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#include "TextureLoaderKtx.h"
#include <Base/Memory.h>
using namespace Death::IO;
using namespace Death::Memory;
namespace nCine
{
std::uint8_t TextureLoaderKtx::fileIdentifier_[] = {
0xAB, 0x4B, 0x54, 0x58, 0x20, 0x31, 0x31, 0xBB, 0x0D, 0x0A, 0x1A, 0x0A
}; // "«KTX 11»\r\n\x1A\n"};
TextureLoaderKtx::TextureLoaderKtx(std::unique_ptr<Stream> fileHandle)
: ITextureLoader(std::move(fileHandle))
{
KtxHeader header;
if (!fileHandle_->IsValid()) {
return;
}
const bool headerRead = readHeader(header);
DEATH_ASSERT(headerRead, "KTX header cannot be read", );
const bool formatParsed = parseFormat(header);
DEATH_ASSERT(formatParsed, "KTX format cannot be parsed", );
hasLoaded_ = true;
}
bool TextureLoaderKtx::readHeader(KtxHeader& header)
{
bool checkPassed = true;
// KTX header is 64 bytes long
fileHandle_->Read(&header, 64);
for (int i = 0; i < KtxIdentifierLength; i++) {
if (header.identifier[i] != fileIdentifier_[i]) {
checkPassed = false;
}
}
DEATH_ASSERT(checkPassed, "Invalid KTX signature", false);
// Checking for the header identifier
DEATH_ASSERT(header.endianess != 0x01020304, "File endianess doesn't match machine one", false);
// Accounting for key-value data and `UInt32 imageSize` from first MIP level
headerSize_ = 64 + AsLE(header.bytesOfKeyValueData) + 4;
width_ = AsLE(header.pixelWidth);
height_ = AsLE(header.pixelHeight);
mipMapCount_ = AsLE(header.numberOfMipmapLevels);
return true;
}
bool TextureLoaderKtx::parseFormat(const KtxHeader& header)
{
const GLenum internalFormat = AsLE(header.glInternalFormat);
const GLenum type = AsLE(header.glType);
loadPixels(internalFormat, type);
if (mipMapCount_ > 1) {
LOGI("MIP Maps: {}", mipMapCount_);
mipDataOffsets_ = std::make_unique<std::uint32_t[]>(mipMapCount_);
mipDataSizes_ = std::make_unique<std::uint32_t[]>(mipMapCount_);
std::uint32_t dataSizesSum = TextureFormat::calculateMipSizes(internalFormat, width_, height_, mipMapCount_, mipDataOffsets_.get(), mipDataSizes_.get());
// HACK: accounting for `UInt32 imageSize` on top of each MIP level
// Excluding the first one, already taken into account in header size
for (std::int32_t i = 1; i < mipMapCount_; i++) {
mipDataOffsets_[i] += 4 * i;
}
dataSizesSum += 4 * mipMapCount_;
if (dataSizesSum != dataSize_) {
LOGW("The sum of MIP maps size ({}) is different than texture total data ({})", dataSizesSum, dataSize_);
}
}
return true;
}
}
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