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---
title: Hello GLSL
slug: Web/API/WebGL_API/By_example/Hello_GLSL
translation_of: Web/API/WebGL_API/By_example/Hello_GLSL
---
<div>{{IncludeSubnav("/en-US/Learn")}}</div>
<p>{{PreviousNext("Learn/WebGL/By_example/Raining_rectangles","Learn/WebGL/By_example/Hello_vertex_attributes")}}</p>
<div id="hello-glsl">
<div class="summary">
<p id="hello-glsl-summary"><span class="seoSummary">该例子将演示一个绘制固态颜色的矩形的简单着色器程序。</span></p>
</div>
<div class="note">
<p><strong>注意：</strong>本例子能在大多数现代桌面版浏览器上运行。但或许不能在移动端或者古老的浏览器上运行。如果canvas显示一片空白，你可以试着用下一个例子检查一下输出是否绘制的是同样的图形。 但要记住在前往下一个例子之前，要仔细阅读本页并动手写代码。</p>
</div>
<p>{{EmbedLiveSample("hello-glsl-source",660,425)}}</p>
<div id="hello-glsl-intro">
<h3 id="用GLSL语言写Hello_World_程序">用GLSL语言写Hello World 程序</h3>
<p>第一个非常简单的着色器程序。</p>
</div>
<div id="hello-glsl-source">
<div class="hidden">
<pre class="brush: html"><p>Hello World! Hello GLSL!</p>
</pre>
<pre class="brush: html"><canvas>Your browser does not seem to support
HTML5 canvas.</canvas>
</pre>
<pre class="brush: css">body {
text-align : center;
}
canvas {
width : 280px;
height : 210px;
margin : auto;
padding : 0;
border : none;
background-color : black;
}
button {
display : block;
font-size : inherit;
margin : auto;
padding : 0.6em;
}
</pre>
</div>
<pre class="brush: html"><script type="x-shader/x-vertex" id="vertex-shader">
#version 100
void main() {
gl_Position = vec4(0.0, 0.0, 0.0, 1.0);
gl_PointSize = 64.0;
}
</script>
</pre>
<pre class="brush: html"><script type="x-shader/x-fragment" id="fragment-shader">
#version 100
void main() {
gl_FragColor = vec4(0.18, 0.54, 0.34, 1.0);
}
</script>
</pre>
<div class="hidden">
<pre class="brush: js">;(function(){
</pre>
</div>
<pre class="brush: js" id="livesample-js">"use strict"
window.addEventListener("load", setupWebGL, false);
var gl,
program;
function setupWebGL (evt) {
window.removeEventListener(evt.type, setupWebGL, false);
if (!(gl = getRenderingContext()))
return;
var source = document.querySelector("#vertex-shader").innerHTML;
var vertexShader = gl.createShader(gl.VERTEX_SHADER);
gl.shaderSource(vertexShader,source);
gl.compileShader(vertexShader);
source = document.querySelector("#fragment-shader").innerHTML
var fragmentShader = gl.createShader(gl.FRAGMENT_SHADER);
gl.shaderSource(fragmentShader,source);
gl.compileShader(fragmentShader);
program = gl.createProgram();
gl.attachShader(program, vertexShader);
gl.attachShader(program, fragmentShader);
gl.linkProgram(program);
gl.detachShader(program, vertexShader);
gl.detachShader(program, fragmentShader);
gl.deleteShader(vertexShader);
gl.deleteShader(fragmentShader);
if (!gl.getProgramParameter(program, gl.LINK_STATUS)) {
var linkErrLog = gl.getProgramInfoLog(program);
cleanup();
document.querySelector("p").innerHTML =
"Shader program did not link successfully. "
+ "Error log: " + linkErrLog;
return;
}
initializeAttributes();
gl.useProgram(program);
gl.drawArrays(gl.POINTS, 0, 1);
cleanup();
}
var buffer;
function initializeAttributes() {
gl.enableVertexAttribArray(0);
buffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
gl.vertexAttribPointer(0, 1, gl.FLOAT, false, 0, 0);
}
function cleanup() {
gl.useProgram(null);
if (buffer)
gl.deleteBuffer(buffer);
if (program)
gl.deleteProgram(program);
}
</pre>
<div class="hidden">
<pre class="brush: js">function getRenderingContext() {
var canvas = document.querySelector("canvas");
canvas.width = canvas.clientWidth;
canvas.height = canvas.clientHeight;
var gl = canvas.getContext("webgl")
|| canvas.getContext("experimental-webgl");
if (!gl) {
var paragraph = document.querySelector("p");
paragraph.innerHTML = "Failed to get WebGL context."
+ "Your browser or device may not support WebGL.";
return null;
}
gl.viewport(0, 0,
gl.drawingBufferWidth, gl.drawingBufferHeight);
gl.clearColor(0.0, 0.0, 0.0, 1.0);
gl.clear(gl.COLOR_BUFFER_BIT);
return gl;
}
</pre>
</div>
<div class="hidden">
<pre class="brush: js">})();
</pre>
</div>
<p>该例子的源代码能在 <a href="https://github.com/idofilin/webgl-by-example/tree/master/hello-glsl">GitHub</a>获得。</p>
</div>
</div>
<p>{{PreviousNext("Learn/WebGL/By_example/Raining_rectangles","Learn/WebGL/By_example/Hello_vertex_attributes")}}</p>
|
