又是一年双十一，祝各位头发少掉点儿呀！！！
嗯，也…
效果
由于一次展示效果不便，所以分成几个小部分展示呀！可以根据鼠标自行体验呦！下面是几个效果之一呀！
更多效果，大家可以去体验呀！！！
源代码
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>兮夜老师</title>
<style>
html, body {
overflow: hidden;
}
body {
margin: 0;
position: absolute;
width: 100%;
height: 100%;
}
canvas {
width: 100%;
height: 100%;
}
</style>
</head>
<body>
<canvas></canvas>
<script>
'use strict';
function _classCallCheck(instance, Constructor) {
if (!(instance instanceof Constructor)) {
throw new TypeError("Cannot call a class as a function"); } }
var canvas = document.getElementsByTagName('canvas')[0];
canvas.width = canvas.clientWidth;
canvas.height = canvas.clientHeight;
var params = {
alpha: false, depth: false, stencil: false, antialias: false };
var gl = canvas.getContext('webgl2', params);
var isWebGL2 = !!gl;
if (!isWebGL2) {
gl = canvas.getContext('webgl', params) || canvas.getContext('experimental-webgl', params);
}
gl.clearColor(0.0, 0.0, 0.0, 1.0);
var halfFloat = gl.getExtension('OES_texture_half_float');
var support_linear_float = gl.getExtension('OES_texture_half_float_linear');
if (isWebGL2) {
gl.getExtension('EXT_color_buffer_float');
support_linear_float = gl.getExtension('OES_texture_float_linear');
}
var TEXTURE_DOWNSAMPLE = 1;
var DENSITY_DISSIPATION = 0.98;
var VELOCITY_DISSIPATION = 0.99;
var SPLAT_RADIUS = 0.005;
var CURL = 30;
var PRESSURE_ITERATIONS = 25;
var GLProgram = function () {
function GLProgram(vertexShader, fragmentShader) {
_classCallCheck(this, GLProgram);
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);
var uniformCount = gl.getProgramParameter(this.program, gl.ACTIVE_UNIFORMS);
for (var i = 0; i < uniformCount; i++) {
var uniformName = gl.getActiveUniform(this.program, i).name;
this.uniforms[uniformName] = gl.getUniformLocation(this.program, uniformName);
}
}
GLProgram.prototype.bind = function bind() {
gl.useProgram(this.program);
};
return GLProgram;
}();
function compileShader(type, source) {
var shader = gl.createShader(type);
gl.shaderSource(shader, source);
gl.compileShader(shader);
if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS)) throw gl.getShaderInfoLog(shader);
return shader;
};
var baseVertexShader = compileShader(gl.VERTEX_SHADER, '\n precision highp float;\n precision mediump sampler2D;\n\n attribute vec2 aPosition;\n varying vec2 vUv;\n varying vec2 vL;\n varying vec2 vR;\n varying vec2 vT;\n varying vec2 vB;\n uniform vec2 texelSize;\n\n void main () {\n vUv = aPosition * 0.5 + 0.5;\n vL = vUv - vec2(texelSize.x, 0.0);\n vR = vUv + vec2(texelSize.x, 0.0);\n vT = vUv + vec2(0.0, texelSize.y);\n vB = vUv - vec2(0.0, texelSize.y);\n gl_Position = vec4(aPosition, 0.0, 1.0);\n }\n');
var displayShader = compileShader(gl.FRAGMENT_SHADER, '\n precision highp float;\n precision mediump sampler2D;\n\n varying vec2 vUv;\n varying vec2 vL;\n varying vec2 vR;\n varying vec2 vT;\n varying vec2 vB;\n uniform sampler2D uTexture;\n\n void main () {\n gl_FragColor = texture2D(uTexture, vUv);\n }\n');
