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425 lines
13 KiB
425 lines
13 KiB
import {
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DataTexture,
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Matrix4,
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RepeatWrapping,
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Vector2,
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Vector3,
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} from 'three';
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/**
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* References:
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* - implemented algorithm - GTAO
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* - https://iryoku.com/downloads/Practical-Realtime-Strategies-for-Accurate-Indirect-Occlusion.pdf
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* - https://github.com/Patapom/GodComplex/blob/master/Tests/TestHBIL/2018%20Mayaux%20-%20Horizon-Based%20Indirect%20Lighting%20(HBIL).pdf
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*
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* - other AO algorithms that are not implemented here:
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* - Screen Space Ambient Occlusion (SSAO), see also SSAOShader.js
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* - http://john-chapman-graphics.blogspot.com/2013/01/ssao-tutorial.html
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* - https://learnopengl.com/Advanced-Lighting/SSAO
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* - https://creativecoding.soe.ucsc.edu/courses/cmpm164/_schedule/AmbientOcclusion.pdf
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* - https://drive.google.com/file/d/1SyagcEVplIm2KkRD3WQYSO9O0Iyi1hfy/edit
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* - Scalable Ambient Occlusion (SAO), see also SAOShader.js
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* - https://casual-effects.com/research/McGuire2012SAO/index.html
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* - https://research.nvidia.com/sites/default/files/pubs/2012-06_Scalable-Ambient-Obscurance/McGuire12SAO.pdf
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* - N8HO
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* - https://github.com/N8python/n8ao
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* - Horizon Based Ambient Occlusion (HBAO)
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* - http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.577.2286&rep=rep1&type=pdf
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* - https://www.derschmale.com/2013/12/20/an-alternative-implementation-for-hbao-2/
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*
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* - further reading
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* - https://ceur-ws.org/Vol-3027/paper5.pdf
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* - https://www.comp.nus.edu.sg/~lowkl/publications/mssao_visual_computer_2012.pdf
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* - https://web.ics.purdue.edu/~tmcgraw/papers/mcgraw-ao-2008.pdf
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* - https://www.activision.com/cdn/research/Practical_Real_Time_Strategies_for_Accurate_Indirect_Occlusion_NEW%20VERSION_COLOR.pdf
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* - https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.390.2463&rep=rep1&type=pdf
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* - https://www.intel.com/content/www/us/en/developer/articles/technical/adaptive-screen-space-ambient-occlusion.html
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*/
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const GTAOShader = {
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name: 'GTAOShader',
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defines: {
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PERSPECTIVE_CAMERA: 1,
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SAMPLES: 16,
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NORMAL_VECTOR_TYPE: 1,
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DEPTH_SWIZZLING: 'x',
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SCREEN_SPACE_RADIUS: 0,
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SCREEN_SPACE_RADIUS_SCALE: 100.0,
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SCENE_CLIP_BOX: 0,
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},
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uniforms: {
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tNormal: { value: null },
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tDepth: { value: null },
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tNoise: { value: null },
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resolution: { value: new Vector2() },
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cameraNear: { value: null },
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cameraFar: { value: null },
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cameraProjectionMatrix: { value: new Matrix4() },
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cameraProjectionMatrixInverse: { value: new Matrix4() },
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cameraWorldMatrix: { value: new Matrix4() },
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radius: { value: 0.25 },
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distanceExponent: { value: 1. },
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thickness: { value: 1. },
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distanceFallOff: { value: 1. },
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scale: { value: 1. },
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sceneBoxMin: { value: new Vector3( - 1, - 1, - 1 ) },
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sceneBoxMax: { value: new Vector3( 1, 1, 1 ) },
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},
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vertexShader: /* glsl */`
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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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fragmentShader: /* glsl */`
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varying vec2 vUv;
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uniform highp sampler2D tNormal;
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uniform highp sampler2D tDepth;
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uniform sampler2D tNoise;
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uniform vec2 resolution;
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uniform float cameraNear;
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uniform float cameraFar;
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uniform mat4 cameraProjectionMatrix;
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uniform mat4 cameraProjectionMatrixInverse;
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uniform mat4 cameraWorldMatrix;
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uniform float radius;
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uniform float distanceExponent;
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uniform float thickness;
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uniform float distanceFallOff;
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uniform float scale;
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#if SCENE_CLIP_BOX == 1
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uniform vec3 sceneBoxMin;
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uniform vec3 sceneBoxMax;
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#endif
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#include <common>
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#include <packing>
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#ifndef FRAGMENT_OUTPUT
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#define FRAGMENT_OUTPUT vec4(vec3(ao), 1.)
