mirror of
https://github.com/PavelDoGreat/WebGL-Fluid-Simulation.git
synced 2025-10-03 17:31:53 +02:00
456 lines
14 KiB
JavaScript
456 lines
14 KiB
JavaScript
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'use strict';
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const canvas = document.getElementsByTagName('canvas')[0];
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const gl = canvas.getContext('webgl', { alpha: false, preserveDrawingBuffer: true });
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if (!gl.getExtension("OES_texture_float")) {
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console.log("does not support OES_texture_float");
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}
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const support_linear_float = gl.getExtension("OES_texture_float_linear");
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if (!support_linear_float) {
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console.log("does not support OES_texture_float_linear");
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}
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resizeCanvas();
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const TEXTURE_DOWNSAMPLE = 2;
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const TEXTURE_WIDTH = 200//gl.drawingBufferWidth >> TEXTURE_DOWNSAMPLE;
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const TEXTURE_HEIGHT = 200//gl.drawingBufferHeight >> TEXTURE_DOWNSAMPLE;
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const CELL_SIZE = 1.0;
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const DENSITY_DISSIPATION = 0.99;
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const VELOCITY_DISSIPATION = 0.999;
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const SPLAT_RADIUS = 0.001;
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const PRESSURE_ITERATIONS = 20;
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class GLProgram {
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constructor (vertexShader, fragmentShader) {
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this.uniforms = {};
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this.program = gl.createProgram();
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gl.attachShader(this.program, vertexShader);
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gl.attachShader(this.program, fragmentShader);
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gl.linkProgram(this.program);
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if (!gl.getProgramParameter(this.program, gl.LINK_STATUS)) {
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throw gl.getProgramInfoLog(this.program);
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}
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const uniformCount = gl.getProgramParameter(this.program, gl.ACTIVE_UNIFORMS);
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for (let i = 0; i < uniformCount; i++) {
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const uniformName = gl.getActiveUniform(this.program, i).name;
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this.uniforms[uniformName] = gl.getUniformLocation(this.program, uniformName);
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}
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}
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bind () {
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gl.useProgram(this.program);
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}
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}
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function compileShader (type, source) {
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const shader = gl.createShader(type);
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gl.shaderSource(shader, source);
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gl.compileShader(shader);
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if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS)) {
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throw gl.getShaderInfoLog(shader);
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}
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return shader;
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};
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const baseVertexShader = compileShader(gl.VERTEX_SHADER, `
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attribute vec2 aPosition;
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varying vec2 vUv;
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varying vec2 vL;
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varying vec2 vR;
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varying vec2 vT;
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varying vec2 vB;
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uniform vec2 texelSize;
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void main () {
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vUv = aPosition * 0.5 + 0.5;
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vL = vUv - vec2(texelSize.x, 0.0);
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vR = vUv + vec2(texelSize.x, 0.0);
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vT = vUv + vec2(0.0, texelSize.y);
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vB = vUv - vec2(0.0, texelSize.y);
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gl_Position = vec4(aPosition, 0.0, 1.0);
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}
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`);
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const displayShader = compileShader(gl.FRAGMENT_SHADER, `
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precision highp float;
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varying vec2 vUv;
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uniform sampler2D uTexture;
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void main () {
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gl_FragColor = texture2D(uTexture, vUv);
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}
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`);
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const initDensityShader = compileShader(gl.FRAGMENT_SHADER, `
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precision highp float;
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varying vec2 vUv;
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void main () {
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float d = mod(floor(vUv.x * 10.0) + floor(vUv.y * 10.0), 2.0);
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gl_FragColor = vec4(vec3(d), 1.0);
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}
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`);
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const initVelocityShader = compileShader(gl.FRAGMENT_SHADER, `
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precision highp float;
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varying vec2 vUv;
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void main () {
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gl_FragColor = vec4(sin(6.28 * vUv.y), sin(6.28 * vUv.x), 0.0, 1.0);
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}
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`);
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const splatShader = compileShader(gl.FRAGMENT_SHADER, `
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precision highp float;
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varying vec2 vUv;
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uniform sampler2D uTarget;
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uniform float aspectRatio;
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uniform vec3 color;
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uniform vec2 point;
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uniform float radius;
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void main () {
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vec2 p = vUv - point.xy;