var splatShader = compileShader(gl.FRAGMENT_SHADER, '\n precision highp float;\n precision mediump sampler2D;\n\n varying vec2 vUv;\n uniform sampler2D uTarget;\n uniform float aspectRatio;\n uniform vec3 color;\n uniform vec2 point;\n uniform float radius;\n\n void main () {\n vec2 p = vUv - point.xy;\n p.x *= aspectRatio;\n vec3 splat = exp(-dot(p, p) / radius) * color;\n vec3 base = texture2D(uTarget, vUv).xyz;\n gl_FragColor = vec4(base + splat, 1.0);\n }\n');
var advectionManualFilteringShader = compileShader(gl.FRAGMENT_SHADER, '\n precision highp float;\n precision mediump sampler2D;\n\n varying vec2 vUv;\n uniform sampler2D uVelocity;\n uniform sampler2D uSource;\n uniform vec2 texelSize;\n uniform float dt;\n uniform float dissipation;\n\n vec4 bilerp (in sampler2D sam, in vec2 p) {\n vec4 st;\n st.xy = floor(p - 0.5) + 0.5;\n st.zw = st.xy + 1.0;\n vec4 uv = st * texelSize.xyxy;\n vec4 a = texture2D(sam, uv.xy);\n vec4 b = texture2D(sam, uv.zy);\n vec4 c = texture2D(sam, uv.xw);\n vec4 d = texture2D(sam, uv.zw);\n vec2 f = p - st.xy;\n return mix(mix(a, b, f.x), mix(c, d, f.x), f.y);\n }\n\n void main () {\n vec2 coord = gl_FragCoord.xy - dt * texture2D(uVelocity, vUv).xy;\n gl_FragColor = dissipation * bilerp(uSource, coord);\n gl_FragColor.a = 1.0;\n }\n');
var advectionShader = compileShader(gl.FRAGMENT_SHADER, '\n precision highp float;\n precision mediump sampler2D;\n\n varying vec2 vUv;\n uniform sampler2D uVelocity;\n uniform sampler2D uSource;\n uniform vec2 texelSize;\n uniform float dt;\n uniform float dissipation;\n\n void main () {\n vec2 coord = vUv - dt * texture2D(uVelocity, vUv).xy * texelSize;\n gl_FragColor = dissipation * texture2D(uSource, coord);\n }\n');
var divergenceShader = compileShader(gl.FRAGMENT_SHADER, '\n precision highp float;\n precision mediump sampler2D;\n\n varying vec2 vUv;\n varying vec2 vL;\n varying vec2 vR;\n varying vec2 vT;\n varying vec2 vB;\n uniform sampler2D uVelocity;\n\n vec2 sampleVelocity (in vec2 uv) {\n vec2 multiplier = vec2(1.0, 1.0);\n if (uv.x < 0.0) { uv.x = 0.0; multiplier.x = -1.0; }\n if (uv.x > 1.0) { uv.x = 1.0; multiplier.x = -1.0; }\n if (uv.y < 0.0) { uv.y = 0.0; multiplier.y = -1.0; }\n if (uv.y > 1.0) { uv.y = 1.0; multiplier.y = -1.0; }\n return multiplier * texture2D(uVelocity, uv).xy;\n }\n\n void main () {\n float L = sampleVelocity(vL).x;\n float R = sampleVelocity(vR).x;\n float T = sampleVelocity(vT).y;\n float B = sampleVelocity(vB).y;\n float div = 0.5 * (R - L + T - B);\n gl_FragColor = vec4(div, 0.0, 0.0, 1.0);\n }\n');
var curlShader = compileShader(gl.FRAGMENT_SHADER, '\n precision highp float;\n precision mediump sampler2D;\n\n varying vec2 vUv;\n varying vec2 vL;\n varying vec2 vR;\n varying vec2 vT;\n varying vec2 vB;\n uniform sampler2D uVelocity;\n\n void main () {\n float L = texture2D(uVelocity, vL).y;\n float R = texture2D(uVelocity, vR).y;\n float T = texture2D(uVelocity, vT).x;\n float B = texture2D(uVelocity, vB).x;\n float vorticity = R - L - T + B;\n gl_FragColor = vec4(vorticity, 0.0, 0.0, 1.0);\n }\n');
