<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
section {
position: relative;
width: 100%;
height: 100vh;
background: #f5f5f5;
}
#pretty-bg {
position: absolute;
width: 100%;
height: 100%;
top: 0;
left: 0;
z-index: 2;
}
</style>
</head>
<body>
<section>
<canvas id="pretty-bg" width="375" height="216"></canvas>
</section>
<div>
<td>R10.</td>
<td>r10</td>
</div>
<script>
'use strict';
const canvas = document.getElementById('pretty-bg');
if (canvas) {
canvas.width = canvas.clientWidth;
canvas.height = canvas.clientHeight;
let config = {
SIM_RESOLUTION: 128,
DYE_RESOLUTION: 512,
DENSITY_DISSIPATION: 0.99,
VELOCITY_DISSIPATION: 0.98,
PRESSURE_DISSIPATION: 0.8,
PRESSURE_ITERATIONS: 20,
CURL: 20,
SPLAT_RADIUS: 0.8,
SHADING: true,
COLORFUL: true,
PAUSED: false,
BACK_COLOR: {
r: 0,
g: 0,
b: 0
},
TRANSPARENT: true
}
function pointerPrototype() {
this.id = -1;
this.x = 0;
this.y = 0;
this.dx = 0;
this.dy = 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 = 128;
config.SHADING = false;
}
if (!ext.supportLinearFiltering)
config.SHADING = 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);
const status = gl.checkFramebufferStatus(gl.FRAMEBUFFER);
if (status != gl.FRAMEBUFFER_COMPLETE)
return false;
return true;
}
function clamp01(input) {
return Math.min(Math.max(input, 0), 1);
}
function isMobile() {
return /Mobi|Android/i.test(navigator.userAgent);
}
class GLProgram {
constructor(vertexShader, fragmentShader) {
this.uniforms = {};
this.program = gl.createProgram();
gl.attachShader(this.program, vertexShader);
gl.attachShader(this.program, fragmentShader);
gl.linkProgram(this.program);
if (!gl.getProgramParameter(this.program, gl.LINK_STATUS))
throw gl.getProgramInfoLog(this.program);
const uniformCount = gl.getProgramParameter(this.program, gl.ACTIVE_UNIFORMS);
for (let i = 0; i < uniformCount; i++) {
const uniformName = gl.getActiveUniform(this.program, i).name;
this.uniforms[uniformName] = gl.getUniformLocation(this.program, uniformName);
}
}
bind() {
gl.useProgram(this.program);
}
}
function compileShader(type, source) {
const shader = gl.createShader(type);
gl.shaderSource(shader, source);
gl.compileShader(shader);
if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS))
throw gl.getShaderInfoLog(shader);
return shader;
};
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 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 backgroundShader = 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 displayShader = compileShader(gl.FRAGMENT_SHADER, `
precision highp float;
precision highp sampler2D;
varying vec2 vUv;
uniform sampler2D uTexture;
void main () {
vec3 C = texture2D(uTexture, vUv).rgb;
float a = max(C.r, max(C.g, C.b));
gl_FragColor = vec4(C, a);
}
`);
const displayShadingShader = 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 uTexture;
uniform vec2 texelSize;
void main () {
vec3 L = texture2D(uTexture, vL).rgb;
vec3 R = texture2D(uTexture, vR).rgb;
vec3 T = texture2D(uTexture, vT).rgb;
vec3 B = texture2D(uTexture, vB).rgb;
vec3 C = texture2D(uTexture, vUv).rgb;
float dx = length(R) - length(L);
float dy = length(T) - length(B);
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.rgb *= diffuse;
float a = max(C.r, max(C.g, C.b));
gl_FragColor = vec4(C, a);
}
`);
