void ProductionCompressorBC5_Luma::compressBlock(ColorSet & set, nvtt::AlphaMode alphaMode, const nvtt::CompressionOptions::Private & compressionOptions, void * output)
{
BlockATI2 * block = new(output) BlockATI2;
AlphaBlock4x4 tmp;
tmp.init(set, /*channel=*/0);
OptimalCompress::compressDXT5A(tmp, &block->x);
// Decode block->x
AlphaBlock4x4 decoded;
block->x.decodeBlock(&decoded);
const float R = 1.0f / 256.0f; // Maximum residual that we can represent. @@ Tweak this.
// Compute residual block.
for (int i = 0; i < 16; i++) {
float in = set.color(i).x; // [0,1]
float out = float(decoded.alpha[i]) / 255.0f; // [0,1]
float residual = (out - in); // [-1,1], but usually [-R,R]
// Normalize residual to [-1,1] range.
residual /= R;
// Pack in [0,1] range.
residual = residual * 0.5f + 0.5f;
tmp.alpha[i] = nv::ftoi_round(nv::saturate(residual) * 255.0f);
}
OptimalCompress::compressDXT5A(tmp, &block->y);
}
void CompressorBC7::compressBlock(ColorSet & tile, AlphaMode alphaMode, const CompressionOptions::Private & compressionOptions, void * output)
{
// !!!UNDONE: support channel weights
// !!!UNDONE: set flags once, not per block (this is especially sketchy since block compression is multithreaded...)
AVPCL::mode_rgb = false;
AVPCL::flag_premult = (alphaMode == AlphaMode_Premultiplied);
AVPCL::flag_nonuniform = false;
AVPCL::flag_nonuniform_ati = false;
// Convert NVTT's tile struct to AVPCL's.
AVPCL::Tile avpclTile(tile.w, tile.h);
memset(avpclTile.data, 0, sizeof(avpclTile.data));
for (uint y = 0; y < tile.h; ++y)
for (uint x = 0; x < tile.w; ++x)
avpclTile.data[y][x] = tile.color(x, y) * 255.0f;
AVPCL::compress(avpclTile, (char *)output);
}
void CompressorBC6::compressBlock(ColorSet & tile, AlphaMode alphaMode, const CompressionOptions::Private & compressionOptions, void * output)
{
// !!!UNDONE: support channel weights
// !!!UNDONE: set flags once, not per block (this is especially sketchy since block compression is multithreaded...)
NV_UNUSED(alphaMode); // ZOH does not support alpha.
if (compressionOptions.pixelType == PixelType_UnsignedFloat ||
compressionOptions.pixelType == PixelType_UnsignedNorm ||
compressionOptions.pixelType == PixelType_UnsignedInt)
{
ZOH::Utils::FORMAT = ZOH::UNSIGNED_F16;
}
else
{
ZOH::Utils::FORMAT = ZOH::SIGNED_F16;
}
// Convert NVTT's tile struct to ZOH's, and convert float to half.
ZOH::Tile zohTile(tile.w, tile.h);
memset(zohTile.data, 0, sizeof(zohTile.data));
memset(zohTile.importance_map, 0, sizeof(zohTile.importance_map));
for (uint y = 0; y < tile.h; ++y)
{
for (uint x = 0; x < tile.w; ++x)
{
Vector3 color = tile.color(x, y).xyz();
uint16 rHalf = to_half(color.x);
uint16 gHalf = to_half(color.y);
uint16 bHalf = to_half(color.z);
zohTile.data[y][x].x = ZOH::Tile::half2float(rHalf);
zohTile.data[y][x].y = ZOH::Tile::half2float(gHalf);
zohTile.data[y][x].z = ZOH::Tile::half2float(bHalf);
zohTile.importance_map[y][x] = 1.0f;
}
}
ZOH::compress(zohTile, (char *)output);
}