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POHow can I use a dynamically sized texture array with glTexImage2D?
 

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  1. POHow can I use a dynamically sized texture array with glTexImage2D?
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    <p>Currently, I'm able to load in a static sized texture which I have created. In this case it's 512 x 512.</p> <p>This code is from the header:</p> <pre><code>#define TEXTURE_WIDTH 512 #define TEXTURE_HEIGHT 512 GLubyte textureArray[TEXTURE_HEIGHT][TEXTURE_WIDTH][4]; </code></pre> <p>Here's the usage of glTexImage2D:</p> <pre><code>glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, TEXTURE_WIDTH, TEXTURE_HEIGHT, 0, GL_RGBA, GL_UNSIGNED_BYTE, textureArray); </code></pre> <p>And here's how I'm populating the array (rough example, not exact copy from my code):</p> <pre><code>for (int i = 0; i &lt; getTexturePixelCount(); i++) { textureArray[column][row][0] = (GLubyte)pixelValue1; textureArray[column][row][1] = (GLubyte)pixelValue2; textureArray[column][row][2] = (GLubyte)pixelValue3; textureArray[column][row][3] = (GLubyte)pixelValue4; } </code></pre> <p>How do I change that so that there's no need for TEXTURE_WIDTH and TEXTURE_HEIGHT? Perhaps I could use a pointer style array and dynamically allocate the memory...</p> <h3>Edit:</h3> <p>I think I see the problem, in C++ it can't really be done. The work around as pointed out by Budric is to use a single dimensional array but use all 3 dimensions multiplied to represent what would be the indexes:</p> <pre><code>GLbyte *array = new GLbyte[xMax * yMax * zMax]; </code></pre> <p>And to access, for example x/y/z of 1/2/3, you'd need to do:</p> <pre><code>GLbyte byte = array[1 * 2 * 3]; </code></pre> <p>However, the problem is, I don't think the <code>glTexImage2D</code> function supports this. Can anyone think of a workaround that would work with this OpenGL function?</p> <h3>Edit 2:</h3> <p>Attention OpenGL developers, this can be overcome by using a single dimensional array of pixels...</p> <blockquote> <p>[0]: column 0 > [1]: row 0 > [2]: channel 0 ... n > [n]: row 1 ... n > [n]: column 1 .. n</p> </blockquote> <p>... no need to use a 3 dimensional array. In this case I've had to use this work around as 3 dimensional arrays are apparently not strictly possible in C++.</p>
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    1. COYou don't simply multiply the indices. It's (rowIndex * numColumns * numColourComponents + columnIndex + colourComponent);
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    2. COOops. Should be (rowIndex * numColumns * numColourComponents + columnIndex*numColourComponents + colourComponent);
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