<body>
<div class="content">
<img src="https://cdn.picui.cn/2024/01/07/659a12f529ddb.jpg"/>
</div>
<canvas></canvas>
</body>{/tabs-pane}
{tabs-pane label="css"}
html, body {
overflow: hidden;
padding: 0;
margin: 0;
}
canvas {
position: fixed;
top: 0;
left: 0;
width: 100%;
height: 100%;
}
.content {
position: fixed;
top: 0;
left: 0;
width: 100%;
height: 100vh;
}
img {
position: absolute;
top: 50%;
left: 50%;
transform: translate(-50%, -50%);
height: 115%;
width: auto;
opacity: 0;
}
@media (min-aspect-ratio: 4/3) {
img {
height: auto;
width: 100%;
}
}
@media (max-aspect-ratio: 3/5) {
img {
left: 30%;
}
}
.overlay {
position: fixed;
top: 50%;
left: 30%;
max-width: 50%;
transform: translate(-50%, -50%);
font-family: sans-serif;
font-size: 10vh;
font-weight: bold;
pointer-events: none;
text-transform: uppercase;
}
@media (max-aspect-ratio: 1/1) {
.overlay {
left: 50%;
width: 90%;
max-width: 90%;
}
}
@media (max-aspect-ratio: 3/5) {
.overlay {
font-size: 5vh;
}
}{/tabs-pane}
{tabs-pane label="js"}
<script type="x-shader/x-fragment" id="vertShader">
precision highp float;
attribute vec2 aPosition;
varying vec2 vUv;
varying vec2 vL;
varying vec2 vR;
varying vec2 vT;
varying vec2 vB;
uniform vec2 u_vertex_texel;
void main () {
vUv = aPosition * .5 + .5;
vL = vUv - vec2(u_vertex_texel.x, 0.);
vR = vUv + vec2(u_vertex_texel.x, 0.);
vT = vUv + vec2(0., u_vertex_texel.y);
vB = vUv - vec2(0., u_vertex_texel.y);
gl_Position = vec4(aPosition, 0., 1.);
}
</script>
<script type="x-shader/x-fragment" id="fragShaderAdvection">
precision highp float;
precision highp sampler2D;
varying vec2 vUv;
uniform sampler2D u_velocity_txr;
uniform sampler2D u_input_txr;
uniform vec2 u_vertex_texel;
uniform vec2 u_output_textel;
uniform float u_dt;
uniform float u_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 - u_dt * bilerp(u_velocity_txr, vUv, u_vertex_texel).xy * u_vertex_texel;
gl_FragColor = u_dissipation * bilerp(u_input_txr, coord, u_output_textel);
gl_FragColor.a = 1.;
}
</script>
<script type="x-shader/x-fragment" id="fragShaderDivergence">
precision highp float;
precision highp sampler2D;
varying highp vec2 vUv;
varying highp vec2 vL;
varying highp vec2 vR;
varying highp vec2 vT;
varying highp vec2 vB;
uniform sampler2D u_velocity_txr;
void main () {
float L = texture2D(u_velocity_txr, vL).x;
float R = texture2D(u_velocity_txr, vR).x;
float T = texture2D(u_velocity_txr, vT).y;
float B = texture2D(u_velocity_txr, vB).y;
float div = .5 * (R - L + T - B);
gl_FragColor = vec4(div, 0., 0., 1.);
}
</script>
<script type="x-shader/x-fragment" id="fragShaderPressure">
precision highp float;
precision highp sampler2D;
varying highp vec2 vUv;
varying highp vec2 vL;
varying highp vec2 vR;
varying highp vec2 vT;
varying highp vec2 vB;
uniform sampler2D u_pressure_txr;
uniform sampler2D u_divergence_txr;
void main () {
float L = texture2D(u_pressure_txr, vL).x;
float R = texture2D(u_pressure_txr, vR).x;
float T = texture2D(u_pressure_txr, vT).x;
float B = texture2D(u_pressure_txr, vB).x;
float C = texture2D(u_pressure_txr, vUv).x;
float divergence = texture2D(u_divergence_txr, vUv).x;
float pressure = (L + R + B + T - divergence) * 0.25;
gl_FragColor = vec4(pressure, 0., 0., 1.);