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#endif
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vec3 getViewPosition(const in vec2 screenPosition, const in float depth) {
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vec4 clipSpacePosition = vec4(vec3(screenPosition, depth) * 2.0 - 1.0, 1.0);
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vec4 viewSpacePosition = cameraProjectionMatrixInverse * clipSpacePosition;
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return viewSpacePosition.xyz / viewSpacePosition.w;
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}
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float getDepth(const vec2 uv) {
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return textureLod(tDepth, uv.xy, 0.0).DEPTH_SWIZZLING;
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}
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float fetchDepth(const ivec2 uv) {
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return texelFetch(tDepth, uv.xy, 0).DEPTH_SWIZZLING;
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}
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float getViewZ(const in float depth) {
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#if PERSPECTIVE_CAMERA == 1
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return perspectiveDepthToViewZ(depth, cameraNear, cameraFar);
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#else
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return orthographicDepthToViewZ(depth, cameraNear, cameraFar);
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#endif
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}
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vec3 computeNormalFromDepth(const vec2 uv) {
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vec2 size = vec2(textureSize(tDepth, 0));
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ivec2 p = ivec2(uv * size);
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float c0 = fetchDepth(p);
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float l2 = fetchDepth(p - ivec2(2, 0));
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float l1 = fetchDepth(p - ivec2(1, 0));
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float r1 = fetchDepth(p + ivec2(1, 0));
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float r2 = fetchDepth(p + ivec2(2, 0));
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float b2 = fetchDepth(p - ivec2(0, 2));
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float b1 = fetchDepth(p - ivec2(0, 1));
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float t1 = fetchDepth(p + ivec2(0, 1));
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float t2 = fetchDepth(p + ivec2(0, 2));
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float dl = abs((2.0 * l1 - l2) - c0);
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float dr = abs((2.0 * r1 - r2) - c0);
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float db = abs((2.0 * b1 - b2) - c0);
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float dt = abs((2.0 * t1 - t2) - c0);
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vec3 ce = getViewPosition(uv, c0).xyz;
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vec3 dpdx = (dl < dr) ? ce - getViewPosition((uv - vec2(1.0 / size.x, 0.0)), l1).xyz : -ce + getViewPosition((uv + vec2(1.0 / size.x, 0.0)), r1).xyz;
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vec3 dpdy = (db < dt) ? ce - getViewPosition((uv - vec2(0.0, 1.0 / size.y)), b1).xyz : -ce + getViewPosition((uv + vec2(0.0, 1.0 / size.y)), t1).xyz;
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return normalize(cross(dpdx, dpdy));
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}
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vec3 getViewNormal(const vec2 uv) {
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#if NORMAL_VECTOR_TYPE == 2
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return normalize(textureLod(tNormal, uv, 0.).rgb);
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#elif NORMAL_VECTOR_TYPE == 1
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return unpackRGBToNormal(textureLod(tNormal, uv, 0.).rgb);
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#else
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return computeNormalFromDepth(uv);
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#endif
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}
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vec3 getSceneUvAndDepth(vec3 sampleViewPos) {
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vec4 sampleClipPos = cameraProjectionMatrix * vec4(sampleViewPos, 1.);
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vec2 sampleUv = sampleClipPos.xy / sampleClipPos.w * 0.5 + 0.5;
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float sampleSceneDepth = getDepth(sampleUv);
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return vec3(sampleUv, sampleSceneDepth);
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}
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void main() {
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float depth = getDepth(vUv.xy);
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if (depth >= 1.0) {
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discard;
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return;
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}
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vec3 viewPos = getViewPosition(vUv, depth);
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vec3 viewNormal = getViewNormal(vUv);
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float radiusToUse = radius;
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float distanceFalloffToUse = thickness;
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#if SCREEN_SPACE_RADIUS == 1
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float radiusScale = getViewPosition(vec2(0.5 + float(SCREEN_SPACE_RADIUS_SCALE) / resolution.x, 0.0), depth).x;
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radiusToUse *= radiusScale;
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distanceFalloffToUse *= radiusScale;
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#endif
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#if SCENE_CLIP_BOX == 1
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vec3 worldPos = (cameraWorldMatrix * vec4(viewPos, 1.0)).xyz;
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float boxDistance = length(max(vec3(0.0), max(sceneBoxMin - worldPos, worldPos - sceneBoxMax)));
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if (boxDistance > radiusToUse) {
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discard;
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return;
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}
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#endif
