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
|
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>WebGL Texture Mipmap</title>
</head>
<body>
<div style="text-align: center">
SE<canvas id="canvas" width="128" height="128"></canvas>VO
</div>
<script id="vertexshader" type="x-shader">
attribute vec2 aVertexPosition;
attribute vec2 aTextureCoord;
varying vec2 vTextureCoord;
uniform float uTime;
void main() {
vTextureCoord = aTextureCoord;
mat4 rotMat = mat4(sin(uTime), 0.0, 0.0, 0.0,
0.0, sin(uTime), 0.0, 0.0,
0.0, 0.0, 1.0, 0.0,
0.0, 0.0, 0.0, 1.0);
gl_Position = rotMat * vec4(aVertexPosition, 0.0, 1.0);
}
</script>
<script id="fragmentshader" type="x-shader">
precision mediump float;
varying vec2 vTextureCoord;
uniform sampler2D uSampler;
void main() {
gl_FragColor = texture2D(uSampler, vTextureCoord);
}
</script>
<script type="text/javascript">
var canvas;
function initWebGL()
{
canvas = document.getElementById("canvas");
var gl = canvas.getContext("webgl") || canvas.getContext("experimental-webgl");
if (!gl) return null; // can't initialize WebGL
return gl;
}
var gl = initWebGL();
// Setup Shaders:
var v = document.getElementById("vertexshader").firstChild.nodeValue;
var f = document.getElementById("fragmentshader").firstChild.nodeValue;
var vs = gl.createShader(gl.VERTEX_SHADER);
gl.shaderSource(vs, v);
gl.compileShader(vs);
if (!gl.getShaderParameter(vs, gl.COMPILE_STATUS)) {
console.log(gl.getShaderInfoLog(vs));
}
var fs = gl.createShader(gl.FRAGMENT_SHADER);
gl.shaderSource(fs, f);
gl.compileShader(fs);
if (!gl.getShaderParameter(fs, gl.COMPILE_STATUS)) {
console.log(gl.getShaderInfoLog(fs));
}
program = gl.createProgram();
gl.attachShader(program, vs);
gl.attachShader(program, fs);
gl.linkProgram(program);
if (!gl.getProgramParameter(program, gl.LINK_STATUS)) {
console.log(gl.getProgramInfoLog(program));
}
gl.useProgram(program);
program.aVertexPosition = gl.getAttribLocation(program, "aVertexPosition");
gl.enableVertexAttribArray(program.aVertexPosition);
program.aTextureCoord = gl.getAttribLocation(program, "aTextureCoord");
gl.enableVertexAttribArray(program.aTextureCoord);
var rustTexture = gl.createTexture();
var rustImage = new Image();
rustImage.onload = function() { handleTextureLoaded(rustImage, rustTexture); }
rustImage.src = "rust-power-of-two.png";
// Setup Geometry
var vertices = new Float32Array([
-1.0, -1.0,
-1.0, 1.0,
1.0, -1.0,
1.0, 1.0 // Square-Coordinates
]);
var textureCoords = new Float32Array([
0.0, 0.0,
0.0, 1.0,
1.0, 0.0,
1.0, 1.0
]);
vbuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, vbuffer);
gl.bufferData(gl.ARRAY_BUFFER, vertices, gl.STATIC_DRAW);
uvbuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, uvbuffer);
gl.bufferData(gl.ARRAY_BUFFER, textureCoords, gl.STATIC_DRAW);
itemSize = 2; // we have 2 coordinates (x,y)
numItems = vertices.length / itemSize; // number of vertices
// Viewport
gl.viewport(0, 0, canvas.width, canvas.height);
program.time = gl.getUniformLocation(program, "uTime");
var start_time = new Date().getTime() / 1000;
setInterval(function () {
gl.clearColor(1, 0, 0, 1);
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
// Draw
gl.bindBuffer(gl.ARRAY_BUFFER, vbuffer);
gl.vertexAttribPointer(program.aVertexPosition, itemSize, gl.FLOAT, false, 0, 0);
gl.bindBuffer(gl.ARRAY_BUFFER, uvbuffer);
gl.vertexAttribPointer(program.aTextureCoord, 2, gl.FLOAT, false, 0, 0);
gl.activeTexture(gl.TEXTURE0);
gl.bindTexture(gl.TEXTURE_2D, rustTexture);
var dt = new Date().getTime() / 1000 - start_time;
gl.uniform1f(program.time, dt);
gl.drawArrays(gl.TRIANGLE_STRIP, 0, numItems);
}, 15);
function handleTextureLoaded(image, texture) {
console.log("handleTextureLoaded, image = " + image);
gl.bindTexture(gl.TEXTURE_2D, texture);
gl.pixelStorei(gl.UNPACK_FLIP_Y_WEBGL, true);
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, image);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR_MIPMAP_NEAREST);
gl.generateMipmap(gl.TEXTURE_2D);
gl.bindTexture(gl.TEXTURE_2D, null);
}
</script>
</body>
</html>
|