}
</script>
<script type="x-shader/x-fragment" id="fragShaderGradientSubtract">
precision highp float;
precision highp sampler2D;
varying highp vec2 vUv;
varying highp vec2 vL;
varying highp vec2 vR;
varying highp vec2 vT;
varying highp vec2 vB;
uniform sampler2D u_pressure_txr;
uniform sampler2D u_velocity_txr;
void main () {
float L = texture2D(u_pressure_txr, vL).x;
float R = texture2D(u_pressure_txr, vR).x;
float T = texture2D(u_pressure_txr, vT).x;
float B = texture2D(u_pressure_txr, vB).x;
vec2 velocity = texture2D(u_velocity_txr, vUv).xy;
velocity.xy -= vec2(R - L, T - B);
gl_FragColor = vec4(velocity, 0., 1.);
}
</script>
<script type="x-shader/x-fragment" id="fragShaderPoint">
precision highp float;
precision highp sampler2D;
varying vec2 vUv;
uniform sampler2D u_input_txr;
uniform float u_ratio;
uniform vec3 u_point_value;
uniform vec2 u_point;
uniform float u_point_size;
void main () {
vec2 p = vUv - u_point.xy;
p.x *= u_ratio;
vec3 splat = pow(2., -dot(p, p) / u_point_size) * u_point_value;
vec3 base = texture2D(u_input_txr, vUv).xyz;
gl_FragColor = vec4(base + splat, 1.);
}
</script>
<script type="x-shader/x-fragment" id="fragShaderDisplay">
precision highp float;
precision highp sampler2D;
varying vec2 vUv;
uniform sampler2D u_output_texture;
void main () {
vec3 C = texture2D(u_output_texture, vUv).rgb;
float a = max(C.r, max(C.g, C.b));
a = pow(.1 * a, .1);
a = clamp(a, 0., 1.);
gl_FragColor = vec4(1. - C, 1. - a);
}
</script>const canvas = document.getElementsByTagName("canvas")[0];
const image = document.getElementsByTagName("img")[0];
canvas.width = canvas.clientWidth;
canvas.height = canvas.clientHeight;
const params = {
SIM_RESOLUTION: 128,
DYE_RESOLUTION: 1024,
DENSITY_DISSIPATION: .995,
VELOCITY_DISSIPATION: .9,
PRESSURE_ITERATIONS: 10,
SPLAT_RADIUS: 3 / window.innerHeight,
color: {r: .8, g: .5, b: .2}
};
const pointer = {
x: .65 * window.innerWidth,
y: .5 * window.innerHeight,
dx: 0,
dy: 0,
moved: false,
firstMove: false // for codepen preview
};
window.setTimeout(() => {
pointer.firstMove = true;
}, 3000);
let prevTimestamp = Date.now();
const gl = canvas.getContext("webgl");
gl.getExtension("OES_texture_float");
let outputColor, velocity, divergence, pressure;
const vertexShader = createShader(
document.getElementById("vertShader").innerHTML,
gl.VERTEX_SHADER);
const splatProgram = createProgram("fragShaderPoint");
const divergenceProgram = createProgram("fragShaderDivergence");
const pressureProgram = createProgram("fragShaderPressure");
const gradientSubtractProgram = createProgram("fragShaderGradientSubtract");
const advectionProgram = createProgram("fragShaderAdvection");
const displayProgram = createProgram("fragShaderDisplay");
initFBOs();
render();
image.style.opacity = "1";
window.addEventListener("resize", () => {
params.SPLAT_RADIUS = 5 / window.innerHeight;
canvas.width = canvas.clientWidth;
canvas.height = canvas.clientHeight;
});
canvas.addEventListener("click", (e) => {
pointer.dx = 10;
pointer.dy = 10;
pointer.x = e.pageX;
pointer.y = e.pageY;
pointer.firstMove = true;
});
canvas.addEventListener("mousemove", (e) => {
pointer.moved = true;
pointer.dx = 5 * (e.pageX - pointer.x);
