ezResult ezImageConversion::BuildPath(ezImageFormat::Enum sourceFormat, ezImageFormat::Enum targetFormat, bool bSourceEqualsTarget,
ezHybridArray<ezImageConversion::ConversionPathNode, 16>& path_out, ezUInt32& numScratchBuffers_out)
{
path_out.Clear();
numScratchBuffers_out = 0;
if (sourceFormat == targetFormat)
{
ConversionPathNode node;
node.m_sourceFormat = sourceFormat;
node.m_targetFormat = targetFormat;
node.m_inPlace = bSourceEqualsTarget;
node.m_sourceBufferIndex = 0;
node.m_targetBufferIndex = 0;
node.m_step = nullptr;
path_out.PushBack(node);
return EZ_SUCCESS;
}
if (!s_conversionTableValid)
{
RebuildConversionTable();
}
for (ezImageFormat::Enum current = sourceFormat; current != targetFormat;)
{
ezUInt32 currentTableIndex = MakeKey(current, targetFormat);
TableEntry entry;
if (!s_conversionTable.TryGetValue(currentTableIndex, entry))
{
return EZ_FAILURE;
}
ezImageConversion::ConversionPathNode step;
step.m_sourceFormat = entry.m_sourceFormat;
step.m_targetFormat = entry.m_targetFormat;
step.m_inPlace = entry.m_flags.IsAnySet(ezImageConversionFlags::InPlace);
step.m_step = entry.m_step;
current = entry.m_targetFormat;
path_out.PushBack(step);
}
ezHybridArray<IntermediateBuffer, 16> scratchBuffers;
scratchBuffers.PushBack(IntermediateBuffer(ezImageFormat::GetBitsPerBlock(targetFormat)));
for (int i = path_out.GetCount() - 1; i >= 0; --i)
{
if (i == path_out.GetCount() - 1)
path_out[i].m_targetBufferIndex = 0;
else
path_out[i].m_targetBufferIndex = path_out[i + 1].m_sourceBufferIndex;
if (i > 0)
{
if (path_out[i].m_inPlace)
{
path_out[i].m_sourceBufferIndex = path_out[i].m_targetBufferIndex;
}
else
{
ezUInt32 bitsPerBlock = ezImageFormat::GetBitsPerBlock(path_out[i].m_sourceFormat);
path_out[i].m_sourceBufferIndex = allocateScratchBufferIndex(scratchBuffers, bitsPerBlock, path_out[i].m_targetBufferIndex);
}
}
}
if (bSourceEqualsTarget)
{
// Enforce constraint that source == target
path_out[0].m_sourceBufferIndex = 0;
// Did we accidentally break the in-place invariant?
if (path_out[0].m_sourceBufferIndex == path_out[0].m_targetBufferIndex && !path_out[0].m_inPlace)
{
if (path_out.GetCount() == 1)
{
// Only a single step, so we need to add a copy step
ezImageConversion::ConversionPathNode copy;
copy.m_inPlace = false;
copy.m_sourceFormat = sourceFormat;
copy.m_targetFormat = sourceFormat;
copy.m_sourceBufferIndex = path_out[0].m_sourceBufferIndex;
copy.m_targetBufferIndex = allocateScratchBufferIndex(scratchBuffers, ezImageFormat::GetBitsPerBlock(path_out[0].m_sourceFormat),
path_out[0].m_sourceBufferIndex);
path_out[0].m_sourceBufferIndex = copy.m_targetBufferIndex;
copy.m_step = nullptr;
path_out.Insert(copy, 0);
}
else
{
// Turn second step to non-inplace
path_out[1].m_inPlace = false;
path_out[1].m_sourceBufferIndex = allocateScratchBufferIndex(
scratchBuffers, ezImageFormat::GetBitsPerBlock(path_out[1].m_sourceFormat), path_out[0].m_sourceBufferIndex);
path_out[0].m_targetBufferIndex = path_out[1].m_sourceBufferIndex;
}
}
}
else
{
path_out[0].m_sourceBufferIndex = scratchBuffers.GetCount();
}
numScratchBuffers_out = scratchBuffers.GetCount() - 1;
return EZ_SUCCESS;
}
