How to use GL_REPEAT to repeat only a selection of a texture atlas? (OpenGL)

Question

How can I repeat a selection of a texture atlas?

For example, my sprite (selection) is within the texture coordinates:

GLfloat textureC         


        

Answer 1

None of the texture wrap modes support the kind of operation you are looking for, i.e. they all map to the full [0,1] range, not some arbitrary subset. You basically have two choices: Either create a new texture that only has the sprite you need from the existing texture or write a GLSL pixel program to map the texture coordinates appropriately.