Begin writing decompression block.

EarthboundBattleBackgrounds/EarthboundBattleBackgrounds/main.cpp

@@ -54,6 +54,79 @@ struct Rom{
 		uint32_t readInt32(){
 			return readInt8()|(readInt8()<<8)|(readInt8()<<16)|(readInt8()<<24);
 		}
+		uint32_t getCompressedSize(uint32_t pointer){
+			uint32_t bpos{};
+			uint32_t pos{pointer};
+			uint32_t bpos2{};
+			while(data[pos]!=0xFF){
+				if(pos>=data.length())throw std::runtime_error{"Unexpected end of data."};
+				char commandType{data[pos]>>5};
+				char length{(data[pos]&0x1F)+1};
+				if(commandType==7){
+					commandType=(data[pos]&0x1C)>>2;
+					length=((data[pos]&3)<<8)+(data[pos+1])+1;
+					++pos;
+				}
+				if(bpos+length<0)throw std::runtime_error("Length ended up negative.");
+				pos++;
+				if(commandType>=4){
+					bpos2=(data[pos]<<8)+data[pos+1];
+					if(bpos2<0)throw std::runtime_error("Reading negative data.");
+					pos+=2;
+				}
+				switch(commandType){
+					case UNCOMPRESSED_BLOCK:{
+						bpos+=length;
+						pos+=length;
+					}break;
+					case RUN_LENGTH_ENCODED_BYTE:{
+						bpos+=length;
+						++pos;
+					}break;
+					case RUN_LENGTH_ENCODED_SHORT:{
+						if(bpos<0)throw std::runtime_error("Reading negative data while reading RLE short.");
+						bpos+=2*length;
+						pos+=2;
+					}break;
+					case INCREMENTAL_SEQUENCE:{
+						bpos+=length;
+						++pos;
+					}break;
+					case REPEAT_PREVIOUS_DATA:{
+						if(bpos2<0)throw std::runtime_error("Reading negative data while repeating previous data.");
+						bpos+=length;
+					}break;
+					case REVERSE_BITS:{
+						if(bpos2<0)throw std::runtime_error("Reading negative data while reversing bits.");
+						bpos+=length;
+					}break;
+					case UNKNOWN_1:{
+						if(bpos2-length+1<0)throw std::runtime_error("Unexpected error in Unkonwn 1.");
+						bpos+=length;
+					}break;
+					case UNKNOWN_2:{throw std::runtime_error("Reached unexpected command.");}break;
+				}
+			}
+			return bpos;
+		}
+		std::vector<uint16_t>decompress(){
+			uint32_t size{getCompressedSize(ptr)};
+			if(size<1)throw std::runtime_error(std::format("Got an invalid data size of {}",size));
+			std::vector<uint16_t>blockOutput;
+			blockOutput.resize(size);
+			decompressBlock(ptr,blockOutput);
+		}
+	private:
+		void decompressBlock(uint32_t ptrStart,std::vector<uint16_t>&block){
+			size_t maxLength{block.size()};
+			uint32_t pos{ptrStart};
+			uint32_t bpos{};
+			uint32_t bpos2{};
+			int read{};
+			while(data[pos]!=0xFF){
+
+			}
+		}
 	};
 
 	struct BattleBackground{
@@ -106,9 +179,19 @@ struct Rom{
 			}
 		}
 	};
+	using Tile=std::array<std::array<int,8>,8>;
+	struct BackgroundGraphics{
+		std::vector<uint16_t>graphicsData;
+		std::vector<Tile>tiles;
+		BackgroundGraphics(std::string_view data,uint16_t index,byte bpp){
+			DataBlock graphicsPointer{data,0xD7A1U+index*4U};
+			graphicsPointer.decompress();
+		}
+	};
 	std::string data;
 	std::vector<BattleBackground>backgrounds;
 	std::vector<BackgroundPalette>palettes;
+	std::vector<BackgroundGraphics>graphics;
 	Rom(){
 		std::ifstream dataStream{"truncated_backgrounds.dat",std::ios_base::binary};
 		while(dataStream.good())data+=dataStream.get();
@@ -121,6 +204,9 @@ struct Rom{
 		for(uint16_t i:std::views::iota(0U,paletteBits.size())){
 			palettes.emplace_back(data,i,paletteBits[i]);
 		}
+		for(uint16_t i:std::views::iota(0U,graphicsBits.size())){
+			
+		}
 	}
 };
 
@@ -144,10 +230,7 @@ public:
 		return true;
 	}
 
-	int yOffset{0};
+	void PaletteDisplayTest(){
-
-	bool OnUserUpdate(float fElapsedTime) override
-	{
 		if(GetMouseWheel()<0)yOffset-=32;
 		if(GetMouseWheel()>0)yOffset+=32;
 
@@ -158,6 +241,13 @@ public:
 			}
 			row++;
 		}
+	}
+
+	int yOffset{0};
+
+	bool OnUserUpdate(float fElapsedTime) override
+	{
+		PaletteDisplayTest();
 		return true;
 	}
 };