pointer.dy = 5 * (e.pageY - pointer.y);
pointer.x = e.pageX;
pointer.y = e.pageY;
pointer.firstMove = true;
});
canvas.addEventListener("touchmove", (e) => {
e.preventDefault();
pointer.moved = true;
pointer.dx = 8 * (e.targetTouches[0].pageX - pointer.x);
pointer.dy = 8 * (e.targetTouches[0].pageY - pointer.y);
pointer.x = e.targetTouches[0].pageX;
pointer.y = e.targetTouches[0].pageY;
pointer.firstMove = true;
});
function createProgram(elId) {
const shader = createShader(
document.getElementById(elId).innerHTML,
gl.FRAGMENT_SHADER);
const program = createShaderProgram(vertexShader, shader);
const uniforms = getUniforms(program);
return {
program, uniforms
}
}
function createShaderProgram(vertexShader, fragmentShader) {
const program = gl.createProgram();
gl.attachShader(program, vertexShader);
gl.attachShader(program, fragmentShader);
gl.linkProgram(program);
if (!gl.getProgramParameter(program, gl.LINK_STATUS)) {
console.error("Unable to initialize the shader program: " + gl.getProgramInfoLog(program));
return null;
}
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 createShader(sourceCode, type) {
const shader = gl.createShader(type);
gl.shaderSource(shader, sourceCode);
gl.compileShader(shader);
if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS)) {
console.error("An error occurred compiling the shaders: " + gl.getShaderInfoLog(shader));
gl.deleteShader(shader);
return null;
}
return shader;
}
function blit(target) {
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);
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);
}
gl.drawElements(gl.TRIANGLES, 6, gl.UNSIGNED_SHORT, 0);
}
function initFBOs() {
const simRes = getResolution(params.SIM_RESOLUTION);
const dyeRes = getResolution(params.DYE_RESOLUTION);
outputColor = createDoubleFBO(dyeRes.width, dyeRes.height);
velocity = createDoubleFBO(simRes.width, simRes.height);
divergence = createFBO(simRes.width, simRes.height, gl.RGB);
pressure = createDoubleFBO(simRes.width, simRes.height, gl.RGB);
}
function getResolution(resolution) {
let aspectRatio = gl.drawingBufferWidth / gl.drawingBufferHeight;
if (aspectRatio < 1)
aspectRatio = 1. / 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 createFBO(w, h, type = gl.RGBA) {
gl.activeTexture(gl.TEXTURE0);
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.CLAMP_TO_EDGE);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
gl.texImage2D(gl.TEXTURE_2D, 0, type, w, h, 0, type, gl.FLOAT, null);
const 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 {
fbo,
width: w,
height: h,
attach(id) {
gl.activeTexture(gl.TEXTURE0 + id);
gl.bindTexture(gl.TEXTURE_2D, texture);
return id;
}
};
}
function createDoubleFBO(w, h, type) {
let fbo1 = createFBO(w, h, type);
let fbo2 = createFBO(w, h, type);
return {
width: w,
height: h,
texelSizeX: 1. / w,
texelSizeY: 1. / h,
read: () => {
return fbo1;
},
write: () => {
return fbo2;
},
swap() {
let temp = fbo1;
fbo1 = fbo2;
fbo2 = temp;
}
}
}
function render() {
const dt = (Date.now() - prevTimestamp) / 1000;
prevTimestamp = Date.now();
if (!pointer.firstMove) {
pointer.moved = true;
const newX = (.65 + .2 * Math.cos(.006 * prevTimestamp) * Math.sin(.008 * prevTimestamp)) * window.innerWidth;
