Custom Code Experiment •
Fluid Background
Source Code View HTML / CSS / JavaScript
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Fluid Background</title>
<style>
* {
margin: 0;
padding: 0;
box-sizing: border-box;
}
body {
background: #000;
overflow: hidden;
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}
#container {
position: relative;
width: 100vw;
height: 100vh;
}
canvas {
display: block;
width: 100%;
height: 100%;
cursor: crosshair;
}
#controls {
position: fixed;
bottom: 20px;
left: 50%;
transform: translateX(-50%);
background: rgba(0, 0, 0, 0.7);
color: white;
padding: 10px 20px;
border-radius: 20px;
display: flex;
gap: 15px;
align-items: center;
z-index: 100;
backdrop-filter: blur(10px);
border: 1px solid rgba(255, 255, 255, 0.1);
}
.control-btn {
background: rgba(255, 255, 255, 0.1);
border: none;
color: white;
padding: 8px 15px;
border-radius: 15px;
cursor: pointer;
transition: all 0.3s ease;
font-size: 14px;
}
.control-btn:hover {
background: rgba(255, 255, 255, 0.2);
transform: translateY(-2px);
}
.control-btn:active {
transform: translateY(0);
}
#title {
position: fixed;
top: 20px;
left: 50%;
transform: translateX(-50%);
color: white;
font-size: 24px;
text-align: center;
z-index: 100;
background: rgba(0, 0, 0, 0.5);
padding: 10px 30px;
border-radius: 15px;
backdrop-filter: blur(10px);
}
#instructions {
position: fixed;
top: 70px;
left: 50%;
transform: translateX(-50%);
color: rgba(255, 255, 255, 0.7);
font-size: 14px;
text-align: center;
z-index: 100;
background: rgba(0, 0, 0, 0.5);
padding: 8px 20px;
border-radius: 10px;
backdrop-filter: blur(10px);
}
.color-picker {
width: 30px;
height: 30px;
border-radius: 50%;
border: 2px solid white;
cursor: pointer;
margin: 0 5px;
transition: transform 0.2s;
}
.color-picker:hover {
transform: scale(1.2);
}
#color-palette {
display: flex;
align-items: center;
margin-right: 10px;
}
@media (max-width: 768px) {
#controls {
flex-wrap: wrap;
justify-content: center;
bottom: 10px;
padding: 8px 15px;
}
#title {
font-size: 18px;
top: 10px;
}
#instructions {
font-size: 12px;
top: 50px;
}
}
</style>
</head>
<body>
<div id="container">
<div id="title">Fluid Simulation</div>
<div id="instructions">Click and drag to interact • Spacebar for multiple splats • P to pause</div>
<canvas></canvas>
<div id="controls">
<div id="color-palette">
<div class="color-picker" style="background: #ff0000;" data-hue="0"></div>
<div class="color-picker" style="background: #00ff00;" data-hue="0.33"></div>
<div class="color-picker" style="background: #0000ff;" data-hue="0.66"></div>
<div class="color-picker" style="background: #ffff00;" data-hue="0.16"></div>
<div class="color-picker" style="background: #ff00ff;" data-hue="0.83"></div>
<div class="color-picker" style="background: #00ffff;" data-hue="0.5"></div>
<div class="color-picker" style="background: #ffffff;" data-hue="random"></div>
</div>
<button class="control-btn" id="pauseBtn">Pause</button>
</div>
</div>
<script>
const config = {
SIM_RESOLUTION: 128,
DYE_RESOLUTION: 1024,
CAPTURE_RESOLUTION: 512,
DENSITY_DISSIPATION: 1,
VELOCITY_DISSIPATION: 0.2,
PRESSURE: 0.8,
PRESSURE_ITERATIONS: 20,
CURL: 30,
SPLAT_RADIUS: 0.25,
SPLAT_FORCE: 6000,
SHADING: true,
COLORFUL: true,
COLOR_UPDATE_SPEED: 10,
PAUSED: false,
BACK_COLOR: { r: 0, g: 0, b: 0 },
TRANSPARENT: false,
BLOOM: true,
BLOOM_ITERATIONS: 8,
BLOOM_RESOLUTION: 256,
BLOOM_INTENSITY: 0.8,
BLOOM_THRESHOLD: 0.6,
BLOOM_SOFT_KNEE: 0.7,
SUNRAYS: true,
SUNRAYS_RESOLUTION: 196,
SUNRAYS_WEIGHT: 1.0,
RANDOM_COLORS: false,
SPLAT_HUE: 0.5
};
document.addEventListener('DOMContentLoaded', function() {
document.querySelectorAll('.color-picker').forEach(picker => {
picker.addEventListener('click', function() {
const hue = this.getAttribute('data-hue');
if (hue === 'random') {
config.RANDOM_COLORS = true;
config.SPLAT_HUE = Math.random();
} else {
config.RANDOM_COLORS = false;
config.SPLAT_HUE = parseFloat(hue);
}
});
});
document.getElementById('pauseBtn').addEventListener('click', function() {
config.PAUSED = !config.PAUSED;
this.textContent = config.PAUSED ? 'Resume' : 'Pause';
});
});
"use strict";
function resizeCanvas() {
let width = scaleByPixelRatio(canvas.clientWidth);
let height = scaleByPixelRatio(canvas.clientHeight);
if (canvas.width != width || canvas.height != height) {
canvas.width = width;
canvas.height = height;
return true;
}
return false;
}
function scaleByPixelRatio(input) {
let pixelRatio = window.devicePixelRatio || 1;
return Math.floor(input * pixelRatio);
}
const canvas = document.getElementsByTagName("canvas")[0];
resizeCanvas();
runSimulation(config);
function runSimulation(config) {
function pointerPrototype() {
this.id = -1;
this.texcoordX = 0;
this.texcoordY = 0;
this.prevTexcoordX = 0;
this.prevTexcoordY = 0;
this.deltaX = 0;
this.deltaY = 0;
this.down = false;
this.moved = false;
this.color = [30, 0, 300];
}
let pointers = [];
let splatStack = [];
pointers.push(new pointerPrototype());
const { gl, ext } = getWebGLContext(canvas);
if (isMobile()) {
config.DYE_RESOLUTION = 512;
}
if (!ext.supportLinearFiltering) {
config.DYE_RESOLUTION = 512;
config.SHADING = false;
config.BLOOM = false;
config.SUNRAYS = false;
}
function getWebGLContext(canvas) {
const params = {
alpha: true,
depth: false,
stencil: false,
antialias: false,
preserveDrawingBuffer: false,
};
let gl = canvas.getContext("webgl2", params);
