<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 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 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="rotatingSquare2.js"></script>

<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>

<canvas id="gl-canvas" width="512" height="512">

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