I am developing paint application in iOS using openGL. Each time i switch the page I save drawing as a .png.When I come back I draw that saved image using texture by making it as power of 2. Now at the time of undo/Redo I clear whole framebuffer and Redraw all (.png+remaining stuff).In this case my performance decrease as I draw each time a large texture image.
Is there any way to solve this problem.
I suggest you don’t save anything to permanent storage unless the application is terminated.
Also, use texture no larger that 1024 x 1024.
Moreover, avoid using .png if you are not taking advantage of the transparency. .jpg are way smaller in size.
That should improve your performance dramatically.