Faster way to scale images than gluScaleImage?

Question

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?

Answer 1

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.

Answer 2

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.