DXT - Revision history

EricChadwick at 13:27, 10 January 2019

2019-01-10T13:27:34Z

EricChadwick: removed old wiki syntax

2015-08-12T14:10:42Z

removed old wiki syntax

EricChadwick: better summary

2015-03-02T03:45:57Z

better summary

Cheeseplus: 4 revisions

2014-07-29T08:42:29Z

4 revisions

EricChadwick: BC data

2010-08-22T20:34:56Z

BC data

EricChadwick: clarification about DXT1a color

2010-08-12T15:01:18Z

clarification about DXT1a color

EricChadwick: removed redundant link

2010-08-03T15:19:12Z

removed redundant link

EricChadwick: new page

2010-08-03T14:53:19Z

new page

New page

= DXT =
DXT is a texture compression format, formerly known as S3TC.

The format can be stored inside many container formats like [[DDS]], [[VTF]], etc. DXT is widely supported on current graphics hardware, meaning it will stay compressed in video memory, allowing the artist to use more or larger textures.

Source images must be power of two in size (i.e. 4x4, 32x8, 256x512, 1024x1024, etc.), and the smallest size is 4x4 (smaller images will be padded out to this size).

There are five DXT formats: DXT1, DXT2, DXT3, DXT4, and DXT5.

== DXT1a ==
Generally the best DXT format for textures with just black and white in the Alpha channel, no grays.
* Compressed, with 1-bit Alpha (just black and white, no grays).
* Smallest file size, half the size of DXT3 and DXT5. Same file size as DXT1c.
* Doesn't work very well on images that have stark color changes, like pixel art.
* DXT1a and DXT1c are the same format, just an internal switch for enabling alpha or not.

== DXT1c ==
Generally the best DXT format for textures without an Alpha channel.
* Compressed, with no Alpha.
* Smallest file size, half the size of DXT3 and DXT5. Same file size as DXT1a.
* Doesn't work very well on images that have stark color changes, like pixel art.
* DXT1a and DXT1c are the same format, just an internal switch for enabling alpha or not.

== DXT2 ==
* Same format as DXT3, except it assumes the alpha is not pre-multiplied.
* Rarely used because it requires extra processing in the shader.

== DXT3 ==
Generally the best DXT format for textures with a sharp Alpha channel.
* Compressed, with "explicit" Alpha.
*# Color is compressed the same as DXT1.
*# In the alpha channel, each pixel is only one of 16 levels of gray.
*# This works well if the alpha values are mostly black and mostly white, with thin anti-aliasing between them.
* Twice the file size of DXT1, same file size as DXT5.

== DXT4 ==
* Same format as DXT5, except it assumes the alpha is not pre-multiplied.
* Rarely used because it requires extra processing in the shader.

== DXT5 ==
Generally the best DXT format for textures with a smooth Alpha channel.
* Compressed, with interpolated Alpha.
** Color is compressed the same as DXT1.
** In the alpha channel, each 4x4 block is compressed separately from the others. Two of the pixels are stored in 256 levels of gray, while the other 14 pixels in the block are interpolated between those two, using 8 levels of gray.
** This works well when each block has a fairly smooth gradation of values, rather than sharp transitions.
* Twice the file size of DXT1, same file size as DXT3.

== Links ==
* [http://msdn.microsoft.com/en-us/library/bb204842%28v=VS.85%29.aspx Compressed Texture Formats (Direct3D 9)] - Microsoft documentation.
* [http://en.wikipedia.org/wiki/S3TC S3 Texture Compression] - Wikipedia page.
* [http://udn.epicgames.com/Two/TextureComparison.html DXTC: DXTC Examples and Technical Comparison] - visual examples from the Unreal Development Kit. Note: "Bright" = 256-color paletted, "DXTC" = [[DXT|DXT3/DXT5]].

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[[Category:TextureFormatRuntime]]

@@ Line 1: / Line 1: @@
 DXT is a texture compression format, formerly known as S3TC. DXT is widely supported on current graphics hardware, meaning it will stay compressed in video memory, allowing the artist to use more or larger textures.
-There are five DXT formats: DXT1, DXT2, DXT3, DXT4, and DXT5. In DirectX 10 it is known as [http://msdn.microsoft.com/en-us/library/bb694531%28VS.85%29.aspx Block Compression] and comes in five basic flavors: BC1, BC2, BC3, BC4, and BC5.
+There are five DXT formats: DXT1, DXT2, DXT3, DXT4, and DXT5.
 The DXT compression format can be stored inside many container files like [[DDS]], [[VTF]], etc. but DDS is the most common file extension.

← Older revision		Revision as of 14:10, 12 August 2015
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−	~~= DXT =~~
	DXT is a texture compression format, formerly known as S3TC. DXT is widely supported on current graphics hardware, meaning it will stay compressed in video memory, allowing the artist to use more or larger textures.		DXT is a texture compression format, formerly known as S3TC. DXT is widely supported on current graphics hardware, meaning it will stay compressed in video memory, allowing the artist to use more or larger textures.

← Older revision	Revision as of 08:42, 29 July 2014
(No difference)

@@ Line 1: / Line 1: @@
 = DXT =
-DXT is a texture compression format, formerly known as S3TC.
+DXT is a texture compression format, formerly known as S3TC. In DirectX 10 it is known as [http://msdn.microsoft.com/en-us/library/bb694531%28VS.85%29.aspx Block Compression] and comes in five basic flavors: BC1, BC2, BC3, BC4, and BC5.
 The format can be stored inside many container formats like [[DDS]], [[VTF]], etc. DXT is widely supported on current graphics hardware, meaning it will stay compressed in video memory, allowing the artist to use more or larger textures.
@@ Line 12: / Line 12: @@
 == DXT1a ==
 Generally the best DXT format for textures with just black and white in the Alpha channel, no grays.
 * Compressed, with 1-bit Alpha (just black and white, no grays).
 * Smallest file size, half the size of DXT3 and DXT5. Same file size as DXT1c.
@@ Line 20: / Line 21: @@
 == DXT1c ==
 Generally the best DXT format for textures without an Alpha channel.
 * Compressed, with no Alpha.
 * Smallest file size, half the size of DXT3 and DXT5. Same file size as DXT1a.
@@ Line 26: / Line 28: @@
 == DXT2 ==
 * Same format as DXT3, except it assumes the alpha is not pre-multiplied.
 * Rarely used because it requires extra processing in the shader.
@@ Line 31: / Line 34: @@
 == DXT3 ==
 Generally the best DXT format for textures with a sharp Alpha channel.
 * Compressed, with "explicit" Alpha.
 *# Color is compressed the same as DXT1.
@@ Line 38: / Line 42: @@
 == DXT4 ==
 * Same format as DXT5, except it assumes the alpha is not pre-multiplied.
 * Rarely used because it requires extra processing in the shader.
@@ Line 43: / Line 48: @@
 == DXT5 ==
 Generally the best DXT format for textures with a smooth Alpha channel.
 * Compressed, with interpolated Alpha.
 ** Color is compressed the same as DXT1.

@@ Line 16: / Line 16: @@
 * Doesn't work very well on images that have stark color changes, like pixel art.
 * DXT1a and DXT1c are the same format, just an internal switch for enabling alpha or not.
 == DXT1c ==

@@ Line 51: / Line 51: @@
 * [http://msdn.microsoft.com/en-us/library/bb204842%28v=VS.85%29.aspx Compressed Texture Formats (Direct3D 9)] - Microsoft documentation.
 * [http://en.wikipedia.org/wiki/S3TC S3 Texture Compression] - Wikipedia page.
-* [http://udn.epicgames.com/Two/TextureComparison.html DXTC: DXTC Examples and Technical Comparison] - visual examples from the Unreal Development Kit. Note: "Bright" = 256-color paletted, "DXTC" = [[DXT|DXT3/DXT5]].
+* [http://udn.epicgames.com/Two/TextureComparison.html DXTC: DXTC Examples and Technical Comparison] - visual examples from the Unreal Development Kit. Note: "Bright" = 256-color paletted, "DXTC" = DXT3/DXT5.
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 [[Category:TextureFormatRuntime]]