Equiv of glDrawpixels that operates on GPU memory?

Question

glDrawPixels(GLsizei width, GLsizei height, GLenum format, GLenum type, const ovid *pixels);

Is there a function like this, except instead of accessing CPU memory, it accesses GPU memory? [Either a texture of a frame buffer object]

Answer 1

If it is in a texture:

• set up orthographic frustum
• disable blending, depth test, etc.
• bind texture
• draw screen-aligned textured quad with correct texture coordinates

I use this in for example in Compositor::_drawPixels

Answer 2

glDrawPixels can read from a Buffer Object. Just do a

glBindBuffer(GL_PIXEL_UNPACK_BUFFER, XXX)

before calling glDrawPixels.

Caveat: glDrawPixels is deprecated...

Answer 3

Use glBlitFramebuffer, which operates on frambuffer objects (Link). Ans this is not deprecated.

You can take advantage of format conversion, scaling and multisampling.

Answer 4

Maybe glCopyPixels?