Immediate backwards compatible support for S3TC-enhanced games. Not that many now but reportedly more in store for
Christmas.
Developer tools and open source code for converting, importing/exporting (via Photoshop plug-in) and writing a real-time
compression encoder as part of an application.
Four new compression algorithms to mix and match within each texture to get the best possible compression (both for file
size and image accuracy) for that particular texture to achieve up to an 8:1 compression ratio. To Quote the 3dfx
Presentation, the four algorithms used are:
1. CC_MIXED (similar to other texture compression schemes): A 4x4 texel block is represented by two bits-per-texel for opaque textures. Additionally, each block has two 16-bit colors stored in an RGB 565 format. The two RGB 565 colors and two additional colors (created by interpolating between the two RGB 565 colors) form the primary colors for this texel block and its associated four color lookup table. A 2-bit index is used to determine which color from the lookup table will be used for each texel in the 4x4 block. Transparent textures are created by making one of the four colors transparent.
2. CC_HI (best for spatial resolution): A 4x8 texel block is represented by three bits-per-texel for opaque and transparent textures. Each block stores two 15-bit colors in an RGB 555 format. The two RGB 555 colors and five additional colors (created by interpolating between the two RGB 555 colors) form the primary colors for this texel block. Additionally, an eighth color is defined to be the transparent color. A 3-bit index is used to determine which color from the 8-entry lookup table will be used for each texel in the 4x8 block.
3. CC_CHROMA (good at complex color areas): A 4x8 texel block is represented by two bits-per-texel for opaque textures. Each block stores four 15-bit colors in an RGB 555 format. All four colors are used directly with no interpolation to form a 4-entry lookup table. The 2-bit index assigned to each texel in the block is used to determine which of the four colors is assigned to each individual texel. Note that Colors4 only applies to opaque textures, as it does not support transparency.
4. CC_ALPHA (gives the best control over complex alpha transparencies at four bits-per-texel): A 4x8 texel block is represented by two bits-per-texel for opaque and transparent textures. Each block stores three 20-bit colors stored in a 5555 format. The first and second 20-bit colors are used for the primary colors of the left 4x4 block, while the second and third colors are used for the primary colors of the right 4x4 block. Two additional colors are created in each block by interpolating between the two primary colors for that block. A 2-bit index is assigned to each texel in the block and a lookup table is used to determine which color is applied to each texel