bug in DecodeEndpoints()

[richgel999]

Hi,
I've been comparing the output of astc-codec vs. another ASTC decoder from Google. I found a decoding issue with void extent blocks, where the output differs from what is expected by the ASTC spec in LDR mode when sRGB enabled. Here's the relevant code:

static std::vector DecodeEndpoints(const VoidExtentData& block) {
EndpointPair eps;
// Original code:
//eps.first[0] = eps.second[0] = (block.r * 255) / 65535;
//eps.first[1] = eps.second[1] = (block.g * 255) / 65535;
//eps.first[2] = eps.second[2] = (block.b * 255) / 65535;
//eps.first[3] = eps.second[3] = (block.a * 255) / 65535;

// Corrected code that generates the expected result with void extent blocks:
eps.first[0] = eps.second[0] = (block.r >> 8);
eps.first[1] = eps.second[1] = (block.g >> 8);
eps.first[2] = eps.second[2] = (block.b >> 8);
eps.first[3] = eps.second[3] = (block.a >> 8);