var vorticityShader = compileShader(gl.FRAGMENT_SHADER, '\n precision highp float;\n precision mediump sampler2D;\n\n varying vec2 vUv;\n varying vec2 vL;\n varying vec2 vR;\n varying vec2 vT;\n varying vec2 vB;\n uniform sampler2D uVelocity;\n uniform sampler2D uCurl;\n uniform float curl;\n uniform float dt;\n\n void main () {\n float L = texture2D(uCurl, vL).y;\n float R = texture2D(uCurl, vR).y;\n float T = texture2D(uCurl, vT).x;\n float B = texture2D(uCurl, vB).x;\n float C = texture2D(uCurl, vUv).x;\n vec2 force = vec2(abs(T) - abs(B), abs(R) - abs(L));\n force *= 1.0 / length(force + 0.00001) * curl * C;\n vec2 vel = texture2D(uVelocity, vUv).xy;\n gl_FragColor = vec4(vel + force * dt, 0.0, 1.0);\n }\n');
var pressureShader = compileShader(gl.FRAGMENT_SHADER, '\n precision highp float;\n precision mediump sampler2D;\n\n varying vec2 vUv;\n varying vec2 vL;\n varying vec2 vR;\n varying vec2 vT;\n varying vec2 vB;\n uniform sampler2D uPressure;\n uniform sampler2D uDivergence;\n\n vec2 boundary (in vec2 uv) {\n uv = min(max(uv, 0.0), 1.0);\n return uv;\n }\n\n void main () {\n float L = texture2D(uPressure, boundary(vL)).x;\n float R = texture2D(uPressure, boundary(vR)).x;\n float T = texture2D(uPressure, boundary(vT)).x;\n float B = texture2D(uPressure, boundary(vB)).x;\n float C = texture2D(uPressure, vUv).x;\n float divergence = texture2D(uDivergence, vUv).x;\n float pressure = (L + R + B + T - divergence) * 0.25;\n gl_FragColor = vec4(pressure, 0.0, 0.0, 1.0);\n }\n');
var gradientSubtractShader = compileShader(gl.FRAGMENT_SHADER, '\n precision highp float;\n precision mediump sampler2D;\n\n varying vec2 vUv;\n varying vec2 vL;\n varying vec2 vR;\n varying vec2 vT;\n varying vec2 vB;\n uniform sampler2D uPressure;\n uniform sampler2D uVelocity;\n\n vec2 boundary (in vec2 uv) {\n uv = min(max(uv, 0.0), 1.0);\n return uv;\n }\n\n void main () {\n float L = texture2D(uPressure, boundary(vL)).x;\n float R = texture2D(uPressure, boundary(vR)).x;\n float T = texture2D(uPressure, boundary(vT)).x;\n float B = texture2D(uPressure, boundary(vB)).x;\n vec2 velocity = texture2D(uVelocity, vUv).xy;\n velocity.xy -= vec2(R - L, T - B);\n gl_FragColor = vec4(velocity, 0.0, 1.0);\n }\n');
var blit = function () {
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 function (destination) {
gl.bindFramebuffer(gl.FRAMEBUFFER, destination);
gl.drawElements(gl.TRIANGLES, 6, gl.UNSIGNED_SHORT, 0);
};
}();
function clear(target) {
gl.bindFramebuffer(gl.FRAMEBUFFER, target);
gl.clear(gl.COLOR_BUFFER_BIT);
}
function createFBO(texId, w, h, internalFormat, format, type, param) {
gl.activeTexture(gl.TEXTURE0 + texId);
var 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);
var 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) {
var fbo1 = createFBO(texId, w, h, internalFormat, format, type, param);
var fbo2 = createFBO(texId + 1, w, h, internalFormat, format, type, param);
return {
get first() {
return fbo1;
},
get second() {
return fbo2;
},
swap: function swap() {
var temp = fbo1;
fbo1 = fbo2;
fbo2 = temp;
}
};
}
var textureWidth = undefined;
var textureHeight = undefined;
var density = undefined;
var velocity = undefined;
var divergence = undefined;
var curl = undefined;
var pressure = undefined;
function initFramebuffers() {
textureWidth = gl.drawingBufferWidth >> TEXTURE_DOWNSAMPLE;
textureHeight = gl.drawingBufferHeight >> TEXTURE_DOWNSAMPLE;
var internalFormat = isWebGL2 ? gl.RGBA16F : gl.RGBA;
var internalFormatRG = isWebGL2 ? gl.RG16F : gl.RGBA;
var formatRG = isWebGL2 ? gl.RG : gl.RGBA;
