[QtCanvas3D] Low FPS if you render multiple objects, each one with its own texture

I modified the framebuffer example to render 100 objects instead of just one. The fps remained high. But then I also loaded the same texture repeatedly for each new object. I attached the modified files.

On my Nexus 5x, FPS dropped to 12-13. On a low-end device, such as my Lenovo A1000 FPS dropped to 2.

I have also noticed a drop in FPS while running the planets example.