Updating a texture in OpenGL with glTexImage2D

Question

Are glTexImage2D and glTexSubImage2D the only ways to pass a buffer of pixels to a texture?

At the moment I use in a setup function glTexImage2D

Answer 1

In modern OpenGL there are 4 different methods to update 2D textures:

1. glTexImage2D - the slowest one, recreates internal data structures.

2. glTexSubImage2D - a bit faster, but can't change the parameters (size, pixel format) of the image.

3. Render-to-texture with FBO - update texture entirely on GPU, very fast. Refer to this answer for more details: https://stackoverflow.com/a/10702468/1065190

4. Pixel Buffer Object PBO - for fast uploads from CPU to GPU, not supported (yet) on OpenGL ES.