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Archived:M3G performance hints for 3D hardware-accelerated devices (Nokia N93 and Nokia N95)

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Article Metadata
Tested with
Devices(s): Nokia N93, Nokia N95
Platform(s): S60 3rd Edition
S60 3rd Edition, FP1
S60 3rd Edition FP1
S60 3rd Edition (initial release)
Created: User:Technical writer 2 (20 Aug 2007)
Last edited: hamishwillee (14 Jun 2012)


M3G performance hints for 3D hardware-accelerated devices (Nokia N93 and Nokia N95)


When using M3G on the Nokia N93 or Nokia N95, you need to be aware of certain performance-related pitfalls.
To begin with, there are some features that are radically more expensive on the Nokia N93 than on phones which have "software acceleration" only:
* 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 Nokia N95, but you still won't get the same performance as on other phones.
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 Nokia N93).
* Clear the color buffer and depth buffer before rendering (especially on the Nokia 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.

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