Add emulator loading and screen (#20)

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## Description
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This PR shows a possible way forward for adding support for emulators.
Superseeds #13 

## Motivation and Context
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<!--- If it fixes/closes/resolves an open issue, please link to the
issue here -->
The ability to load partial ROM's and/or overwrite parts of them is
required by emulators, patches and potentially gameshark/action replay.

## 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.
- [ ] 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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Signed-off-by: GITHUB_USER <GITHUB_USER_EMAIL>

---------

Co-authored-by: Mateusz Faderewski <sc@mateuszfaderewski.pl>

Makefile

@@ -45,6 +45,7 @@ SRCS = \
 	menu/views/file_info.c \
 	menu/views/image_viewer.c \
 	menu/views/load.c \
+	menu/views/load_emulator.c \
 	menu/views/music_player.c \
 	menu/views/startup.c \
 	menu/views/system_info.c \

README.md

@@ -26,6 +26,13 @@ To use boxart, you need to place png files of size 158x112 in the folder `sd://m
 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 from https://mega.nz/file/6cNGwSqI#8X5ukb65n3YMlGaUtSOGXkKo9HxVnnMOgqn94Epcr7w
 
+### Emulator support
+Emulators should be added to the `sd:/emulators/` folder
+
+The menu currently supports the following emulators and associated ROM's:
+* neon64v2 (https://github.com/hcs64/neon64v2) - emu.nes
+* gb64 (https://lambertjamesd.github.io/gb64/romwrapper/romwrapper.html) - emu.gb, emu.gbc
+
 
 # Developer documentation
 **Work in progress!**

libdragon

@@ -1 +1 @@
-Subproject commit 4409fe77e208aaef77800b684602d4ea5a74da0b
+Subproject commit e37421e8e392e51470bb9dc6b5cd7a7419eeb10c

src/flashcart/flashcart.c

@@ -32,6 +32,7 @@ static flashcart_t *flashcart = &((flashcart_t) {
     .init = dummy_init,
     .deinit = NULL,
     .load_rom = NULL,
+    .load_file = NULL,
     .load_save = NULL,
     .set_save_type = NULL,
     .set_save_writeback = NULL,
@@ -111,6 +112,13 @@ flashcart_error_t flashcart_load_rom (char *rom_path, bool byte_swap, flashcart_
     return error;
 }
 
+flashcart_error_t flashcart_load_file (char *file_path, uint32_t start_offset_address) {
+    if ((file_path == NULL) || (!file_exists(file_path))) {
+        return FLASHCART_ERROR_ARGS;
+    }
+    return flashcart->load_file(file_path, start_offset_address);
+}
+
 flashcart_error_t flashcart_load_save (char *save_path, flashcart_save_type_t save_type) {
     flashcart_error_t error;
     uint32_t sectors[WRITEBACK_MAX_SECTORS] __attribute__((aligned(8)));

src/flashcart/flashcart.h

@@ -42,6 +42,7 @@ typedef struct {
     flashcart_error_t (*init) (void);
     flashcart_error_t (*deinit) (void);
     flashcart_error_t (*load_rom) (char *rom_path, flashcart_progress_callback_t *progress);
+    flashcart_error_t (*load_file) (char *file_path, uint32_t start_offset_address);
     flashcart_error_t (*load_save) (char *save_path);
     flashcart_error_t (*set_save_type) (flashcart_save_type_t save_type);
     flashcart_error_t (*set_save_writeback) (uint32_t *sectors);
@@ -51,6 +52,7 @@ typedef struct {
 flashcart_error_t flashcart_init (void);
 flashcart_error_t flashcart_deinit (void);
 flashcart_error_t flashcart_load_rom (char *rom_path, bool byte_swap, flashcart_progress_callback_t *progress);
+flashcart_error_t flashcart_load_file (char *file_path, uint32_t start_offset_address);
 flashcart_error_t flashcart_load_save (char *save_path, flashcart_save_type_t save_type);
 
 

src/flashcart/sc64/sc64.c

@@ -193,6 +193,34 @@ static flashcart_error_t sc64_load_rom (char *rom_path, flashcart_progress_callb
     return FLASHCART_OK;
 }
 
+static flashcart_error_t sc64_load_file (char *file_path, uint32_t start_offset_address) {
+    FIL fil;
+    UINT br;
+
+    if (f_open(&fil, file_path, FA_READ) != FR_OK) {
+        return FLASHCART_ERROR_LOAD;
+    }
+
+    fix_file_size(&fil);
+
+    size_t file_size = f_size(&fil);
+
+    if (file_size > MiB(8)) { // FIXME: should be checked with the start offset address.
+        f_close(&fil);
+        return FLASHCART_ERROR_LOAD;
+    }
+
+    if (f_read(&fil, (void *) (ROM_ADDRESS + start_offset_address), file_size, &br) != FR_OK) {
+        f_close(&fil);
+        return FLASHCART_ERROR_LOAD;
+    }
+
+    if (f_close(&fil) != FR_OK) {
+        return FLASHCART_ERROR_LOAD;
+    }
+    return FLASHCART_OK;
+}
+
 static flashcart_error_t sc64_load_save (char *save_path) {
     void *address = NULL;
     uint32_t value;
@@ -294,6 +322,7 @@ static flashcart_t flashcart_sc64 = {
     .init = sc64_init,
     .deinit = sc64_deinit,
     .load_rom = sc64_load_rom,
+    .load_file = sc64_load_file,
     .load_save = sc64_load_save,
     .set_save_type = sc64_set_save_type,
     .set_save_writeback = sc64_set_save_writeback,

src/menu/menu.c

@@ -141,6 +141,10 @@ void menu_run (boot_params_t *boot_params) {
                     view_load_display(menu, display);
                     break;
 