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 advectionManualFilteringShader = 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 () {
vec2 coord = vUv - dt * bilerp(uVelocity, vUv, texelSize).xy * texelSize;
gl_FragColor = dissipation * bilerp(uSource, coord, dyeTexelSize);
gl_FragColor.a = 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 float dt;
uniform float dissipation;
void main () {
vec2 coord = vUv - dt * texture2D(uVelocity, vUv).xy * texelSize;
gl_FragColor = dissipation * texture2D(uSource, coord);
gl_FragColor.a = 1.0;
}
`);
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 vel = texture2D(uVelocity, vUv).xy;
gl_FragColor = vec4(vel + force * dt, 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;
vec2 boundary (vec2 uv) {
return uv;
// uncomment if you use wrap or repeat texture mode
// uv = min(max(uv, 0.0), 1.0);
// return uv;
}
void main () {
float L = texture2D(uPressure, boundary(vL)).x;
float R = texture2D(uPressure, boundary(vR)).x;
float T = texture2D(uPressure, boundary(vT)).x;
float B = texture2D(uPressure, boundary(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;
vec2 boundary (vec2 uv) {
return uv;
// uv = min(max(uv, 0.0), 1.0);
// return uv;
}
void main () {
float L = texture2D(uPressure, boundary(vL)).x;
float R = texture2D(uPressure, boundary(vR)).x;
float T = texture2D(uPressure, boundary(vT)).x;
float B = texture2D(uPressure, boundary(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 (destination) => {
gl.bindFramebuffer(gl.FRAMEBUFFER, destination);
gl.drawElements(gl.TRIANGLES, 6, gl.UNSIGNED_SHORT, 0);
}
})();
let simWidth;
let simHeight;
let dyeWidth;
let dyeHeight;
let density;
let velocity;
let divergence;
let curl;
let pressure;
const clearProgram = new GLProgram(baseVertexShader, clearShader);
const colorProgram = new GLProgram(baseVertexShader, colorShader);
const backgroundProgram = new GLProgram(baseVertexShader, backgroundShader);
const displayProgram = new GLProgram(baseVertexShader, displayShader);
const displayShadingProgram = new GLProgram(baseVertexShader, displayShadingShader);
const splatProgram = new GLProgram(baseVertexShader, splatShader);
const advectionProgram = new GLProgram(baseVertexShader, ext.supportLinearFiltering ? advectionShader : advectionManualFilteringShader);
const divergenceProgram = new GLProgram(baseVertexShader, divergenceShader);
const curlProgram = new GLProgram(baseVertexShader, curlShader);
const vorticityProgram = new GLProgram(baseVertexShader, vorticityShader);
const pressureProgram = new GLProgram(baseVertexShader, pressureShader);
const gradienSubtractProgram = new GLProgram(baseVertexShader, gradientSubtractShader);
function initFramebuffers() {
let simRes = getResolution(config.SIM_RESOLUTION);
let dyeRes = getResolution(config.DYE_RESOLUTION);
simWidth = simRes.width;
simHeight = simRes.height;
dyeWidth = dyeRes.width;
dyeHeight = dyeRes.height;
const texType = ext.halfFloatTexType;
const rgba = ext.formatRGBA;
const rg = ext.formatRG;
const r = ext.formatR;
density = createDoubleFBO(2, dyeWidth, dyeHeight, rgba.internalFormat, rgba.format, texType, ext.supportLinearFiltering ? gl.LINEAR : gl.NEAREST);
velocity = createDoubleFBO(0, simWidth, simHeight, rg.internalFormat, rg.format, texType, ext.supportLinearFiltering ? gl.LINEAR : gl.NEAREST);
divergence = createFBO(4, simWidth, simHeight, r.internalFormat, r.format, texType, gl.NEAREST);
