Unreal Engine 4 (UE4) offers a wide range of options when it comes to compressing the textures that are using in your projects. In the following document you will find descriptions for what each type of compression does and what it should be used for.
Default (DXT1 /5, BC1 /3 on DX11) Texture Compression
| Compression Format | Alpha Support | Usage |
|---|---|---|
| DXT1 | No | This compression format should be used for any textures that do not require the use of an alpha channel. |
| DXT5 | Yes | This compression format should be used for any textures that require the use of an alpha channel. |
Normalmap (DXT5, BC5 on DX11)
| Compression Format | Alpha Support | Usage |
|---|---|---|
| BC5 | No | The Normalmap (DXT5, BC5 on DX11) texture compression format is used to compress normal maps. |
Masks (no sRGB)
| Compression Format | Alpha Support | Usage |
|---|---|---|
| DXT1 / DXT5 | Yes | This compression format should be used with any textures that are to be used as masks as this will disable sRGB as texture masks should not be gamma corrected. |
Grayscale (R8 RGB8 sRGB)
| Compression Format | Alpha Support | Usage |
|---|---|---|
| G8 | No | This compression format should be used for any textures that are going to be used as black and white masks. |
Displacement Map (8 / 16bit)
| Compression Format | Alpha Support | Usage |
|---|---|---|
| G8 | Yes | This compression format should be used for any textures that are required for surface displacement. |
Vector Displacement Map (RGB8)
| Compression Format | Alpha Support | Usage |
|---|---|---|
| B8G8R8A8 | Yes | This compression format should be used for any textures that are used to displace surfaces in the X, Y and Z position. |
HDR (RGB, no sRGB)
| Compression Format | Alpha Support | Usage |
|---|---|---|
| FloatRGBA | Yes | This compression format should be used for any textures that are used for image based lighting or skyboxes. |
User Interface 2D (RGBA)
| Compression Format | Alpha Support | Usage |
|---|---|---|
| B8G8R8A8 | Yes | This compression format should be used for any textures that are to be used for the user interface. |
Alpha (no sRGB, BC4 on DX11)
| Compression Format | Alpha Support | Usage |
|---|---|---|
| BC4 | No | This compression format should be used for any textures that are to be used as alpha masks. |
Distance Field Font (R8)
| Compression Format | Alpha Support | Usage |
|---|---|---|
| G8 | Yes | This compression format should be used for any textures that are to be used as fonts that use distance fields. |
HDR Compressed (RGB, BC6H, DX11)
| Compression Format | Alpha Support | Usage |
|---|---|---|
| FloatRGBA | Yes | This compression format should be used for any HDR textures that need to be compressed. |
BC7 (DX11, optional A)
| Compression Format | Alpha Support | Usage |
|---|---|---|
| B8G8R8A8 | Yes | This compression format should be used for any textures that need high quality compression. |