 0;
	
	return 1;
}

int make_mb2() {
	struct k3GLSLV *v = !k3IsCore ? k3ShaderGLSLV(
		"uniform vec2 u_sz;"							"\n"
		"varying vec2 v_uv;"							"\n"
		"void main() {"									"\n"
		"	v_uv = gl_Vertex.xy * (1.0 + 1.0 / u_sz) * 0.5 + 0.5;"			"\n"
		"	gl_Position = vec4(gl_Vertex.xy, 0, 1);"	"\n"
		"}"												"\n"
	, NULL) : k3ShaderGLSLV(
		"#version 330\n"
		"uniform vec2 u_sz;"							"\n"
		"const vec4 positions[3] = vec4[3] (vec4(-1, -1, 0, 1), vec4(3, -1, 0, 1), vec4(-1, 3, 0, 1));\n"
		"out vec2 v_uv;"								"\n"
		"void main() {"									"\n"
		"	v_uv = positions[gl_VertexID].xy * (1.0 + 1.0 / u_sz) * 0.5 + 0.5;"	"\n"
		"	gl_Position = positions[gl_VertexID];"		"\n"
		"}"												"\n"
	, NULL);
	
	if(!v) return 0;
	
	struct k3GLSLF *f = !k3IsCore ? k3ShaderGLSLF(
		"uniform sampler2D u_tex;"												"\n"
		"varying vec2 v_uv;"													"\n"
		"vec3 get_col(vec2 uv) {"												"\n"
		"	vec3 col = texture2D(u_tex, uv).rgb;"								"\n"
		"	return col;"														"\n"
		"}"																		"\n"
		"void main() {"															"\n"
		"	vec3 c = vec3(0);"													"\n"
		"	c += 0.0020 * get_col(v_uv + vec2(0, -4.0 / 256.0));"				"\n"
		"	c += 0.0060 * get_col(v_uv + vec2(0, -3.0 / 256.0));"				"\n"
		"	c += 0.0606 * get_col(v_uv + vec2(0, -2.0 / 256.0));"				"\n"
		"	c += 0.2417 * get_col(v_uv + vec2(0, -1.0 / 256.0));"				"\n"
		"	c += 0.3829 * get_col(v_uv + vec2(0, +0.0 / 256.0));"				"\n"
		"	c += 0.2417 * get_col(v_uv + vec2(0, +1.0 / 256.0));"				"\n"
		"	c += 0.0606 * get_col(v_uv + vec2(0, +2.0 / 256.0));"				"\n"
		"	c += 0.0060 * get_col(v_uv + vec2(0, +3.0 / 256.0));"				"\n"
		"	c += 0.0020 * get_col(v_uv + vec2(0, +4.0 / 256.0));"				"\n"
		"	gl_FragColor = vec4(c, 1);"											"\n"
		"}"																		"\n"
	, NULL) : k3ShaderGLSLF(
		"#version 330\n"
		"uniform sampler2D u_tex;"												"\n"
		"in vec2 v_uv;"																"\n"
		"out vec4 fragcolor;"														"\n"
		"vec3 get_col(vec2 uv) {"												"\n"
		"	vec3 col = texture2D(u_tex, uv).rgb;"								"\n"
		"	return col;"														"\n"
		"}"																		"\n"
		"void main() {"															"\n"
		"	vec3 c = vec3(0);"													"\n"
		"	c += 0.0020 * get_col(v_uv + vec2(0, -4.0 / 256.0));"				"\n"
		"	c += 0.0060 * get_col(v_uv + vec2(0, -3.0 / 256.0));"				"\n"
		"	c += 0.0606 * get_col(v_uv + vec2(0, -2.0 / 256.0));"				"\n"
		"	c += 0.2417 * get_col(v_uv + vec2(0, -1.0 / 256.0));"				"\n"
		"	c += 0.3829 * get_col(v_uv + vec2(0, +0.0 / 256.0));"				"\n"
		"	c += 0.2417 * get_col(v_uv + vec2(0, +1.0 / 256.0));"				"\n"
		"	c += 0.0606 * get_col(v_uv + vec2(0, +2.0 / 256.0));"				"\n"
		"	c += 0.0060 * get_col(v_uv + vec2(0, +3.0 / 256.0));"				"\n"
		"	c += 0.0020 * get_col(v_uv + vec2(0, +4.0 / 256.0));"				"\n"
		"	fragcolor = vec4(c, 1);"												"\n"
		"}"																		"\n"
	, NULL);
	
	if(!f) return 0;
	
	minibloom2 = k3ProgramGLSL(v, f, NULL);
	
	if(!minibloom2) return 0;
	
