add per-game custom palettes

libgambatte/libretro/libretro.cpp

@@ -5,6 +5,8 @@
 
 #include <assert.h>
 #include <stdio.h>
+#include <fstream>
+#include <sstream>
 
 static retro_video_refresh_t video_cb;
 static retro_input_poll_t input_poll_cb;
@@ -132,6 +134,31 @@ bool retro_unserialize(const void *data, size_t size)
 void retro_cheat_reset() {}
 void retro_cheat_set(unsigned, bool, const char *) {}
 
+
+static std::string basename(std::string filename) {
+	// Remove directory if present.
+	// Do this before extension removal incase directory has a period character.
+	const size_t last_slash_idx = filename.find_last_of("\\/");
+	if (std::string::npos != last_slash_idx)
+	{
+	    filename.erase(0, last_slash_idx + 1);
+	}
+
+	// Remove extension if present.
+	const size_t period_idx = filename.rfind('.');
+	if (std::string::npos != period_idx)
+	{
+	    filename.erase(period_idx);
+	}
+
+	return filename;
+}
+
+static bool startswith(const std::string s1, const std::string prefix) {
+    return(s1.compare(0, prefix.length(), prefix)==0);
+}
+
+
 bool retro_load_game(const struct retro_game_info *info)
 {
    bool can_dupe = false;
@@ -149,9 +176,105 @@ bool retro_load_game(const struct retro_game_info *info)
       return false;
    }
 
-   return !gb.load(info->data, info->size);
+   bool load_result = gb.load(info->data, info->size);
+   if(load_result==true) return false;
+   // else
+
+   //std::string internal_game_name = gb.romTitle(); // available only in latest Gambatte
+   std::string internal_game_name = reinterpret_cast<const char *>((char*)info->data + 0x134);
+   /* ALTERNATIVE:
+   char title[0x11] = {0};
+   memcpy(title, info->data + 0x134, 0x10);
+   std::string internal_game_name = title;
+   */
+   // ALTERNATIVE2: pass via "info->meta"
+
+   // TODO: check GBC BIOS builtin palettes
+   /*
+   for (unsigned palnum = 0; palnum < 3; ++palnum)
+	for (unsigned colornum = 0; colornum < 4; ++colornum) {
+		unsigned rgb32 = ...
+		gb.setDmgPaletteColor(palnum, colornum, rgb32);
+	}
+   */
+
+   const char *system_directory_c = NULL;
+   environ_cb(RETRO_ENVIRONMENT_GET_SYSTEM_DIRECTORY, &system_directory_c);
+   if(system_directory_c==NULL) {
+      fprintf(stderr, "[Gambatte]: no system directory defined, unable to look for custom palettes.\n");
+      return(true);
+   }
+   std::string system_directory(system_directory_c);
+
+   const char *input_rom_path = info->path;
+   std::string custom_palette_path = system_directory + "/palettes/" + basename(input_rom_path) + ".pal";
+   std::ifstream palette_file( custom_palette_path.c_str() ); // try to open the palette file in read-only mode
+   if(!palette_file.is_open()) {
+   	// try again with the internal game name from the ROM header
+   	custom_palette_path = system_directory + "/palettes/" + internal_game_name + ".pal";
+   	palette_file.open(custom_palette_path.c_str());
+   }
+   if(!palette_file.is_open()) {
+   	// try again with default.pal
+   	custom_palette_path = system_directory + "/palettes/" + "default.pal";
+   	palette_file.open(custom_palette_path.c_str());
+   }
+   if(!palette_file.is_open()) {
+   	// unable to find any custom palette file
+   	return(true);
+   }
+
+   // fprintf(stderr, "[Gambatte]: using custom palette %s.\n", custom_palette_path.c_str());
+   unsigned rgb32 = 0;
+   unsigned line_count = 0;
+   for( std::string line; getline( palette_file, line ); ) // iterate over file lines
+   {
+      line_count++;
+      if(line.find("=")==std::string::npos) continue; // current line does not contain a palette color definition, so go to next line
+
+      std::string line_value = line.substr( line.find("=")+1 ); // extract the color value string
+      std::stringstream ss(line_value); // convert the color value to int
+      //rgb32 = ss >> rgb32 ? rgb32 : 0; // if number conversion fail set it to 0
+      ss >> rgb32;
+      if(!ss) {
+         //fprintf(stderr, "[Gambatte]: unable to read palette color in %s, line %d (color left as default).\n", custom_palette_path.c_str(), line_count);
+         continue;
+      }
+
+      if(startswith(line, "Background0="))
+      	 gb.setDmgPaletteColor(0, 0, rgb32);
+      else if(startswith(line, "Background1="))
+      	 gb.setDmgPaletteColor(0, 1, rgb32);
+      else if(startswith(line, "Background2="))
+      	 gb.setDmgPaletteColor(0, 2, rgb32);      	
+      else if(startswith(line, "Background3="))
+      	 gb.setDmgPaletteColor(0, 3, rgb32);
+      else if(startswith(line, "Sprite%2010="))
+      	 gb.setDmgPaletteColor(1, 0, rgb32);
+      else if(startswith(line, "Sprite%2011="))
+      	 gb.setDmgPaletteColor(1, 1, rgb32);
+      else if(startswith(line, "Sprite%2012="))
+      	 gb.setDmgPaletteColor(1, 2, rgb32);
+      else if(startswith(line, "Sprite%2013="))
+      	 gb.setDmgPaletteColor(1, 3, rgb32);
+      else if(startswith(line, "Sprite%2020="))
+      	 gb.setDmgPaletteColor(2, 0, rgb32);
+      else if(startswith(line, "Sprite%2021="))
+      	 gb.setDmgPaletteColor(2, 1, rgb32);
+      else if(startswith(line, "Sprite%2022="))
+      	 gb.setDmgPaletteColor(2, 2, rgb32);  
+      else if(startswith(line, "Sprite%2023="))
+      	 gb.setDmgPaletteColor(2, 3, rgb32);
+      // else
+      // TODO: print warnings on invalid lines?
+
+   } // endfor
+
+   palette_file.close();
+   return(true);
 }
 
+
 bool retro_load_game_special(unsigned, const struct retro_game_info*, size_t) { return false; }
 
 void retro_unload_game() {}