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    <p>You can store your height data in a texture and then use <code>texture2D</code> function in vertex shader to modify the current height of the vertex.</p> <p>With this setup you can have single mesh and simply adjust the height of each vertex by the value stored in the texture.</p> <p>If you are sure that you are GPU-bound, the texture format used for looking up the height data can also be further optimized. Say your heightmap ranges from <code>0-255</code>, given the <code>GL_RGBA</code> format you can use the same texture for rendering up to 4 frames (first frame read the height from the red component, next frame from the blue component, etc.). Making the backing texture twice as big (1280x960) will further allow you to store up to 16 frames within a single texture. Another thing worth mentioning with regard to textures is that using the native format for your GPU can also bolster performance in both GPU/IO-bound scenarios. For iDevices this format is <a href="http://en.wikipedia.org/wiki/PVRTC" rel="nofollow">PVRTC</a>.</p> <p>I really think that the problem is just the allocation of 300k+ vertices each frame alone ... that adds up to 640 * 480 * 3 * 4 = <strong>3 686 400 bytes</strong> allocated every frame and you didn't mention after how many frames you stop allocating the memory (wait... <em>do you?</em>). That's way too much for such resource constrained environment.</p>
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    1. COThank you arul, this is most enlightening. I'll certainly implement the texture2D idea. At the moment I am keeping all the data in memory simply because I only want to read from disk once. Clearly that isn't working. Ultimately, I want to play a sequence of any length. My idea was to concatenate all the object files into one, but how would I go about streaming a file like that from disk as you would, say, a 3Gb movie file? Each file just contains a list of 640*480 floats. Figure 3 minutes of animation at 24fps and you're getting into about that size. Isn't streaming the only option?
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    2. COYes it is, but you need to stream in only the important data, which in this case is the heightfield map. The theoretical IO-throughput needed is 29.4912MB/s (isn't that too much for iDevices?). I think that storing the height info as floats is overkill. Assuming you're interfacing with Kinect, you get the depth info with 13-bits precision, and the remaining 19-bits are wasted. Try implementing the texture2D lookup method and then profile the code to find out where the bottleneck is (I bet on IO-throughput).
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    3. COGreat, thank you so much for your help. So, just to be clear: a) Rewrite the Kinect raw files to only use much smaller data types (unsigned short, perhaps?) b) Stream the data in using the NSDataReadingMappedAlways option that Tommy suggested and c) use texture2D method to pass the height data to the vertex shader. Does that sound about right? Can I dump the contents of the NSDataReadingMappedAlways directly into here:? `glVertexAttribPointer(vertexHandle, 3, GL_FLOAT, GL_FALSE, 0, (const GLvoid*)vertices);`
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