[taarnio]

If you're using M3G on the Nokia N93 or the upcoming N95, you need to be aware of certain performance-related pitfalls. We may be able to come up with a proper document about that, but it will no doubt take some time, so I'm just posting here the most important pieces of information.

To begin with, there are some features that are radically more expensive on the N93 than our "software accelerated" phones:

* CompositingMode.setColorWriteEnable(false)
* CompositingMode.setAlphaWriteEnable(false)
* PolygonMode.setTwoSidedLightingEnable(true)
* Graphics3D.bindTarget(Graphics)
* Graphics3D.bindTarget(Image2D)
* Graphics3D.setViewport(...) (in mid-frame)
* new Image2D(...)
* Image2D.set(...)

Some of these are going to be lesser problems on the N95, but you're still not going to get the same perf as on other phones.

Then some quick tips on how to get around the issues:

* Keep color and alpha writes enabled in CompositingMode.
* Keep two-sided lighting disabled in PolygonMode.
* Use the OVERWRITE flag at bindTarget (note: not available on the N93).
* Clear the color buffer and depth buffer before rendering (especially on the N93).
* Do not use MIDP to draw 2D backgrounds. Draw them as texture-mapped quads instead.
* Unlike 2D backgrounds, 2D overlays carry no significant performance penalty.
* Keep the viewport full-screen. In particular, do not change it while rendering.
* Use immutable (rather than mutable) Image2Ds wherever possible.

Good luck,
Tomi