Sorry if this question about is a bit broad.
In the game I'm making, I need an isometric view with some altitude, which means players can go behind a hill, and be partly or totally hidden. To avoid re-drawing the whole view tile after tile every time a player moves, I decided to put each horizontal line of tiles in cache and draw each line, one after another from top to bottom. This works pretty well, I think FPS are correct and everything, but memory usage could soon be a problem : a 50*50 map means 99 lines resulting in 98Mo , a 100*100 map means 199 lines and 388 Mo.
Here is a line : http://img35.imageshack.us/img35/8866/10698169.png (sorry, as a new user, I can't use image tags)
The memory consumption will grow even bigger if I allow higher altitude (each line will be stored in a higher Surface object).
I'm wondering if this cache system was really a good idea... I could code a bit better so that lines are stored in the smallest possible Surface, but there will still be a big memory consumption.
Do you have any advice, any feedback on my system ? Is it worth optimizing, or should I forget this cache-idea ?