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vec2 noiseResolution = vec2(textureSize(tNoise, 0));
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vec2 noiseUv = vUv * resolution / noiseResolution;
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vec4 noiseTexel = textureLod(tNoise, noiseUv, 0.0);
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vec3 randomVec = noiseTexel.xyz * 2.0 - 1.0;
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vec3 tangent = normalize(vec3(randomVec.xy, 0.));
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vec3 bitangent = vec3(-tangent.y, tangent.x, 0.);
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mat3 kernelMatrix = mat3(tangent, bitangent, vec3(0., 0., 1.));
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const int DIRECTIONS = SAMPLES < 30 ? 3 : 5;
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const int STEPS = (SAMPLES + DIRECTIONS - 1) / DIRECTIONS;
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float ao = 0.0, totalWeight = 0.0;
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for (int i = 0; i < DIRECTIONS; ++i) {
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float angle = float(i) / float(DIRECTIONS) * PI;
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vec4 sampleDir = vec4(cos(angle), sin(angle), 0., 0.5 + 0.5 * noiseTexel.w);
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sampleDir.xyz = normalize(kernelMatrix * sampleDir.xyz);
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vec3 viewDir = normalize(-viewPos.xyz);
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vec3 sliceBitangent = normalize(cross(sampleDir.xyz, viewDir));
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vec3 sliceTangent = cross(sliceBitangent, viewDir);
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vec3 normalInSlice = normalize(viewNormal - sliceBitangent * dot(viewNormal, sliceBitangent));
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vec3 tangentToNormalInSlice = cross(normalInSlice, sliceBitangent);
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vec2 cosHorizons = vec2(dot(viewDir, tangentToNormalInSlice), dot(viewDir, -tangentToNormalInSlice));
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for (int j = 0; j < STEPS; ++j) {
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vec3 sampleViewOffset = sampleDir.xyz * radiusToUse * sampleDir.w * pow(float(j + 1) / float(STEPS), distanceExponent);
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vec3 sampleSceneUvDepth = getSceneUvAndDepth(viewPos + sampleViewOffset);
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vec3 sampleSceneViewPos = getViewPosition(sampleSceneUvDepth.xy, sampleSceneUvDepth.z);
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vec3 viewDelta = sampleSceneViewPos - viewPos;
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if (abs(viewDelta.z) < thickness) {
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float sampleCosHorizon = dot(viewDir, normalize(viewDelta));
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cosHorizons.x += max(0., (sampleCosHorizon - cosHorizons.x) * mix(1., 2. / float(j + 2), distanceFallOff));
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}
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sampleSceneUvDepth = getSceneUvAndDepth(viewPos - sampleViewOffset);
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sampleSceneViewPos = getViewPosition(sampleSceneUvDepth.xy, sampleSceneUvDepth.z);
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viewDelta = sampleSceneViewPos - viewPos;
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if (abs(viewDelta.z) < thickness) {
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float sampleCosHorizon = dot(viewDir, normalize(viewDelta));
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cosHorizons.y += max(0., (sampleCosHorizon - cosHorizons.y) * mix(1., 2. / float(j + 2), distanceFallOff));
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}
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}
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vec2 sinHorizons = sqrt(1. - cosHorizons * cosHorizons);
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float nx = dot(normalInSlice, sliceTangent);
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float ny = dot(normalInSlice, viewDir);
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float nxb = 1. / 2. * (acos(cosHorizons.y) - acos(cosHorizons.x) + sinHorizons.x * cosHorizons.x - sinHorizons.y * cosHorizons.y);
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float nyb = 1. / 2. * (2. - cosHorizons.x * cosHorizons.x - cosHorizons.y * cosHorizons.y);
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float occlusion = nx * nxb + ny * nyb;
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ao += occlusion;
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}
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ao = clamp(ao / float(DIRECTIONS), 0., 1.);
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#if SCENE_CLIP_BOX == 1
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ao = mix(ao, 1., smoothstep(0., radiusToUse, boxDistance));
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#endif
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ao = pow(ao, scale);
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gl_FragColor = FRAGMENT_OUTPUT;
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}`
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};
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const GTAODepthShader = {
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name: 'GTAODepthShader',
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defines: {
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PERSPECTIVE_CAMERA: 1
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},
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uniforms: {
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tDepth: { value: null },
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cameraNear: { value: null },
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cameraFar: { value: null },
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},
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vertexShader: /* glsl */`
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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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fragmentShader: /* glsl */`
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uniform sampler2D tDepth;
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uniform float cameraNear;
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uniform float cameraFar;
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varying vec2 vUv;
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#include <packing>
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float getLinearDepth( const in vec2 screenPosition ) {
