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Unreal Tournament III Tips
This information is provided by DGUnreal. Please do not copy this and post it
elsewhere.
Textures
For 24-bit RGB textures specify CompressionNoAlpha on import to produce a DXT1 texture.
For 32-bit ARGB textures leave CompressionNoAlpha unchecked to produce a DXT5 texture.
Specular and Opacity information is best placed into the Alpha Channel of a 32-bit DXT5
texture instead of using two 24-bit DXT1 textures. While two DXT1 textures are the
same file size as one DXT5, in the engine a DXT5 uses one TextureSampler whereas two
DXT1's will use two TextureSamplers. Video adapters commonly have 16 TextureSamplers
(SM3 and SM4).
Since the TEXTUREGROUP_World maximum is 1024, there is no reason to use standard textures
greater than this resolution (1024x1024) on world geometry. If a texture must be
larger than any specific Group maximum, be sure to choose a Group that supports the
texture size natively and doesn't drop mips. Be careful with using too many 2048 and
larger textures, especially when targetting support for the PS3. By overriding the
default use of Texture Groups, you may impact the texture memory pool and cause issues on
systems with less video memory.
For 2048 and 4096 textures for world use you can override them into the
TEXTUREGROUP_RenderTarget. This supports mips/LODs from 1 to 4096. Use this
with care so that you do not impact the texture memory pool.
The LODBias is calculated before the LODGroup range.
An LODBias of 0 is the main texture resolution. An LODBias of 1 is the first mip
down of the texture, eg. a 1024x1024 texture that has and LODBias of 1 results in the
512x512 mip being chosen.
After the LODBias is calculated, then the texture mip is checked that it fits in the
LODGroup range, and adjusted if necessary. For example, a 1024x1024 texture with
LODBias of 1 uses the 512x512 mip, if it is in the TEXTUREGROUP_World Group, it is then
checked to see if it fits within the Group's Minimum and Maximum range, which in this case
is 1 and 1024.
The LODBias on an individual texture can be positive or negative so that it can offset the
default LODBias specified for each LODGroup to either higher or lower mip values.
8192 textures can be imported but currently are not natively supported at mip 0 with the
current LODGroups.
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