Texture formats overview

Direct X Texture formats (DXTn) are licensed use of S3 Graphics Ltd S3 Texture Compression (S3TC) technology.

S3TC Format Comparison

S3TC (aka DXTn or DXTC)

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

• Problem Resolving (FSX) - A selection of hints & tips for resolving those issues & configuring FSX.