const isWebGL2 = !!gl;
if (!isWebGL2)
gl =
canvas.getContext("webgl", params) ||
canvas.getContext("experimental-webgl", params);
let halfFloat;
let supportLinearFiltering;
if (isWebGL2) {
gl.getExtension("EXT_color_buffer_float");
supportLinearFiltering = gl.getExtension("OES_texture_float_linear");
} else {
halfFloat = gl.getExtension("OES_texture_half_float");
supportLinearFiltering = gl.getExtension("OES_texture_half_float_linear");
}
gl.clearColor(0.0, 0.0, 0.0, 1.0);
const halfFloatTexType = isWebGL2
? gl.HALF_FLOAT
: halfFloat.HALF_FLOAT_OES;
let formatRGBA;
let formatRG;
let formatR;
if (isWebGL2) {
formatRGBA = getSupportedFormat(
gl,
gl.RGBA16F,
gl.RGBA,
halfFloatTexType
);
formatRG = getSupportedFormat(gl, gl.RG16F, gl.RG, halfFloatTexType);
formatR = getSupportedFormat(gl, gl.R16F, gl.RED, halfFloatTexType);
} else {
formatRGBA = getSupportedFormat(gl, gl.RGBA, gl.RGBA, halfFloatTexType);
formatRG = getSupportedFormat(gl, gl.RGBA, gl.RGBA, halfFloatTexType);
formatR = getSupportedFormat(gl, gl.RGBA, gl.RGBA, halfFloatTexType);
}
return {
gl,
ext: {
formatRGBA,
formatRG,
formatR,
halfFloatTexType,
supportLinearFiltering,
},
};
}
function getSupportedFormat(gl, internalFormat, format, type) {
if (!supportRenderTextureFormat(gl, internalFormat, format, type)) {
switch (internalFormat) {
case gl.R16F:
return getSupportedFormat(gl, gl.RG16F, gl.RG, type);
case gl.RG16F:
return getSupportedFormat(gl, gl.RGBA16F, gl.RGBA, type);
default:
return null;
}
}
return {
internalFormat,
format,
};
}
function supportRenderTextureFormat(gl, internalFormat, format, type) {
let texture = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, texture);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
gl.texImage2D(
gl.TEXTURE_2D,
0,
internalFormat,
4,
4,
0,
format,
type,
null
);
let fbo = gl.createFramebuffer();
gl.bindFramebuffer(gl.FRAMEBUFFER, fbo);
gl.framebufferTexture2D(
gl.FRAMEBUFFER,
gl.COLOR_ATTACHMENT0,
gl.TEXTURE_2D,
texture,
0
);
let status = gl.checkFramebufferStatus(gl.FRAMEBUFFER);
return status == gl.FRAMEBUFFER_COMPLETE;
}
function isMobile() {
return /Mobi|Android/i.test(navigator.userAgent);
}
function captureScreenshot() {
let res = getResolution(config.CAPTURE_RESOLUTION);
let target = createFBO(
res.width,
res.height,
ext.formatRGBA.internalFormat,
ext.formatRGBA.format,
ext.halfFloatTexType,
gl.NEAREST
);
render(target);
let texture = framebufferToTexture(target);
texture = normalizeTexture(texture, target.width, target.height);
let captureCanvas = textureToCanvas(texture, target.width, target.height);
let datauri = captureCanvas.toDataURL();
downloadURI("fluid.png", datauri);
URL.revokeObjectURL(datauri);
}
function framebufferToTexture(target) {
gl.bindFramebuffer(gl.FRAMEBUFFER, target.fbo);
let length = target.width * target.height * 4;
let texture = new Float32Array(length);
gl.readPixels(
0,
0,
target.width,
target.height,
gl.RGBA,
gl.FLOAT,
texture
);
return texture;
}
function normalizeTexture(texture, width, height) {
let result = new Uint8Array(texture.length);
let id = 0;
for (let i = height - 1; i >= 0; i--) {
for (let j = 0; j < width; j++) {
let nid = i * width * 4 + j * 4;
result[nid + 0] = clamp01(texture[id + 0]) * 255;
result[nid + 1] = clamp01(texture[id + 1]) * 255;
result[nid + 2] = clamp01(texture[id + 2]) * 255;
result[nid + 3] = clamp01(texture[id + 3]) * 255;
id += 4;
}
}
return result;
}
function clamp01(input) {
return Math.min(Math.max(input, 0), 1);
}
function textureToCanvas(texture, width, height) {
let captureCanvas = document.createElement("canvas");
let ctx = captureCanvas.getContext("2d");
captureCanvas.width = width;
captureCanvas.height = height;
let imageData = ctx.createImageData(width, height);
imageData.data.set(texture);
ctx.putImageData(imageData, 0, 0);
return captureCanvas;
}
function downloadURI(filename, uri) {
let link = document.createElement("a");
link.download = filename;
link.href = uri;
document.body.appendChild(link);
link.click();
document.body.removeChild(link);
}
class Material {
constructor(vertexShader, fragmentShaderSource) {
this.vertexShader = vertexShader;
this.fragmentShaderSource = fragmentShaderSource;
this.programs = [];
this.activeProgram = null;
this.uniforms = [];
}
setKeywords(keywords) {
let hash = 0;
for (let i = 0; i < keywords.length; i++) hash += hashCode(keywords[i]);
let program = this.programs[hash];
if (program == null) {
let fragmentShader = compileShader(
gl.FRAGMENT_SHADER,
this.fragmentShaderSource,
keywords
);
program = createProgram(this.vertexShader, fragmentShader);
this.programs[hash] = program;
}
if (program == this.activeProgram) return;
this.uniforms = getUniforms(program);
this.activeProgram = program;
}
bind() {
gl.useProgram(this.activeProgram);
}
}
class Program {
constructor(vertexShader, fragmentShader) {
this.uniforms = {};
this.program = createProgram(vertexShader, fragmentShader);
this.uniforms = getUniforms(this.program);
}
bind() {
gl.useProgram(this.program);
}
}
function createProgram(vertexShader, fragmentShader) {
let program = gl.createProgram();
gl.attachShader(program, vertexShader);
gl.attachShader(program, fragmentShader);
gl.linkProgram(program);
if (!gl.getProgramParameter(program, gl.LINK_STATUS))
console.trace(gl.getProgramInfoLog(program));
return program;
}
function getUniforms(program) {
let uniforms = [];
