Add ability for 3 letter ID for boxart (#47)

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## Description
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Allows boxart to be 3 letters by checking the "media type" if required.
It continues to be compatible with 2 letters.
Also update sodium64 rom address (changed in
d006af4870).

## Motivation and Context
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<!--- If it fixes/closes/resolves an open issue, please link to the
issue here -->
Fixes an issue for at least `DZ` which shares the same ID between
Dezaemon 3D for the 64DD and Duke Nukem: Zero Hour Cartridge.

## How Has This Been Tested?
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## Types of changes
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the boxes that apply: -->
- [x] Improvement (non-breaking change that adds a new feature)
- [ ] Bug fix (fixes an issue)
- [ ] Breaking change (breaking change)
- [ ] Config and build (change in the configuration and build system,
has no impact on code or features)

## Checklist:
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- [x] My code follows the code style of this project.
- [x] My change requires a change to the documentation.
- [x] I have updated the documentation accordingly.
- [ ] I have added tests to cover my changes.
- [ ] All new and existing tests passed.

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README.md

@@ -40,8 +40,10 @@ The aim is to replace [Altra64](https://github.com/networkfusion/altra64) and [E
 
 #### ROM Boxart
 To use boxart, you need to place png files of size 158x112 in the folder `/menu/boxart` on the SD card.
-Each file must be named according to the 2 letter ROM ID. e.g. for goldeneye, this would be `GE.png`.
-A known set of PNG files can be downloaded [here](https://mega.nz/file/6cNGwSqI#8X5ukb65n3YMlGaUtSOGXkKo9HxVnnMOgqn94Epcr7w).
+Each file must be named according to the 2 letter ROM ID, or 3 letter ROM ID including media type.
+i.e. for GoldenEye 2 letters, this would be `GE.png`.
+i.e. for GoldenEye 3 letters, this would be `NGE.png`.
+A known set of PNG files using 2 letter ID's can be downloaded [here](https://mega.nz/file/6cNGwSqI#8X5ukb65n3YMlGaUtSOGXkKo9HxVnnMOgqn94Epcr7w).
 
 #### Emulator support
 Emulators should be added to the `/emulators` directory on the SD card.

src/menu/cart_load.c

@@ -91,7 +91,6 @@ cart_load_err_t cart_load_emulator (menu_t *menu, cart_load_emu_type_t emu_type,
         case CART_LOAD_EMU_TYPE_SNES:
             path_push(path, "sodium64.z64");
             save_type = FLASHCART_SAVE_TYPE_SRAM;
-            emulated_rom_offset = 0x104000;
             break;
         case CART_LOAD_EMU_TYPE_GAMEBOY:
             path_push(path, "gb.v64");
@@ -124,6 +123,7 @@ cart_load_err_t cart_load_emulator (menu_t *menu, cart_load_emu_type_t emu_type,
 
     switch (emu_type) {
         case CART_LOAD_EMU_TYPE_SNES:
+            // The emulator expects the header to be removed from the ROM being uploaded.
             emulated_file_offset = ((file_get_size(path_get(path)) & 0x3FF) == 0x200) ? 0x200 : 0;
             break;
         default:

src/menu/components.h

@@ -59,7 +59,7 @@ typedef struct {
     surface_t *image;
 } component_boxart_t;
 
-component_boxart_t *component_boxart_init (uint16_t id);
+component_boxart_t *component_boxart_init (uint8_t media_type, uint16_t id);
 void component_boxart_free (component_boxart_t *b);
 void component_boxart_draw (component_boxart_t *b);
 

src/menu/components/boxart.c

@@ -4,6 +4,7 @@
 #include "../path.h"
 #include "../png_decoder.h"
 #include "constants.h"
+#include "utils/fs.h"
 
 
 #define BOXART_DIRECTORY    "sd:/menu/boxart"
@@ -16,14 +17,18 @@ static void png_decoder_callback (png_err_t err, surface_t *decoded_image, void
 }
 
 
-component_boxart_t *component_boxart_init (uint16_t id) {
+component_boxart_t *component_boxart_init (uint8_t media_type, uint16_t id) {
     component_boxart_t *b = calloc(1, sizeof(component_boxart_t));
 
     if (b) {
         b->loading = true;
+        char *path = alloca(strlen(BOXART_DIRECTORY) + 1 + 7 + 1); // allocate for the largest path.
+        sprintf(path, "%s/%c%c%c.png", BOXART_DIRECTORY, (media_type & 0xFF), ((id >> 8) & 0xFF), (id & 0xFF));
 
-        char *path = alloca(strlen(BOXART_DIRECTORY) + 1 + 6 + 1);
-        sprintf(path, "%s/%c%c.png", BOXART_DIRECTORY, ((id >> 8) & 0xFF), (id & 0xFF));
+        // if the file does not exist, also check for just the id.
+        if (!file_exists(path)) {
+            sprintf(path, "%s/%c%c.png", BOXART_DIRECTORY, ((id >> 8) & 0xFF), (id & 0xFF));
+        }
 
         if (png_decoder_start(path, BOXART_WIDTH, BOXART_HEIGHT, png_decoder_callback, b) != PNG_OK) {
             free(b);

src/menu/views/load_rom.c

@@ -250,7 +250,7 @@ void view_load_rom_init (menu_t *menu) {
 
     rom_header = file_read_rom_header(path_get(path));
 
-    boxart = component_boxart_init(rom_header.metadata.unique_identifier);
+    boxart = component_boxart_init(rom_header.metadata.media_type, rom_header.metadata.unique_identifier);
 
     path_free(path);
 }