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p.x *= aspectRatio;
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vec3 splat = exp(-dot(p, p) / radius) * color;
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vec3 base = texture2D(uTarget, vUv).xyz;
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gl_FragColor = vec4(base + splat, 1.0);
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}
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`);
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const advectionManualFilteringShader = compileShader(gl.FRAGMENT_SHADER, `
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precision highp float;
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varying vec2 vUv;
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uniform sampler2D uVelocity;
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uniform sampler2D uSource;
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uniform vec2 texelSize;
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uniform float rdx;
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uniform float dt;
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uniform float dissipation;
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vec4 bilerp (sampler2D sam, vec2 p) {
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vec4 st;
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st.xy = floor(p - 0.5) + 0.5;
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st.zw = st.xy + 1.0;
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vec4 uv = st * texelSize.xyxy;
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vec4 a = texture2D(sam, uv.xy);
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vec4 b = texture2D(sam, uv.zy);
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vec4 c = texture2D(sam, uv.xw);
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vec4 d = texture2D(sam, uv.zw);
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vec2 f = p - st.xy;
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return mix(mix(a, b, f.x), mix(c, d, f.x), f.y);
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}
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void main () {
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vec2 coord = gl_FragCoord.xy - rdx * dt * texture2D(uVelocity, vUv).xy;
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gl_FragColor = dissipation * bilerp(uSource, coord);
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gl_FragColor.a = 1.0;
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}
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`);
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const advectionShader = compileShader(gl.FRAGMENT_SHADER, `
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precision highp float;
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varying vec2 vUv;
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uniform sampler2D uVelocity;
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uniform sampler2D uSource;
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uniform vec2 texelSize;
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uniform float rdx;
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uniform float dt;
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uniform float dissipation;
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void main () {
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vec2 coord = vUv - rdx * dt * texture2D(uVelocity, vUv).xy * texelSize;
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gl_FragColor = dissipation * texture2D(uSource, coord);
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gl_FragColor.a = 1.0;
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}
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`);
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const divergenceShader = compileShader(gl.FRAGMENT_SHADER, `
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precision highp float;
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varying vec2 vUv;
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varying vec2 vL;
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varying vec2 vR;
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varying vec2 vT;
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varying vec2 vB;
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uniform sampler2D uVelocity;
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uniform float halfrdx;
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void main () {
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vec2 L = texture2D(uVelocity, vL).xy;
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vec2 R = texture2D(uVelocity, vR).xy;
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vec2 T = texture2D(uVelocity, vT).xy;
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vec2 B = texture2D(uVelocity, vB).xy;
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float div = halfrdx * (R.x - L.x + T.y - B.y);
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gl_FragColor = vec4(div, 0.0, 0.0, 1.0);
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}
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`);
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const pressureShader = compileShader(gl.FRAGMENT_SHADER, `
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precision highp float;
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varying vec2 vUv;
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varying vec2 vL;
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varying vec2 vR;
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varying vec2 vT;
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varying vec2 vB;
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uniform sampler2D uPressure;
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uniform sampler2D uDivergence;
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uniform float alpha;
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void main () {
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float L = texture2D(uPressure, vL).x;
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float R = texture2D(uPressure, vR).x;
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float T = texture2D(uPressure, vT).x;
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float B = texture2D(uPressure, vB).x;
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float divergence = texture2D(uDivergence, vUv).x;
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float pressure = (L + R + B + T + alpha * divergence) * .25;
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gl_FragColor = vec4(pressure, 0.0, 0.0, 1.0);
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}
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`);
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const gradientSubtractShader = compileShader(gl.FRAGMENT_SHADER, `
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precision highp float;
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varying vec2 vUv;
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varying vec2 vL;
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varying vec2 vR;
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varying vec2 vT;
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varying vec2 vB;
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uniform sampler2D uPressure;
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uniform sampler2D uVelocity;
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uniform float halfrdx;
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void main () {
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float L = texture2D(uPressure, vL).x;
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float R = texture2D(uPressure, vR).x;
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float T = texture2D(uPressure, vT).x;
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float B = texture2D(uPressure, vB).x;
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vec2 velocity = texture2D(uVelocity, vUv).xy;