let uniformCount = gl.getProgramParameter(program, gl.ACTIVE_UNIFORMS);
for (let i = 0; i < uniformCount; i++) {
let uniformName = gl.getActiveUniform(program, i).name;
uniforms[uniformName] = gl.getUniformLocation(program, uniformName);
}
return uniforms;
}
function compileShader(type, source, keywords) {
source = addKeywords(source, keywords);
const shader = gl.createShader(type);
gl.shaderSource(shader, source);
gl.compileShader(shader);
if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS))
console.trace(gl.getShaderInfoLog(shader));
return shader;
}
function addKeywords(source, keywords) {
if (keywords == null) return source;
let keywordsString = "";
keywords.forEach((keyword) => {
keywordsString += "#define " + keyword + "\n";
});
return keywordsString + source;
}
const baseVertexShader = compileShader(
gl.VERTEX_SHADER,
`
precision highp float;
attribute vec2 aPosition;
varying vec2 vUv;
varying vec2 vL;
varying vec2 vR;
varying vec2 vT;
varying vec2 vB;
uniform vec2 texelSize;
void main () {
vUv = aPosition * 0.5 + 0.5;
vL = vUv - vec2(texelSize.x, 0.0);
vR = vUv + vec2(texelSize.x, 0.0);
vT = vUv + vec2(0.0, texelSize.y);
vB = vUv - vec2(0.0, texelSize.y);
gl_Position = vec4(aPosition, 0.0, 1.0);
}
`
);
const blurVertexShader = compileShader(
gl.VERTEX_SHADER,
`
precision highp float;
attribute vec2 aPosition;
varying vec2 vUv;
varying vec2 vL;
varying vec2 vR;
uniform vec2 texelSize;
void main () {
vUv = aPosition * 0.5 + 0.5;
float offset = 1.33333333;
vL = vUv - texelSize * offset;
vR = vUv + texelSize * offset;
gl_Position = vec4(aPosition, 0.0, 1.0);
}
`
);
const blurShader = compileShader(
gl.FRAGMENT_SHADER,
`
precision mediump float;
precision mediump sampler2D;
varying vec2 vUv;
varying vec2 vL;
varying vec2 vR;
uniform sampler2D uTexture;
void main () {
vec4 sum = texture2D(uTexture, vUv) * 0.29411764;
sum += texture2D(uTexture, vL) * 0.35294117;
sum += texture2D(uTexture, vR) * 0.35294117;
gl_FragColor = sum;
}
`
);
const copyShader = compileShader(
gl.FRAGMENT_SHADER,
`
precision mediump float;
precision mediump sampler2D;
varying highp vec2 vUv;
uniform sampler2D uTexture;
void main () {
gl_FragColor = texture2D(uTexture, vUv);
}
`
);
const clearShader = compileShader(
gl.FRAGMENT_SHADER,
`
precision mediump float;
precision mediump sampler2D;
varying highp vec2 vUv;
uniform sampler2D uTexture;
uniform float value;
void main () {
gl_FragColor = value * texture2D(uTexture, vUv);
}
`
);
const colorShader = compileShader(
gl.FRAGMENT_SHADER,
`
precision mediump float;
uniform vec4 color;
void main () {
gl_FragColor = color;
}
`
);
const checkerboardShader = compileShader(
gl.FRAGMENT_SHADER,
`
precision highp float;
precision highp sampler2D;
varying vec2 vUv;
uniform sampler2D uTexture;
uniform float aspectRatio;
#define SCALE 25.0
void main () {
vec2 uv = floor(vUv * SCALE * vec2(aspectRatio, 1.0));
float v = mod(uv.x + uv.y, 2.0);
v = v * 0.1 + 0.8;
gl_FragColor = vec4(vec3(v), 1.0);
}
`
);
const displayShaderSource = `
precision highp float;
precision highp sampler2D;
varying vec2 vUv;
varying vec2 vL;
varying vec2 vR;
varying vec2 vT;
varying vec2 vB;
uniform sampler2D uTexture;
uniform sampler2D uBloom;
uniform sampler2D uSunrays;
uniform sampler2D uDithering;
uniform vec2 ditherScale;
uniform vec2 texelSize;
vec3 linearToGamma (vec3 color) {
color = max(color, vec3(0));
return max(1.055 * pow(color, vec3(0.416666667)) - 0.055, vec3(0));
}
void main () {
vec3 c = texture2D(uTexture, vUv).rgb;
#ifdef SHADING
vec3 lc = texture2D(uTexture, vL).rgb;
vec3 rc = texture2D(uTexture, vR).rgb;
vec3 tc = texture2D(uTexture, vT).rgb;
vec3 bc = texture2D(uTexture, vB).rgb;
float dx = length(rc) - length(lc);
float dy = length(tc) - length(bc);
vec3 n = normalize(vec3(dx, dy, length(texelSize)));
vec3 l = vec3(0.0, 0.0, 1.0);
float diffuse = clamp(dot(n, l) + 0.7, 0.7, 1.0);
c *= diffuse;
#endif
#ifdef BLOOM
vec3 bloom = texture2D(uBloom, vUv).rgb;
#endif
#ifdef SUNRAYS
float sunrays = texture2D(uSunrays, vUv).r;
c *= sunrays;
#ifdef BLOOM
bloom *= sunrays;
#endif
#endif
#ifdef BLOOM
float noise = texture2D(uDithering, vUv * ditherScale).r;
noise = noise * 2.0 - 1.0;
bloom += noise / 255.0;
bloom = linearToGamma(bloom);
c += bloom;
#endif
float a = max(c.r, max(c.g, c.b));
gl_FragColor = vec4(c, a);
}
`;
const bloomPrefilterShader = compileShader(
gl.FRAGMENT_SHADER,
`
precision mediump float;
precision mediump sampler2D;
varying vec2 vUv;
uniform sampler2D uTexture;
uniform vec3 curve;
uniform float threshold;
void main () {
vec3 c = texture2D(uTexture, vUv).rgb;
float br = max(c.r, max(c.g, c.b));
float rq = clamp(br - curve.x, 0.0, curve.y);
rq = curve.z * rq * rq;
c *= max(rq, br - threshold) / max(br, 0.0001);
gl_FragColor = vec4(c, 0.0);
}
`
);
const bloomBlurShader = compileShader(
gl.FRAGMENT_SHADER,
`
precision mediump float;
precision mediump sampler2D;
varying vec2 vL;
varying vec2 vR;
varying vec2 vT;
varying vec2 vB;
uniform sampler2D uTexture;
void main () {
vec4 sum = vec4(0.0);
sum += texture2D(uTexture, vL);
sum += texture2D(uTexture, vR);
sum += texture2D(uTexture, vT);
sum += texture2D(uTexture, vB);
sum *= 0.25;
gl_FragColor = sum;
}
`
);
const bloomFinalShader = compileShader(
gl.FRAGMENT_SHADER,
`
precision mediump float;
precision mediump sampler2D;
varying vec2 vL;
varying vec2 vR;
varying vec2 vT;
varying vec2 vB;
