可可西

webGL简单例子(klayge)

  当前的WebGL版本是1.0,其实际上是个OpenGL ES 2.0的Javascript绑定,也就是可以用Javascript来调用OpenGL ES 2.0的函数,在网页中实现3D渲染。WebGL是桌面、移动、嵌入式平台通吃,只要支持OpenGL ES 2.0的平台就可以用WebGL。使用了WebGL的Web游戏等程序可以做到和本地桌面程序一样的绚烂。

  目前支持WebGL的浏览器有Firefox 4.0 Beta、Chrome 9.0、Opera预览版、Safari每日构建版,NV和AMD的驱动都已经支持桌面的OpenGL ES 2.0,所以也就等于支持了WebGL。

  这个例子主要是用于测试不同浏览器对WebGL的支持情况,它来自于这里:http://www.klayge.org/html/webgl_test.html  通过这个例子可以了解一个最简单的WebGL程序是如何写成的!另外,可通过这个网页WebGLReport来查看浏览器对WebGL的支持情况。

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
<html>
    <head>
        <title>WebGL test</title>
        <meta http-equiv="content-type" content="text/html; charset=ISO-8859-1">
 
        <script id="shader-vs" type="x-shader/x-vertex">
            attribute vec3 position;
             
            uniform mat4 mv;
            uniform mat4 proj;
 
            void main()
            {
                gl_Position = proj * mv * vec4(position, 1.0);
            }
        </script>
        <script id="shader-fs" type="x-shader/x-fragment">
            void main()
            {
                gl_FragColor = vec4(0.8, 0.8, 0.0, 1.0);
            }
        </script>
 
        <script type="text/javascript">          
            // Initialises WebGL and creates the 3D scene.
            function loadScene()
            {
                var canvas = document.getElementById("webGLCanvas");
                if (!canvas.getContext)
                {
                    alert("There's no canvas available.");
                    return;
                }
 
                var gl = canvas.getContext("experimental-webgl");
                if (!gl)
                {
                    alert("There's no WebGL context available.");
                    return;
                }
 
                var vendor_info = document.getElementById("vendor_info");
                var renderer_info = document.getElementById("renderer_info");
                var version_info = document.getElementById("version_info");
                var ext_info = document.getElementById("ext_info");
                vendor_info.innerHTML = gl.getParameter(gl.VENDOR);
                renderer_info.innerHTML = gl.getParameter(gl.RENDERER);
                version_info.innerHTML = gl.getParameter(gl.VERSION);
                var exts = gl.getSupportedExtensions();
                var s = "";
                for (index in exts)
                {
                    s += exts[index] + "<br />";
                }
                ext_info.innerHTML = s;
 
                 
                gl.viewport(0, 0, canvas.width, canvas.height);
                 
                var vertexShaderScript = document.getElementById("shader-vs");
                var vertexShader = gl.createShader(gl.VERTEX_SHADER);
                gl.shaderSource(vertexShader, vertexShaderScript.text);
                gl.compileShader(vertexShader);
                if (!gl.getShaderParameter(vertexShader, gl.COMPILE_STATUS))
                {
                    alert("Unable to compile the vertex shader");
                    gl.deleteShader(vertexShader);
                    return;
                }
                 
                var fragmentShaderScript = document.getElementById("shader-fs");
                var fragmentShader = gl.createShader(gl.FRAGMENT_SHADER);
                gl.shaderSource(fragmentShader, fragmentShaderScript.text);
                gl.compileShader(fragmentShader);
                if (!gl.getShaderParameter(fragmentShader, gl.COMPILE_STATUS))
                {
                    alert("Unable to compile the fragment shader");
                    gl.deleteShader(fragmentShader);
                    return;
                }
 
                gl.program = gl.createProgram();
                gl.attachShader(gl.program, vertexShader);
                gl.attachShader(gl.program, fragmentShader);
                gl.linkProgram(gl.program);
                if (!gl.getProgramParameter(gl.program, gl.LINK_STATUS))
                {
                    alert("Unable to link shaders");
                    gl.deleteProgram(gl.program);
                    gl.deleteProgram(vertexShader);
                    gl.deleteProgram(fragmentShader);
                    return;
                }
 
