Doodle3D-Slicer/three.js-master/examples/js/shaders/ParallaxShader.js
2015-06-12 15:58:26 +02:00

183 lines
5.1 KiB
JavaScript
Executable File

// Parallax Occlusion shaders from
// http://sunandblackcat.com/tipFullView.php?topicid=28
// No tangent-space transforms logic based on
// http://mmikkelsen3d.blogspot.sk/2012/02/parallaxpoc-mapping-and-no-tangent.html
THREE.ParallaxShader = {
// Ordered from fastest to best quality.
modes: {
none: 'NO_PARALLAX',
basic: 'USE_BASIC_PARALLAX',
steep: 'USE_STEEP_PARALLAX',
occlusion: 'USE_OCLUSION_PARALLAX', // a.k.a. POM
relief: 'USE_RELIEF_PARALLAX',
},
uniforms: {
"bumpMap": { type: "t", value: null },
"map": { type: "t", value: null },
"parallaxScale": { type: "f", value: null },
"parallaxMinLayers": { type: "f", value: null },
"parallaxMaxLayers": { type: "f", value: null }
},
vertexShader: [
"varying vec2 vUv;",
"varying vec3 vViewPosition;",
"varying vec3 vNormal;",
"void main() {",
"vUv = uv;",
"vec4 mvPosition = modelViewMatrix * vec4( position, 1.0 );",
"vViewPosition = -mvPosition.xyz;",
"vNormal = normalize( normalMatrix * normal );",
"gl_Position = projectionMatrix * mvPosition;",
"}"
].join( "\n" ),
fragmentShader: [
"uniform sampler2D bumpMap;",
"uniform sampler2D map;",
"uniform float parallaxScale;",
"uniform float parallaxMinLayers;",
"uniform float parallaxMaxLayers;",
"varying vec2 vUv;",
"varying vec3 vViewPosition;",
"varying vec3 vNormal;",
"#ifdef USE_BASIC_PARALLAX",
"vec2 parallaxMap( in vec3 V ) {",
"float initialHeight = texture2D( bumpMap, vUv ).r;",
// No Offset Limitting: messy, floating output at grazing angles.
//"vec2 texCoordOffset = parallaxScale * V.xy / V.z * initialHeight;",
// Offset Limiting
"vec2 texCoordOffset = parallaxScale * V.xy * initialHeight;",
"return vUv - texCoordOffset;",
"}",
"#else",
"vec2 parallaxMap( in vec3 V ) {",
// Determine number of layers from angle between V and N
"float numLayers = mix( parallaxMaxLayers, parallaxMinLayers, abs( dot( vec3( 0.0, 0.0, 1.0 ), V ) ) );",
"float layerHeight = 1.0 / numLayers;",
"float currentLayerHeight = 0.0;",
// Shift of texture coordinates for each iteration
"vec2 dtex = parallaxScale * V.xy / V.z / numLayers;",
"vec2 currentTextureCoords = vUv;",
"float heightFromTexture = texture2D( bumpMap, currentTextureCoords ).r;",
// while ( heightFromTexture > currentLayerHeight )
"for ( int i = 0; i == 0; i += 0 ) {",
"if ( heightFromTexture <= currentLayerHeight ) {",
"break;",
"}",
"currentLayerHeight += layerHeight;",
// Shift texture coordinates along vector V
"currentTextureCoords -= dtex;",
"heightFromTexture = texture2D( bumpMap, currentTextureCoords ).r;",
"}",
"#ifdef USE_STEEP_PARALLAX",
"return currentTextureCoords;",
"#elif defined( USE_RELIEF_PARALLAX )",
"vec2 deltaTexCoord = dtex / 2.0;",
"float deltaHeight = layerHeight / 2.0;",
// Return to the mid point of previous layer
"currentTextureCoords += deltaTexCoord;",
"currentLayerHeight -= deltaHeight;",
// Binary search to increase precision of Steep Parallax Mapping
"const int numSearches = 5;",
"for ( int i = 0; i < numSearches; i += 1 ) {",
"deltaTexCoord /= 2.0;",
"deltaHeight /= 2.0;",
"heightFromTexture = texture2D( bumpMap, currentTextureCoords ).r;",
// Shift along or against vector V
"if( heightFromTexture > currentLayerHeight ) {", // Below the surface
"currentTextureCoords -= deltaTexCoord;",
"currentLayerHeight += deltaHeight;",
"} else {", // above the surface
"currentTextureCoords += deltaTexCoord;",
"currentLayerHeight -= deltaHeight;",
"}",
"}",
"return currentTextureCoords;",
"#elif defined( USE_OCLUSION_PARALLAX )",
"vec2 prevTCoords = currentTextureCoords + dtex;",
// Heights for linear interpolation
"float nextH = heightFromTexture - currentLayerHeight;",
"float prevH = texture2D( bumpMap, prevTCoords ).r - currentLayerHeight + layerHeight;",
// Proportions for linear interpolation
"float weight = nextH / ( nextH - prevH );",
// Interpolation of texture coordinates
"return prevTCoords * weight + currentTextureCoords * ( 1.0 - weight );",
"#else", // NO_PARALLAX
"return vUv;",
"#endif",
"}",
"#endif",
"vec2 perturbUv( vec3 surfPosition, vec3 surfNormal, vec3 viewPosition ) {",
"vec2 texDx = dFdx( vUv );",
"vec2 texDy = dFdy( vUv );",
"vec3 vSigmaX = dFdx( surfPosition );",
"vec3 vSigmaY = dFdy( surfPosition );",
"vec3 vR1 = cross( vSigmaY, surfNormal );",
"vec3 vR2 = cross( surfNormal, vSigmaX );",
"float fDet = dot( vSigmaX, vR1 );",
"vec2 vProjVscr = ( 1.0 / fDet ) * vec2( dot( vR1, viewPosition ), dot( vR2, viewPosition ) );",
"vec3 vProjVtex;",
"vProjVtex.xy = texDx * vProjVscr.x + texDy * vProjVscr.y;",
"vProjVtex.z = dot( surfNormal, viewPosition );",
"return parallaxMap( vProjVtex );",
"}",
"void main() {",
"vec2 mapUv = perturbUv( -vViewPosition, normalize( vNormal ), normalize( vViewPosition ) );",
"gl_FragColor = texture2D( map, mapUv );",
"}",
].join( "\n" )
};