uniform sampler2D uTexture;
uniform float intensity;
void main () {
vec4 sum = vec4(0.0);
sum += texture2D(uTexture, vL);
sum += texture2D(uTexture, vR);
sum += texture2D(uTexture, vT);
sum += texture2D(uTexture, vB);
sum *= 0.25;
gl_FragColor = sum * intensity;
}
`
);
const sunraysMaskShader = compileShader(
gl.FRAGMENT_SHADER,
`
precision highp float;
precision highp sampler2D;
varying vec2 vUv;
uniform sampler2D uTexture;
void main () {
vec4 c = texture2D(uTexture, vUv);
float br = max(c.r, max(c.g, c.b));
c.a = 1.0 - min(max(br * 20.0, 0.0), 0.8);
gl_FragColor = c;
}
`
);
const sunraysShader = compileShader(
gl.FRAGMENT_SHADER,
`
precision highp float;
precision highp sampler2D;
varying vec2 vUv;
uniform sampler2D uTexture;
uniform float weight;
#define ITERATIONS 16
void main () {
float Density = 0.3;
float Decay = 0.95;
float Exposure = 0.7;
vec2 coord = vUv;
vec2 dir = vUv - 0.5;
dir *= 1.0 / float(ITERATIONS) * Density;
float illuminationDecay = 1.0;
float color = texture2D(uTexture, vUv).a;
for (int i = 0; i < ITERATIONS; i++)
{
coord -= dir;
float col = texture2D(uTexture, coord).a;
color += col * illuminationDecay * weight;
illuminationDecay *= Decay;
}
gl_FragColor = vec4(color * Exposure, 0.0, 0.0, 1.0);
}
`
);
const splatShader = compileShader(
gl.FRAGMENT_SHADER,
`
precision highp float;
precision highp sampler2D;
varying vec2 vUv;
uniform sampler2D uTarget;
uniform float aspectRatio;
uniform vec3 color;
uniform vec2 point;
uniform float radius;
void main () {
vec2 p = vUv - point.xy;
p.x *= aspectRatio;
vec3 splat = exp(-dot(p, p) / radius) * color;
vec3 base = texture2D(uTarget, vUv).xyz;
gl_FragColor = vec4(base + splat, 1.0);
}
`
);
const advectionShader = compileShader(
gl.FRAGMENT_SHADER,
`
precision highp float;
precision highp sampler2D;
varying vec2 vUv;
uniform sampler2D uVelocity;
uniform sampler2D uSource;
uniform vec2 texelSize;
uniform vec2 dyeTexelSize;
uniform float dt;
uniform float dissipation;
vec4 bilerp (sampler2D sam, vec2 uv, vec2 tsize) {
vec2 st = uv / tsize - 0.5;
vec2 iuv = floor(st);
vec2 fuv = fract(st);
vec4 a = texture2D(sam, (iuv + vec2(0.5, 0.5)) * tsize);
vec4 b = texture2D(sam, (iuv + vec2(1.5, 0.5)) * tsize);
vec4 c = texture2D(sam, (iuv + vec2(0.5, 1.5)) * tsize);
vec4 d = texture2D(sam, (iuv + vec2(1.5, 1.5)) * tsize);
return mix(mix(a, b, fuv.x), mix(c, d, fuv.x), fuv.y);
}
void main () {
#ifdef MANUAL_FILTERING
vec2 coord = vUv - dt * bilerp(uVelocity, vUv, texelSize).xy * texelSize;
vec4 result = bilerp(uSource, coord, dyeTexelSize);
#else
vec2 coord = vUv - dt * texture2D(uVelocity, vUv).xy * texelSize;
vec4 result = texture2D(uSource, coord);
#endif
float decay = 1.0 + dissipation * dt;
gl_FragColor = result / decay;
}`,
ext.supportLinearFiltering ? null : ["MANUAL_FILTERING"]
);
const divergenceShader = compileShader(
gl.FRAGMENT_SHADER,
`
precision mediump float;
precision mediump sampler2D;
varying highp vec2 vUv;
varying highp vec2 vL;
varying highp vec2 vR;
varying highp vec2 vT;
varying highp vec2 vB;
uniform sampler2D uVelocity;
void main () {
float L = texture2D(uVelocity, vL).x;
float R = texture2D(uVelocity, vR).x;
float T = texture2D(uVelocity, vT).y;
float B = texture2D(uVelocity, vB).y;
vec2 C = texture2D(uVelocity, vUv).xy;
if (vL.x < 0.0) { L = -C.x; }
if (vR.x > 1.0) { R = -C.x; }
if (vT.y > 1.0) { T = -C.y; }
if (vB.y < 0.0) { B = -C.y; }
float div = 0.5 * (R - L + T - B);
gl_FragColor = vec4(div, 0.0, 0.0, 1.0);
}
`
);
const curlShader = compileShader(
gl.FRAGMENT_SHADER,
`
precision mediump float;
precision mediump sampler2D;
varying highp vec2 vUv;
varying highp vec2 vL;
varying highp vec2 vR;
varying highp vec2 vT;
varying highp vec2 vB;
uniform sampler2D uVelocity;
void main () {
float L = texture2D(uVelocity, vL).y;
float R = texture2D(uVelocity, vR).y;
float T = texture2D(uVelocity, vT).x;
float B = texture2D(uVelocity, vB).x;
float vorticity = R - L - T + B;
gl_FragColor = vec4(0.5 * vorticity, 0.0, 0.0, 1.0);
}
`
);
const vorticityShader = compileShader(
gl.FRAGMENT_SHADER,
`
precision highp float;
precision highp sampler2D;
varying vec2 vUv;
varying vec2 vL;
varying vec2 vR;
varying vec2 vT;
varying vec2 vB;
uniform sampler2D uVelocity;
uniform sampler2D uCurl;
uniform float curl;
uniform float dt;
void main () {
float L = texture2D(uCurl, vL).x;
float R = texture2D(uCurl, vR).x;
float T = texture2D(uCurl, vT).x;
float B = texture2D(uCurl, vB).x;
float C = texture2D(uCurl, vUv).x;
vec2 force = 0.5 * vec2(abs(T) - abs(B), abs(R) - abs(L));
force /= length(force) + 0.0001;
force *= curl * C;
force.y *= -1.0;
vec2 velocity = texture2D(uVelocity, vUv).xy;
velocity += force * dt;
velocity = min(max(velocity, -1000.0), 1000.0);
gl_FragColor = vec4(velocity, 0.0, 1.0);
}
`
);
const pressureShader = compileShader(
gl.FRAGMENT_SHADER,
`
precision mediump float;
precision mediump sampler2D;
varying highp vec2 vUv;
varying highp vec2 vL;
varying highp vec2 vR;
varying highp vec2 vT;
varying highp vec2 vB;
uniform sampler2D uPressure;
uniform sampler2D uDivergence;
void main () {
float L = texture2D(uPressure, vL).x;
float R = texture2D(uPressure, vR).x;
float T = texture2D(uPressure, vT).x;
float B = texture2D(uPressure, vB).x;
float C = texture2D(uPressure, vUv).x;
float divergence = texture2D(uDivergence, vUv).x;
float pressure = (L + R + B + T - divergence) * 0.25;
gl_FragColor = vec4(pressure, 0.0, 0.0, 1.0);
