This is a variation of the "display image" demo, with textures created entirely from code, both on the CPU and on the GPU. You should use the GPU if possible, since it has much higher performance as long as the processing can be parallelized, but there are cases that are sequential in nature where the GPU just don't help and you must use the CPU.
Updated 2017 and 2022. C++ version 2024 (which essentially means using the latest common files)
Old version: