How to optimize tile rendering?

冰镇汽水

I am developping a 2D tile-based game with dx9 and get a headache.
My map(1024*768) consists of many tiles. If I call drawprimitive for each tile to draw it directly to the backbuffer, a performance penalty will hurt me. So now i create a surface(1024*768) and set it as the render target and call DrawPrimitives to draw every tile to this surface and after this I can draw this surface to the backbuffer with only one drawprimitive. But this needs a lot of video memory. If this game is running on a computer with a graphic card of less than 64M, the surface can`t be created, and some strange effect will be met.
So any of U have any suggestion for me. Thanks a lot!

conquerors

how many vertex(the max numbers) be used in one render target?

zybx

Using an intermediate render target is equal to rendering directly to back buffer.
Tiles which share same source image can be rendered together.
Use DrawPrimitivesUP to render dynamic vertex arrays consists of several quads. The bandwidth is sufficient to transfer small amount of vertices.
Small source images can be merged into large textures (i.e. 1024x1024, MANAGED POOL recommended) to reduce DrawPrimitivesUP calls.

千里马肝

It's not about vertics and RT. Too many DP called caused this issue.
For your reference:
1. atlas your all image of tiles
2. one vertex buffer of your scene used the same one texture with only different world position and uv
3. so you can render your 2d scene by few DP
4. draw these viewable tiles by camera (where you are)

Please hang over your bed:
25k batches/s @ 100% 1GHz CPU

ReallyBigBug

chiglish.wo xi huan.