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Restrictions
[D3D9 Restrictions]

In this section we describe the general restrictions of D3D9 RenderWare Graphics. It is difficult to provide specific details since they are dependent on the level of support that individual video card drivers supply.

• When the Windows desktop is set to use 256 colors, RenderWare Graphics applications do not support windowed mode. Full screen modes are still available.

• The internally managed vertex buffers require 1 MB of free storage upon starting RenderWare for hardware TnL video cards, and 256 KB for non-hardware TnL cards.

• By default, rasters of type rwRASTERTYPECAMERATEXTURE and rwRASTERTYPEZBUFFER are created with the same bit depth as the main back buffer and main z-buffer, respectively. If the application tries to force a different bit depth, RwRasterCreate may fail depending on the level of support from the video card driver.

• Point and spot lights (rpLIGHTPOINT, rpLIGHTSPOT, rpLIGHTSPOTSOFT) only influence vertices that lie within the range (radius) of the light. However, low tessellated geometry that moves in and out of the light's range will exhibit "light popping". This is due to the light model used by D3D9 in that there is a discontinuity in itensity on either side of the light range, i.e. zero just outside and a positive non-zero value just inside the range.

• If the flags argument to RwCameraShowRaster alternates between rwRASTERFLIPDONTWAIT and rwRASTERFLIPWAITVSYNC during run-time, then performance will be reduced since the D3D9 device and all video memory is repeatedly destroyed and recreated. See RwRasterFlipMode.

• A limitation in some video cards, e.g. GeForce3, insist that the stride of an rwRASTERTYPECAMERA or rwRASTERTYPECAMERATEXTURE raster must be at least 64 bytes.

• RpAtomicInstance is only supported for those atomics containing geometries that are never reinstanced. For RenderWare Graphics these are geometries without skin, patch, morph, dmorph or toon information.

• RWD3D9 is using automatic generation of mipmaps in hardware if supported by the video card, when creating a raster with the flag rwRASTERFORMATAUTOMIPMAP or when RwTextureSetAutoMipmapping is enabled. That means the video card driver will handle all the mipmap levels in video memory, saving system memory and making the upload of textures faster. But, that also means that only the first level of the mipmap chain is available for locking, so the return value from RwRasterGetNumLevels will be 1.

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