38 lines
1.0 KiB
GLSL
38 lines
1.0 KiB
GLSL
in vec2 v_texCoord0;
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uniform sampler2D tex0;
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uniform int maxSteps;
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uniform int step;
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out vec4 o_color;
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void main() {
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float stepwidth = 1.0 / pow(2.0, min(float(maxSteps), float(step+1)));
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float bestDistance = 1E10;
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vec2 bestCoord = vec2(-100.0);
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vec2 bestColor = vec2(-1.0);
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vec2 is = vec2(1.0) / vec2(textureSize(tex0, 0));
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float found = 0.0;
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for (int y = -1; y <= 1; ++y) {
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for (int x = -1; x <= 1; ++x) {
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vec2 sampleCoord = v_texCoord0 + vec2(stepwidth) * vec2(x,y);
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vec4 data = texture( tex0, sampleCoord);
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vec2 seedCoord = data.xy;
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vec2 seedColor = data.zw;
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float dist = length(seedCoord - v_texCoord0);
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if ((seedCoord.x >= 0.0 && seedCoord.y >= 0.0) && dist <= bestDistance)
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{
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found = 1.0;
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bestDistance = dist;
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bestCoord = seedCoord;
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bestColor = seedColor;
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}
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}
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}
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o_color = vec4(bestCoord, bestColor.r, 1.0);
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} |