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weston/libweston/renderer-gl/fragment.glsl

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/*
* Copyright 2012 Intel Corporation
* Copyright 2015,2019,2021 Collabora, Ltd.
* Copyright 2016 NVIDIA Corporation
* Copyright 2021 Advanced Micro Devices, Inc.
*
* 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 (including the
* next paragraph) 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.
*/
/* GLSL version 1.00 ES, defined in gl-shaders.c */
/* For annotating shader compile-time constant arguments */
#define compile_const const
/*
* Enumeration of shader variants, must match enum gl_shader_texture_variant.
*/
#define SHADER_VARIANT_RGBX 1
#define SHADER_VARIANT_RGBA 2
#define SHADER_VARIANT_Y_U_V 3
#define SHADER_VARIANT_Y_UV 4
#define SHADER_VARIANT_Y_XUXV 5
#define SHADER_VARIANT_XYUV 6
#define SHADER_VARIANT_SOLID 7
#define SHADER_VARIANT_EXTERNAL 8
/* enum gl_shader_color_curve */
#define SHADER_COLOR_CURVE_IDENTITY 0
#define SHADER_COLOR_CURVE_LUT_3x1D 1
/* enum gl_shader_color_mapping */
#define SHADER_COLOR_MAPPING_IDENTITY 0
#define SHADER_COLOR_MAPPING_3DLUT 1
#if DEF_VARIANT == SHADER_VARIANT_EXTERNAL
#extension GL_OES_EGL_image_external : require
#endif
#if DEF_COLOR_MAPPING == SHADER_COLOR_MAPPING_3DLUT
#extension GL_OES_texture_3D : require
#endif
#ifdef GL_FRAGMENT_PRECISION_HIGH
#define HIGHPRECISION highp
#else
#define HIGHPRECISION mediump
#endif
precision HIGHPRECISION float;
/*
* These undeclared identifiers will be #defined by a runtime generated code
* snippet.
*/
compile_const int c_variant = DEF_VARIANT;
compile_const bool c_input_is_premult = DEF_INPUT_IS_PREMULT;
compile_const bool c_green_tint = DEF_GREEN_TINT;
compile_const int c_color_pre_curve = DEF_COLOR_PRE_CURVE;
compile_const int c_color_mapping = DEF_COLOR_MAPPING;
vec4
yuva2rgba(vec4 yuva)
{
vec4 color_out;
float Y, su, sv;
/* ITU-R BT.601 & BT.709 quantization (limited range) */
/* Y = 255/219 * (x - 16/256) */
Y = 1.16438356 * (yuva.x - 0.0625);
/* Remove offset 128/256, but the 255/224 multiplier comes later */
su = yuva.y - 0.5;
sv = yuva.z - 0.5;
/*
* ITU-R BT.601 encoding coefficients (inverse), with the
* 255/224 limited range multiplier already included in the
* factors for su (Cb) and sv (Cr).
*/
color_out.r = Y + 1.59602678 * sv;
color_out.g = Y - 0.39176229 * su - 0.81296764 * sv;
color_out.b = Y + 2.01723214 * su;
color_out.a = yuva.w;
return color_out;
}
#if DEF_VARIANT == SHADER_VARIANT_EXTERNAL
uniform samplerExternalOES tex;
#else
uniform sampler2D tex;
#endif
varying vec2 v_texcoord;
uniform sampler2D tex1;
uniform sampler2D tex2;
uniform float alpha;
uniform vec4 unicolor;
uniform HIGHPRECISION sampler2D color_pre_curve_lut_2d;
uniform HIGHPRECISION vec2 color_pre_curve_lut_scale_offset;
#if DEF_COLOR_MAPPING == SHADER_COLOR_MAPPING_3DLUT
uniform HIGHPRECISION sampler3D color_mapping_lut_3d;
uniform HIGHPRECISION vec2 color_mapping_lut_scale_offset;
#endif
vec4
sample_input_texture()
{
vec4 yuva = vec4(0.0, 0.0, 0.0, 1.0);
/* Producing RGBA directly */
if (c_variant == SHADER_VARIANT_SOLID)
return unicolor;
if (c_variant == SHADER_VARIANT_RGBA ||
c_variant == SHADER_VARIANT_EXTERNAL) {
return texture2D(tex, v_texcoord);
}
if (c_variant == SHADER_VARIANT_RGBX)
return vec4(texture2D(tex, v_texcoord).rgb, 1.0);
/* Requires conversion to RGBA */
if (c_variant == SHADER_VARIANT_Y_U_V) {
yuva.x = texture2D(tex, v_texcoord).x;
yuva.y = texture2D(tex1, v_texcoord).x;
yuva.z = texture2D(tex2, v_texcoord).x;
} else if (c_variant == SHADER_VARIANT_Y_UV) {
yuva.x = texture2D(tex, v_texcoord).x;
yuva.yz = texture2D(tex1, v_texcoord).rg;
} else if (c_variant == SHADER_VARIANT_Y_XUXV) {
yuva.x = texture2D(tex, v_texcoord).x;
yuva.yz = texture2D(tex1, v_texcoord).ga;
} else if (c_variant == SHADER_VARIANT_XYUV) {
yuva.xyz = texture2D(tex, v_texcoord).bgr;
} else {
/* Never reached, bad variant value. */
return vec4(1.0, 0.3, 1.0, 1.0);
}
return yuva2rgba(yuva);
}
/*
* Texture coordinates go from 0.0 to 1.0 corresponding to texture edges.
