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POHow to make this polygon render as a complete shape rather than a crescent?
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  1. POHow to make this polygon render as a complete shape rather than a crescent?
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    copied!<p>I'm using the following javascript function to create an array of vertices to pass to a buffer when creating a shape. It should calculate the vertices of an n-sided regular polygon with the first vertex located at the origin. The buffers are then created and stored as properties on the shape object that was passed to the function.</p> <pre><code>var vertices = []; // Create each vertex by calculating the position of the new vertex relative // to the old then adding on to the old position // Begin by setting up the first vertex at the origin vertices [0] = 0.0; vertices [1] = 0.0; vertices [2] = 0.0; var oldX = 0.0; var oldY = 0.0; for (var i = 0; i &lt; shape.numberOfSides; i++) { var theta = i * 2 * Math.PI / shape.numberOfSides; var y = shape.sideLength * Math.sin(theta); var x = shape.sideLength * Math.cos(theta); y += oldY; x += oldX; var start = (i+1) * 3; vertices [start] = x; vertices [start + 1] = y; vertices [start + 2] = 0.0; oldX = x; oldY = y; } // Create a buffer and store the vertices on it shape.verticesBuffer = gl.createBuffer(); gl.bindBuffer(gl.ARRAY_BUFFER, shape.verticesBuffer); gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(vertices), gl.STATIC_DRAW); </code></pre> <p>This works absolutely fine for triangles, but for pentagons or above the shape is not complete - it looks like a crescent. I've included a screenshot below of the working triangle and a non-working hexagon, both created with the same function.</p> <p><a href="http://i39.tinypic.com/ndoj8z.png" rel="nofollow">http://i39.tinypic.com/ndoj8z.png</a></p> <p>Can anyone see what it is that I'm doing wrong?</p>
 

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