Show background preview when selecting it

arm9/Makefile

@@ -15,8 +15,8 @@ include $(DEVKITARM)/ds_rules
 # all directories are relative to this makefile
 #---------------------------------------------------------------------------------
 BUILD		:=	build
-SOURCES		:=	src src/nand src/nand/polarssl src/nand/twltool
+SOURCES		:=	src src/lzw src/nand src/nand/polarssl src/nand/twltool
-INCLUDES	:=	include src/nand
+INCLUDES	:=	include src/nand src/lzw
 DATA		:=
 
 

arm9/src/bgMenu.cpp

@@ -9,6 +9,7 @@
 #include <format>
 #include <nds.h>
 #include <dirent.h>
+#include <memory>
 #include <string>
 #include <vector>
 
@@ -51,7 +52,8 @@ std::span<uint8_t> backgroundMenu()
 	clearScreen(&topScreen);
 
 	//menu
-	Menu* m = newMenu();
+	auto mSptr = std::shared_ptr<Menu>(newMenu(), freeMenu);
+	auto* m = mSptr.get();
 	setMenuHeader(m, "BACKGROUNDS");
 	
 	const auto& bgs = getBackgroundList();
@@ -68,6 +70,7 @@ std::span<uint8_t> backgroundMenu()
 	//bottom screen
 	printMenu(m);
 
+	while (!programEnd) {
 		while (!programEnd)
 		{
 			swiWaitForVBlank();
@@ -86,15 +89,24 @@ std::span<uint8_t> backgroundMenu()
 		}
 
 		auto selection = static_cast<size_t>(m->cursor);
-	freeMenu(m);
 
-	if(selection < bgs.size()) {
+		if(selection > bgs.size())
+			return {};
 		try {
-			return parseGif(bgs[selection].second.data(), currentlyLoadedGif);
+			const auto res = parseGif(bgs[selection].second.data(), currentlyLoadedGif, bgGetGfxPtr(bgGifTop));
+			bgHide(topScreen.bgId);
+			bgShow(bgGifTop);
+			auto confirmed = (choiceBox("Confirm this background?") == YES);
+			bgShow(topScreen.bgId);
+			bgHide(bgGifTop);
+			if(confirmed)
+				return res;
 		} catch(const std::exception& e) {
 			messageBox(std::format("\x1B[31mError:\x1B[33m The image could not\n"
 								   "be loaded: {}", e.what()).data());
 		}
+
+		printMenu(m);
 	}
 
 	return {};

arm9/src/gifConverter.cpp

@@ -2,7 +2,6 @@
 #include <cstring>
 #include <cstdio>
 #include <cstdint>
-#include <format>
 #include <memory>
 #include <stdexcept>
 #include <vector>
@@ -10,6 +9,8 @@
 #include "storage.h"
 #include "unlaunch.h"
 
+#include "lzw/lzw.hpp"
+
 struct Gif {
     struct Header {
         char signature[6];
@@ -24,7 +25,7 @@ struct Gif {
     } __attribute__ ((__packed__)) header;
     static_assert(sizeof(Header) == 13);
 
-    std::array<uint8_t, 256 * 3> colorTable;
+    std::array<uint8_t, 256 * 3> colorTable{};
     size_t numColors;
 
     struct Frame {
@@ -51,7 +52,7 @@ struct Gif {
 static constexpr auto WIDTH = 256;
 static constexpr auto HEIGHT = 192;
 
-Gif getGif(std::string_view path) {
+Gif getGif(std::string_view path, volatile uint16_t* decompressedData) {
     Gif gif;
     auto file = fopen(path.data(), "rb");
     if (!file)
@@ -139,10 +140,29 @@ Gif getGif(std::string_view path) {
             }
 
             frame.image.lzwMinimumCodeSize = fgetc(file);
+
+            LZWReader reader(frame.image.lzwMinimumCodeSize, [&, it = decompressedData](auto begin, auto end) mutable {
+                const auto ds_color_table = [&]{
+                    std::array<uint16_t, 256> ret{};
+                    for(int i = 0; i < numColors; ++i){
+                        auto r = color_table[(i * 3) + 0] >> 3;
+                        auto g = color_table[(i * 3) + 1] >> 3;
+                        auto b = color_table[(i * 3) + 2] >> 3;
+                        ret[i] =  RGB15(r,g,b) | BIT(15);
+                    }
+                    return ret;
+                }();
+                std::transform(begin, end, it, [&](auto idx) {
+                    return ds_color_table[idx];
+                });
+                it += std::distance(begin, end);
+            });
+
             while (uint8_t size = fgetc(file)) {
                 std::vector<uint8_t> dataChunk;
                 dataChunk.resize(size);
                 fread(dataChunk.data(), 1, size, file);
+                reader.decode(dataChunk.begin(), dataChunk.end());
                 frame.image.imageDataChunks.push_back(std::move(dataChunk));
             }
 