var texType = isWebGL2 ? gl.HALF_FLOAT : halfFloat.HALF_FLOAT_OES;
density = createDoubleFBO(0, textureWidth, textureHeight, internalFormat, gl.RGBA, texType, support_linear_float ? gl.LINEAR : gl.NEAREST);
velocity = createDoubleFBO(2, textureWidth, textureHeight, internalFormatRG, formatRG, texType, support_linear_float ? gl.LINEAR : gl.NEAREST);
divergence = createFBO(4, textureWidth, textureHeight, internalFormatRG, formatRG, texType, gl.NEAREST);
curl = createFBO(5, textureWidth, textureHeight, internalFormatRG, formatRG, texType, gl.NEAREST);
pressure = createDoubleFBO(6, textureWidth, textureHeight, internalFormatRG, formatRG, texType, gl.NEAREST);
}
initFramebuffers();
var displayProgram = new GLProgram(baseVertexShader, displayShader);
var splatProgram = new GLProgram(baseVertexShader, splatShader);
var advectionProgram = new GLProgram(baseVertexShader, support_linear_float ? advectionShader : advectionManualFilteringShader);
var divergenceProgram = new GLProgram(baseVertexShader, divergenceShader);
var curlProgram = new GLProgram(baseVertexShader, curlShader);
var vorticityProgram = new GLProgram(baseVertexShader, vorticityShader);
var pressureProgram = new GLProgram(baseVertexShader, pressureShader);
var gradienSubtractProgram = new GLProgram(baseVertexShader, gradientSubtractShader);
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];
}
var pointers = [];
pointers.push(new pointerPrototype());
for (var i = 0; i < 10; i++) {
var color = [Math.random() * 10, Math.random() * 10, Math.random() * 10];
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);
splat(x, y, dx, dy, color);
}
var lastTime = Date.now();
Update();
function Update() {
resizeCanvas();
var dt = Math.min((Date.now() - lastTime) / 1000, 0.016);
lastTime = Date.now();
gl.viewport(0, 0, textureWidth, textureHeight);
advectionProgram.bind();
gl.uniform2f(advectionProgram.uniforms.texelSize, 1.0 / textureWidth, 1.0 / textureHeight);
gl.uniform1i(advectionProgram.uniforms.uVelocity, velocity.first[2]);
gl.uniform1i(advectionProgram.uniforms.uSource, velocity.first[2]);
gl.uniform1f(advectionProgram.uniforms.dt, dt);
gl.uniform1f(advectionProgram.uniforms.dissipation, VELOCITY_DISSIPATION);
blit(velocity.second[1]);
velocity.swap();
gl.uniform1i(advectionProgram.uniforms.uVelocity, velocity.first[2]);
gl.uniform1i(advectionProgram.uniforms.uSource, density.first[2]);
gl.uniform1f(advectionProgram.uniforms.dissipation, DENSITY_DISSIPATION);
blit(density.second[1]);
density.swap();
for (var i = 0; i < pointers.length; i++) {
var pointer = pointers[i];
if (pointer.moved) {
splat(pointer.x, pointer.y, pointer.dx, pointer.dy, pointer.color);
pointer.moved = false;
}
}
curlProgram.bind();
gl.uniform2f(curlProgram.uniforms.texelSize, 1.0 / textureWidth, 1.0 / textureHeight);
gl.uniform1i(curlProgram.uniforms.uVelocity, velocity.first[2]);
blit(curl[1]);
vorticityProgram.bind();
gl.uniform2f(vorticityProgram.uniforms.texelSize, 1.0 / textureWidth, 1.0 / textureHeight);
gl.uniform1i(vorticityProgram.uniforms.uVelocity, velocity.first[2]);
gl.uniform1i(vorticityProgram.uniforms.uCurl, curl[2]);
gl.uniform1f(vorticityProgram.uniforms.curl, CURL);
