ChannelPacking

Channel packing is a game art term for a bitmap that has different grayscale images in each of its channels... Red, Green, and Blue. Alpha can also be used as a fourth channel. This saves Memory, but increases Shaders complexity.

Compression Artifacts

If you save a channel-packed texture using DXT compression, it will introduce blocky artifacts to your channels. For details, see Normal map#Normal_Map_Compression.

Tools

• Channel Shuffle
• Photoshop Channels

Examples

Two channel-packed textures, which store a total of six unique textures, see An exercise in modular textures - Scifi lab UDK on the Polycount Forum. Image by Tor 'Snefer' Frick.

A channel-packed texture used to texture an entire scene, see [UDK Oil Rig Observation Outpost] on the Polycount Forum. Image by Wiktor 'Disting' Öhman.

A channel-packed texture used in Mass Effect 3, see Mass Effect 3 art - Marc-Antoine Hamelin on the Polycount Forum. Image by Marc-Antoine 'Marcan' Hamelin.

• For more examples and tutorials see Texture atlas and MultiTexture.

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