// Adapted from
// https://www.geeks3d.com/20110405/fxaa-fast-approximate-anti-aliasing-demo-glsl-opengl-test-radeon-geforce/3/
#version 460
#ifdef VULKAN
#define BINDING_COLOR_TEXTURE 1
#else // ^^^ Vulkan ^^^ // vvv OpenGL vvv
#define BINDING_COLOR_TEXTURE 0
#endif
layout (location = 0) in vec4 posPos;
layout (location = 0) out vec4 frag_color;
layout (binding = BINDING_COLOR_TEXTURE) uniform sampler2D input_texture;
const float FXAA_SPAN_MAX = 8.0;
const float FXAA_REDUCE_MUL = 1.0 / 8.0;
const float FXAA_REDUCE_MIN = 1.0 / 128.0;
#define FxaaTexLod0(t, p) textureLod(t, p, 0.0)
#define FxaaTexOff(t, p, o) textureLodOffset(t, p, 0.0, o)
vec3 FxaaPixelShader(vec4 posPos, sampler2D tex) {
vec3 rgbNW = FxaaTexLod0(tex, posPos.zw).xyz;
vec3 rgbNE = FxaaTexOff(tex, posPos.zw, ivec2(1,0)).xyz;
vec3 rgbSW = FxaaTexOff(tex, posPos.zw, ivec2(0,1)).xyz;
vec3 rgbSE = FxaaTexOff(tex, posPos.zw, ivec2(1,1)).xyz;
vec3 rgbM = FxaaTexLod0(tex, posPos.xy).xyz;
/*---------------------------------------------------------*/
vec3 luma = vec3(0.299, 0.587, 0.114);
float lumaNW = dot(rgbNW, luma);
float lumaNE = dot(rgbNE, luma);
float lumaSW = dot(rgbSW, luma);
float lumaSE = dot(rgbSE, luma);
float lumaM = dot(rgbM, luma);
/*---------------------------------------------------------*/
float lumaMin = min(lumaM, min(min(lumaNW, lumaNE), min(lumaSW, lumaSE)));
float lumaMax = max(lumaM, max(max(lumaNW, lumaNE), max(lumaSW, lumaSE)));
/*---------------------------------------------------------*/
vec2 dir;
dir.x = -((lumaNW + lumaNE) - (lumaSW + lumaSE));
dir.y = ((lumaNW + lumaSW) - (lumaNE + lumaSE));
/*---------------------------------------------------------*/
float dirReduce = max(
(lumaNW + lumaNE + lumaSW + lumaSE) * (0.25 * FXAA_REDUCE_MUL),
FXAA_REDUCE_MIN);
float rcpDirMin = 1.0/(min(abs(dir.x), abs(dir.y)) + dirReduce);
dir = min(vec2( FXAA_SPAN_MAX, FXAA_SPAN_MAX),
max(vec2(-FXAA_SPAN_MAX, -FXAA_SPAN_MAX),
dir * rcpDirMin)) / textureSize(tex, 0);
/*--------------------------------------------------------*/
vec3 rgbA = (1.0 / 2.0) * (
FxaaTexLod0(tex, posPos.xy + dir * (1.0 / 3.0 - 0.5)).xyz +
FxaaTexLod0(tex, posPos.xy + dir * (2.0 / 3.0 - 0.5)).xyz);
vec3 rgbB = rgbA * (1.0 / 2.0) + (1.0 / 4.0) * (
FxaaTexLod0(tex, posPos.xy + dir * (0.0 / 3.0 - 0.5)).xyz +
FxaaTexLod0(tex, posPos.xy + dir * (3.0 / 3.0 - 0.5)).xyz);
float lumaB = dot(rgbB, luma);
if((lumaB < lumaMin) || (lumaB > lumaMax)) return rgbA;
return rgbB;
}
void main() {
frag_color = vec4(FxaaPixelShader(posPos, input_texture), 1.0);
}