}
`
);
const gradientSubtractShader = compileShader(
gl.FRAGMENT_SHADER,
`
precision mediump float;
precision mediump sampler2D;
varying highp vec2 vUv;
varying highp vec2 vL;
varying highp vec2 vR;
varying highp vec2 vT;
varying highp vec2 vB;
uniform sampler2D uPressure;
uniform sampler2D uVelocity;
void main () {
float L = texture2D(uPressure, vL).x;
float R = texture2D(uPressure, vR).x;
float T = texture2D(uPressure, vT).x;
float B = texture2D(uPressure, vB).x;
vec2 velocity = texture2D(uVelocity, vUv).xy;
velocity.xy -= vec2(R - L, T - B);
gl_FragColor = vec4(velocity, 0.0, 1.0);
}
`
);
const blit = (() => {
gl.bindBuffer(gl.ARRAY_BUFFER, gl.createBuffer());
gl.bufferData(
gl.ARRAY_BUFFER,
new Float32Array([-1, -1, -1, 1, 1, 1, 1, -1]),
gl.STATIC_DRAW
);
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, gl.createBuffer());
gl.bufferData(
gl.ELEMENT_ARRAY_BUFFER,
new Uint16Array([0, 1, 2, 0, 2, 3]),
gl.STATIC_DRAW
);
gl.vertexAttribPointer(0, 2, gl.FLOAT, false, 0, 0);
gl.enableVertexAttribArray(0);
return (target, clear = false) => {
if (target == null) {
gl.viewport(0, 0, gl.drawingBufferWidth, gl.drawingBufferHeight);
gl.bindFramebuffer(gl.FRAMEBUFFER, null);
} else {
gl.viewport(0, 0, target.width, target.height);
gl.bindFramebuffer(gl.FRAMEBUFFER, target.fbo);
}
if (clear) {
gl.clearColor(0.0, 0.0, 0.0, 1.0);
gl.clear(gl.COLOR_BUFFER_BIT);
}
gl.drawElements(gl.TRIANGLES, 6, gl.UNSIGNED_SHORT, 0);
};
})();
function CHECK_FRAMEBUFFER_STATUS() {
let status = gl.checkFramebufferStatus(gl.FRAMEBUFFER);
if (status != gl.FRAMEBUFFER_COMPLETE)
console.trace("Framebuffer error: " + status);
}
let dye;
let velocity;
let divergence;
let curl;
let pressure;
let bloom;
let bloomFramebuffers = [];
let sunrays;
let sunraysTemp;
function createDitheringTexture() {
const size = 64;
const texture = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, texture);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.REPEAT);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.REPEAT);
const data = new Uint8Array(size * size);
for (let i = 0; i < size * size; i++) {
data[i] = Math.floor(Math.random() * 256);
}
gl.texImage2D(
gl.TEXTURE_2D,
0,
gl.LUMINANCE,
size,
size,
0,
gl.LUMINANCE,
gl.UNSIGNED_BYTE,
data
);
return {
texture,
width: size,
height: size,
attach(id) {
gl.activeTexture(gl.TEXTURE0 + id);
gl.bindTexture(gl.TEXTURE_2D, texture);
return id;
},
};
}
let ditheringTexture = createDitheringTexture();
const blurProgram = new Program(blurVertexShader, blurShader);
const copyProgram = new Program(baseVertexShader, copyShader);
const clearProgram = new Program(baseVertexShader, clearShader);
const colorProgram = new Program(baseVertexShader, colorShader);
const checkerboardProgram = new Program(baseVertexShader, checkerboardShader);
const bloomPrefilterProgram = new Program(
baseVertexShader,
bloomPrefilterShader
);
const bloomBlurProgram = new Program(baseVertexShader, bloomBlurShader);
const bloomFinalProgram = new Program(baseVertexShader, bloomFinalShader);
const sunraysMaskProgram = new Program(baseVertexShader, sunraysMaskShader);
const sunraysProgram = new Program(baseVertexShader, sunraysShader);
const splatProgram = new Program(baseVertexShader, splatShader);
const advectionProgram = new Program(baseVertexShader, advectionShader);
const divergenceProgram = new Program(baseVertexShader, divergenceShader);
const curlProgram = new Program(baseVertexShader, curlShader);
const vorticityProgram = new Program(baseVertexShader, vorticityShader);
const pressureProgram = new Program(baseVertexShader, pressureShader);
const gradienSubtractProgram = new Program(
baseVertexShader,
gradientSubtractShader
);
const displayMaterial = new Material(baseVertexShader, displayShaderSource);
function initFramebuffers() {
let simRes = getResolution(config.SIM_RESOLUTION);
let dyeRes = getResolution(config.DYE_RESOLUTION);
const texType = ext.halfFloatTexType;
const rgba = ext.formatRGBA;
const rg = ext.formatRG;
const r = ext.formatR;
const filtering = ext.supportLinearFiltering ? gl.LINEAR : gl.NEAREST;
gl.disable(gl.BLEND);
if (dye == null)
dye = createDoubleFBO(
dyeRes.width,
dyeRes.height,
rgba.internalFormat,
rgba.format,
texType,
filtering
);
else
dye = resizeDoubleFBO(
dye,
dyeRes.width,
dyeRes.height,
rgba.internalFormat,
rgba.format,
texType,
filtering
);
if (velocity == null)
velocity = createDoubleFBO(
simRes.width,
simRes.height,
rg.internalFormat,
rg.format,
texType,
filtering
);
else
velocity = resizeDoubleFBO(
velocity,
simRes.width,
simRes.height,
rg.internalFormat,
rg.format,
texType,
filtering
);
divergence = createFBO(
simRes.width,
simRes.height,
r.internalFormat,
r.format,
texType,
gl.NEAREST
);
curl = createFBO(
simRes.width,
simRes.height,
r.internalFormat,
r.format,
texType,
gl.NEAREST
);
pressure = createDoubleFBO(
simRes.width,
simRes.height,
r.internalFormat,
r.format,
texType,
gl.NEAREST
);
initBloomFramebuffers();
initSunraysFramebuffers();
}
function initBloomFramebuffers() {
let res = getResolution(config.BLOOM_RESOLUTION);
const texType = ext.halfFloatTexType;
const rgba = ext.formatRGBA;
const filtering = ext.supportLinearFiltering ? gl.LINEAR : gl.NEAREST;
bloom = createFBO(
res.width,
res.height,
rgba.internalFormat,
rgba.format,
texType,
filtering
);
bloomFramebuffers.length = 0;
for (let i = 0; i < config.BLOOM_ITERATIONS; i++) {
