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
|
<!DOCTYPE html>
<head>
<meta charset="utf-8"/>
<title>Космата окръжност</title>
<script src="webgl-fmi.js"></script>
<script id="vshader" type="x-shader/x-vertex">
attribute vec2 aXY;
attribute vec3 aRGB;
varying vec3 vRGB;
void main ()
{
gl_Position = vec4(aXY,0,1);
gl_PointSize = 4.0;
vRGB = aRGB;
}
</script>
<script id="fshader" type="x-shader/x-fragment">
precision mediump float;
varying vec3 vRGB;
void main( )
{
gl_FragColor = vec4(vRGB,1);
}
</script>
<script>
function start( )
{
gl = getContext("picasso");
glprog = getProgram("vshader","fshader");
aXY = gl.getAttribLocation(glprog,"aXY");
aRGB = gl.getAttribLocation(glprog,"aRGB");
gl.clearColor(1,1,1,1);
gl.clear(gl.COLOR_BUFFER_BIT);
var n = 150;
const aspectRatio = 600 / 400;
var points = [];
const circleR = 0.7;
const maxHairAddon = 0.3;
const hairyDegr = 360 / n;
for (var degr = 0; degr < 360; degr++) {
var x = Math.sin(2.0 * Math.PI * degr / 360) / aspectRatio;
var y = Math.cos(2.0 * Math.PI * degr / 360);
points.push(x * circleR, y * circleR, 0, 0, 0);
if (degr % hairyDegr < 1) {
var r = random(0.05, maxHairAddon);
points.push(x * (circleR + r), y * (circleR + r), 0, 0, 0);
points.push(x * circleR, y * circleR, 0, 0, 0);
}
}
var buf = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, buf);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(points), gl.STATIC_DRAW);
gl.vertexAttribPointer(aXY, 2, gl.FLOAT, false, 5 * FLOATS, 0 * FLOATS);
gl.vertexAttribPointer(aRGB, 3, gl.FLOAT, false, 5 * FLOATS, 2 * FLOATS);
gl.enableVertexAttribArray(aXY);
gl.enableVertexAttribArray(aRGB);
gl.drawArrays(gl.LINE_LOOP, 0, 360 + 2 * n);
}
</script>
</head>
<body onload="start()">
<h2>Космата окръжност</h2>
<noscript>
Искаме JavaScript, но няма!
</noscript>
<canvas id="picasso" width="600" height="400" style="border: solid;">
Искаме canvas, но няма!
</canvas>
</body>
|