@@ -199,7 +219,7 @@ std::span<uint8_t> writeGif(const Gif& gif, std::array<uint8_t, MAX_GIF_SIZE>& o
 }
 
 
-std::span<uint8_t> parseGif(const char* path, std::array<uint8_t, MAX_GIF_SIZE>& outArr) {
+std::span<uint8_t> parseGif(const char* path, std::array<uint8_t, MAX_GIF_SIZE>& outArr, volatile uint16_t* decompressedData) {
-	const auto gif = getGif(path);
+    const auto gif = getGif(path, decompressedData);
     return writeGif(gif, outArr);
 }

arm9/src/gifConverter.h

@@ -7,6 +7,6 @@
 
 #include "unlaunch.h"
 
-std::span<uint8_t> parseGif(const char* path, std::array<uint8_t, MAX_GIF_SIZE>& outArr);
+std::span<uint8_t> parseGif(const char* path, std::array<uint8_t, MAX_GIF_SIZE>& outArr, volatile uint16_t* decompressedData);
 
 #endif //GIF_CONVERTER_H

arm9/src/lzw/lzw.cpp

@@ -0,0 +1,125 @@
+#include "lzw.hpp"
+
+u16 LZWReader::readLSB(std::vector<u8>::iterator &begin, const std::vector<u8>::iterator &end) {
+	while (nBits < width) {
+		if (begin == end) {
+			err = true;
+			return 0;
+		}
+		u8 x = *(begin++);
+		bits |= x << nBits;
+		nBits += 8;
+	}
+	u16 code = bits & ((1 << width) - 1);
+	bits >>= width;
+	nBits -= width;
+	return code;
+}
+
+bool LZWReader::decode(std::vector<u8>::iterator begin, std::vector<u8>::iterator end) {
+	o = 0;
+	err = false;
+	// Loop over the code stream, converting codes into decompressed bytes.
+	while (begin != end) {
+		u16 code = readLSB(begin, end);
+		if (err) {
+			flush();
+			return false;
+		}
+
+		if (code < clear) { // Literal
+			output[o++] = code;
+			if (last != DECODER_INVALID_CODE) {
+				// Save what the hi code expands to.
+				suffix[hi] = code;
+				prefix[hi] = last;
+			}
+		} else if (code == clear) { // Clear
+			width = 1 + litWidth;
+			hi = eof;
+			overflow = 1 << width;
+			last = DECODER_INVALID_CODE;
+			continue;
+		} else if (code == eof) { // End
+			flush();
+			return true;
+		} else if (code <= hi) {
+			u16 c = code;
+			uint i = output.size() - 1;
+			if (code == hi && last != DECODER_INVALID_CODE) {
+				// code == hi is a special case which expands to the last expansion
+				// followed by the head of the last expansion. To find the head, we walk
+				// the prefix chain until we find a literal code.
+				c = last;
+				while (c >= clear)
+					c = prefix[c];
+				output[i] = c;
+				i--;
+				c = last;
+			}
+			// Copy the suffix chain into output and then write that to w.
+			while (c >= clear) {
+				output[i] = suffix[c];
+				i--;
+				c = prefix[c];
+			}
+			output[i] = c;
+			std::copy(output.begin() + i, output.end(), output.begin() + o);
+			o += std::distance(output.begin() + i, output.end());
+			if (last != DECODER_INVALID_CODE) {
+				// Save what the hi code expands to
+				suffix[hi] = c;
+				prefix[hi] = last;
+			}
+		} else { // Error
+			flush();
+			return false;
+		}
+
+		last = code;
+		hi++;
+		if (hi >= overflow) {
+			if (hi > overflow) {
+				flush();
+				return false;
+			}
+
+			if (width == MAX_WIDTH) {
+				last = DECODER_INVALID_CODE;
+				// Undo the d.hi++ a few lines above, so that (1) we maintain
+				// the invariant that d.hi < d.overflow, and (2) d.hi does not
+				// eventually overflow a uint16.
+				hi--;
+			} else {
+				width++;
+				overflow = 1 << width;
+			}
+		}
+		if (o >= FLUSH_BUFFER) {
+			flush();
+		}
+	}
+
+	flush();
+	return true;
+}
+
+LZWReader::LZWReader(int minCodeSize, std::function<void(u8_itr, u8_itr)> flushFunction) : litWidth(minCodeSize), flushFn(flushFunction) {
+	width = 1 + litWidth;
+	clear = 1 << litWidth;
+	eof = clear + 1;
+	hi = clear + 1;
+	overflow = 1 << width;
+	last = DECODER_INVALID_CODE;
+
+	suffix = std::vector<u8>(1 << MAX_WIDTH);
+	prefix = std::vector<u16>(1 << MAX_WIDTH);
+	output = std::vector<u8>(2 * (1 << MAX_WIDTH));
+}
+
+void LZWReader::flush(void) {
+	if (flushFn && o > 0) {
+		flushFn(output.begin(), output.begin() + o);
+	}
+	o = 0;
+}

