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Terrain rendering performance

Started by fosh Mar 18, 2005 at 2:55 AM 2 replies 750+ views

Original Post

Mar 18, 2005 at 2:55 AM

g'day all. When rendering terrain, that is stored as a regular heightfield, is there any reason to pass vertex data to the card as triangles rather than quads? At the moment, im got a path to render as triangles or render as quads. The quads path runs at about 110fps, and the triangles runs at about 70fps...which about corresponds to what you'd expect the decrease in fps to be based on the change in the number of vertices required for each path. Both are rendered into a display list once, and then called every frame. I realise that you should be able to see a bit of visible difference...breaking each quad into 2 tris obviously allows it to be bent in the middle, but im not seeing much. Are there any other reasons to go with triangles? cheers, Scott

Cygon

110

Cygon

Mar 18, 2005 at 3:23 AM

Internally, only triangles can be rendered, so your quads will eventually be converted to triangles before they are rendered.

You should see some speed gain from vertex caching and batching if you use indexed triangle strips. I'm mainly using Direct3D, but I think to do this in OpenGL you have to create a VBO and somehow set up an index buffer for it.

-Markus-

fosh

Author

fosh

Mar 18, 2005 at 5:21 AM

ah, thanks for that!
i totally forgot about triangle strips.
ill give that a shot.

Aiursrage2k

Mar 18, 2005 at 9:41 PM

One of the slowest operations in the 3d pipeline is changing the textures, so a very simple optimization would be to sort your data by texture.

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