let width = res.width >> (i + 1);
let height = res.height >> (i + 1);
if (width < 2 || height < 2) break;
let fbo = createFBO(
width,
height,
rgba.internalFormat,
rgba.format,
texType,
filtering
);
bloomFramebuffers.push(fbo);
}
}
function initSunraysFramebuffers() {
let res = getResolution(config.SUNRAYS_RESOLUTION);
const texType = ext.halfFloatTexType;
const r = ext.formatR;
const filtering = ext.supportLinearFiltering ? gl.LINEAR : gl.NEAREST;
sunrays = createFBO(
res.width,
res.height,
r.internalFormat,
r.format,
texType,
filtering
);
sunraysTemp = createFBO(
res.width,
res.height,
r.internalFormat,
r.format,
texType,
filtering
);
}
function createFBO(w, h, internalFormat, format, type, param) {
gl.activeTexture(gl.TEXTURE0);
let texture = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, texture);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, param);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, param);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
gl.texImage2D(
gl.TEXTURE_2D,
0,
internalFormat,
w,
h,
0,
format,
type,
null
);
let fbo = gl.createFramebuffer();
gl.bindFramebuffer(gl.FRAMEBUFFER, fbo);
gl.framebufferTexture2D(
gl.FRAMEBUFFER,
gl.COLOR_ATTACHMENT0,
gl.TEXTURE_2D,
texture,
0
);
gl.viewport(0, 0, w, h);
gl.clear(gl.COLOR_BUFFER_BIT);
let texelSizeX = 1.0 / w;
let texelSizeY = 1.0 / h;
return {
texture,
fbo,
width: w,
height: h,
texelSizeX,
texelSizeY,
attach(id) {
gl.activeTexture(gl.TEXTURE0 + id);
gl.bindTexture(gl.TEXTURE_2D, texture);
return id;
},
};
}
function createDoubleFBO(w, h, internalFormat, format, type, param) {
let fbo1 = createFBO(w, h, internalFormat, format, type, param);
let fbo2 = createFBO(w, h, internalFormat, format, type, param);
return {
width: w,
height: h,
texelSizeX: fbo1.texelSizeX,
texelSizeY: fbo1.texelSizeY,
get read() {
return fbo1;
},
set read(value) {
fbo1 = value;
},
get write() {
return fbo2;
},
set write(value) {
fbo2 = value;
},
swap() {
let temp = fbo1;
fbo1 = fbo2;
fbo2 = temp;
},
};
}
function resizeFBO(target, w, h, internalFormat, format, type, param) {
let newFBO = createFBO(w, h, internalFormat, format, type, param);
copyProgram.bind();
gl.uniform1i(copyProgram.uniforms.uTexture, target.attach(0));
blit(newFBO);
return newFBO;
}
function resizeDoubleFBO(target, w, h, internalFormat, format, type, param) {
if (target.width == w && target.height == h) return target;
target.read = resizeFBO(
target.read,
w,
h,
internalFormat,
format,
type,
param
);
target.write = createFBO(w, h, internalFormat, format, type, param);
target.width = w;
target.height = h;
target.texelSizeX = 1.0 / w;
target.texelSizeY = 1.0 / h;
return target;
}
function updateKeywords() {
let displayKeywords = [];
if (config.SHADING) displayKeywords.push("SHADING");
if (config.BLOOM) displayKeywords.push("BLOOM");
if (config.SUNRAYS) displayKeywords.push("SUNRAYS");
displayMaterial.setKeywords(displayKeywords);
}
updateKeywords();
initFramebuffers();
multipleSplats(parseInt(Math.random() * 20) + 5);
let lastUpdateTime = Date.now();
let colorUpdateTimer = 0.0;
update();
function update() {
const dt = calcDeltaTime();
if (resizeCanvas()) initFramebuffers();
updateColors(dt);
applyInputs();
if (!config.PAUSED) step(dt);
render(null);
requestAnimationFrame(update);
}
function calcDeltaTime() {
let now = Date.now();
let dt = (now - lastUpdateTime) / 1000;
dt = Math.min(dt, 0.016666);
lastUpdateTime = now;
return dt;
}
function updateColors(dt) {
if (!config.COLORFUL) return;
colorUpdateTimer += dt * config.COLOR_UPDATE_SPEED;
if (colorUpdateTimer >= 1) {
colorUpdateTimer = wrap(colorUpdateTimer, 0, 1);
pointers.forEach((p) => {
p.color = generateColor();
});
}
}
function applyInputs() {
if (splatStack.length > 0) multipleSplats(splatStack.pop());
pointers.forEach((p) => {
if (p.moved) {
p.moved = false;
splatPointer(p);
}
});
}
function step(dt) {
gl.disable(gl.BLEND);
curlProgram.bind();
gl.uniform2f(
curlProgram.uniforms.texelSize,
velocity.texelSizeX,
velocity.texelSizeY
);
gl.uniform1i(curlProgram.uniforms.uVelocity, velocity.read.attach(0));
blit(curl);
vorticityProgram.bind();
gl.uniform2f(
vorticityProgram.uniforms.texelSize,
velocity.texelSizeX,
velocity.texelSizeY
);
gl.uniform1i(vorticityProgram.uniforms.uVelocity, velocity.read.attach(0));
gl.uniform1i(vorticityProgram.uniforms.uCurl, curl.attach(1));
gl.uniform1f(vorticityProgram.uniforms.curl, config.CURL);
gl.uniform1f(vorticityProgram.uniforms.dt, dt);
blit(velocity.write);
velocity.swap();
divergenceProgram.bind();
gl.uniform2f(
divergenceProgram.uniforms.texelSize,
velocity.texelSizeX,
velocity.texelSizeY
);
gl.uniform1i(divergenceProgram.uniforms.uVelocity, velocity.read.attach(0));
blit(divergence);
clearProgram.bind();
gl.uniform1i(clearProgram.uniforms.uTexture, pressure.read.attach(0));
gl.uniform1f(clearProgram.uniforms.value, config.PRESSURE);
blit(pressure.write);
pressure.swap();
pressureProgram.bind();
gl.uniform2f(
pressureProgram.uniforms.texelSize,
velocity.texelSizeX,
velocity.texelSizeY
);
gl.uniform1i(pressureProgram.uniforms.uDivergence, divergence.attach(0));
for (let i = 0; i < config.PRESSURE_ITERATIONS; i++) {
gl.uniform1i(pressureProgram.uniforms.uPressure, pressure.read.attach(1));
blit(pressure.write);
pressure.swap();
}
gradienSubtractProgram.bind();
gl.uniform2f(
gradienSubtractProgram.uniforms.texelSize,
