bsnes/shaders/Pixellate.OpenGL.shader

45 lines
1.8 KiB
GLSL

<?xml version="1.0" encoding="UTF-8"?>
<shader language="GLSL">
<vertex><![CDATA[
void main() {
gl_Position = ftransform();
gl_TexCoord[0] = gl_MultiTexCoord0;
}
]]></vertex>
<fragment filter="nearest"><![CDATA[
uniform sampler2D rubyTexture;
uniform vec2 rubyTextureSize;
void main() {
vec2 texelSize = 1.0 / rubyTextureSize;
vec2 range;
range.x = dFdx(gl_TexCoord[0].x) / 2.0 * 0.99;
range.y = dFdy(gl_TexCoord[0].y) / 2.0 * 0.99;
float left = gl_TexCoord[0].x - range.x;
float top = gl_TexCoord[0].y + range.y;
float right = gl_TexCoord[0].x + range.x;
float bottom = gl_TexCoord[0].y - range.y;
vec4 topLeftColor = texture2D(rubyTexture, (floor(vec2(left, top) / texelSize) + 0.5) * texelSize);
vec4 bottomRightColor = texture2D(rubyTexture, (floor(vec2(right, bottom) / texelSize) + 0.5) * texelSize);
vec4 bottomLeftColor = texture2D(rubyTexture, (floor(vec2(left, bottom) / texelSize) + 0.5) * texelSize);
vec4 topRightColor = texture2D(rubyTexture, (floor(vec2(right, top) / texelSize) + 0.5) * texelSize);
vec2 border = clamp(round(gl_TexCoord[0] / texelSize) * texelSize, vec2(left, bottom), vec2(right, top));
float totalArea = 4.0 * range.x * range.y;
vec4 averageColor;
averageColor = ((border.x - left) * (top - border.y) / totalArea) * topLeftColor;
averageColor += ((right - border.x) * (border.y - bottom) / totalArea) * bottomRightColor;
averageColor += ((border.x - left) * (border.y - bottom) / totalArea) * bottomLeftColor;
averageColor += ((right - border.x) * (top - border.y) / totalArea) * topRightColor;
gl_FragColor = averageColor;
}
]]></fragment>
</shader>