const newY = (.5 + .12 * Math.sin(.01 * prevTimestamp)) * window.innerHeight;
pointer.dx = 10 * (newX - pointer.x);
pointer.dy = 10 * (newY - pointer.y);
pointer.x = newX;
pointer.y = newY;
}
if (pointer.moved) {
pointer.moved = false;
gl.useProgram(splatProgram.program);
gl.uniform1i(splatProgram.uniforms.u_input_txr, velocity.read().attach(0));
gl.uniform1f(splatProgram.uniforms.u_ratio, canvas.width / canvas.height);
gl.uniform2f(splatProgram.uniforms.u_point, pointer.x / canvas.width, 1 - pointer.y / canvas.height);
gl.uniform3f(splatProgram.uniforms.u_point_value, pointer.dx, -pointer.dy, 1);
gl.uniform1f(splatProgram.uniforms.u_point_size, params.SPLAT_RADIUS);
blit(velocity.write());
velocity.swap();
gl.uniform1i(splatProgram.uniforms.u_input_txr, outputColor.read().attach(0));
gl.uniform3f(splatProgram.uniforms.u_point_value, 1. - params.color.r, 1. - params.color.g, 1. - params.color.b);
blit(outputColor.write());
outputColor.swap();
}
gl.useProgram(divergenceProgram.program);
gl.uniform2f(divergenceProgram.uniforms.u_vertex_texel, velocity.texelSizeX, velocity.texelSizeY);
gl.uniform1i(divergenceProgram.uniforms.u_velocity_txr, velocity.read().attach(0));
blit(divergence);
gl.useProgram(pressureProgram.program);
gl.uniform2f(pressureProgram.uniforms.u_vertex_texel, velocity.texelSizeX, velocity.texelSizeY);
gl.uniform1i(pressureProgram.uniforms.u_divergence_txr, divergence.attach(0));
for (let i = 0; i < params.PRESSURE_ITERATIONS; i++) {
gl.uniform1i(pressureProgram.uniforms.u_pressure_txr, pressure.read().attach(1));
blit(pressure.write());
pressure.swap();
}
gl.useProgram(gradientSubtractProgram.program);
gl.uniform2f(gradientSubtractProgram.uniforms.u_vertex_texel, velocity.texelSizeX, velocity.texelSizeY);
gl.uniform1i(gradientSubtractProgram.uniforms.u_pressure_txr, pressure.read().attach(0));
gl.uniform1i(gradientSubtractProgram.uniforms.u_velocity_txr, velocity.read().attach(1));
blit(velocity.write());
velocity.swap();
gl.useProgram(advectionProgram.program);
gl.uniform2f(advectionProgram.uniforms.u_vertex_texel, velocity.texelSizeX, velocity.texelSizeY);
gl.uniform2f(advectionProgram.uniforms.u_output_textel, velocity.texelSizeX, velocity.texelSizeY);
gl.uniform1i(advectionProgram.uniforms.u_velocity_txr, velocity.read().attach(0));
gl.uniform1i(advectionProgram.uniforms.u_input_txr, velocity.read().attach(0));
gl.uniform1f(advectionProgram.uniforms.u_dt, dt);
gl.uniform1f(advectionProgram.uniforms.u_dissipation, params.VELOCITY_DISSIPATION);
blit(velocity.write());
velocity.swap();
gl.uniform2f(advectionProgram.uniforms.u_output_textel, outputColor.texelSizeX, outputColor.texelSizeY);
gl.uniform1i(advectionProgram.uniforms.u_velocity_txr, velocity.read().attach(0));
gl.uniform1i(advectionProgram.uniforms.u_input_txr, outputColor.read().attach(1));
gl.uniform1f(advectionProgram.uniforms.u_dissipation, params.DENSITY_DISSIPATION);
blit(outputColor.write());
outputColor.swap();
gl.useProgram(displayProgram.program);
gl.uniform1i(displayProgram.uniforms.u_output_texture, outputColor.read().attach(0));
blit();
requestAnimationFrame(render);
}{/tabs-pane}
代码来自CodePenWebGL liquid masking
评语 (0)