weston/libweston/renderer-gl/fragment.glsl
Pekka Paalanen 477bdc85c9 gl-renderer: rewrite fragment shaders
The main goal of this patch is to improve the readability of how and
what fragment shaders are generated.

Instead of having C code that assembles each shader variant from literal
string snippets, create one big fragment shader source that has
everything in it. This relies on a GLSL compiler to optimize statically
false conditions and unused uniforms away.

Having all the fragment shader code in one file, uncluttered by C string
literal syntax, improves readability significantly. A disadvantage is
that the code is more verbose, but it allows comments much better.

The actual shader code is kept unchanged except:
- FRAGMENT_CONVERT_YUV macro is now a proper function
- GLSL version is explicitly set to 1.00 ES
- RGBA and EXTERNAL use the same path, the difference is how the sampler
  is declared

Further shader code consolidation is possible, but is left for another
time.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>
2021-02-25 13:16:02 +02:00

131 lines
3.8 KiB
GLSL

/*
* Copyright 2012 Intel Corporation
* Copyright 2015,2019 Collabora, Ltd.
* Copyright 2016 NVIDIA Corporation
*
* 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 */
/*
* Enumeration of shader variants.
*/
#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
#if DEF_VARIANT == SHADER_VARIANT_EXTERNAL
#extension GL_OES_EGL_image_external : require
#endif
precision mediump float;
/*
* These undeclared identifiers will be #defined by a runtime generated code
* snippet.
*/
const int c_variant = DEF_VARIANT;
const bool c_debug = DEF_DEBUG;
vec4
yuva2rgba(float y, float u, float v, float a)
{
vec4 color_out;
y *= a;
u *= a;
v *= a;
color_out.r = y + 1.59602678 * v;
color_out.g = y - 0.39176229 * u - 0.81296764 * v;
color_out.b = y + 2.01723214 * u;
color_out.a = a;
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 color;
void
main()
{
float y, u, v;
if (c_variant == SHADER_VARIANT_RGBA ||
c_variant == SHADER_VARIANT_EXTERNAL) {
gl_FragColor = alpha * texture2D(tex, v_texcoord);
} else if (c_variant == SHADER_VARIANT_RGBX) {
gl_FragColor.rgb = alpha * texture2D(tex, v_texcoord).rgb;
gl_FragColor.a = alpha;
} else if (c_variant == SHADER_VARIANT_Y_U_V) {
y = 1.16438356 * (texture2D(tex, v_texcoord).x - 0.0625);
u = texture2D(tex1, v_texcoord).x - 0.5;
v = texture2D(tex2, v_texcoord).x - 0.5;
gl_FragColor = yuva2rgba(y, u, v, alpha);
} else if (c_variant == SHADER_VARIANT_Y_UV) {
y = 1.16438356 * (texture2D(tex, v_texcoord).x - 0.0625);
u = texture2D(tex1, v_texcoord).r - 0.5;
v = texture2D(tex1, v_texcoord).g - 0.5;
gl_FragColor = yuva2rgba(y, u, v, alpha);
} else if (c_variant == SHADER_VARIANT_Y_XUXV) {
y = 1.16438356 * (texture2D(tex, v_texcoord).x - 0.0625);
u = texture2D(tex1, v_texcoord).g - 0.5;
v = texture2D(tex1, v_texcoord).a - 0.5;
gl_FragColor = yuva2rgba(y, u, v, alpha);
} else if (c_variant == SHADER_VARIANT_XYUV) {
y = 1.16438356 * (texture2D(tex, v_texcoord).b - 0.0625);
u = texture2D(tex, v_texcoord).g - 0.5;
v = texture2D(tex, v_texcoord).r - 0.5;
gl_FragColor = yuva2rgba(y, u, v, alpha);
} else if (c_variant == SHADER_VARIANT_SOLID) {
gl_FragColor = alpha * color;
} else {
/* Never reached, bad variant value. */
gl_FragColor = vec4(1.0, 0.3, 1.0, 1.0);
}
if (c_debug)
gl_FragColor = vec4(0.0, 0.3, 0.0, 0.2) + gl_FragColor * 0.8;
}