BC7 in turn is a high quality but lower compression ratio algorithm that solves the gradient issues S3TC faces, but for a 24bit RGB texture it’s only a 3:1 compression ratio versus 6:1 for S3TC (32bit RGBA fares better both are 4:1).ĪSTC Image Quality Comparison: Original, 4x4 (8bpp), 6圆 (3.56bpp), & 8x8 (2bpp) block size In the Direct3D world where S3TC is standard, we’ve seen Microsoft add specialized formats for normal maps and other texture types that are not color maps, but only relatively recently did they add another color map compression method with BC7. So what makes ASTC next-generation anyhow? Since the introduction of S3TC in the 90s, various parties have been attempting to improve on texture compression with limited results.

Only once all parties are satisfied with ASTC to the point that it’s ready to be implemented into hardware can it meaningfully be moved into the core OpenGL specifications. In the meantime Khronos is introducing it as an optional feature of OpenGL ES 3.0 and OpenGL 4.3 in order to solicit feedback from hardware and software developers. ASTC was the winning proposal in Khronos's search for a next-generation texture compression format, with the ARM/AMD bloc beating out NVIDIA and their ZIL proposal.Īs the winning proposal in that search, if all goes according to plan ASTC will eventually become OpenGL and OpenGL ES’s mandatory next generation texture compression algorithm. The reward at the end of that quest is Adaptive Scalable Texture Compression (ASTC), a new texture compression format first introduced by ARM in late in 2011. So while Khronos has ETC right now, in the future they want better texture compression and are now taking the first steps to make that happen. At the same time however, the ETC format itself is approaching several years old, and not unlike S3TC it’s only designed for a limited number of cases. As we’ve noted in our rundowns of OpenGL and OpenGL ES, the inclusion of ETC texture compression support as part of the core OpenGL standards has finally given OpenGL a standard texture compression format after a number of years.

Opengl 4.3 amd