//This file is automatically rebuilt by the Cesium build process.
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export default "#define SAMPLES 8\n\
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\n\
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uniform float delta;\n\
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uniform float sigma;\n\
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uniform float direction; // 0.0 for x direction, 1.0 for y direction\n\
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\n\
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uniform sampler2D colorTexture;\n\
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\n\
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#ifdef USE_STEP_SIZE\n\
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uniform float stepSize;\n\
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#else\n\
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uniform vec2 step;\n\
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#endif\n\
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\n\
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varying vec2 v_textureCoordinates;\n\
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\n\
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// Incremental Computation of the Gaussian:\n\
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// https://developer.nvidia.com/gpugems/GPUGems3/gpugems3_ch40.html\n\
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\n\
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void main()\n\
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{\n\
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vec2 st = v_textureCoordinates;\n\
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vec2 dir = vec2(1.0 - direction, direction);\n\
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\n\
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#ifdef USE_STEP_SIZE\n\
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vec2 step = vec2(stepSize * (czm_pixelRatio / czm_viewport.zw));\n\
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#else\n\
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vec2 step = step;\n\
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#endif\n\
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\n\
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vec3 g;\n\
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g.x = 1.0 / (sqrt(czm_twoPi) * sigma);\n\
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g.y = exp((-0.5 * delta * delta) / (sigma * sigma));\n\
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g.z = g.y * g.y;\n\
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\n\
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vec4 result = texture2D(colorTexture, st) * g.x;\n\
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for (int i = 1; i < SAMPLES; ++i)\n\
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{\n\
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g.xy *= g.yz;\n\
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\n\
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vec2 offset = float(i) * dir * step;\n\
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result += texture2D(colorTexture, st - offset) * g.x;\n\
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result += texture2D(colorTexture, st + offset) * g.x;\n\
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}\n\
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\n\
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gl_FragColor = result;\n\
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}\n\
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";
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