threejs 多边形折射效果
时间: 2023-07-25 15:03:24 浏览: 50
threejs 中实现多边形折射效果可以使用 ShaderMaterial 来自定义材质,并使用顶点着色器和片元着色器实现折射效果。
具体实现步骤如下:
1. 编写顶点着色器
顶点着色器主要负责将顶点坐标和法线传递给片元着色器。
```
varying vec3 vNormal;
void main() {
vNormal = normal;
gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
}
```
2. 编写片元着色器
片元着色器实现折射效果,其中 refract 函数可以计算出入射向量在法线上的折射向量。
```
uniform float iTime;
varying vec3 vNormal;
void main() {
vec3 I = normalize(vec3(modelViewMatrix * vec4(position, 1.0)));
vec3 N = normalize(vec3(modelViewMatrix * vec4(vNormal, 0.0)));
float eta = 1.05;
vec3 R = refract(I, N, eta);
gl_FragColor = vec4(0.5 + 0.5 * sin(iTime), 0.5 + 0.5 * cos(iTime), 1.0, 1.0);
gl_FragColor.a = 0.2;
gl_FragColor.rgb *= 1.0 - smoothstep(0.0, 1.0, length(R.xy));
}
```
3. 创建 ShaderMaterial
使用 THREE.ShaderMaterial 创建一个新的材质,并将顶点着色器和片元着色器设置进去。
```
var material = new THREE.ShaderMaterial({
uniforms: {
iTime: { value: 0 }
},
vertexShader: document.getElementById('vertexShader').textContent,
fragmentShader: document.getElementById('fragmentShader').textContent,
side: THREE.DoubleSide
});
```
4. 应用材质
将 ShaderMaterial 应用到需要折射效果的对象上。
```
var mesh = new THREE.Mesh(geometry, material);
scene.add(mesh);
```
5. 渲染场景
在渲染循环中更新时间,以实现动态效果。
```
function render() {
requestAnimationFrame(render);
material.uniforms.iTime.value += 0.01;
renderer.render(scene, camera);
}
render();
```
完整代码示例:
```
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Three.js - Refraction</title>
<style>
body {
margin: 0;
overflow: hidden;
}
canvas {
width: 100vw;
height: 100vh;
}
</style>
</head>
<body>
<script src="https://cdn.jsdelivr.net/npm/three@0.128.0/build/three.min.js"></script>
<script id="vertexShader" type="x-shader/x-vertex">
varying vec3 vNormal;
void main() {
vNormal = normal;
gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
}
</script>
<script id="fragmentShader" type="x-shader/x-fragment">
uniform float iTime;
varying vec3 vNormal;
void main() {
vec3 I = normalize(vec3(modelViewMatrix * vec4(position, 1.0)));
vec3 N = normalize(vec3(modelViewMatrix * vec4(vNormal, 0.0)));
float eta = 1.05;
vec3 R = refract(I, N, eta);
gl_FragColor = vec4(0.5 + 0.5 * sin(iTime), 0.5 + 0.5 * cos(iTime), 1.0, 1.0);
gl_FragColor.a = 0.2;
gl_FragColor.rgb *= 1.0 - smoothstep(0.0, 1.0, length(R.xy));
}
</script>
<script>
var scene = new THREE.Scene();
var camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 0.1, 1000);
camera.position.z = 5;
var geometry = new THREE.BoxGeometry(1, 1, 1);
var material = new THREE.ShaderMaterial({
uniforms: {
iTime: { value: 0 }
},
vertexShader: document.getElementById('vertexShader').textContent,
fragmentShader: document.getElementById('fragmentShader').textContent,
side: THREE.DoubleSide
});
var mesh = new THREE.Mesh(geometry, material);
scene.add(mesh);
var renderer = new THREE.WebGLRenderer();
renderer.setSize(window.innerWidth, window.innerHeight);
document.body.appendChild(renderer.domElement);
function render() {
requestAnimationFrame(render);
material.uniforms.iTime.value += 0.01;
renderer.render(scene, camera);
}
render();
</script>
</body>
</html>
```