three.js/examples/js/shaders/SAOShader.js

( function () {

	/**
 * TODO
 */

	var SAOShader = {
		defines: {
			'NUM_SAMPLES': 7,
			'NUM_RINGS': 4,
			'NORMAL_TEXTURE': 0,
			'DIFFUSE_TEXTURE': 0,
			'DEPTH_PACKING': 1,
			'PERSPECTIVE_CAMERA': 1
		},
		uniforms: {
			'tDepth': {
				value: null
			},
			'tDiffuse': {
				value: null
			},
			'tNormal': {
				value: null
			},
			'size': {
				value: new THREE.Vector2( 512, 512 )
			},
			'cameraNear': {
				value: 1
			},
			'cameraFar': {
				value: 100
			},
			'cameraProjectionMatrix': {
				value: new THREE.Matrix4()
			},
			'cameraInverseProjectionMatrix': {
				value: new THREE.Matrix4()
			},
			'scale': {
				value: 1.0
			},
			'intensity': {
				value: 0.1
			},
			'bias': {
				value: 0.5
			},
			'minResolution': {
				value: 0.0
			},
			'kernelRadius': {
				value: 100.0
			},
			'randomSeed': {
				value: 0.0
			}
		},
		vertexShader: [ 'varying vec2 vUv;', 'void main() {', '	vUv = uv;', '	gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );', '}' ].join( '\n' ),
		fragmentShader: [ '#include <common>', 'varying vec2 vUv;', '#if DIFFUSE_TEXTURE == 1', 'uniform sampler2D tDiffuse;', '#endif', 'uniform sampler2D tDepth;', '#if NORMAL_TEXTURE == 1', 'uniform sampler2D tNormal;', '#endif', 'uniform float cameraNear;', 'uniform float cameraFar;', 'uniform mat4 cameraProjectionMatrix;', 'uniform mat4 cameraInverseProjectionMatrix;', 'uniform float scale;', 'uniform float intensity;', 'uniform float bias;', 'uniform float kernelRadius;', 'uniform float minResolution;', 'uniform vec2 size;', 'uniform float randomSeed;', '// RGBA depth', '#include <packing>', 'vec4 getDefaultColor( const in vec2 screenPosition ) {', '	#if DIFFUSE_TEXTURE == 1', '	return texture2D( tDiffuse, vUv );', '	#else', '	return vec4( 1.0 );', '	#endif', '}', 'float getDepth( const in vec2 screenPosition ) {', '	#if DEPTH_PACKING == 1', '	return unpackRGBAToDepth( texture2D( tDepth, screenPosition ) );', '	#else', '	return texture2D( tDepth, screenPosition ).x;', '	#endif', '}', 'float getViewZ( const in float depth ) {', '	#if PERSPECTIVE_CAMERA == 1', '	return perspectiveDepthToViewZ( depth, cameraNear, cameraFar );', '	#else', '	return orthographicDepthToViewZ( depth, cameraNear, cameraFar );', '	#endif', '}', 'vec3 getViewPosition( const in vec2 screenPosition, const in float depth, const in float viewZ ) {', '	float clipW = cameraProjectionMatrix[2][3] * viewZ + cameraProjectionMatrix[3][3];', '	vec4 clipPosition = vec4( ( vec3( screenPosition, depth ) - 0.5 ) * 2.0, 1.0 );', '	clipPosition *= clipW; // unprojection.', '	return ( cameraInverseProjectionMatrix * clipPosition ).xyz;', '}', 'vec3 getViewNormal( const in vec3 viewPosition, const in vec2 screenPosition ) {', '	#if NORMAL_TEXTURE == 1', '	return unpackRGBToNormal( texture2D( tNormal, screenPosition ).xyz );', '	#else', '	return normalize( cross( dFdx( viewPosition ), dFdy( viewPosition ) ) );', '	#endif', '}', 'float scaleDividedByCameraFar;', 'float minResolutionMultipliedByCameraFar;', 'float getOcclusion( const in vec3 centerViewPosition, const in vec3 centerViewNormal, const in vec3 sampleViewPosition ) {', '	vec3 viewDelta = sampleViewPosition - centerViewPosition;', '	float viewDistance = length( viewDelta );', '	float scaledScreenDistance = scaleDividedByCameraFar * viewDistance;', '	return max(0.0, (dot(centerViewNormal, viewDelta) - minResolutionMultipliedByCameraFar) / scaledScreenDistance - bias) / (1.0 + pow2( scaledScreenDistance ) );', '}', '// moving costly divides into consts', 'const float ANGLE_STEP = PI2 * float( NUM_RINGS ) / float( NUM_SAMPLES );', 'const float INV_NUM_SAMPLES = 1.0 / float( NUM_SAMPLES );', 'float getAmbientOcclusion( const in vec3 centerViewPosition ) {', '	// precompute some variables require in getOcclusion.', '	scaleDividedByCameraFar = scale / cameraFar;', '	minResolutionMultipliedByCameraFar = minResolution * cameraFar;', '	vec3 centerViewNormal = getViewNormal( centerViewPosition, vUv );', '	// jsfiddle that shows sample pattern: https://jsfiddle.net/a16ff1p7/', '	float angle = rand( vUv + randomSeed ) * PI2;', '	vec2 radius = vec2( kernelRadius * INV_NUM_SAMPLES ) / size;', '	vec2 radiusStep = radius;', '	float occlusionSum = 0.0;', '	float weightSum = 0.0;', '	for( int i = 0; i < NUM_SAMPLES; i ++ ) {', '		vec2 sampleUv = vUv + vec2( cos( angle ), sin( angle ) ) * radius;', '		radius += radiusStep;', '		angle += ANGLE_STEP;', '		float sampleDepth = getDepth( sampleUv );', '		if( sampleDepth >= ( 1.0 - EPSILON ) ) {', '			continue;', '		}', '		float sampleViewZ = getViewZ( sampleDepth );', '		vec3 sampleViewPosition = getViewPosition( sampleUv, sampleDepth, sampleViewZ );', '		occlusionSum += getOcclusion( centerViewPosition, centerViewNormal, sampleViewPosition );', '		weightSum += 1.0;', '	}', '	if( weightSum == 0.0 ) discard;', '	return occlusionSum * ( intensity / weightSum );', '}', 'void main() {', '	float centerDepth = getDepth( vUv );', '	if( centerDepth >= ( 1.0 - EPSILON ) ) {', '		discard;', '	}', '	float centerViewZ = getViewZ( centerDepth );', '	vec3 viewPosition = getViewPosition( vUv, centerDepth, centerViewZ );', '	float ambientOcclusion = getAmbientOcclusion( viewPosition );', '	gl_FragColor = getDefaultColor( vUv );', '	gl_FragColor.xyz *=	1.0 - ambientOcclusion;', '}' ].join( '\n' )
	};

	THREE.SAOShader = SAOShader;

} )();