curl = createFBO(5, simWidth, simHeight, r.internalFormat, r.format, texType, gl.NEAREST);
pressure = createDoubleFBO(6, simWidth, simHeight, r.internalFormat, r.format, texType, gl.NEAREST);
}
function getResolution(resolution) {
let aspectRatio = gl.drawingBufferWidth / gl.drawingBufferHeight;
if (aspectRatio < 1)
aspectRatio = 1.0 / aspectRatio;
let max = Math.round(resolution * aspectRatio);
let min = Math.round(resolution);
if (gl.drawingBufferWidth > gl.drawingBufferHeight)
return {
width: max,
height: min
};
else
return {
width: min,
height: max
};
}
function createFBO(texId, w, h, internalFormat, format, type, param) {
gl.activeTexture(gl.TEXTURE0 + texId);
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);
return {
texture,
fbo,
texId
};
}
function createDoubleFBO(texId, w, h, internalFormat, format, type, param) {
let fbo1 = createFBO(texId, w, h, internalFormat, format, type, param);
let fbo2 = createFBO(texId + 1, w, h, internalFormat, format, type, param);
return {
get read() {
return fbo1;
},
get write() {
return fbo2;
},
swap() {
let temp = fbo1;
fbo1 = fbo2;
fbo2 = temp;
}
}
}
initFramebuffers();
let lastColorChangeTime = Date.now();
update();
function update() {
resizeCanvas();
input();
if (!config.PAUSED)
step(0.016);
render(null);
requestAnimationFrame(update);
}
function input() {
if (splatStack.length > 0)
multipleSplats(splatStack.pop());
for (let i = 0; i < pointers.length; i++) {
const p = pointers[i];
if (p.moved) {
splat(p.x, p.y, p.dx, p.dy, p.color);
p.moved = false;
}
}
if (!config.COLORFUL)
return;
if (lastColorChangeTime + 100 < Date.now()) {
lastColorChangeTime = Date.now();
for (let i = 0; i < pointers.length; i++) {
const p = pointers[i];
p.color = generateColor();
}
}
}
function step(dt) {
gl.disable(gl.BLEND);
gl.viewport(0, 0, simWidth, simHeight);
curlProgram.bind();
gl.uniform2f(curlProgram.uniforms.texelSize, 1.0 / simWidth, 1.0 / simHeight);
gl.uniform1i(curlProgram.uniforms.uVelocity, velocity.read.texId);
blit(curl.fbo);
vorticityProgram.bind();
gl.uniform2f(vorticityProgram.uniforms.texelSize, 1.0 / simWidth, 1.0 / simHeight);
gl.uniform1i(vorticityProgram.uniforms.uVelocity, velocity.read.texId);
gl.uniform1i(vorticityProgram.uniforms.uCurl, curl.texId);
gl.uniform1f(vorticityProgram.uniforms.curl, config.CURL);
gl.uniform1f(vorticityProgram.uniforms.dt, dt);
blit(velocity.write.fbo);
velocity.swap();
divergenceProgram.bind();
gl.uniform2f(divergenceProgram.uniforms.texelSize, 1.0 / simWidth, 1.0 / simHeight);
gl.uniform1i(divergenceProgram.uniforms.uVelocity, velocity.read.texId);
blit(divergence.fbo);
clearProgram.bind();
let pressureTexId = pressure.read.texId;
gl.activeTexture(gl.TEXTURE0 + pressureTexId);
gl.bindTexture(gl.TEXTURE_2D, pressure.read.texture);
gl.uniform1i(clearProgram.uniforms.uTexture, pressureTexId);
gl.uniform1f(clearProgram.uniforms.value, config.PRESSURE_DISSIPATION);
blit(pressure.write.fbo);
pressure.swap();
pressureProgram.bind();
gl.uniform2f(pressureProgram.uniforms.texelSize, 1.0 / simWidth, 1.0 / simHeight);
gl.uniform1i(pressureProgram.uniforms.uDivergence, divergence.texId);
pressureTexId = pressure.read.texId;
gl.uniform1i(pressureProgram.uniforms.uPressure, pressureTexId);
gl.activeTexture(gl.TEXTURE0 + pressureTexId);
for (let i = 0; i < config.PRESSURE_ITERATIONS; i++) {
gl.bindTexture(gl.TEXTURE_2D, pressure.read.texture);
blit(pressure.write.fbo);
pressure.swap();
}
gradienSubtractProgram.bind();
gl.uniform2f(gradienSubtractProgram.uniforms.texelSize, 1.0 / simWidth, 1.0 / simHeight);
gl.uniform1i(gradienSubtractProgram.uniforms.uPressure, pressure.read.texId);
gl.uniform1i(gradienSubtractProgram.uniforms.uVelocity, velocity.read.texId);
blit(velocity.write.fbo);
velocity.swap();
advectionProgram.bind();
gl.uniform2f(advectionProgram.uniforms.texelSize, 1.0 / simWidth, 1.0 / simHeight);
if (!ext.supportLinearFiltering)
gl.uniform2f(advectionProgram.uniforms.dyeTexelSize, 1.0 / simWidth, 1.0 / simHeight);
gl.uniform1i(advectionProgram.uniforms.uVelocity, velocity.read.texId);
gl.uniform1i(advectionProgram.uniforms.uSource, velocity.read.texId);
gl.uniform1f(advectionProgram.uniforms.dt, dt);
gl.uniform1f(advectionProgram.uniforms.dissipation, config.VELOCITY_DISSIPATION);
blit(velocity.write.fbo);
velocity.swap();
gl.viewport(0, 0, dyeWidth, dyeHeight);
if (!ext.supportLinearFiltering)
gl.uniform2f(advectionProgram.uniforms.dyeTexelSize, 1.0 / dyeWidth, 1.0 / dyeHeight);
gl.uniform1i(advectionProgram.uniforms.uVelocity, velocity.read.texId);
gl.uniform1i(advectionProgram.uniforms.uSource, density.read.texId);
gl.uniform1f(advectionProgram.uniforms.dissipation, config.DENSITY_DISSIPATION);
blit(density.write.fbo);
density.swap();
}
function render(target) {
if (target == null || !config.TRANSPARENT) {
gl.blendFunc(gl.ONE, gl.ONE_MINUS_SRC_ALPHA);
gl.enable(gl.BLEND);
} else {
gl.disable(gl.BLEND);
}
let width = target == null ? gl.drawingBufferWidth : dyeWidth;
let height = target == null ? gl.drawingBufferHeight : dyeHeight;
gl.viewport(0, 0, width, height);
if (!config.TRANSPARENT) {
colorProgram.bind();
let bc = config.BACK_COLOR;
gl.uniform4f(colorProgram.uniforms.color, bc.r / 255, bc.g / 255, bc.b / 255, 1);
blit(target);
}
if (target == null && config.TRANSPARENT) {
backgroundProgram.bind();
// gl.uniform1f(backgroundProgram.uniforms.aspectRatio, canvas.width / canvas.height);
// blit(null);
}
if (config.SHADING) {
displayShadingProgram.bind();
gl.uniform2f(displayShadingProgram.uniforms.texelSize, 1.0 / width, 1.0 / height);
gl.uniform1i(displayShadingProgram.uniforms.uTexture, density.read.texId);
} else {
displayProgram.bind();
gl.uniform1i(displayProgram.uniforms.uTexture, density.read.texId);
}
blit(target);
}
function splat(x, y, dx, dy, color) {
gl.viewport(0, 0, simWidth, simHeight);
splatProgram.bind();
gl.uniform1i(splatProgram.uniforms.uTarget, velocity.read.texId);
gl.uniform1f(splatProgram.uniforms.aspectRatio, canvas.width / canvas.height);
gl.uniform2f(splatProgram.uniforms.point, x / canvas.width, 1.0 - y / canvas.height);
gl.uniform3f(splatProgram.uniforms.color, dx, -dy, 1.0);
gl.uniform1f(splatProgram.uniforms.radius, config.SPLAT_RADIUS / 100.0);
blit(velocity.write.fbo);
velocity.swap();
gl.viewport(0, 0, dyeWidth, dyeHeight);
gl.uniform1i(splatProgram.uniforms.uTarget, density.read.texId);
gl.uniform3f(splatProgram.uniforms.color, color.r, color.g, color.b);
blit(density.write.fbo);
density.swap();
}
function multipleSplats(amount, move = false) {
for (let i = 0; i < amount; i++) {
const color = generateColor();
color.r *= 10.0;
color.g *= 10.0;
color.b *= 10.0;
