go-opengl-pixel/examples/shaders/raycaster/fxaa-fs.glsl

63 lines
2.2 KiB
GLSL

#version 330 core
in vec2 texcoords;
uniform vec4 u_texbounds;
uniform sampler2D u_texture;
uniform vec2 u_resolution;
uniform float u_amount;
uniform float u_time;
uniform vec2 u_mouse;
out vec4 fragColor;
#define FXAA_REDUCE_MIN (1.0/128.0)
#define FXAA_REDUCE_MUL (1.0/8.0)
#define FXAA_SPAN_MAX 8.0
void main() {
vec2 uv = (texcoords - u_texbounds.xy) / u_texbounds.zw;
vec2 res = 1. / u_resolution;
vec3 rgbNW = texture( u_texture, ( uv.xy + vec2( -1.0, -1.0 ) * res ) ).xyz;
vec3 rgbNE = texture( u_texture, ( uv.xy + vec2( 1.0, -1.0 ) * res ) ).xyz;
vec3 rgbSW = texture( u_texture, ( uv.xy + vec2( -1.0, 1.0 ) * res ) ).xyz;
vec3 rgbSE = texture( u_texture, ( uv.xy + vec2( 1.0, 1.0 ) * res ) ).xyz;
vec4 rgbaM = texture( u_texture, uv.xy * res );
vec3 rgbM = rgbaM.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)) * res;
vec4 rgbA = (1.0/2.0) * (
texture(u_texture, uv.xy + dir * (1.0/3.0 - 0.5)) +
texture(u_texture, uv.xy + dir * (2.0/3.0 - 0.5)));
vec4 rgbB = rgbA * (1.0/2.0) + (1.0/4.0) * (
texture(u_texture, uv.xy + dir * (0.0/3.0 - 0.5)) +
texture(u_texture, uv.xy + dir * (3.0/3.0 - 0.5)));
float lumaB = dot(rgbB, vec4(luma, 0.0));
if ( ( lumaB < lumaMin ) || ( lumaB > lumaMax ) ) {
fragColor = rgbA;
} else {
fragColor = rgbB;
}
//fragColor = vec4( texture( u_texture,uv ).xyz, 1. );
}