/**
* @author alteredq / http://alteredqualia.com/
*
* Screen-space ambient occlusion shader
* - ported from
* SSAO GLSL shader v1.2
* assembled by Martins Upitis (martinsh) (http://devlog-martinsh.blogspot.com)
* original technique is made by ArKano22 (http://www.gamedev.net/topic/550699-ssao-no-halo-artifacts/)
* - modifications
* - modified to use RGBA packed depth texture (use clear color 1,1,1,1 for depth pass)
* - refactoring and optimizations
*/
THREE.SSAOShader = {
uniforms: {
"tDiffuse": { value: null },
"tDepth": { value: null },
"size": { value: new THREE.Vector2( 512, 512 ) },
"cameraNear": { value: 1 },
"cameraFar": { value: 100 },
"radius": { value: 32 },
"onlyAO": { value: 0 },
"aoClamp": { value: 0.25 },
"lumInfluence": { value: 0.7 }
},
vertexShader: [
"varying vec2 vUv;",
"void main() {",
"vUv = uv;",
"gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );",
"}"
].join( "\n" ),
fragmentShader: [
"uniform float cameraNear;",
"uniform float cameraFar;",
"#ifdef USE_LOGDEPTHBUF",
"uniform float logDepthBufFC;",
"#endif",
"uniform float radius;", // ao radius
"uniform bool onlyAO;", // use only ambient occlusion pass?
"uniform vec2 size;", // texture width, height
"uniform float aoClamp;", // depth clamp - reduces haloing at screen edges
"uniform float lumInfluence;", // how much luminance affects occlusion
"uniform sampler2D tDiffuse;",
"uniform sampler2D tDepth;",
"varying vec2 vUv;",
// "#define PI 3.14159265",
"#define DL 2.399963229728653", // PI * ( 3.0 - sqrt( 5.0 ) )
"#define EULER 2.718281828459045",
// user variables
"const int samples = 64;", // ao sample count
"const bool useNoise = true;", // use noise instead of pattern for sample dithering
"const float noiseAmount = 0.0004;", // dithering amount
"const float diffArea = 0.4;", // self-shadowing reduction
"const float gDisplace = 0.4;", // gauss bell center
// RGBA depth
"#include <packing>",
// generating noise / pattern texture for dithering
"vec2 rand( const vec2 coord ) {",
"vec2 noise;",
"if ( useNoise ) {",
"float nx = dot ( coord, vec2( 12.9898, 78.233 ) );",
"float ny = dot ( coord, vec2( 12.9898, 78.233 ) * 2.0 );",
"noise = clamp( fract ( 43758.5453 * sin( vec2( nx, ny ) ) ), 0.0, 1.0 );",
"} else {",
"float ff = fract( 1.0 - coord.s * ( size.x / 2.0 ) );",
"float gg = fract( coord.t * ( size.y / 2.0 ) );",
"noise = vec2( 0.25, 0.75 ) * vec2( ff ) + vec2( 0.75, 0.25 ) * gg;",
"}",
"return ( noise * 2.0 - 1.0 ) * noiseAmount;",
"}",
"float readDepth( const in vec2 coord ) {",
"float cameraFarPlusNear = cameraFar + cameraNear;",
"float cameraFarMinusNear = cameraFar - cameraNear;",
"float cameraCoef = 2.0 * cameraNear;",
"#ifdef USE_LOGDEPTHBUF",
"float logz = unpackRGBAToDepth( texture2D( tDepth, coord ) );",
"float w = pow(2.0, (logz / logDepthBufFC)) - 1.0;",
"float z = (logz / w) + 1.0;",
"#else",
"float z = unpackRGBAToDepth( texture2D( tDepth, coord ) );",
"#endif",
"return cameraCoef / ( cameraFarPlusNear - z * cameraFarMinusNear );",
"}",
"float compareDepths( const in float depth1, const in float depth2, inout int far ) {",
"float garea = 8.0;", // gauss bell width
"float diff = ( depth1 - depth2 ) * 100.0;", // depth difference (0-100)
// reduce left bell width to avoid self-shadowing
"if ( diff < gDisplace ) {",
"garea = diffArea;",
"} else {",
"far = 1;",
"}",
"float dd = diff - gDisplace;",
"float gauss = pow( EULER, -2.0 * ( dd * dd ) / ( garea * garea ) );",
"return gauss;",
"}",
"float calcAO( float depth, float dw, float dh ) {",
"vec2 vv = vec2( dw, dh );",
"vec2 coord1 = vUv + radius * vv;",
"vec2 coord2 = vUv - radius * vv;",
"float temp1 = 0.0;",
"float temp2 = 0.0;",
"int far = 0;",
"temp1 = compareDepths( depth, readDepth( coord1 ), far );",
// DEPTH EXTRAPOLATION
"if ( far > 0 ) {",
"temp2 = compareDepths( readDepth( coord2 ), depth, far );",
"temp1 += ( 1.0 - temp1 ) * temp2;",
"}",
"return temp1;",
"}",
"void main() {",
"vec2 noise = rand( vUv );",
"float depth = readDepth( vUv );",
"float tt = clamp( depth, aoClamp, 1.0 );",
"float w = ( 1.0 / size.x ) / tt + ( noise.x * ( 1.0 - noise.x ) );",
"float h = ( 1.0 / size.y ) / tt + ( noise.y * ( 1.0 - noise.y ) );",
"float ao = 0.0;",
"float dz = 1.0 / float( samples );",
"float l = 0.0;",
"float z = 1.0 - dz / 2.0;",
"for ( int i = 0; i <= samples; i ++ ) {",
"float r = sqrt( 1.0 - z );",
"float pw = cos( l ) * r;",
"float ph = sin( l ) * r;",
"ao += calcAO( depth, pw * w, ph * h );",
"z = z - dz;",
"l = l + DL;",
"}",
"ao /= float( samples );",
"ao = 1.0 - ao;",
"vec3 color = texture2D( tDiffuse, vUv ).rgb;",
"vec3 lumcoeff = vec3( 0.299, 0.587, 0.114 );",
"float lum = dot( color.rgb, lumcoeff );",
"vec3 luminance = vec3( lum );",
"vec3 final = vec3( color * mix( vec3( ao ), vec3( 1.0 ), luminance * lumInfluence ) );", // mix( color * ao, white, luminance )
"if ( onlyAO ) {",
"final = vec3( mix( vec3( ao ), vec3( 1.0 ), luminance * lumInfluence ) );", // ambient occlusion only
"}",
"gl_FragColor = vec4( final, 1.0 );",
"}"
].join( "\n" )
};
