如何从外部文件加载着色器?三.文件加载器

zlo*_*lon 1 javascript three.js

我想从外部文件加载着色器。这个着色器是正确的,因为它在插入<script>标签时工作。我执行以下操作:

var loader = new THREE.FileLoader();
loader.load('shader.vert',function ( data ) {vShader =  data;},);
loader.load('shader.frag',function ( data ) {fShader =  data;},);
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后来我把它用作:

var material = new THREE.ShaderMaterial({
    uniforms: uniforms,
    vertexShader: vShader,
    fragmentShader: fShader,

});
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问题是当我重新加载页面时我出错了,着色器没有定义。当我在控制台中输入 vShader 时,它会打印出我想要的内容。当我开始调试时(init() 函数内的断点未定义。

你能解释一下我的错误吗?

整个代码:

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">

    <script src="https://threejs.org/build/three.min.js"></script>

</head>
<body>
<div class="WebGL-output" id="WebGL-output"></div>
<script id="vertexShader" type="x-shader/x-vertex" src="shader.vert">
varying vec2 vUv;
void main() {
vUv = uv;
gl_Position = projectionMatrix * modelViewMatrix * vec4(position,1.0);
}
</script>
<script id="fragmentShader" type="x-shader/x-fragment">
uniform vec3 color;
varying vec2 vUv;
void main() {
gl_FragColor = vec4(color,1.);
}
</script>

<script>
var renderer,uniforms,vShader,fShader,camera,scene;
var loader = new THREE.FileLoader();
init();
animate();
function init(){
renderer = new THREE.WebGLRenderer
renderer.setSize(window.innerWidth, window.innerHeight);
document.getElementById('WebGL-output').appendChild(renderer.domElement);
camera = new THREE.PerspectiveCamera(70, window.innerWidth / window.innerHeight, 1, 10000);
camera.position.z = 5000;
scene = new THREE.Scene();

//******* DO NOT WORK
loader.load('plaid.frag',function ( data ) {fShader =  data;},);
loader.load('plaid.vert',function ( data ) {vShader =  data;},);
// ****** WORK
//fShader = document.getElementById('fragmentShader').text;
//vShader = document.getElementById('vertexShader').text;

// **************************
uniforms = {
    "color" : {
        type : "c",
        //value :new THREE.Color(0xf0f0f0)
        value :new THREE.Color(0x00ff00)
    },
};


var material = new THREE.ShaderMaterial({
    uniforms: uniforms,
    vertexShader: vShader,
    fragmentShader: fShader,
});

// Create circles and add to scene.
var geometry = new THREE.CircleGeometry(100, 50);
mesh = new THREE.Mesh(geometry, material);
scene.add(mesh);

var light = new THREE.AmbientLight(0x000000); // soft white light
scene.add(light);
}
function animate() {
requestAnimationFrame(animate);
renderer.render(scene, camera);
}
</script>
</body>
</html>
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cla*_*l3r 6

我使我的 init 函数异步:

async function init() {

    let frag_shader = await (await fetch('simple.frag')).text();

    console.log(frag_shader);

    // ..

}
init();
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gma*_*man 5

你的错误是在浏览器中加载文件是异步的。所以首先你有这个代码

loader.load('plaid.frag',function ( data ) {fShader =  data;},);
loader.load('plaid.vert',function ( data ) {vShader =  data;},);
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这些功能你所做的设置fShadervShader不会被后来称为直到一段时间(需要多长时间怎么过下载的文件)

但是,只需几行就可以立即使用它们fShadervShader即使它们尚未下载

var material = new THREE.ShaderMaterial({
    uniforms: uniforms,
    vertexShader: vShader,
    fragmentShader: fShader,
});
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如果您真的想从外部文件加载,则需要构建代码以等待它们下载。

作为一个例子

loader.load('plaid.frag',function ( data ) {fShader =  data;},);
loader.load('plaid.vert',function ( data ) {vShader =  data;},);
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