quote:Original post by c t o a n
This refers to rendering the scene with color writes disabled. This translates into only writing the z-value of all polygons in the scene into the z-buffer.
Once the z-buffer is filled with all visible polygons, you re-render your scene with full detail, and if the polygon is invisible in the final result, it will fail the z-test and no more work will be put into it.
This is only really helpful if you are fill-bound in your engine, but this method really sucks if you''re transform-bound (because you have to transform all your polygons twice)
Chris Pergrossi
My Realm | "Good Morning, Dave"
Also if you cannot afford sending all that data through the rendering pipe twice, you can achieve roughly the same effect by sorting your batches front to back. Depending on how big your batches are it can either help or be pointless.
Don''t forget about occlusion queries either. If a surface has multiple passes, do an occlusion query on it on the first pass then a bit later in the rendering pipe, test the occlusion query, if no pixels were rendered don''t render the second pass.
There are tons of ways to improve fillrate performance.