Update atlas metadata encoding, now with compression

openVulkanoCpp/Scene/Text/FontAtlas.cpp

@@ -6,9 +6,11 @@
 
 #include "FontAtlas.hpp"
 #include "Base/Logger.hpp"
+#include "Base/Wrapper.hpp"
 #include "Image/ImageLoader.hpp"
 #include "Extensions/STBZlibCompressor.hpp"
 #include <fstream>
+#include <zstd.h>
 #define STBI_MSC_SECURE_CRT
 #define STB_IMAGE_WRITE_IMPLEMENTATION
 #define STBIW_ZLIB_COMPRESS Extensions::STBZlibCompressor
@@ -36,26 +38,66 @@ namespace OpenVulkano::Scene
 	{
 		if (!*this) { Logger::DATA->warn("Can't save empty font atlas!"); return; };
 
-		stbi_flip_vertically_on_write(1);
-		std::string p = path.string();
-		stbi_write_png(p.c_str(), m_texture.resolution.x, m_texture.resolution.y, m_texture.format.GetBytesPerPixel(),
-					   m_texture.textureBuffer, m_texture.format.GetBytesPerPixel() * m_texture.resolution.x);
+		std::fstream fs(path, std::ios_base::out | std::ios_base::binary);
 
-		std::fstream fs(path, std::ios_base::out | std::ios_base::binary | std::ios_base::app);
-		fs.write(reinterpret_cast<const char*>(&m_metadata), sizeof(Metadata));
-		uint64_t metadataBytes = sizeof(Metadata);
-		for (const auto& [key, val] : m_glyphs)
+		// Save image
 		{
-			fs.write(reinterpret_cast<const char*>(&key), sizeof(uint32_t));
-			fs.write(reinterpret_cast<const char*>(&val), sizeof(GlyphInfo));
-			metadataBytes += sizeof(uint32_t) + sizeof(GlyphInfo);
+			stbi_flip_vertically_on_write(1);
+			int pngSize;
+			UniqueMalloc<uint8_t> png(stbi_write_png_to_mem(static_cast<const uint8_t*>(m_texture.textureBuffer), m_texture.format.GetBytesPerPixel() * m_texture.resolution.x, m_texture.resolution.x, m_texture.resolution.y, m_texture.format.GetBytesPerPixel(), &pngSize));
+			fs.write(reinterpret_cast<const std::ostream::char_type*>(png.get()), pngSize);
 		}
-		fs.write(reinterpret_cast<const char*>(&metadataBytes), sizeof(uint64_t));
+
+		// Save metadata
+		{
+			const Array<char> metadata = SerializeMetadata();
+			Array<char> compressed(ZSTD_compressBound(metadata.Size()));
+			size_t compressedSize = ZSTD_compress(compressed.Data(), compressed.Size(), metadata.Data(), metadata.Size(), 5);
+			if (ZSTD_isError(compressedSize)) throw std::runtime_error(std::string("Compression failed: ") + ZSTD_getErrorName(compressedSize));
+			fs.write(compressed.Data(), compressedSize);
+			fs.write(reinterpret_cast<const char*>(&compressedSize), sizeof(uint64_t));
+		}
+
 		FontAtlasFileFlags flags;
 		fs.write(reinterpret_cast<const char*>(&flags), sizeof(FontAtlasFileFlags));
 		fs.close();
 	}
 
+	Array<char> FontAtlas::SerializeMetadata() const
+	{
+		Array<char> data(sizeof(Metadata) + m_glyphs.size() * (sizeof(GlyphInfo) + sizeof(uint32_t)));
+		char* ptr = data.Data();
+		memcpy(ptr, &m_metadata, sizeof(Metadata));
+		ptr += sizeof(Metadata);
+		for (const auto& [key, val] : m_glyphs)
+		{
+			memcpy(ptr, &key, sizeof(uint32_t));
+			ptr += sizeof(uint32_t);
+			memcpy(ptr, &val, sizeof(GlyphInfo));
+			ptr += sizeof(GlyphInfo);
+		}
+		return data;
+	}
+
+	void FontAtlas::DeserializeMetadata(const std::span<char>& data)
+	{
+		const char* d = data.data();
+		const char* end = data.data() + data.size();
+		uint32_t unicode = 0;
+
+		std::memcpy(&m_metadata, d, sizeof(Metadata));
+		d += sizeof(Metadata);
+		while (d < end)
+		{
+			std::memcpy(&unicode, d, sizeof(uint32_t));
+			d += sizeof(uint32_t);
+			GlyphInfo& info = m_glyphs[unicode];
+			std::memcpy(&info, d, sizeof(GlyphInfo));
+			d += sizeof(GlyphInfo);
+		}
+	}
+
+
 	void FontAtlas::Load(const std::span<char> data)
 	{
 		if (data.size() < 16) { Logger::DATA->warn("Font atlas file is invalid!"); return; };
@@ -101,6 +143,15 @@ namespace OpenVulkano::Scene
 
 	void FontAtlas::LoadNew(const std::span<char> data)
 	{
+		size_t originalSize = ZSTD_getFrameContentSize(data.data(), data.size());
+		if (originalSize == ZSTD_CONTENTSIZE_ERROR) throw std::runtime_error("Not compressed by zstd");
+		if (originalSize == ZSTD_CONTENTSIZE_UNKNOWN) throw std::runtime_error("Original size unknown");
+
+		Array<char> metadata(originalSize);
+		size_t decompressedBytes = ZSTD_decompress(metadata.Data(), metadata.Size(), data.data(), data.size());
+		if (ZSTD_isError(decompressedBytes))  throw std::runtime_error(std::string("Decompression failed: ") + ZSTD_getErrorName(decompressedBytes));
+		if (decompressedBytes != originalSize) throw std::runtime_error("Decompressed size does not match expected size");
+		DeserializeMetadata(metadata);
 	}
 
 	void FontAtlas::LoadImage(const std::span<char> data)

openVulkanoCpp/Scene/Text/FontAtlas.hpp

@@ -41,6 +41,9 @@ namespace OpenVulkano::Scene
 		void LoadNew(std::span<char> data);
 		void LoadImage(std::span<char> data);
 
+		Array<char> SerializeMetadata() const;
+		void DeserializeMetadata(const std::span<char>& data);
+
 	public:
 		FontAtlas() = default;
 		FontAtlas(const Math::Vector2ui textureResolution, const double lineHeight, const FontAtlasType atlasType) { Init(textureResolution, lineHeight, atlasType); }