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Uthman

how slow is slow?

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so I know glVertexPointer is a 'slow' call (as opposed to glVertex3f, but considering glVertex3f would have to be called a gazillion times compared to the once glVertexPointer is where we get our speed. anyhow, how slow is 'slow'? Im trying to optimize my custom file format which, for now, issues: one glVertexPointer call one glTexCoordPointer call and one glNormalPointer call per mesh per model. is this okay or is it not good enough?

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Profiling would be a good idea indeed. In my program glVertexPointer is the heaviest of the pointer calls, but you should find that glDrawArrays/DrawElements/etc are much heavier.

Beyond that, it depends on how you are going to use your model format. Your current method would be good for props or animated characters. For a level model though, there is possibly going to be 100s of meshes within a model.

The ideal setup is to have a single set of vertices, texcoords, normals, etc for an entire model. I would choose to ignore the whole concept of user-defined "meshes" (Only for engine purposes, not for modelling, obviously). Sort the geometry by texture, and you end up with the least amount of calls possible.

rendering would then be:
one glVertexPointer/glTexCoordPointer/glNormalPointer
and one glDrawArrays/Elements call for each texture used by the model.


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