	return 1;
}

int make_tonemapper() {
	struct k3GLSLV *v = !k3IsCore ? k3ShaderGLSLV(
		"varying vec2 v_uv;"							"\n"
		"void main() {"									"\n"
		"	v_uv = gl_Vertex.xy * 0.5 + 0.5;"			"\n"
		"	gl_Position = vec4(gl_Vertex.xy, 0, 1);"	"\n"
		"}"												"\n"
	, NULL) : k3ShaderGLSLV(
		"#version 330\n"
		"const vec4 positions[3] = vec4[3] (vec4(-1, -1, 0, 1), vec4(3, -1, 0, 1), vec4(-1, 3, 0, 1));\n"
		"out vec2 v_uv;"								"\n"
		"void main() {"									"\n"
		"	v_uv = positions[gl_VertexID].xy * 0.5 + 0.5;"	"\n"
		"	gl_Position = positions[gl_VertexID];"		"\n"
		"}"												"\n"
	, NULL);
	
	if(!v) return 0;
	
	struct k3GLSLF *f = k3ShaderGLSLF(
		"uniform sampler2D u_tex;"													"\n"
		"varying vec2 v_uv;"														"\n"
		"const vec3 WHITE = vec3(0.95045592705, 1.0, 1.08905775076);"				"\n"
		"const mat3 RGB_2_XYZ = (mat3("												"\n"
		"	0.4124564, 0.2126729, 0.0193339,"										"\n"
		"	0.3575761, 0.7151522, 0.1191920,"										"\n"
		"	0.1804375, 0.0721750, 0.9503041"										"\n"
		"));"																		"\n"
		"const mat3 XYZ_2_RGB = (mat3("												"\n"
		"	 3.2404542,-0.9692660, 0.0556434,"										"\n"
		"	-1.5371385, 1.8760108,-0.2040259,"										"\n"
		"	-0.4985314, 0.0415560, 1.0572252"										"\n"
		"));"																		"\n"
		"float XYZ_TO_LAB_F(float x) {"
		"	return x > 0.00885645167 ? pow(x, 0.333333333) : 7.78703703704 * x + 0.13793103448;"
		"}"
		"vec3 XYZ_TO_LAB(vec3 xyz) {"
		"	vec3 xyz_scaled = xyz / WHITE;"
		"	xyz_scaled = vec3("
		"		XYZ_TO_LAB_F(xyz_scaled.x),"
		"		XYZ_TO_LAB_F(xyz_scaled.y),"
		"		XYZ_TO_LAB_F(xyz_scaled.z)"
		"	);"
		"	return vec3("
		"		(1.16 * xyz_scaled.y) - 0.16,"
		"		5.0 * (xyz_scaled.x - xyz_scaled.y),"
		"		2.0 * (xyz_scaled.y - xyz_scaled.z)"
		"	);"
		"}"
		"float LAB_TO_XYZ_F(float x) {"
		"	return (x > 0.206897) ? x * x * x : (0.12841854934 * (x - 0.137931034));"
		"}"
		"vec3 LAB_TO_XYZ(vec3 Lab) {"
		"	float w = (Lab.x + 0.16) / 1.16;"
		"	return WHITE * vec3("
		"		LAB_TO_XYZ_F(w + Lab.y / 5.0),"
		"		LAB_TO_XYZ_F(w),"
		"		LAB_TO_XYZ_F(w - Lab.z / 2.0)"
		"	);"
		"}"
		"vec3 toner(vec3 col, float whitepoint, float saturation) {"				"\n"
		"	vec3 xyz = RGB_2_XYZ * col;"											"\n"
		"	vec3 lab = XYZ_TO_LAB(xyz);"											"\n"
		"	lab.yz *= saturation;"													"\n"
		"	float n = lab.x * (1.0 + (lab.x / (whitepoint * whitepoint)));"			"\n"
		"	lab.x = n / (1.0 + lab.x);"												"\n"
		"	xyz = LAB_TO_XYZ(lab);"													"\n"
		"	return XYZ_2_RGB * xyz;"												"\n"
		"}"																			"\n"
		"vec3 get_col(vec2 uv) {"													"\n"
		"	vec3 col = texture2D(u_tex, uv).rgb;"									"\n"
		"	col = toner(col, 0.80, 1.0);"											"\n"
		"	return col;"															"\n"
		"}"																			"\n"
		"void main() {"																"\n"
		"	gl_FragColor = vec4(get_col(v_uv), 1);"									"\n"
		"}"																			"\n"
	, NULL);
	
	if(!f) return 0;
	
	tonemapper = k3ProgramGLSL(v, f, NULL);
	
	if(!tonemapper) return 0;
	
	return 1;
}

int k3BloomInit() {
	if(!k3IsCore && !GLAD_GL_ARB_shading_language_100) {
		return 0;
	}
	
	if(!make_mb1()) return 0;
	if(!make_mb2()) return 0;
	if(!make_tonemapper()) return 0;
	
	return 1;
}

int k3Bloom(struct k3Offscreen *a, struct k3Offscreen *b) {
	if(!minibloom1) return 0;
	if(!minibloom2) return 0;
	
	assert(b);
	
	k3BeginOffscreen(b);
	k3BlitToScreenEffect(a, false, k3_GLSL, minibloom1, NULL);
	k3EndOffscreen(b);
	
	k3BlitToScreenEffect(b, true, k3_GLSL, minibloom2, NULL);
	
	return 1;
}

struct k3GLSLP *k3ToneMapper() {
	return tonemapper;
}