58 lines
1.3 KiB
GLSL
58 lines
1.3 KiB
GLSL
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#ifdef GL_ES
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precision mediump float;
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#endif
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uniform mat3 worldToOutput;
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uniform vec4 outputRect;
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varying vec4 inputRect[1];
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varying mat3 worldToInput[1];
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uniform vec2 center;
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uniform float radius;
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uniform float blur;
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float det(mat3 m) { return m[0][0] * m[1][1] - m[0][1] * m[1][0]; }
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float scale = sqrt(abs(det(worldToOutput)));
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vec2 center_ = (worldToOutput * vec3(center, 1.0)).xy;
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float rad_ = scale * max(radius, 0.0);
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void addPoint(inout vec4 rect, vec2 p) {
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rect.xy = min(rect.xy, p);
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rect.zw = max(rect.zw, p);
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}
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void addBlurredPointBox(inout vec4 rect, vec2 p)
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{
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vec2 v = p - center_;
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float vLength = length(v);
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float dist = max(length(v) - rad_, 0.0);
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float b = blur * dist;
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v *= (b / max(vLength, 0.01));
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addPoint(rect, p - v);
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addPoint(rect, p + v);
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}
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void main( void )
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{
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worldToInput[0] = worldToOutput; // Let the input and output references be the same
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inputRect[0] = outputRect;
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// Add the bounding box of each blurred corner
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addBlurredPointBox(inputRect[0], outputRect.xy);
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addBlurredPointBox(inputRect[0], outputRect.xw);
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addBlurredPointBox(inputRect[0], outputRect.zy);
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addBlurredPointBox(inputRect[0], outputRect.zw);
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gl_Position = vec4(0.0); // Does not link without
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}
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