Threejs中的ShaderMaterial可以使用自定義的shader，參數vertexShader和fragmentShader分別對應頂點着色器和片段着色器的內容（由GLSL寫成）。
頂點着色器和片段着色器的內容可以分別放到一個<script>標籤內
<script id="vs" type="x-shader/x-vertex">
varying vec4 vPosition;
void main() {
gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );
vPosition = gl_Position;
}
</script>
<script id="fs" type="x-shader/x-fragment">
varying vec4 vPosition;
void main() {
gl_FragColor = vec4(vPosition.x+0.5,vPosition.y+0.5,vPosition.z+0.5,1.0);
}
</script>
然後可以通過下面的方式創建ShaderMaterial
var material = new THREE.ShaderMaterial( {
vertexShader: document.getElementById( 'vs' ).textContent.trim(),
fragmentShader: document.getElementById( 'fs' ).textContent.trim()
} );
將上面的材質賦予模型後，模型的頂點顏色與頂點的位置相關，完整代碼如下
<!DOCTYPE html>
<html>
<head>
<meta charset='utf-8'/>
<title>threejs custom shader</title>
</head>
<body>
<div id="container"/>
<script src="three.js"></script>
<script id="vs" type="x-shader/x-vertex">
varying vec4 vPosition;
void main() {
gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );
vPosition = gl_Position;
}
</script>
<script id="fs" type="x-shader/x-fragment">
varying vec4 vPosition;
void main() {
gl_FragColor = vec4(vPosition.x+0.5,vPosition.y+0.5,vPosition.z+0.5,1.0);
}
</script>
<script>
var scene = new THREE.Scene();
var camera = new THREE.PerspectiveCamera(90,window.innerWidth/window.innerHeight,0.1,1000);
var renderer = new THREE.WebGLRenderer();
renderer.setSize( window.innerWidth, window.innerHeight );
container = document.getElementById("container");
container.appendChild(renderer.domElement);
var geometry=new THREE.BoxGeometry(1,1,1);
var material = new THREE.ShaderMaterial( {
vertexShader: document.getElementById( 'vs' ).textContent.trim(),
fragmentShader: document.getElementById( 'fs' ).textContent.trim()
} );
var cube = new THREE.Mesh(geometry,material);
scene.add(cube);
camera.position.z=5;
var animate = function()
{
requestAnimationFrame(animate);
cube.rotation.x += 0.01;
cube.rotation.y += 0.01;
renderer.render(scene,camera);
};
animate();
</script>
</body>
</html>
該實例創建一個轉動的立方體，各頂點處的顏色由該頂點的位置決定，運行後的效果
通過自定義shader可以實現各種複雜材質效果，而不侷限於threejs已有的材質類型。