Well. My question is very simple : I would like to do « arithmetics » operations between 2 images, of any size, with OpenGL. But, i don''t want to do "Logicals Operations" but "Arithmetics Operations". The "Arithmetic Operator" can to be an add/soustract/divide/multiplicate... operation. So, how to do this by using OpenGL, in order to use the hardware acceleration ? ! (here, time is critical). Yes, i don''t want to do a "software" procedure, but a "hardware" procedure (using the 3D cards). Perhaps with textures (blending of 2 textures), but the problem is the SIZE : it must to be a multiple of two, not any size. Anybody has got an idea ? ! Thanks. .JuJ. (french)