Add a build-time option to change the resources directory.

Normally, SameBoy would use executable-relative paths for any
resource files, which posed problems for packaging the software
by distributions, which usually prefer FHS-compliant file locations.

This commit makes it possible to specify an alternative base
directory with a compile-time environment variable.

Makefile

@@ -33,6 +33,10 @@ BIN := build/bin
 OBJ := build/obj
 BOOTROMS_DIR ?= $(BIN)/BootROMs
 
+ifdef DATA_DIR
+CFLAGS += -DDATA_DIR="\"$(DATA_DIR)\""
+endif
+
 # Set tools
 
 # Use clang if it's available.

README.md

@@ -46,6 +46,8 @@ On Windows, SameBoy also requires:
  * [GnuWin](http://gnuwin32.sourceforge.net/)
  * Running vcvars32 before running make. Make sure all required tools and libraries are in %PATH% and %lib%, respectively.
 
-To compile, simply run `make`. The targets are cocoa (Default for macOS), sdl (Default for everything else), libretro, bootroms and tester. You may also specify CONF=debug (default), CONF=release or CONF=native_release to control optimization and symbols. native_release is faster than release, but is optimized to the host's CPU and therefore is not portable. You may set BOOTROMS_DIR=... to a directory containing precompiled dmg_boot.bin and cgb_boot.bin files, otherwise the build system will compile and use SameBoy's own boot ROMs.
+To compile, simply run `make`. The targets are `cocoa` (Default for macOS), `sdl` (Default for everything else), `libretro`, `bootroms` and `tester`. You may also specify `CONF=debug` (default), `CONF=release` or `CONF=native_release` to control optimization and symbols. `native_release` is faster than `release`, but is optimized to the host's CPU and therefore is not portable. You may set `BOOTROMS_DIR=...` to a directory containing precompiled `dmg_boot.bin` and `cgb_boot.bin` files, otherwise the build system will compile and use SameBoy's own boot ROMs.
+
+By default, the SDL port will look for resource files with a path relative to executable. If you are packaging SameBoy, you may wish to override this by setting the `DATA_DIR` variable during compilation to the target path of the directory containing all files (apart from the executable, that's not necessary) from the `build/bin/SDL` directory in the source tree. Make sure the variable ends with a `/` character.
 
 SameBoy was compiled and tested on macOS, Ubuntu and 32-bit Windows 7.

SDL/gui.c

@@ -746,7 +746,7 @@ void run_gui(bool is_running)
     /* Draw the background screen */
     static SDL_Surface *converted_background = NULL;
     if (!converted_background) {
-        SDL_Surface *background = SDL_LoadBMP(executable_relative_path("background.bmp"));
+        SDL_Surface *background = SDL_LoadBMP(resource_path("background.bmp"));
         SDL_SetPaletteColors(background->format->palette, gui_palette, 0, 4);
         converted_background = SDL_ConvertSurface(background, pixel_format, 0);
         SDL_LockSurface(converted_background);

SDL/main.c

@@ -426,7 +426,7 @@ restart:
     bool error = false;
     start_capturing_logs();
     const char * const boot_roms[] = {"dmg_boot.bin", "cgb_boot.bin", "agb_boot.bin"};
-    error = GB_load_boot_rom(&gb, executable_relative_path(boot_roms[configuration.model]));
+    error = GB_load_boot_rom(&gb, resource_path(boot_roms[configuration.model]));
     end_capturing_logs(true, error);
     
     start_capturing_logs();
@@ -442,7 +442,7 @@ restart:
     GB_load_battery(&gb, battery_save_path);
     
     /* Configure symbols */
-    GB_debugger_load_symbol_file(&gb, executable_relative_path("registers.sym"));
+    GB_debugger_load_symbol_file(&gb, resource_path("registers.sym"));
     
     char symbols_path[path_length + 5];
     replace_extension(filename, path_length, symbols_path, ".sym");

SDL/shader.c

@@ -78,7 +78,7 @@ bool init_shader_with_name(shader_t *shader, const char *name)
     static signed long filter_token_location = 0;
     
     if (!master_shader_code[0]) {
-        FILE *master_shader_f = fopen(executable_relative_path("Shaders/MasterShader.fsh"), "r");
+        FILE *master_shader_f = fopen(resource_path("Shaders/MasterShader.fsh"), "r");
         if (!master_shader_f) return false;
         fread(master_shader_code, 1, sizeof(master_shader_code) - 1, master_shader_f);
         fclose(master_shader_f);
@@ -92,7 +92,7 @@ bool init_shader_with_name(shader_t *shader, const char *name)
     char shader_path[1024];
     sprintf(shader_path, "Shaders/%s.fsh", name);
     
-    FILE *shader_f = fopen(executable_relative_path(shader_path), "r");
+    FILE *shader_f = fopen(resource_path(shader_path), "r");
     if (!shader_f) return false;
     memset(shader_code, 0, sizeof(shader_code));
     fread(shader_code, 1, sizeof(shader_code) - 1, shader_f);

SDL/utils.c

@@ -3,8 +3,11 @@
 #include <string.h>
 #include "utils.h"
 
-const char *executable_folder(void)
+const char *resource_folder(void)
 {
+#ifdef DATA_DIR
+    return DATA_DIR;
+#else
     static const char *ret = NULL;
     if (!ret) {
         ret = SDL_GetBasePath();
@@ -13,12 +16,13 @@ const char *executable_folder(void)
         }
     }
     return ret;
+#endif
 }
 
-char *executable_relative_path(const char *filename)
+char *resource_path(const char *filename)
 {
     static char path[1024];
-    snprintf(path, sizeof(path), "%s%s", executable_folder(), filename);
+    snprintf(path, sizeof(path), "%s%s", resource_folder(), filename);
     return path;
 }
 

SDL/utils.h

@@ -2,8 +2,8 @@
 #define utils_h
 #include <stddef.h>
 
-const char *executable_folder(void);
-char *executable_relative_path(const char *filename);
+const char *resource_folder(void);
+char *resource_path(const char *filename);
 void replace_extension(const char *src, size_t length, char *dest, const char *ext);
 
 #endif /* utils_h */