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#if PERSPECTIVE_CAMERA == 1
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float fragCoordZ = texture2D( tDepth, screenPosition ).x;
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float viewZ = perspectiveDepthToViewZ( fragCoordZ, cameraNear, cameraFar );
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return viewZToOrthographicDepth( viewZ, cameraNear, cameraFar );
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#else
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return texture2D( tDepth, screenPosition ).x;
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#endif
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}
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void main() {
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float depth = getLinearDepth( vUv );
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gl_FragColor = vec4( vec3( 1.0 - depth ), 1.0 );
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}`
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};
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const GTAOBlendShader = {
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name: 'GTAOBlendShader',
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uniforms: {
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tDiffuse: { value: null },
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intensity: { value: 1.0 }
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},
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vertexShader: /* glsl */`
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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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fragmentShader: /* glsl */`
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uniform float intensity;
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uniform sampler2D tDiffuse;
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varying vec2 vUv;
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void main() {
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vec4 texel = texture2D( tDiffuse, vUv );
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gl_FragColor = vec4(mix(vec3(1.), texel.rgb, intensity), texel.a);
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}`
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};
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function generateMagicSquareNoise( size = 5 ) {
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const noiseSize = Math.floor( size ) % 2 === 0 ? Math.floor( size ) + 1 : Math.floor( size );
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const magicSquare = generateMagicSquare( noiseSize );
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const noiseSquareSize = magicSquare.length;
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const data = new Uint8Array( noiseSquareSize * 4 );
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for ( let inx = 0; inx < noiseSquareSize; ++ inx ) {
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const iAng = magicSquare[ inx ];
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const angle = ( 2 * Math.PI * iAng ) / noiseSquareSize;
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const randomVec = new Vector3(
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Math.cos( angle ),
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Math.sin( angle ),
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0
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).normalize();
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data[ inx * 4 ] = ( randomVec.x * 0.5 + 0.5 ) * 255;
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data[ inx * 4 + 1 ] = ( randomVec.y * 0.5 + 0.5 ) * 255;
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data[ inx * 4 + 2 ] = 127;
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data[ inx * 4 + 3 ] = 255;
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}
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const noiseTexture = new DataTexture( data, noiseSize, noiseSize );
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noiseTexture.wrapS = RepeatWrapping;
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noiseTexture.wrapT = RepeatWrapping;
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noiseTexture.needsUpdate = true;
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return noiseTexture;
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}
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function generateMagicSquare( size ) {
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const noiseSize = Math.floor( size ) % 2 === 0 ? Math.floor( size ) + 1 : Math.floor( size );
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const noiseSquareSize = noiseSize * noiseSize;
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const magicSquare = Array( noiseSquareSize ).fill( 0 );
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let i = Math.floor( noiseSize / 2 );
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let j = noiseSize - 1;
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for ( let num = 1; num <= noiseSquareSize; ) {
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if ( i === - 1 && j === noiseSize ) {
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j = noiseSize - 2;
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i = 0;
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} else {
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if ( j === noiseSize ) {
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j = 0;
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}
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if ( i < 0 ) {
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i = noiseSize - 1;
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}
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}
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if ( magicSquare[ i * noiseSize + j ] !== 0 ) {
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j -= 2;
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i ++;
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continue;
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} else {
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magicSquare[ i * noiseSize + j ] = num ++;
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}
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j ++;
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i --;
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}
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return magicSquare;
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}
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export { generateMagicSquareNoise, GTAOShader, GTAODepthShader, GTAOBlendShader };
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