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velocity.xy -= halfrdx * vec2(R - L, T - B);
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gl_FragColor = vec4(velocity, 0.0, 1.0);
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}
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`);
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const blit = (() => {
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gl.bindBuffer(gl.ARRAY_BUFFER, gl.createBuffer());
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gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([-1, -1, -1, 1, 1, 1, 1, -1]), gl.STATIC_DRAW);
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gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, gl.createBuffer());
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gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, new Uint16Array([0, 1, 2, 0, 2, 3]), gl.STATIC_DRAW);
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gl.vertexAttribPointer(0, 2, gl.FLOAT, false, 0, 0);
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gl.enableVertexAttribArray(0);
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return (destination) => {
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gl.bindFramebuffer(gl.FRAMEBUFFER, destination);
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gl.drawElements(gl.TRIANGLES, 6, gl.UNSIGNED_SHORT, 0);
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}
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})();
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function clear (target) {
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gl.bindFramebuffer(gl.FRAMEBUFFER, target);
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gl.clearColor(0.0, 0.0, 0.0, 1.0);
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gl.clear(gl.COLOR_BUFFER_BIT);
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}
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let texId = -1;
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function createFBO (width, height, format, type) {
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texId++;
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gl.activeTexture(gl.TEXTURE0 + texId);
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var texture = gl.createTexture();
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gl.bindTexture(gl.TEXTURE_2D, texture);
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gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, type);
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gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, type);
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gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
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gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
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gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, width, height, 0, gl.RGBA, format, null);
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var fbo = gl.createFramebuffer();
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gl.bindFramebuffer(gl.FRAMEBUFFER, fbo);
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gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, texture, 0);
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gl.viewport(0, 0, width, height);
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gl.clearColor(0.0, 0.0, 0.0, 1.0);
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gl.clear(gl.COLOR_BUFFER_BIT);
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return [texture, fbo, texId];
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}
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function createDoubleFBO (width, height, format, type) {
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let fbo1 = createFBO(width, height, format, type);
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let fbo2 = createFBO(width, height, format, type);
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return {
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get first () {
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return fbo1;
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},
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get second () {
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return fbo2;
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},
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swap: () => {
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let temp = fbo1;
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fbo1 = fbo2;
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fbo2 = temp;
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}
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}
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}
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let density = createDoubleFBO(TEXTURE_WIDTH, TEXTURE_HEIGHT, gl.FLOAT, support_linear_float ? gl.LINEAR : gl.NEAREST);
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let velocity = createDoubleFBO(TEXTURE_WIDTH, TEXTURE_HEIGHT, gl.FLOAT, support_linear_float ? gl.LINEAR : gl.NEAREST);
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let divergence = createFBO(TEXTURE_WIDTH, TEXTURE_HEIGHT, gl.FLOAT, gl.NEAREST);
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let pressure = createDoubleFBO(TEXTURE_WIDTH, TEXTURE_HEIGHT, gl.FLOAT, gl.NEAREST);
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const displayProgram = new GLProgram(baseVertexShader, displayShader);
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const splatProgram = new GLProgram(baseVertexShader, splatShader);
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const initDensityProgram = new GLProgram(baseVertexShader, initDensityShader);
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const initVelocityProgram = new GLProgram(baseVertexShader, initVelocityShader);
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const advectionProgram = new GLProgram(baseVertexShader, support_linear_float ? advectionShader : advectionManualFilteringShader);
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const divergenceProgram = new GLProgram(baseVertexShader, divergenceShader);
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const pressureProgram = new GLProgram(baseVertexShader, pressureShader);
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const gradienSubtractProgram = new GLProgram(baseVertexShader, gradientSubtractShader);
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let pointer = {
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x: 0,
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y: 0,
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deltax: 0,
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deltay: 0,
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down: false,
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moved: false,
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color: [0.4, 0, 1]
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}
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initDensityProgram.bind();
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blit(density.first[1]);
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initVelocityProgram.bind();
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blit(velocity.first[1]);
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Update();
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function Update () {
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resizeCanvas();
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gl.viewport(0, 0, TEXTURE_WIDTH, TEXTURE_HEIGHT);
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advectionProgram.bind();
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gl.uniform2f(advectionProgram.uniforms.texelSize, 1.0 / TEXTURE_WIDTH, 1.0 / TEXTURE_HEIGHT);
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gl.uniform1i(advectionProgram.uniforms.uVelocity, velocity.first[2]);
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gl.uniform1i(advectionProgram.uniforms.uSource, velocity.first[2]);