* When we do LUT look-ups with linear filtering, the correct range to sample
* from is not from edge to edge, but center of first texel to center of last
* texel. This follows because with LUTs, you have the exact end points given,
* you never extrapolate but only interpolate.
* The scale and offset are precomputed to achieve this mapping.
*/
float
lut_texcoord(float x, vec2 scale_offset)
{
return x * scale_offset.s + scale_offset.t;
}
vec3
lut_texcoord(vec3 pos, vec2 scale_offset)
{
return pos * scale_offset.s + scale_offset.t;
}
/*
* Sample a 1D LUT which is a single row of a 2D texture. The 2D texture has
* four rows so that the centers of texels have precise y-coordinates.
*/
float
sample_color_pre_curve_lut_2d(float x, compile_const int row)
{
float tx = lut_texcoord(x, color_pre_curve_lut_scale_offset);
return texture2D(color_pre_curve_lut_2d,
vec2(tx, (float(row) + 0.5) / 4.0)).x;
}
vec3
color_pre_curve(vec3 color)
{
vec3 ret;
if (c_color_pre_curve == SHADER_COLOR_CURVE_IDENTITY) {
return color;
} else if (c_color_pre_curve == SHADER_COLOR_CURVE_LUT_3x1D) {
ret.r = sample_color_pre_curve_lut_2d(color.r, 0);
ret.g = sample_color_pre_curve_lut_2d(color.g, 1);
ret.b = sample_color_pre_curve_lut_2d(color.b, 2);
return ret;
} else {
/* Never reached, bad c_color_pre_curve. */
return vec3(1.0, 0.3, 1.0);
}
}
vec3
sample_color_mapping_lut_3d(vec3 color)
{
vec3 pos, ret = vec3(0.0, 0.0, 0.0);
#if DEF_COLOR_MAPPING == SHADER_COLOR_MAPPING_3DLUT
pos = lut_texcoord(color, color_mapping_lut_scale_offset);
ret = texture3D(color_mapping_lut_3d, pos).rgb;
#endif
return ret;
}
vec3
color_mapping(vec3 color)
{
if (c_color_mapping == SHADER_COLOR_MAPPING_IDENTITY)
return color;
else if (c_color_mapping == SHADER_COLOR_MAPPING_3DLUT)
return sample_color_mapping_lut_3d(color);
else /* Never reached, bad c_color_mapping. */
return vec3(1.0, 0.3, 1.0);
}
vec4
color_pipeline(vec4 color)
{
/* View alpha (opacity) */
color.a *= alpha;
color.rgb = color_pre_curve(color.rgb);
color.rgb = color_mapping(color.rgb);
return color;
}
void
main()
{
vec4 color;
/* Electrical (non-linear) RGBA values, may be premult or not */
color = sample_input_texture();
/* Ensure straight alpha */
if (c_input_is_premult) {
if (color.a == 0.0)
color.rgb = vec3(0, 0, 0);
else
color.rgb *= 1.0 / color.a;
}
color = color_pipeline(color);
/* pre-multiply for blending */
color.rgb *= color.a;
if (c_green_tint)
color = vec4(0.0, 0.3, 0.0, 0.2) + color * 0.8;
gl_FragColor = color;
}