openGL textures that are not 2^x in dimention

Question

I'm trying to display a picture in an openGL environment. The picture's origninal dimensions are 3648x2432, and I want to display it with a 256x384 image. The problem is, 384 is not a power of 2, and when I try to display it, it looks stretched. How can I fix that?

Answer 1

There's three ways of doing this that I know of -

• The one Albert suggested (resize it until it fits).
• Subdivide the texture into 2**n-sized rectangles, and piece them together in some way.
• See if you can use GL_ARB_texture_non_power_of_two. It's probably best to avoid it though, since it looks like it's an Xorg-specific extension.

Answer 2

You can resize your texture so it is a power of two (skew your texture so that when it is mapped onto the object it looks correct).

Answer 3

ARB_texture_rectangle is probably what you're looking for. It lets you bind to GL_TEXTURE_RECTANGLE_ARB instead of GL_TEXTURE_2D, and you can load an image with non power-of-2 dimensions. Be aware that your texture coordinates will range from [0..w]x[0..h] instead of [0..1]x[0..1].

Answer 4

If GL_EXT_texture_rectangle is true then use GL_TEXTURE_RECTANGLE_EXT for the first param in glEnable() and GLBindTexture() calls.