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
|
<!--
Copyright (c) 2019 The Khronos Group Inc.
Use of this source code is governed by an MIT-style license that can be
found in the LICENSE.txt file.
-->
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<!-- This is a visual test that programs must have both a vertex and
fragment shader attached; the fixed function pipeline on the
desktop must remain disabled. -->
<script type="application/javascript">
function log() {
var s = "";
for (var i = 0; i < arguments.length; ++i) {
s += arguments[i] + " ";
}
document.getElementById("log").innerHTML += s + "<br>";
}
function go() {
var gl = document.getElementById("c").getContext("experimental-webgl");
gl.clearColor(0.0, 0.0, 0.0, 0.0);
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
var vs = gl.createShader(gl.VERTEX_SHADER);
gl.shaderSource(vs, "attribute vec4 aVertex; attribute vec4 aColor; varying vec4 vColor; void main() { vColor = aColor; gl_Position = aVertex; }");
gl.compileShader(vs);
var fs = gl.createShader(gl.FRAGMENT_SHADER);
gl.shaderSource(fs, "precision mediump float; varying vec4 vColor; void main() { gl_FragColor = vColor; }");
gl.compileShader(fs);
var prog = gl.createProgram();
gl.attachShader(prog, vs);
// don't attach a fragment shader -- may use fixed pipeline on desktop if the implementation doesn't check!
//gl.attachShader(prog, fs);
gl.bindAttribLocation(prog, 0, "aVertex");
gl.bindAttribLocation(prog, 1, "aColor");
gl.linkProgram(prog);
var vbuf = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, vbuf);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([
-1.0, -1.0, 0.0, 1.0,
-1.0, 1.0, 0.0, 1.0,
1.0, -1.0, 0.0, 1.0,
1.0, 1.0, 0.0, 1.0]), gl.STATIC_DRAW);
gl.vertexAttribPointer(0, 4, gl.FLOAT, false, 0, 0);
var cbuf = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, cbuf);
gl.bufferData(gl.ARRAY_BUFFER, new Uint8Array([255, 0, 0,
0, 255, 0,
0, 0, 255,
255, 255, 0]), gl.STATIC_DRAW);
gl.vertexAttribPointer(1, 3, gl.UNSIGNED_BYTE, false, 0, 0);
gl.enableVertexAttribArray(0);
gl.enableVertexAttribArray(1);
gl.useProgram(prog);
gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4);
log("glError", "0x" + gl.getError().toString(16));
}
</script>
</head>
<body onload="go()">
<p>Should be green in the rectangle below:</p>
<canvas style="background: green;" id="c"></canvas>
<div id="log"></div>
</body>
</html>
|
