I'm porting a C++ game to Android using the NDK and there's one bottleneck that's really slowing down the code: gluScaleImage().
Does anyone know of a faster way to scale image textures?
Scaling images is computationally expensive (even when you're using heavily optimized code/functions). If you're doing this a lot during runtime, you should probably rethink your design.
If this is just about displaying images with various sizes, why not create a textured quad and scale it to the requested size? The texture could always be the same size then.
Not familiar with the android's hardware scaling abilities, but if
gluScaleImage() doesn't utilize hardware, you should find something that does. Be aware that your performance will then be hardware-dependent as well as CPU speed-dependent (try to find a friend with an older, slower android device to test). If this doesn't help you may want to cache the rotated graphics. When learning SDL I was surprised to find that the planes in this game have a long sprite sheet with ~16 rotations in an image for each of the two colors of plane.