'use strict'; const canvas = document.getElementsByTagName('canvas')[0]; canvas.width = canvas.clientWidth; canvas.height = canvas.clientHeight; let config = { SIM_RESOLUTION: 128, DYE_RESOLUTION: 512, DENSITY_DISSIPATION: 0.97, VELOCITY_DISSIPATION: 0.98, PRESSURE_DISSIPATION: 0.8, PRESSURE_ITERATIONS: 20, CURL: 30, SPLAT_RADIUS: 0.5, SHADING: true, COLORFUL: true, 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 } 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 = []; let bloomFramebuffers = []; pointers.push(new pointerPrototype()); const { gl, ext } = getWebGLContext(canvas); if (isMobile()) config.SHADING = false; if (!ext.supportLinearFiltering) { config.SHADING = false; config.BLOOM = 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 captureScreenshot () { colorProgram.bind(); gl.uniform4f(colorProgram.uniforms.color, 0, 0, 0, 1); blit(density.write.fbo); render(density.write.fbo); gl.bindFramebuffer(gl.FRAMEBUFFER, density.write.fbo); let length = dyeWidth * dyeHeight * 4; let pixels = new Float32Array(length); gl.readPixels(0, 0, dyeWidth, dyeHeight, gl.RGBA, gl.FLOAT, pixels); let newPixels = new Uint8Array(length); let id = 0; for (let i = dyeHeight - 1; i >= 0; i--) { for (let j = 0; j < dyeWidth; j++) { let nid = i * dyeWidth * 4 + j * 4; newPixels[nid + 0] = clamp01(pixels[id + 0]) * 255; newPixels[nid + 1] = clamp01(pixels[id + 1]) * 255; newPixels[nid + 2] = clamp01(pixels[id + 2]) * 255; newPixels[nid + 3] = clamp01(pixels[id + 3]) * 255; id += 4; } } let captureCanvas = document.createElement('canvas'); let ctx = captureCanvas.getContext('2d'); captureCanvas.width = dyeWidth; captureCanvas.height = dyeHeight; let imageData = ctx.createImageData(dyeWidth, dyeHeight); imageData.data.set(newPixels); ctx.putImageData(imageData, 0, 0); let datauri = captureCanvas.toDataURL(); downloadURI("fluid.png", datauri); URL.revokeObjectURL(datauri); } function clamp01 (input) { return Math.min(Math.max(input, 0), 1); } 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); } 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 displayBloomShader = compileShader(gl.FRAGMENT_SHADER, ` precision highp float; precision highp sampler2D; varying vec2 vUv; uniform sampler2D uTexture; uniform sampler2D uBloom; uniform sampler2D uDithering; uniform vec2 ditherScale; void main () { vec3 C = texture2D(uTexture, vUv).rgb; vec3 bloom = texture2D(uBloom, vUv).rgb; vec3 noise = texture2D(uDithering, vUv * ditherScale).rgb; noise = noise * 2.0 - 1.0; bloom += noise / 800.0; bloom = pow(bloom.rgb, vec3(1.0 / 2.2)); C += bloom; 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 displayBloomShadingShader = 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 sampler2D uBloom; uniform sampler2D uDithering; uniform vec2 ditherScale; 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 *= diffuse; vec3 bloom = texture2D(uBloom, vUv).rgb; vec3 noise = texture2D(uDithering, vUv * ditherScale).rgb; noise = noise * 2.0 - 1.0; bloom += noise / 800.0; bloom = pow(bloom.rgb, vec3(1.0 / 2.2)); C += bloom; 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 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; let bloom; let ditheringTexture = createTextureAsync('LDR_RGB1_0.png'); 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 displayBloomProgram = new GLProgram(baseVertexShader, displayBloomShader); const displayShadingProgram = new GLProgram(baseVertexShader, displayShadingShader); const displayBloomShadingProgram = new GLProgram(baseVertexShader, displayBloomShadingShader); const bloomPrefilterProgram = new GLProgram(baseVertexShader, bloomPrefilterShader); const bloomBlurProgram = new GLProgram(baseVertexShader, bloomBlurShader); const bloomFinalProgram = new GLProgram(baseVertexShader, bloomFinalShader); 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; const filtering = ext.supportLinearFiltering ? gl.LINEAR : gl.NEAREST; if (density == null) density = createDoubleFBO(dyeWidth, dyeHeight, rgba.internalFormat, rgba.format, texType, filtering); else density = resizeDoubleFBO(density, dyeWidth, dyeHeight, rgba.internalFormat, rgba.format, texType, filtering); if (velocity == null) velocity = createDoubleFBO(simWidth, simHeight, rg.internalFormat, rg.format, texType, filtering); else velocity = resizeDoubleFBO(velocity, simWidth, simHeight, rg.internalFormat, rg.format, texType, filtering); divergence = createFBO (simWidth, simHeight, r.internalFormat, r.format, texType, gl.NEAREST); curl = createFBO (simWidth, simHeight, r.internalFormat, r.format, texType, gl.NEAREST); pressure = createDoubleFBO(simWidth, simHeight, r.internalFormat, r.format, texType, gl.NEAREST); initBloomFramebuffers(); } 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 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); return { texture, fbo, width: w, height: h, 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 { 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); clearProgram.bind(); gl.uniform1i(clearProgram.uniforms.uTexture, target.attach(0)); gl.uniform1f(clearProgram.uniforms.value, 1); blit(newFBO.fbo); return newFBO; } function resizeDoubleFBO (target, w, h, internalFormat, format, type, param) { target.read = resizeFBO(target.read, w, h, internalFormat, format, type, param); target.write = createFBO(w, h, internalFormat, format, type, param); return target; } function createTextureAsync (url) { let texture = gl.createTexture(); gl.bindTexture(gl.TEXTURE_2D, texture); gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR); gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR); gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.REPEAT); gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.REPEAT); gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGB, 1, 1, 0, gl.RGB, gl.UNSIGNED_BYTE, new Uint8Array([255, 255, 255])); let obj = { texture, width: 1, height: 1, attach (id) { gl.activeTexture(gl.TEXTURE0 + id); gl.bindTexture(gl.TEXTURE_2D, texture); return id; } }; let image = new Image(); image.onload = () => { obj.width = image.width; obj.height = image.height; gl.bindTexture(gl.TEXTURE_2D, texture); gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGB, gl.RGB, gl.UNSIGNED_BYTE, image); }; image.src = url; return obj; } initFramebuffers(); multipleSplats(parseInt(Math.random() * 20) + 5); 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.attach(0)); blit(curl.fbo); vorticityProgram.bind(); gl.uniform2f(vorticityProgram.uniforms.texelSize, 1.0 / simWidth, 1.0 / simHeight); 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.fbo); velocity.swap(); divergenceProgram.bind(); gl.uniform2f(divergenceProgram.uniforms.texelSize, 1.0 / simWidth, 1.0 / simHeight); gl.uniform1i(divergenceProgram.uniforms.uVelocity, velocity.read.attach(0)); blit(divergence.fbo); clearProgram.bind(); gl.uniform1i(clearProgram.uniforms.uTexture, pressure.read.attach(0)); 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.attach(0)); for (let i = 0; i < config.PRESSURE_ITERATIONS; i++) { gl.uniform1i(pressureProgram.uniforms.uPressure, pressure.read.attach(1)); 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.attach(0)); gl.uniform1i(gradienSubtractProgram.uniforms.uVelocity, velocity.read.attach(1)); 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); 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.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.attach(0)); gl.uniform1i(advectionProgram.uniforms.uSource, density.read.attach(1)); gl.uniform1f(advectionProgram.uniforms.dissipation, config.DENSITY_DISSIPATION); blit(density.write.fbo); density.swap(); } function render (target) { if (config.BLOOM) applyBloom(density.read, bloom); 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) { let program = config.BLOOM ? displayBloomShadingProgram : displayShadingProgram; program.bind(); gl.uniform2f(program.uniforms.texelSize, 1.0 / width, 1.0 / height); gl.uniform1i(program.uniforms.uTexture, density.read.attach(0)); if (config.BLOOM) { gl.uniform1i(program.uniforms.uBloom, bloom.attach(1)); gl.uniform1i(program.uniforms.uDithering, ditheringTexture.attach(2)); let scale = getTextureScale(ditheringTexture, width, height); gl.uniform2f(program.uniforms.ditherScale, scale.x, scale.y); } } else { let program = config.BLOOM ? displayBloomProgram : displayProgram; program.bind(); gl.uniform1i(program.uniforms.uTexture, density.read.attach(0)); if (config.BLOOM) { gl.uniform1i(program.uniforms.uBloom, bloom.attach(1)); gl.uniform1i(program.uniforms.uDithering, ditheringTexture.attach(2)); let scale = getTextureScale(ditheringTexture, width, height); gl.uniform2f(program.uniforms.ditherScale, scale.x, scale.y); } } 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)); gl.viewport(0, 0, last.width, last.height); blit(last.fbo); bloomBlurProgram.bind(); for (let i = 0; i < bloomFramebuffers.length; i++) { let dest = bloomFramebuffers[i]; gl.uniform2f(bloomBlurProgram.uniforms.texelSize, 1.0 / last.width, 1.0 / last.height); gl.uniform1i(bloomBlurProgram.uniforms.uTexture, last.attach(0)); gl.viewport(0, 0, dest.width, dest.height); blit(dest.fbo); 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, 1.0 / last.width, 1.0 / last.height); gl.uniform1i(bloomBlurProgram.uniforms.uTexture, last.attach(0)); gl.viewport(0, 0, baseTex.width, baseTex.height); blit(baseTex.fbo); last = baseTex; } gl.disable(gl.BLEND); bloomFinalProgram.bind(); gl.uniform2f(bloomFinalProgram.uniforms.texelSize, 1.0 / last.width, 1.0 / last.height); gl.uniform1i(bloomFinalProgram.uniforms.uTexture, last.attach(0)); gl.uniform1f(bloomFinalProgram.uniforms.intensity, config.BLOOM_INTENSITY); gl.viewport(0, 0, destination.width, destination.height); blit(destination.fbo); } function splat (x, y, dx, dy, color) { gl.viewport(0, 0, simWidth, simHeight); 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 / 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.attach(0)); gl.uniform3f(splatProgram.uniforms.color, color.r, color.g, color.b); blit(density.write.fbo); density.swap(); } 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 = canvas.width * Math.random(); const y = canvas.height * Math.random(); const dx = 1000 * (Math.random() - 0.5); const 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(); } } canvas.addEventListener('mousemove', e => { pointers[0].moved = pointers[0].down; pointers[0].dx = (e.offsetX - pointers[0].x) * 5.0; pointers[0].dy = (e.offsetY - pointers[0].y) * 5.0; pointers[0].x = e.offsetX; pointers[0].y = e.offsetY; }); canvas.addEventListener('touchmove', e => { 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].down = true; 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.code === 'KeyP') config.PAUSED = !config.PAUSED; if (e.key === ' ') splatStack.push(parseInt(Math.random() * 20) + 5); }); function generateColor () { let c = HSVtoRGB(Math.random(), 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 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 getTextureScale (texture, width, height) { return { x: width / texture.width, y: height / texture.height }; }