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https://github.com/DanielnetoDotCom/YouPHPTube
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99 lines
1.8 KiB
JavaScript
99 lines
1.8 KiB
JavaScript
/**
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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': { value: null },
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'uImageIncrement': { value: new THREE.Vector2( 0.001953125, 0.0 ) },
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'cKernel': { 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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