mirror of
https://github.com/Doodle3D/Doodle3D-Slicer.git
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74 lines
1.6 KiB
JavaScript
74 lines
1.6 KiB
JavaScript
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/**
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* @author zz85 / https://github.com/zz85 | https://www.lab4games.net/zz85/blog
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*
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* Edge Detection Shader using Sobel filter
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* Based on http://rastergrid.com/blog/2011/01/frei-chen-edge-detector
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*
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* aspect: vec2 of (1/width, 1/height)
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*/
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THREE.EdgeShader2 = {
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uniforms: {
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"tDiffuse": { type: "t", value: null },
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"aspect": { type: "v2", value: new THREE.Vector2( 512, 512 ) },
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},
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vertexShader: [
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"varying vec2 vUv;",
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"void main() {",
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"vUv = uv;",
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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 sampler2D tDiffuse;",
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"varying vec2 vUv;",
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"uniform vec2 aspect;",
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"vec2 texel = vec2(1.0 / aspect.x, 1.0 / aspect.y);",
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"mat3 G[2];",
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"const mat3 g0 = mat3( 1.0, 2.0, 1.0, 0.0, 0.0, 0.0, -1.0, -2.0, -1.0 );",
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"const mat3 g1 = mat3( 1.0, 0.0, -1.0, 2.0, 0.0, -2.0, 1.0, 0.0, -1.0 );",
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"void main(void)",
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"{",
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"mat3 I;",
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"float cnv[2];",
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"vec3 sample;",
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"G[0] = g0;",
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"G[1] = g1;",
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/* fetch the 3x3 neighbourhood and use the RGB vector's length as intensity value */
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"for (float i=0.0; i<3.0; i++)",
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"for (float j=0.0; j<3.0; j++) {",
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"sample = texture2D( tDiffuse, vUv + texel * vec2(i-1.0,j-1.0) ).rgb;",
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"I[int(i)][int(j)] = length(sample);",
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"}",
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/* calculate the convolution values for all the masks */
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"for (int i=0; i<2; i++) {",
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"float dp3 = dot(G[i][0], I[0]) + dot(G[i][1], I[1]) + dot(G[i][2], I[2]);",
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"cnv[i] = dp3 * dp3; ",
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"}",
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"gl_FragColor = vec4(0.5 * sqrt(cnv[0]*cnv[0]+cnv[1]*cnv[1]));",
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"} ",
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].join("\n")
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};
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