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6 months ago
import {
Matrix4,
Vector2
} from 'three';
/**
* TODO
*/
const SAOShader = {
name: 'SAOShader',
defines: {
'NUM_SAMPLES': 7,
'NUM_RINGS': 4,
'DIFFUSE_TEXTURE': 0,
'PERSPECTIVE_CAMERA': 1
},
uniforms: {
'tDepth': { value: null },
'tDiffuse': { value: null },
'tNormal': { value: null },
'size': { value: new Vector2( 512, 512 ) },
'cameraNear': { value: 1 },
'cameraFar': { value: 100 },
'cameraProjectionMatrix': { value: new Matrix4() },
'cameraInverseProjectionMatrix': { value: new 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: /* glsl */`
varying vec2 vUv;
void main() {
vUv = uv;
gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );
}`,
fragmentShader: /* glsl */`
#include <common>
varying vec2 vUv;
#if DIFFUSE_TEXTURE == 1
uniform sampler2D tDiffuse;
#endif
uniform highp sampler2D tDepth;
uniform highp sampler2D tNormal;
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 ) {
return texture2D( tDepth, screenPosition ).x;
}
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 ) {
return unpackRGBToNormal( texture2D( tNormal, screenPosition ).xyz );
}
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;
}`
};
export { SAOShader };