var x = canvas.width * Math.random();
var y = canvas.height * Math.random();
var dx = 1000 * (Math.random() - 0.5);
var dy = 1000 * (Math.random() - 0.5);
if (move) {
x = canvas.width / 2;
y = canvas.height / 2;
dx = 1000 * (Math.random() - 0.5);
dy = 1000 * (Math.random() - 0.5);
}
splat(x, y, dx, dy, color);
}
}
function resizeCanvas() {
if (canvas.width != canvas.clientWidth || canvas.height != canvas.clientHeight) {
canvas.width = canvas.clientWidth;
canvas.height = canvas.clientHeight;
initFramebuffers();
}
}
// setInterval(function(){
// multipleSplats(1, true);
// },900)
var my_dx = 0;
var my_dy = 0;
var my_color = generateColor();
canvas.addEventListener('mousemove', e => {
splat(e.offsetX,e.offsetY, (e.offsetX - my_dx)*5, (e.offsetY - my_dy)*5, my_color);
my_dx = e.offsetX;
my_dy = e.offsetY;
});
setInterval(function(){
my_color = generateColor();
}, 500);
// var f = true;
canvas.addEventListener('touchmove', e => {
// if (f){
// f = false;
// }
// multipleSplats(1, true);
e.preventDefault();
const touches = e.targetTouches;
for (let i = 0; i < touches.length; i++) {
let pointer = pointers[i];
pointer.moved = pointer.down;
pointer.dx = (touches[i].pageX - pointer.x) * 8.0;
pointer.dy = (touches[i].pageY - pointer.y) * 8.0;
pointer.x = touches[i].pageX;
pointer.y = touches[i].pageY;
}
}, false);
// canvas.addEventListener('mousedown', () => {
// pointers[0].color = generateColor();
// });
// pointers[0].color = generateColor();
canvas.addEventListener('touchstart', e => {
e.preventDefault();
const touches = e.targetTouches;
for (let i = 0; i < touches.length; i++) {
if (i >= pointers.length)
pointers.push(new pointerPrototype());
pointers[i].id = touches[i].identifier;
pointers[i].down = true;
pointers[i].x = touches[i].pageX;
pointers[i].y = touches[i].pageY;
pointers[i].color = generateColor();
}
});
window.addEventListener('mouseup', () => {
pointers[0].down = false;
});
window.addEventListener('touchend', e => {
const touches = e.changedTouches;
for (let i = 0; i < touches.length; i++)
for (let j = 0; j < pointers.length; j++)
if (touches[i].identifier == pointers[j].id)
pointers[j].down = false;
});
window.addEventListener('keydown', e => {
if (e.key === 'p')
config.PAUSED = !config.PAUSED;
});
function generateColor() {
// let c = HSVtoRGB(0.2518, 0.9430, 0.7569);
// var f = Math.random(1);
// console.log(f);
// let colors = [
// HSVtoRGB(0.4713, 0.4819, 0.7569),
// HSVtoRGB(0.6104, 0.3776, 0.7686),
// HSVtoRGB(0.0254, 0.5481, 0.9373),
// HSVtoRGB(0.0608, 0.4948, 0.7608),
// HSVtoRGB(0.6140, 0.0748, 0.9961),
// ]
// let first = HSVtoRGB(0.4713, 0.4819, 0.7569);
// let second = HSVtoRGB(0.6104, 0.3776, 0.7686);
// let third = HSVtoRGB(0.0254, 0.5481, 0.9373);
// let fourth = HSVtoRGB(0.0608, 0.4948, 0.7608);
// let fifth = HSVtoRGB(0.6140, 0.0748, 0.9961);
// let f = getRandomInt(0,4);
// let c;
// c = colors[f];
// let c = {
// r = 100,
// g = 193,
// b = 177
// };
// console.log(c);
// c.r *= 0.1;
// c.g *= 0.1;
// c.b *= 0.1;
let c = HSVtoRGB(Math.random(), 1.0, 1.0);
c.r *= 0.15;
c.g *= 0.15;
c.b *= 0.15;
return c;
return c;
}
function getRandomInt(min, max) {
min = Math.ceil(min);
max = Math.floor(max);
return Math.floor(Math.random() * (max - min + 1)) + min;
}
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
};
}
}
</script>
</body>
</html> 
