mirror of
https://github.com/jiawanlong/Cesium-Examples.git
synced 2025-11-04 09:14:17 +00:00
365 lines
9.1 KiB
JavaScript
365 lines
9.1 KiB
JavaScript
import {
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Matrix4,
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Vector2
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} from 'three';
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/**
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* References:
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* https://lettier.github.io/3d-game-shaders-for-beginners/screen-space-reflection.html
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*/
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const SSRShader = {
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defines: {
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MAX_STEP: 0,
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PERSPECTIVE_CAMERA: true,
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DISTANCE_ATTENUATION: true,
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FRESNEL: true,
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INFINITE_THICK: false,
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SELECTIVE: false,
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},
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uniforms: {
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'tDiffuse': { value: null },
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'tNormal': { value: null },
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'tMetalness': { value: null },
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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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'resolution': { value: new Vector2() },
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'cameraProjectionMatrix': { value: new Matrix4() },
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'cameraInverseProjectionMatrix': { value: new Matrix4() },
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'opacity': { value: .5 },
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'maxDistance': { value: 180 },
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'cameraRange': { value: 0 },
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'thickness': { value: .018 }
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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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`,
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fragmentShader: /* glsl */`
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// precision highp float;
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precision highp sampler2D;
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varying vec2 vUv;
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uniform sampler2D tDepth;
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uniform sampler2D tNormal;
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uniform sampler2D tMetalness;
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uniform sampler2D tDiffuse;
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uniform float cameraRange;
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uniform vec2 resolution;
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uniform float opacity;
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uniform float cameraNear;
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uniform float cameraFar;
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uniform float maxDistance;
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uniform float thickness;
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uniform mat4 cameraProjectionMatrix;
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uniform mat4 cameraInverseProjectionMatrix;
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#include <packing>
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float pointToLineDistance(vec3 x0, vec3 x1, vec3 x2) {
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//x0: point, x1: linePointA, x2: linePointB
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//https://mathworld.wolfram.com/Point-LineDistance3-Dimensional.html
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return length(cross(x0-x1,x0-x2))/length(x2-x1);
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}
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float pointPlaneDistance(vec3 point,vec3 planePoint,vec3 planeNormal){
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// https://mathworld.wolfram.com/Point-PlaneDistance.html
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//// https://en.wikipedia.org/wiki/Plane_(geometry)
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//// http://paulbourke.net/geometry/pointlineplane/
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float a=planeNormal.x,b=planeNormal.y,c=planeNormal.z;
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float x0=point.x,y0=point.y,z0=point.z;
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float x=planePoint.x,y=planePoint.y,z=planePoint.z;
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float d=-(a*x+b*y+c*z);
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float distance=(a*x0+b*y0+c*z0+d)/sqrt(a*a+b*b+c*c);
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return distance;
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}
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float getDepth( const in vec2 uv ) {
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return texture2D( tDepth, uv ).x;
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}
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float getViewZ( const in float depth ) {
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#ifdef PERSPECTIVE_CAMERA
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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 getViewPosition( const in vec2 uv, const in float depth/*clip space*/, const in float clipW ) {
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vec4 clipPosition = vec4( ( vec3( uv, depth ) - 0.5 ) * 2.0, 1.0 );//ndc
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clipPosition *= clipW; //clip
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return ( cameraInverseProjectionMatrix * clipPosition ).xyz;//view
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}
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vec3 getViewNormal( const in vec2 uv ) {
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return unpackRGBToNormal( texture2D( tNormal, uv ).xyz );
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}
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vec2 viewPositionToXY(vec3 viewPosition){
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vec2 xy;
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vec4 clip=cameraProjectionMatrix*vec4(viewPosition,1);
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xy=clip.xy;//clip
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float clipW=clip.w;
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xy/=clipW;//NDC
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xy=(xy+1.)/2.;//uv
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xy*=resolution;//screen
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return xy;
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}
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void main(){
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#ifdef SELECTIVE
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float metalness=texture2D(tMetalness,vUv).r;
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if(metalness==0.) return;
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#endif
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float depth = getDepth( vUv );
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float viewZ = getViewZ( depth );
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if(-viewZ>=cameraFar) return;
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float clipW = cameraProjectionMatrix[2][3] * viewZ+cameraProjectionMatrix[3][3];
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vec3 viewPosition=getViewPosition( vUv, depth, clipW );
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vec2 d0=gl_FragCoord.xy;
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vec2 d1;
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vec3 viewNormal=getViewNormal( vUv );
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#ifdef PERSPECTIVE_CAMERA
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vec3 viewIncidentDir=normalize(viewPosition);
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vec3 viewReflectDir=reflect(viewIncidentDir,viewNormal);
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#else
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vec3 viewIncidentDir=vec3(0,0,-1);
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vec3 viewReflectDir=reflect(viewIncidentDir,viewNormal);
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#endif
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float maxReflectRayLen=maxDistance/dot(-viewIncidentDir,viewNormal);
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// dot(a,b)==length(a)*length(b)*cos(theta) // https://www.mathsisfun.com/algebra/vectors-dot-product.html
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// if(a.isNormalized&&b.isNormalized) dot(a,b)==cos(theta)
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// maxDistance/maxReflectRayLen=cos(theta)
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// maxDistance/maxReflectRayLen==dot(a,b)
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// maxReflectRayLen==maxDistance/dot(a,b)
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vec3 d1viewPosition=viewPosition+viewReflectDir*maxReflectRayLen;
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#ifdef PERSPECTIVE_CAMERA
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if(d1viewPosition.z>-cameraNear){
