Chap3/rotatingSquare3.html

<!DOCTYPE html>
<html>
<meta http-equiv="Content-Type" content="text/html;charset=utf-8" >
<title>Rotating Square</title>

<script id="vertex-shader" type="x-shader/x-vertex">
attribute vec4 vPosition;
uniform float theta;

void
main()
{
    float s = sin( theta );
    float c = cos( theta );

    gl_Position.x = -s * vPosition.y + c * vPosition.x;
    gl_Position.y =  s * vPosition.x + c * vPosition.y;
    gl_Position.z = 0.0;
    gl_Position.w = 1.0;
}
</script>

<script id="fragment-shader" type="x-shader/x-fragment">

precision mediump float;

void
main()
{
    gl_FragColor = vec4( 1.0, 0.0, 0.0, 1.0 );
}
</script>


<script type="text/javascript" src="../Common/webgl-utils.js"></script>
<script type="text/javascript" src="../Common/initShaders.js"></script>
<script type="text/javascript" src="../Common/MV.js"></script>
<script type="text/javascript" src="rotatingSquare3.js"></script>
</head>

<body>
<div>
speed 0% <input id="slider" type="range"
 min="0" max="100" step="10" value="50" />
 100%
</div>


<button id="Direction">Change Rotation Direction</button>

<select id="Controls" size="3">
    <option value="0">Toggle Rotation Direction</option>
    <option value="1">Spin Faster</option>
    <option value="2">Spin Slower</option>
</select>

<canvas id="gl-canvas" width="512" height="512">
Oops ... your browser doesn't support the HTML5 canvas element
</canvas>
</body>
</html>