Palette reading and rendering implemented.

EarthboundBattleBackgrounds/EarthboundBattleBackgrounds/main.cpp

@@ -1,6 +1,9 @@
 #define OLC_PGE_APPLICATION
 #include "olcPixelGameEngine.h"
 
+#include <ranges>
+
+using namespace olc;
 
 struct Rom{
 	const static uint16_t MIN_INDEX{};
@@ -18,6 +21,23 @@ struct Rom{
 		UNKNOWN_2,
 	};
 
+	static uint32_t snesToHex(uint32_t addr,bool header=true){
+		uint32_t newAddr{addr};
+		if(newAddr>=0x400000&&newAddr<0x600000);//NO-OP
+		else if(newAddr>=0xC00000&&newAddr<0x1000000)newAddr-=0xC00000;
+		else throw std::out_of_range{std::format("SNES address out of range: {}",newAddr)};
+
+		if(header)newAddr+=0x200;
+		return newAddr-0xA0200;
+	}
+	static uint32_t hexToSnes(uint32_t addr,bool header=true){
+		uint32_t newAddr{addr};
+		if(header)newAddr-=0x200;
+		if(newAddr>=0&&newAddr<0x400000)return newAddr+0xC00000;
+		else if(newAddr>=0x400000&&newAddr<0x600000)return newAddr;
+		else throw std::out_of_range{std::format("File offset out of range: {}",newAddr)};
+	}
+
 	struct DataBlock{
 		uint32_t addr,ptr;
 		std::string_view data;
@@ -66,17 +86,41 @@ struct Rom{
 			return (data[13]<<24)+(data[14]<<16)+(data[15]<<8)+data[16];
 		}
 	};
+	struct BackgroundPalette{
+		std::vector<Pixel>colors;
+		byte bpp;
+		uint32_t addr;
+		BackgroundPalette(std::string_view data,uint16_t index,byte bpp)
+		:bpp(bpp){
+			DataBlock pointer{data,0xDAD9U+index*4U};
+			uint32_t addr=snesToHex(pointer.readInt32());
+			DataBlock dataBlock{data,addr};
+			this->addr=addr;
+			if(bpp!=2&&bpp!=4)throw std::invalid_argument{std::format("Palette Error: Incorrect color depth specified. Must be 2 or 4, provided {}",bpp)};
+			for(uint8_t i:std::views::iota(0,pow(2,bpp))){
+				uint16_t clr16{dataBlock.readShort()};
+				uint8_t b{((clr16>>10)&31)*8U};
+				uint8_t g{((clr16>>5)&31)*8U};
+				uint8_t r{(clr16&31)*8U};
+				colors.emplace_back(r,g,b);
+			}
+		}
+	};
 	std::string data;
 	std::vector<BattleBackground>backgrounds;
+	std::vector<BackgroundPalette>palettes;
 	Rom(){
 		std::ifstream dataStream{"truncated_backgrounds.dat",std::ios_base::binary};
 		while(dataStream.good())data+=dataStream.get();
 			
-		for(uint16_t i=0;i<=MAX_INDEX;i++){
+		for(uint16_t i:std::views::iota(0U,MAX_INDEX+1U)){
 			backgrounds.emplace_back(data,i);
 			paletteBits[backgrounds.back().paletteInd]=backgrounds.back().bbp;
 			graphicsBits[backgrounds.back().graphicsInd]=backgrounds.back().bbp;
 		}
+		for(uint16_t i:std::views::iota(0U,paletteBits.size())){
+			palettes.emplace_back(data,i,paletteBits[i]);
+		}
 	}
 };
 
@@ -100,9 +144,20 @@ public:
 		return true;
 	}
 
+	int yOffset{0};
+
 	bool OnUserUpdate(float fElapsedTime) override
 	{
-		
+		if(GetMouseWheel()<0)yOffset-=32;
+		if(GetMouseWheel()>0)yOffset+=32;
+
+		for(uint8_t row=0;Rom::BackgroundPalette&palette:rom.palettes){
+			for(uint8_t index=0;Pixel&col:palette.colors){
+				FillRectDecal(vf2d{index*8.f+8,row*8.f+yOffset},{8,8},col);
+				index++;
+			}
+			row++;
+		}
 		return true;
 	}
 };