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https://github.com/Doodle3D/Doodle3D-Slicer.git
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102 lines
1.9 KiB
JavaScript
Executable File
102 lines
1.9 KiB
JavaScript
Executable File
/**
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* @author alteredq / http://alteredqualia.com/
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*
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* Convolution shader
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* ported from o3d sample to WebGL / GLSL
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* http://o3d.googlecode.com/svn/trunk/samples/convolution.html
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*/
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THREE.ConvolutionShader = {
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defines: {
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"KERNEL_SIZE_FLOAT": "25.0",
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"KERNEL_SIZE_INT": "25",
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},
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uniforms: {
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"tDiffuse": { type: "t", value: null },
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"uImageIncrement": { type: "v2", value: new THREE.Vector2( 0.001953125, 0.0 ) },
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"cKernel": { type: "fv1", value: [] }
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},
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vertexShader: [
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"uniform vec2 uImageIncrement;",
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"varying vec2 vUv;",
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"void main() {",
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"vUv = uv - ( ( KERNEL_SIZE_FLOAT - 1.0 ) / 2.0 ) * uImageIncrement;",
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"gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );",
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"}"
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].join("\n"),
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fragmentShader: [
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"uniform float cKernel[ KERNEL_SIZE_INT ];",
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"uniform sampler2D tDiffuse;",
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"uniform vec2 uImageIncrement;",
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"varying vec2 vUv;",
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"void main() {",
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"vec2 imageCoord = vUv;",
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"vec4 sum = vec4( 0.0, 0.0, 0.0, 0.0 );",
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"for( int i = 0; i < KERNEL_SIZE_INT; i ++ ) {",
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"sum += texture2D( tDiffuse, imageCoord ) * cKernel[ i ];",
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"imageCoord += uImageIncrement;",
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"}",
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"gl_FragColor = sum;",
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"}"
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].join("\n"),
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buildKernel: function ( sigma ) {
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// We lop off the sqrt(2 * pi) * sigma term, since we're going to normalize anyway.
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function gauss( x, sigma ) {
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return Math.exp( - ( x * x ) / ( 2.0 * sigma * sigma ) );
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}
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var i, values, sum, halfWidth, kMaxKernelSize = 25, kernelSize = 2 * Math.ceil( sigma * 3.0 ) + 1;
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if ( kernelSize > kMaxKernelSize ) kernelSize = kMaxKernelSize;
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halfWidth = ( kernelSize - 1 ) * 0.5;
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values = new Array( kernelSize );
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sum = 0.0;
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for ( i = 0; i < kernelSize; ++ i ) {
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values[ i ] = gauss( i - halfWidth, sigma );
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sum += values[ i ];
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}
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// normalize the kernel
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for ( i = 0; i < kernelSize; ++ i ) values[ i ] /= sum;
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return values;
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}
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};
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