I'm trying to get a firm grasp on the texture compression formats available with OpenGL. Am I getting warm?
S3TC: Equivalent to BC1, BC2 and BC3. As far as I know no version of OpenGL has any guarantees as to whether this is supported, but it is probably available on just about every modern desktop GPU. Safe to assume it is supported?
RGTC: Equivalent to BC4 and BC5.
Not sure what the spec says, but I'm guessing that like S3TC it is probably not mandatory but likely supported on any DirectX 10 or 11 hardware. RGTC appears in the OpenGL 4.3 core spec, it may have been added earlier. Safe to assume it is supported?
BPTC: Equivalent to BC6H and BC7. Mandatory since OpenGL 4.2. Being core doesn't necessarily guarantee actual hardware support, but I think it is safe to assume that any DirectX 11 hardware will support it natively.
ETC2, EAC: New texture compression format, no DirectX equivalent. Mandatory since OpenGL 4.3, but as far as I know, no GPU currently has hardware support, which means that current implementations of OpenGL 4.3+ are going to be implementing it inside the driver, negating any benefit from it.
ASTC: New texture compression format, no DirectX equivalent. Not mandatory in any version of OpenGL (as of 4.4) and not supported by modern desktop GPUs yet.
Edited by Chris_F, 29 November 2013 - 06:02 PM.