Method LoadPng

src/engine/gfx/image_loader.cpp:136–272

}

bool CImageLoader::LoadPng(CByteBufferReader &Reader, const char *pContextName, CImageInfo &Image, int &PngliteIncompatible)
{
	CUserErrorStruct UserErrorStruct = {&Reader, pContextName, {}};

	if(setjmp(UserErrorStruct.m_JmpBuf))
	{
		return false;
	}

	png_structp pPngStruct = png_create_read_struct(PNG_LIBPNG_VER_STRING, &UserErrorStruct, PngErrorCallback, PngWarningCallback);
	if(pPngStruct == nullptr)
	{
		log_error("png", "libpng internal failure: png_create_read_struct failed.");
		return false;
	}

	png_infop pPngInfo = nullptr;
	png_bytepp pRowPointers = nullptr;
	int Height = 0; // ensure this is not undefined for the Cleanup function
	const auto &&Cleanup = [&]() {
		if(pRowPointers != nullptr)
		{
			for(int y = 0; y < Height; ++y)
			{
				delete[] pRowPointers[y];
			}
		}
		delete[] pRowPointers;
		if(pPngInfo != nullptr)
		{
			png_destroy_info_struct(pPngStruct, &pPngInfo);
		}
		png_destroy_read_struct(&pPngStruct, nullptr, nullptr);
	};
	if(setjmp(UserErrorStruct.m_JmpBuf))
	{
		Cleanup();
		return false;
	}

	pPngInfo = png_create_info_struct(pPngStruct);
	if(pPngInfo == nullptr)
	{
		Cleanup();
		log_error("png", "libpng internal failure: png_create_info_struct failed.");
		return false;
	}

	png_byte aSignature[8];
	if(!Reader.Read(aSignature, sizeof(aSignature)) || png_sig_cmp(aSignature, 0, sizeof(aSignature)) != 0)
	{
		Cleanup();
		log_error("png", "file is not a valid PNG file (signature mismatch).");
		return false;
	}

	png_set_read_fn(pPngStruct, (png_bytep)&Reader, PngReadDataCallback);
	png_set_sig_bytes(pPngStruct, sizeof(aSignature));