velocity.texelSizeX,
velocity.texelSizeY
);
gl.uniform1i(
gradienSubtractProgram.uniforms.uPressure,
pressure.read.attach(0)
);
gl.uniform1i(
gradienSubtractProgram.uniforms.uVelocity,
velocity.read.attach(1)
);
blit(velocity.write);
velocity.swap();
advectionProgram.bind();
gl.uniform2f(
advectionProgram.uniforms.texelSize,
velocity.texelSizeX,
velocity.texelSizeY
);
if (!ext.supportLinearFiltering)
gl.uniform2f(
advectionProgram.uniforms.dyeTexelSize,
velocity.texelSizeX,
velocity.texelSizeY
);
let velocityId = velocity.read.attach(0);
gl.uniform1i(advectionProgram.uniforms.uVelocity, velocityId);
gl.uniform1i(advectionProgram.uniforms.uSource, velocityId);
gl.uniform1f(advectionProgram.uniforms.dt, dt);
gl.uniform1f(
advectionProgram.uniforms.dissipation,
config.VELOCITY_DISSIPATION
);
blit(velocity.write);
velocity.swap();
if (!ext.supportLinearFiltering)
gl.uniform2f(
advectionProgram.uniforms.dyeTexelSize,
dye.texelSizeX,
dye.texelSizeY
);
gl.uniform1i(advectionProgram.uniforms.uVelocity, velocity.read.attach(0));
gl.uniform1i(advectionProgram.uniforms.uSource, dye.read.attach(1));
gl.uniform1f(
advectionProgram.uniforms.dissipation,
config.DENSITY_DISSIPATION
);
blit(dye.write);
dye.swap();
}
function render(target) {
if (config.BLOOM) applyBloom(dye.read, bloom);
if (config.SUNRAYS) {
applySunrays(dye.read, dye.write, sunrays);
blur(sunrays, sunraysTemp, 1);
}
if (target == null || !config.TRANSPARENT) {
gl.blendFunc(gl.ONE, gl.ONE_MINUS_SRC_ALPHA);
gl.enable(gl.BLEND);
} else {
gl.disable(gl.BLEND);
}
if (!config.TRANSPARENT)
drawColor(target, normalizeColor(config.BACK_COLOR));
if (target == null && config.TRANSPARENT) drawCheckerboard(target);
drawDisplay(target);
}
function drawColor(target, color) {
colorProgram.bind();
gl.uniform4f(colorProgram.uniforms.color, color.r, color.g, color.b, 1);
blit(target);
}
function drawCheckerboard(target) {
checkerboardProgram.bind();
gl.uniform1f(
checkerboardProgram.uniforms.aspectRatio,
canvas.width / canvas.height
);
blit(target);
}
function drawDisplay(target) {
let width = target == null ? gl.drawingBufferWidth : target.width;
let height = target == null ? gl.drawingBufferHeight : target.height;
displayMaterial.bind();
if (config.SHADING)
gl.uniform2f(
displayMaterial.uniforms.texelSize,
1.0 / width,
1.0 / height
);
gl.uniform1i(displayMaterial.uniforms.uTexture, dye.read.attach(0));
if (config.BLOOM) {
gl.uniform1i(displayMaterial.uniforms.uBloom, bloom.attach(1));
gl.uniform1i(
displayMaterial.uniforms.uDithering,
ditheringTexture.attach(2)
);
let scale = getTextureScale(ditheringTexture, width, height);
gl.uniform2f(displayMaterial.uniforms.ditherScale, scale.x, scale.y);
}
if (config.SUNRAYS)
gl.uniform1i(displayMaterial.uniforms.uSunrays, sunrays.attach(3));
blit(target);
}
function applyBloom(source, destination) {
if (bloomFramebuffers.length < 2) return;
let last = destination;
gl.disable(gl.BLEND);
bloomPrefilterProgram.bind();
let knee = config.BLOOM_THRESHOLD * config.BLOOM_SOFT_KNEE + 0.0001;
let curve0 = config.BLOOM_THRESHOLD - knee;
let curve1 = knee * 2;
let curve2 = 0.25 / knee;
gl.uniform3f(bloomPrefilterProgram.uniforms.curve, curve0, curve1, curve2);
gl.uniform1f(
bloomPrefilterProgram.uniforms.threshold,
config.BLOOM_THRESHOLD
);
gl.uniform1i(bloomPrefilterProgram.uniforms.uTexture, source.attach(0));
blit(last);
bloomBlurProgram.bind();
for (let i = 0; i < bloomFramebuffers.length; i++) {
let dest = bloomFramebuffers[i];
gl.uniform2f(
bloomBlurProgram.uniforms.texelSize,
last.texelSizeX,
last.texelSizeY
);
gl.uniform1i(bloomBlurProgram.uniforms.uTexture, last.attach(0));
blit(dest);
last = dest;
}
gl.blendFunc(gl.ONE, gl.ONE);
gl.enable(gl.BLEND);
for (let i = bloomFramebuffers.length - 2; i >= 0; i--) {
let baseTex = bloomFramebuffers[i];
gl.uniform2f(
bloomBlurProgram.uniforms.texelSize,
last.texelSizeX,
last.texelSizeY
);
gl.uniform1i(bloomBlurProgram.uniforms.uTexture, last.attach(0));
gl.viewport(0, 0, baseTex.width, baseTex.height);
blit(baseTex);
last = baseTex;
}
gl.disable(gl.BLEND);
bloomFinalProgram.bind();
gl.uniform2f(
bloomFinalProgram.uniforms.texelSize,
last.texelSizeX,
last.texelSizeY
);
gl.uniform1i(bloomFinalProgram.uniforms.uTexture, last.attach(0));
gl.uniform1f(bloomFinalProgram.uniforms.intensity, config.BLOOM_INTENSITY);
blit(destination);
}
function applySunrays(source, mask, destination) {
gl.disable(gl.BLEND);
sunraysMaskProgram.bind();
gl.uniform1i(sunraysMaskProgram.uniforms.uTexture, source.attach(0));
blit(mask);
sunraysProgram.bind();
gl.uniform1f(sunraysProgram.uniforms.weight, config.SUNRAYS_WEIGHT);
gl.uniform1i(sunraysProgram.uniforms.uTexture, mask.attach(0));
blit(destination);
}
function blur(target, temp, iterations) {
blurProgram.bind();
for (let i = 0; i < iterations; i++) {
gl.uniform2f(blurProgram.uniforms.texelSize, target.texelSizeX, 0.0);
gl.uniform1i(blurProgram.uniforms.uTexture, target.attach(0));
blit(temp);
gl.uniform2f(blurProgram.uniforms.texelSize, 0.0, target.texelSizeY);
gl.uniform1i(blurProgram.uniforms.uTexture, temp.attach(0));
blit(target);
}
}
function splatPointer(pointer) {
let dx = pointer.deltaX * config.SPLAT_FORCE;
let dy = pointer.deltaY * config.SPLAT_FORCE;
splat(pointer.texcoordX, pointer.texcoordY, dx, dy, pointer.color);
}
function multipleSplats(amount) {
for (let i = 0; i < amount; i++) {