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//https://tutorial.math.lamar.edu/Classes/CalcIII/EqnsOfLines.aspx
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float t=(-cameraNear-viewPosition.z)/viewReflectDir.z;
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d1viewPosition=viewPosition+viewReflectDir*t;
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}
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#endif
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d1=viewPositionToXY(d1viewPosition);
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float totalLen=length(d1-d0);
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float xLen=d1.x-d0.x;
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float yLen=d1.y-d0.y;
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float totalStep=max(abs(xLen),abs(yLen));
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float xSpan=xLen/totalStep;
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float ySpan=yLen/totalStep;
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for(float i=0.;i<float(MAX_STEP);i++){
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if(i>=totalStep) break;
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vec2 xy=vec2(d0.x+i*xSpan,d0.y+i*ySpan);
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if(xy.x<0.||xy.x>resolution.x||xy.y<0.||xy.y>resolution.y) break;
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float s=length(xy-d0)/totalLen;
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vec2 uv=xy/resolution;
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float d = getDepth(uv);
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float vZ = getViewZ( d );
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if(-vZ>=cameraFar) continue;
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float cW = cameraProjectionMatrix[2][3] * vZ+cameraProjectionMatrix[3][3];
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vec3 vP=getViewPosition( uv, d, cW );
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#ifdef PERSPECTIVE_CAMERA
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// https://comp.nus.edu.sg/~lowkl/publications/lowk_persp_interp_techrep.pdf
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float recipVPZ=1./viewPosition.z;
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float viewReflectRayZ=1./(recipVPZ+s*(1./d1viewPosition.z-recipVPZ));
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#else
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float viewReflectRayZ=viewPosition.z+s*(d1viewPosition.z-viewPosition.z);
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#endif
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// if(viewReflectRayZ>vZ) continue; // will cause "npm run make-screenshot webgl_postprocessing_ssr" high probability hang.
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// https://github.com/mrdoob/three.js/pull/21539#issuecomment-821061164
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if(viewReflectRayZ<=vZ){
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bool hit;
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#ifdef INFINITE_THICK
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hit=true;
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#else
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float away=pointToLineDistance(vP,viewPosition,d1viewPosition);
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float minThickness;
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vec2 xyNeighbor=xy;
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xyNeighbor.x+=1.;
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vec2 uvNeighbor=xyNeighbor/resolution;
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vec3 vPNeighbor=getViewPosition(uvNeighbor,d,cW);
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minThickness=vPNeighbor.x-vP.x;
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minThickness*=3.;
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float tk=max(minThickness,thickness);
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hit=away<=tk;
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#endif
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if(hit){
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vec3 vN=getViewNormal( uv );
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if(dot(viewReflectDir,vN)>=0.) continue;
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float distance=pointPlaneDistance(vP,viewPosition,viewNormal);
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if(distance>maxDistance) break;
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float op=opacity;
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#ifdef DISTANCE_ATTENUATION
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float ratio=1.-(distance/maxDistance);
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float attenuation=ratio*ratio;
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op=opacity*attenuation;
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#endif
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#ifdef FRESNEL
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float fresnelCoe=(dot(viewIncidentDir,viewReflectDir)+1.)/2.;
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op*=fresnelCoe;
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#endif
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vec4 reflectColor=texture2D(tDiffuse,uv);
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gl_FragColor.xyz=reflectColor.xyz;
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gl_FragColor.a=op;
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break;
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}
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}
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}
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}
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`
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};
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const SSRDepthShader = {
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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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`,
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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 uv ) {
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#if PERSPECTIVE_CAMERA == 1
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float fragCoordZ = texture2D( tDepth, uv ).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, uv ).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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float d = 1.0 - depth;
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// d=(d-.999)*1000.;
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gl_FragColor = vec4( vec3( d ), 1.0 );
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}
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`
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};
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const SSRBlurShader = {
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uniforms: {
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'tDiffuse': { value: null },
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'resolution': { value: new Vector2() },
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'opacity': { value: .5 },
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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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`,
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fragmentShader: /* glsl */`
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uniform sampler2D tDiffuse;
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uniform vec2 resolution;
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varying vec2 vUv;
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void main() {
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//reverse engineering from PhotoShop blur filter, then change coefficient
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vec2 texelSize = ( 1.0 / resolution );
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vec4 c=texture2D(tDiffuse,vUv);
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vec2 offset;
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offset=(vec2(-1,0))*texelSize;
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vec4 cl=texture2D(tDiffuse,vUv+offset);
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offset=(vec2(1,0))*texelSize;
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vec4 cr=texture2D(tDiffuse,vUv+offset);
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offset=(vec2(0,-1))*texelSize;
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vec4 cb=texture2D(tDiffuse,vUv+offset);
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offset=(vec2(0,1))*texelSize;
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vec4 ct=texture2D(tDiffuse,vUv+offset);
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// float coeCenter=.5;
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// float coeSide=.125;
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float coeCenter=.2;
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float coeSide=.2;
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float a=c.a*coeCenter+cl.a*coeSide+cr.a*coeSide+cb.a*coeSide+ct.a*coeSide;
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vec3 rgb=(c.rgb*c.a*coeCenter+cl.rgb*cl.a*coeSide+cr.rgb*cr.a*coeSide+cb.rgb*cb.a*coeSide+ct.rgb*ct.a*coeSide)/a;
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gl_FragColor=vec4(rgb,a);
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}
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`
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};
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export { SSRShader, SSRDepthShader, SSRBlurShader };
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