arm9/src/lzw/lzw.hpp

@@ -0,0 +1,44 @@
+#ifndef LZW_HPP
+#define LZW_HPP
+
+#include <nds.h>
+#include <functional>
+#include <vector>
+
+typedef unsigned int uint;
+typedef std::vector<u8>::const_iterator u8_itr;
+
+class LZWReader {
+	constexpr static u16 MAX_WIDTH = 12;
+	constexpr static u16 DECODER_INVALID_CODE = 0xFFFF;
+	constexpr static u16 FLUSH_BUFFER = 1 << MAX_WIDTH;
+
+	int litWidth;
+	std::function<void(u8_itr, u8_itr)> flushFn;
+	u32 bits = 0;
+	uint nBits = 0;
+	uint width;
+	bool err = false;
+
+	u16 clear, eof, hi, overflow, last;
+
+	std::vector<u8> suffix;
+	std::vector<u16> prefix;
+
+	std::vector<u8> output;
+	int o = 0;
+	// std::vector<u8> toRead;
+
+	u16 readLSB(std::vector<u8>::iterator &it, const std::vector<u8>::iterator &end);
+
+	int read(std::vector<u8> &buffer);
+
+	void flush(void);
+
+public:
+	LZWReader(int minCodeSize, std::function<void(u8_itr, u8_itr)> flushFunction);
+
+	bool decode(std::vector<u8>::iterator begin, std::vector<u8>::iterator end);
+};
+
+#endif

arm9/src/main.cpp

@@ -35,6 +35,9 @@ static bool isLauncherVersionSupported = true;
 PrintConsole topScreen;
 PrintConsole bottomScreen;
 
+int bgGifTop;
+int bgGifBottom;
+
 struct Stage2 {
     Sha1Digest sha;
     bool unlaunch_supported;
@@ -71,20 +74,22 @@ enum {
 
 static void setupScreens()
 {
-	REG_DISPCNT = MODE_FB0;
+	videoSetMode(MODE_5_2D);
-	VRAM_A_CR = VRAM_ENABLE;
+	videoSetModeSub(MODE_5_2D);
-
-	videoSetMode(MODE_0_2D);
-	videoSetModeSub(MODE_0_2D);
 
 	vramSetBankA(VRAM_A_MAIN_BG);
 	vramSetBankC(VRAM_C_SUB_BG);
 
-	consoleInit(&topScreen, 3, BgType_Text4bpp, BgSize_T_256x256, 31, 0, true, true);
+	consoleInit(&topScreen, 1, BgType_Text4bpp, BgSize_T_256x256, 14, 0, true, true);
-	consoleInit(&bottomScreen, 3, BgType_Text4bpp, BgSize_T_256x256, 31, 0, false, true);
+	consoleInit(&bottomScreen, 1, BgType_Text4bpp, BgSize_T_256x256, 14, 0, false, true);
 
 	clearScreen(&bottomScreen);
 
+	bgGifTop = bgInit(3, BgType_Bmp16, BgSize_B16_256x256, 2, 0);
+	bgHide(bgGifTop);
+	bgGifBottom = bgInitSub(3, BgType_Bmp16, BgSize_B16_256x256, 2, 0);
+	bgHide(bgGifBottom);
+
 	VRAM_A[100] = 0xFFFF;
 }
 

arm9/src/main.h

@@ -16,6 +16,9 @@ extern volatile u8 batteryLevel;
 extern PrintConsole topScreen;
 extern PrintConsole bottomScreen;
 
+extern int bgGifTop;
+extern int bgGifBottom;
+
 void clearScreen(PrintConsole* screen);
 
 #ifdef __cplusplus