const color = generateColor();
color.r *= 10.0;
color.g *= 10.0;
color.b *= 10.0;
const x = Math.random();
const y = Math.random();
const dx = 1000 * (Math.random() - 0.5);
const dy = 1000 * (Math.random() - 0.5);
splat(x, y, dx, dy, color);
}
}
function splat(x, y, dx, dy, color) {
splatProgram.bind();
gl.uniform1i(splatProgram.uniforms.uTarget, velocity.read.attach(0));
gl.uniform1f(
splatProgram.uniforms.aspectRatio,
canvas.width / canvas.height
);
gl.uniform2f(splatProgram.uniforms.point, x, y);
gl.uniform3f(splatProgram.uniforms.color, dx, dy, 0.0);
gl.uniform1f(
splatProgram.uniforms.radius,
correctRadius(config.SPLAT_RADIUS / 100.0)
);
blit(velocity.write);
velocity.swap();
gl.uniform1i(splatProgram.uniforms.uTarget, dye.read.attach(0));
gl.uniform3f(splatProgram.uniforms.color, color.r, color.g, color.b);
blit(dye.write);
dye.swap();
}
function correctRadius(radius) {
let aspectRatio = canvas.width / canvas.height;
if (aspectRatio > 1) radius *= aspectRatio;
return radius;
}
canvas.addEventListener("mousemove", (e) => {
let pointer = pointers[0];
let posX = scaleByPixelRatio(e.offsetX);
let posY = scaleByPixelRatio(e.offsetY);
if (!pointer.down) {
updatePointerDownData(pointer, -1, posX, posY);
}
updatePointerMoveData(pointer, posX, posY);
});
window.addEventListener("mouseup", () => {
updatePointerUpData(pointers[0]);
});
canvas.addEventListener("touchstart", (e) => {
e.preventDefault();
const touches = e.targetTouches;
while (touches.length >= pointers.length)
pointers.push(new pointerPrototype());
for (let i = 0; i < touches.length; i++) {
let posX = scaleByPixelRatio(touches[i].pageX);
let posY = scaleByPixelRatio(touches[i].pageY);
updatePointerDownData(pointers[i + 1], touches[i].identifier, posX, posY);
}
});
canvas.addEventListener(
"touchmove",
(e) => {
e.preventDefault();
const touches = e.targetTouches;
for (let i = 0; i < touches.length; i++) {
let pointer = pointers[i + 1];
if (!pointer.down) continue;
let posX = scaleByPixelRatio(touches[i].pageX);
let posY = scaleByPixelRatio(touches[i].pageY);
updatePointerMoveData(pointer, posX, posY);
}
},
false
);
window.addEventListener("touchend", (e) => {
const touches = e.changedTouches;
for (let i = 0; i < touches.length; i++) {
let pointer = pointers.find((p) => p.id == touches[i].identifier);
if (pointer == null) continue;
updatePointerUpData(pointer);
}
});
window.addEventListener("keydown", (e) => {
if (e.code === "KeyP") config.PAUSED = !config.PAUSED;
if (e.key === " ") splatStack.push(parseInt(Math.random() * 20) + 5);
});
function updatePointerDownData(pointer, id, posX, posY) {
pointer.id = id;
pointer.down = true;
pointer.moved = false;
pointer.texcoordX = posX / canvas.width;
pointer.texcoordY = 1.0 - posY / canvas.height;
pointer.prevTexcoordX = pointer.texcoordX;
pointer.prevTexcoordY = pointer.texcoordY;
pointer.deltaX = 0;
pointer.deltaY = 0;
pointer.color = generateColor();
}
function updatePointerMoveData(pointer, posX, posY) {
pointer.prevTexcoordX = pointer.texcoordX;
pointer.prevTexcoordY = pointer.texcoordY;
pointer.texcoordX = posX / canvas.width;
pointer.texcoordY = 1.0 - posY / canvas.height;
pointer.deltaX = correctDeltaX(pointer.texcoordX - pointer.prevTexcoordX);
pointer.deltaY = correctDeltaY(pointer.texcoordY - pointer.prevTexcoordY);
pointer.moved =
Math.abs(pointer.deltaX) > 0 || Math.abs(pointer.deltaY) > 0;
}
function updatePointerUpData(pointer) {
pointer.down = false;
}
function correctDeltaX(delta) {
let aspectRatio = canvas.width / canvas.height;
if (aspectRatio < 1) delta *= aspectRatio;
return delta;
}
function correctDeltaY(delta) {
let aspectRatio = canvas.width / canvas.height;
if (aspectRatio > 1) delta /= aspectRatio;
return delta;
}
function generateColor() {
if (config.RANDOM_COLORS) {
let c = HSVtoRGB(Math.random(), 1.0, 1.0);
c.r *= 0.15;
c.g *= 0.15;
c.b *= 0.15;
return c;
} else {
let c = HSVtoRGB(config.SPLAT_HUE, 1.0, 1.0);
c.r *= 0.15;
c.g *= 0.15;
c.b *= 0.15;
return c;
}
}
function HSVtoRGB(h, s, v) {
let r, g, b, i, f, p, q, t;
i = Math.floor(h * 6);
f = h * 6 - i;
p = v * (1 - s);
q = v * (1 - f * s);
t = v * (1 - (1 - f) * s);
switch (i % 6) {
case 0:
(r = v), (g = t), (b = p);
break;
case 1:
(r = q), (g = v), (b = p);
break;
case 2:
(r = p), (g = v), (b = t);
break;
case 3:
(r = p), (g = q), (b = v);
break;
case 4:
(r = t), (g = p), (b = v);
break;
case 5:
(r = v), (g = p), (b = q);
break;
}
return {
r,
g,
b,
};
}
function normalizeColor(input) {
let output = {
r: input.r / 255,
g: input.g / 255,
b: input.b / 255,
};
return output;
}
function wrap(value, min, max) {
let range = max - min;
if (range == 0) return min;
return ((value - min) % range) + min;
}
function getResolution(resolution) {
let aspectRatio = gl.drawingBufferWidth / gl.drawingBufferHeight;
if (aspectRatio < 1) aspectRatio = 1.0 / aspectRatio;
let min = Math.round(resolution);
let max = Math.round(resolution * aspectRatio);
if (gl.drawingBufferWidth > gl.drawingBufferHeight)
return { width: max, height: min };
else return { width: min, height: max };
}
function getTextureScale(texture, width, height) {
return {
x: width / texture.width,
y: height / texture.height,
};
}
function hashCode(s) {
if (s.length == 0) return 0;
let hash = 0;
for (let i = 0; i < s.length; i++) {
hash = (hash << 5) - hash + s.charCodeAt(i);
hash |= 0;
}
return hash;
}
}
</script>
</body>
</html>