gl.uniform1f(vorticityProgram.uniforms.dt, dt);
blit(velocity.second[1]);
velocity.swap();
divergenceProgram.bind();
gl.uniform2f(divergenceProgram.uniforms.texelSize, 1.0 / textureWidth, 1.0 / textureHeight);
gl.uniform1i(divergenceProgram.uniforms.uVelocity, velocity.first[2]);
blit(divergence[1]);
clear(pressure.first[1]);
pressureProgram.bind();
gl.uniform2f(pressureProgram.uniforms.texelSize, 1.0 / textureWidth, 1.0 / textureHeight);
gl.uniform1i(pressureProgram.uniforms.uDivergence, divergence[2]);
for (var i = 0; i < PRESSURE_ITERATIONS; i++) {
gl.uniform1i(pressureProgram.uniforms.uPressure, pressure.first[2]);
blit(pressure.second[1]);
pressure.swap();
}
gradienSubtractProgram.bind();
gl.uniform2f(gradienSubtractProgram.uniforms.texelSize, 1.0 / textureWidth, 1.0 / textureHeight);
gl.uniform1i(gradienSubtractProgram.uniforms.uPressure, pressure.first[2]);
gl.uniform1i(gradienSubtractProgram.uniforms.uVelocity, velocity.first[2]);
blit(velocity.second[1]);
velocity.swap();
gl.viewport(0, 0, gl.drawingBufferWidth, gl.drawingBufferHeight);
displayProgram.bind();
gl.uniform1i(displayProgram.uniforms.uTexture, density.first[2]);
blit(null);
requestAnimationFrame(Update);
}
function splat(x, y, dx, dy, color) {
splatProgram.bind();
gl.uniform1i(splatProgram.uniforms.uTarget, velocity.first[2]);
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, SPLAT_RADIUS);
blit(velocity.second[1]);
velocity.swap();
gl.uniform1i(splatProgram.uniforms.uTarget, density.first[2]);
gl.uniform3f(splatProgram.uniforms.color, color[0] * 0.3, color[1] * 0.3, color[2] * 0.3);
blit(density.second[1]);
density.swap();
}
function resizeCanvas() {
if (canvas.width != canvas.clientWidth || canvas.height != canvas.clientHeight) {
canvas.width = canvas.clientWidth;
canvas.height = canvas.clientHeight;
initFramebuffers();
}
}
canvas.addEventListener('mousemove', function (e) {
pointers[0].moved = pointers[0].down;
pointers[0].dx = (e.offsetX - pointers[0].x) * 10.0;
pointers[0].dy = (e.offsetY - pointers[0].y) * 10.0;
pointers[0].x = e.offsetX;
pointers[0].y = e.offsetY;
});
canvas.addEventListener('touchmove', function (e) {
e.preventDefault();
var touches = e.targetTouches;
for (var i = 0; i < e.touches.length; i++) {
var pointer = pointers[i];
pointer.moved = pointer.down;
pointer.dx = (touches[i].pageX - pointer.x) * 10.0;
pointer.dy = (touches[i].pageY - pointer.y) * 10.0;
pointer.x = touches[i].pageX;
pointer.y = touches[i].pageY;
}
}, false);
canvas.addEventListener('mousedown', function () {
pointers[0].down = true;
pointers[0].color = [Math.random() + 0.2, Math.random() + 0.2, Math.random() + 0.2];
});
canvas.addEventListener('touchstart', function (e) {
var touches = e.targetTouches;
for (var 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 = [Math.random() + 0.2, Math.random() + 0.2, Math.random() + 0.2];
}
});
window.addEventListener('mouseup', function () {
pointers[0].down = false;
});
window.addEventListener('touchend', function (e) {
var touches = e.changedTouches;
for (var i = 0; i < touches.length; i++) {
for (var j = 0; j < pointers.length; j++) {
if (touches[i].identifier == pointers[j].id) pointers[j].down = false;
}
}
});
</script>
</body>
</html>