                gl.clearColor(0.2, 0.4, 0.6, 1.0);
                gl.clearDepth(1.0);
                gl.enable(gl.DEPTH_TEST);
                gl.depthFunc(gl.LEQUAL);
                 
                var vertexBuffer = gl.createBuffer();
                gl.bindBuffer(gl.ARRAY_BUFFER, vertexBuffer);
                var vertices = new Float32Array([
                    0.0,   1.0, 1.0,
                    -1.0, -1.0, 1.0,
                    1.0,  -1.0, 1.0
                ]);
     
                gl.bufferData(gl.ARRAY_BUFFER, vertices, gl.STATIC_DRAW);
                 
                gl.useProgram(gl.program);
                var vertexPosition = gl.getAttribLocation(gl.program, "position");
                gl.enableVertexAttribArray(vertexPosition);
                gl.vertexAttribPointer(vertexPosition, 3, gl.FLOAT, false, 0, 0);
 
                gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
                 
                var fov = 90.0;
                var aspect = canvas.width / canvas.height;
                var nearPlane = 1.0;
                var farPlane = 100.0;
                var top = nearPlane * Math.tan(fov / 2 * Math.PI / 180);
                var bottom = -top;
                var right = top * aspect;
                var left = -right;
 
                var a = (right + left) / (right - left);
                var b = (top + bottom) / (top - bottom);
                var c = (farPlane + nearPlane) / (farPlane - nearPlane);
                var d = (2 * farPlane * nearPlane) / (farPlane - nearPlane);
                var x = (2 * nearPlane) / (right - left);
                var y = (2 * nearPlane) / (top - bottom);
                var perspectiveMatrix = new Float32Array([
                    x, 0, a, 0,
                    0, y, b, 0,
                    0, 0, c, d,
                    0, 0, -1, 0
                ]);
                 
                var modelViewMatrix = new Float32Array([
                    1, 0, 0, 0,
                    0, 1, 0, 0,
                    0, 0, 1, 0,
                    0, 0, 0, 1
                ]);
 
                gl.uniformMatrix4fv(gl.getUniformLocation(gl.program, "proj"), false, perspectiveMatrix);
                gl.uniformMatrix4fv(gl.getUniformLocation(gl.program, "mv"), false, modelViewMatrix);
 
                gl.drawArrays(gl.TRIANGLES, 0, vertices.length / 3);
            }
        </script>
    </head>
     
    <body onload="loadScene()">
        <h1>WebGL Test</h1>
        <h3>Vendor</h3>
        <p id="vendor_info"></p>
        <h3>Renderer</h3>
        <p id="renderer_info"></p>
        <h3>Version</h3>
        <p id="version_info"></p>
        <h3>Extensions</h3>
        <p id="ext_info"></p>
        <h3>Rendering</h3>
        <canvas id="webGLCanvas" width="640" height="480"></canvas>
         
<script type="text/javascript">
  var _gaq = _gaq || [];
  _gaq.push(['_setAccount', 'UA-16460301-1']);
  _gaq.push(['_trackPageview']);
 
  (function() {
    var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true;
    ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js';
    var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s);
  })();
</script>
    </body>
</html>

posted on   可可西  阅读(2824)  评论(0编辑  收藏  举报

编辑推荐:
· AI与.NET技术实操系列(二):开始使用ML.NET
· 记一次.NET内存居高不下排查解决与启示
· 探究高空视频全景AR技术的实现原理
· 理解Rust引用及其生命周期标识(上)
· 浏览器原生「磁吸」效果!Anchor Positioning 锚点定位神器解析
阅读排行:
· 全程不用写代码,我用AI程序员写了一个飞机大战
· DeepSeek 开源周回顾「GitHub 热点速览」
· 记一次.NET内存居高不下排查解决与启示
· MongoDB 8.0这个新功能碉堡了,比商业数据库还牛
· .NET10 - 预览版1新功能体验(一)

导航

统计信息

点击右上角即可分享
微信分享提示