repetitive drawing problem

Hi. Any help you can give me on this will be highly appreciated. My problem is as follows:

I need to draw some shapes on the screen (simple shapes: rectangles, triangles, etc.) and I have the code to draw them using a lot of "int 10h"s ... or I will, very soon. The problem is that I need to draw many of those shapes on the screen, and calling the interrupt-based procedure each time I need to draw 1 shape is very slow... I was wondering if there is a way to draw the shapes once in some unseen area of the screen and then just copying that into the visible area. I'm using video mode 12h.

Thanks in advance.