OpenGL textured image is blurry

I am trying to create a mipmapped textured image that represents elevation. The image must be 940 x 618. I realize that my texture must开发者_Go百科 have a width and height of a power of 2. As of now I have tried to incrementally go through doing all my texturing in squares (eg 64 x 64, or 128 x 128, even 512 x 512), but the image still comes out blurry. Any idea of how to better texture an image of this size?

Use a 1024x1024 texture and put your image in just a part of the image, 940x618. Then use the values 940.0/1024.0 and 618.0/1024.0 for the max texture coordinates, or scale the TEXTURE_MATRIX. This will make a 1:1 mapping for your pixels. You might also need to shift the model half a pixel to get a perfect fit, this depends on your model setup and view.

This is the technic I used in this screensaver I made for the Mac. http://memention.com/void/ It grabs the screen contents and uses it as a texture on some 3D effects and I really wanted a pixel perfect fit.

As far as I know, modern technologies do not require you to use a power of 2 for your dimensions. Just know however, that if this code is run an older machine, you'll have some problems. How old is your machine?

The texture is probably not mapped 1:1, and you have GL_LINEAR or GL_NEAREST filtering. Try higher resolution texture, mipmapping, and 1:1 screen mapping.

Use a 940x618 sized texture (if this is truly the size of the surface it's applied to) and set the texture's minification/magnification to use GL_LINEAR. That should give you the results you're after.