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gl.uniform1f(advectionProgram.uniforms.rdx, 1.0 / CELL_SIZE);
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gl.uniform1f(advectionProgram.uniforms.dt, 0.16);
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gl.uniform1f(advectionProgram.uniforms.dissipation, VELOCITY_DISSIPATION);
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blit(velocity.second[1]);
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velocity.swap();
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gl.uniform1i(advectionProgram.uniforms.uVelocity, velocity.first[2]);
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gl.uniform1i(advectionProgram.uniforms.uSource, density.first[2]);
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gl.uniform1f(advectionProgram.uniforms.dissipation, DENSITY_DISSIPATION);
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blit(density.second[1]);
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density.swap();
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if (pointer.moved)
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{
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splatProgram.bind();
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gl.uniform1i(splatProgram.uniforms.uTarget, velocity.first[2]);
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gl.uniform1f(splatProgram.uniforms.aspectRatio, TEXTURE_WIDTH / TEXTURE_HEIGHT);
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gl.uniform2f(splatProgram.uniforms.point, pointer.x / canvas.width, 1.0 - pointer.y / canvas.height);
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gl.uniform3f(splatProgram.uniforms.color, pointer.deltax, -pointer.deltay, 1.0);
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gl.uniform1f(splatProgram.uniforms.radius, SPLAT_RADIUS);
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blit(velocity.second[1]);
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velocity.swap();
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gl.uniform1i(splatProgram.uniforms.uTarget, density.first[2]);
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gl.uniform3f(splatProgram.uniforms.color, pointer.color[0] * 0.1, pointer.color[1] * 0.1, pointer.color[2] * 0.1);
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blit(density.second[1]);
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density.swap();
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}
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divergenceProgram.bind();
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gl.uniform2f(divergenceProgram.uniforms.texelSize, 1.0 / TEXTURE_WIDTH, 1.0 / TEXTURE_HEIGHT);
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gl.uniform1i(divergenceProgram.uniforms.uVelocity, velocity.first[2]);
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gl.uniform1f(divergenceProgram.uniforms.halfrdx, 0.5 / CELL_SIZE);
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blit(divergence[1]);
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clear(pressure.first[1]);
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pressureProgram.bind();
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gl.uniform2f(pressureProgram.uniforms.texelSize, 1.0 / TEXTURE_WIDTH, 1.0 / TEXTURE_HEIGHT);
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gl.uniform1i(pressureProgram.uniforms.uDivergence, divergence[2]);
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gl.uniform1f(pressureProgram.uniforms.alpha, -CELL_SIZE * CELL_SIZE);
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for (let i = 0; i < PRESSURE_ITERATIONS; i++) {
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gl.uniform1i(pressureProgram.uniforms.uPressure, pressure.first[2]);
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blit(pressure.second[1]);
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pressure.swap();
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}
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gradienSubtractProgram.bind();
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gl.uniform2f(gradienSubtractProgram.uniforms.texelSize, 1.0 / TEXTURE_WIDTH, 1.0 / TEXTURE_HEIGHT);
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gl.uniform1i(gradienSubtractProgram.uniforms.uPressure, pressure.first[2]);
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gl.uniform1i(gradienSubtractProgram.uniforms.uVelocity, velocity.first[2]);
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gl.uniform1f(gradienSubtractProgram.uniforms.halfrdx, 0.5 / CELL_SIZE);
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blit(velocity.second[1]);
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velocity.swap();
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gl.viewport(0, 0, gl.drawingBufferWidth, gl.drawingBufferHeight);
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displayProgram.bind();
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gl.uniform1i(displayProgram.uniforms.uTexture, density.first[2]);
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blit(null);
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pointer.moved = false;
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requestAnimationFrame(Update);
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}
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function resizeCanvas () {
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if (canvas.width != canvas.clientWidth || canvas.height != canvas.clientHeight) {
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const displayHeight = canvas.clientHeight;
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canvas.width = canvas.clientWidth;
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canvas.height = displayHeight;
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}
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}
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canvas.addEventListener('mousemove', (e) => {
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pointer.moved = pointer.down;
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pointer.deltax = e.offsetX - pointer.x;
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pointer.deltay = e.offsetY - pointer.y;
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pointer.x = e.offsetX;
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pointer.y = e.offsetY;
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});
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canvas.addEventListener('touchmove', (e) => {
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e.preventDefault();
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const touch = e.touches[0];
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pointer.moved = pointer.down;
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pointer.deltax = touch.offsetX - pointer.x;
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pointer.deltay = touch.offsetY - pointer.y;
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pointer.x = touch.offsetX;
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pointer.y = touch.offsetY;
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});
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canvas.addEventListener('mousedown', onPointerDown);
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canvas.addEventListener('touchstart', onPointerDown);
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window.addEventListener('mouseup', onPointerUp);
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window.addEventListener('touchend', onPointerUp);
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function onPointerDown () {
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pointer.down = true;
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pointer.color = [Math.random() + 0.5, Math.random() + 0.5, Math.random()];
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}
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function onPointerUp () {
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pointer.down = false;
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} |