light/modules/asset_parser/src/assets/texture.cpp

#include <asset_parser/assets/texture.hpp>
#include <lz4.h>
#include <nlohmann/json.hpp>

namespace Assets {

using namespace nlohmann;

auto read_texture_info(AssetFile *file) -> TextureInfo
{
	json texture_meta_data = json::parse(file->json);

	return TextureInfo {
		.size            = texture_meta_data["bufferSize"],
		.compression_mode = texture_meta_data["compression"],
		.format          = texture_meta_data["format"],
		.pixel_size      = {
		         texture_meta_data["width"],
		         texture_meta_data["height"],
		         0,
        },
		.original_file = texture_meta_data["originalFile"],
	};
}

void unpack_texture(
    TextureInfo *info,
    const void *source_buffer,
    size_t source_size,
    void *destination
)
{
	if (info->compression_mode == CompressionMode::LZ4)
	{
		LZ4_decompress_safe(
		    (const char *)source_buffer,
		    (char *)destination,
		    source_size,
		    info->size
		);
	}
	else
	{
		memcpy(destination, source_buffer, source_size);
	}
}

auto pack_texture(TextureInfo *info, void *pixel_data) -> AssetFile
{
	json metadata;
	metadata["format"] = info->format;
	metadata["width"] = info->pixel_size[0];
	metadata["height"] = info->pixel_size[1];
	metadata["bufferSize"] = info->size;
	metadata["originalFile"] = info->original_file;
	metadata["compression"] = CompressionMode::LZ4;

	AssetFile file;
	file.type = AssetFile::Type::Texture;
	file.version = 1u;

	const int compress_staging = LZ4_compressBound(info->size);
	file.blob.resize(compress_staging);
	const int compression_size = LZ4_compress_default(
	    (const char *)pixel_data,
	    (char *)file.blob.data(),
	    info->size,
	    compress_staging
	);
	file.blob.resize(compression_size);


	metadata["compression"] = CompressionMode::LZ4;

	file.json = metadata.dump();

	return file;
}

} // namespace Assets