Texture formats overview
From FSDeveloper Wiki
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Direct X Texture formats (DXTn) are licensed use of S3 Graphics Ltd S3 Texture Compression (S3TC) technology.
Contents
S3TC Format Comparison
DXT4/5 use an interpolated alpha scheme, they generally produce superior results for alpha (transparency) gradients than DXT2/3.
Some consider DXT5 to be the most flexible general purpose compression codec.
| FOURCC | FS versions | Description | Alpha premultiplied? | Compression ratio | Texture Type |
|---|---|---|---|---|---|
| DXT1 | All ¹ | 1-bit Alpha / Opaque | N/A | 8:1 | Simple non-alpha |
| DXT2 | Not supported | Explicit alpha | Yes | 4:1 | Sharp alpha |
| DXT3 | All | Explicit alpha | No | 4:1 | Sharp alpha |
| DXT4 | Not supported | Interpolated alpha | Yes | 4:1 | Gradient alpha |
| DXT5 | FSX only | Interpolated alpha | No | 4:1 | Gradient alpha |
Notes
- ¹ DXT1 with an alpha may cause transparency issues in FSX SP2.
- Mixing DXT1 & DXT3 textures may cause performance problems.
- For any packages requiring dual FS9 & FSX compatibility, to minimize any transparency issues, recommend using DXT3 type .
- For conversion utilities, see the Tools section below.
Alpha Types
INSERT explanation of alpha types, or a link to.
- 1-bit Alpha - placeholder
- Explicit alpha - placeholder
- Interpolated alpha - placeholder
- Simple non-alpha - placeholder
- Sharp alpha - placeholder
- Gradient alpha - placeholder
Tools
| Tool | Description | Rating | Availability | URL |
| Image Tool | Official - All formats manipulation | * * * * * | SDK | SDK |
| DXTBmp | 16/24/32 bit and DXT Extended Bitmap Manipulation ² | * * * | Freeware | Click button at foot of page (SizeMb) |
| Tool Name | Descriptive blurb | ????? | Payware | Download Page (SizeMb) |
| ColorPix | Colour grabbing tool. | * * * * * | Freeware | Download Page (SizeMb) |
- ² DXTBmp - Not suitable for generating FSX DDS textures, (incompatible type output).
- ColorPix - Useful for colour-matching when correcting overlaid transparency issues.
Related
See also
- Problem Resolving (FSX) - A selection of hints & tips for resolving those issues & configuring FSX.
- Texturing - Alpha channel - Transparency - PhotoShop
- Modeling and Texturing - Optimising for performance
External links
- Direct3D - Exposes the advanced graphics capabilities of 3D graphics hardware, including z-buffering, anti-aliasing, alpha blending, mipmapping, atmospheric effects, and perspective-correct texture mapping.
- Bump Mapping - A technique where at each pixel, a perturbation to the surface normal of the object being rendered is looked up in a heightmap and applied before the illumination calculation is done.
- Normal Mapping - An application of bump mapping. A bump map is usually calculated based on a single-channel (interpreted as grayscale) image, the source for the normals in normal mapping is usually a multichannel image (x, y and z channels) derived from a set of more detailed versions of the objects.
- DirectDraw Surface (aka .dds) - A file format used for storing textures and cubic environment maps, both compressed and uncompressed.
- 3Dc - A lossy data compression algorithm for normal maps invented and first implemented by ATI. It builds upon the earlier DXT5 algorithm and is an open standard. 3Dc is now implemented by both ATI and NVIDIA.