+                case MENU_MODE_EMULATOR_LOAD:
+                    view_load_emulator_display(menu, display);
+                    break;
+
                 case MENU_MODE_ERROR:
                     view_error_display(menu, display);
                     break;
@@ -191,6 +195,10 @@ void menu_run (boot_params_t *boot_params) {
                         view_load_init(menu);
                         break;
 
+                    case MENU_MODE_EMULATOR_LOAD:
+                        view_load_emulator_init(menu);
+                        break;
+
                     case MENU_MODE_ERROR:
                         view_error_init(menu);
                         break;

src/menu/menu_state.h

@@ -28,6 +28,7 @@ typedef enum {
     MENU_MODE_MUSIC_PLAYER,
     MENU_MODE_CREDITS,
     MENU_MODE_LOAD,
+    MENU_MODE_EMULATOR_LOAD,
     MENU_MODE_ERROR,
     MENU_MODE_FAULT,
     MENU_MODE_BOOT,
@@ -37,6 +38,7 @@ typedef enum {
 typedef enum {
     ENTRY_TYPE_DIR,
     ENTRY_TYPE_ROM,
+    ENTRY_TYPE_EMULATOR,
     ENTRY_TYPE_SAVE,
     ENTRY_TYPE_IMAGE,
     ENTRY_TYPE_MUSIC,

src/menu/views/browser.c

@@ -10,6 +10,7 @@
 
 
 static const char *rom_extensions[] = { "z64", "n64", "v64", NULL };
+static const char *emulator_extensions[] = { "nes", "gb", "gbc", "smc", "gen", "smd", NULL };
 static const char *save_extensions[] = { "sav", NULL }; // TODO: "eep", "sra", "srm", "fla" could be used if transfered from different flashcarts.
 static const char *image_extensions[] = { "png", NULL };
 static const char *music_extensions[] = { "mp3", NULL };
@@ -28,6 +29,10 @@ static int compare_entry (const void *pa, const void *pb) {
             return -1;
         } else if (b->type == ENTRY_TYPE_ROM) {
             return 1;
+        } else if (a->type == ENTRY_TYPE_EMULATOR) {
+            return -1;
+        } else if (b->type == ENTRY_TYPE_EMULATOR) {
+            return 1;
         } else if (a->type == ENTRY_TYPE_SAVE) {
             return -1;
         } else if (b->type == ENTRY_TYPE_SAVE) {
@@ -90,6 +95,8 @@ static bool load_directory (menu_t *menu) {
             entry->type = ENTRY_TYPE_DIR;
         } else if (file_has_extensions(info.fname, rom_extensions)) {
             entry->type = ENTRY_TYPE_ROM;
+        }else if (file_has_extensions(info.fname, emulator_extensions)) {
+            entry->type = ENTRY_TYPE_EMULATOR;
         } else if (file_has_extensions(info.fname, save_extensions)) {
             entry->type = ENTRY_TYPE_SAVE;
         } else if (file_has_extensions(info.fname, image_extensions)) {
@@ -188,6 +195,9 @@ static void process (menu_t *menu) {
             case ENTRY_TYPE_ROM:
                 menu->next_mode = MENU_MODE_LOAD;
                 break;
+            case ENTRY_TYPE_EMULATOR:
+                menu->next_mode = MENU_MODE_EMULATOR_LOAD;
+                break;
             case ENTRY_TYPE_IMAGE:
                 menu->next_mode = MENU_MODE_IMAGE_VIEWER;
                 break;

src/menu/views/load_emulator.c

@@ -0,0 +1,197 @@
+#include <libdragon.h>
+
+#include "boot/boot.h"
+#include "flashcart/flashcart.h"
+#include "views.h"
+#include "utils/fs.h"
+
+#ifndef EMULATOR_FOLDER
+#define EMULATOR_FOLDER "/emulators/"
+#endif
+
+static const char *emu_nes_rom_extensions[] = { "nes", NULL };
+static const char *emu_gameboy_rom_extensions[] = { "gb", NULL };
+static const char *emu_gameboy_color_rom_extensions[] = { "gbc", NULL };
+static const char *emu_sega_rom_extensions[] = {"smc", "gen", "smd", NULL };
+
+const uint32_t eum_rom_start_address = 0x200000;
+
+static bool load_pending;
+
+static void draw_progress (float progress) {
+    surface_t *d = display_try_get();
+
+    if (d) {
+        rdpq_attach(d, NULL);
+
+        component_background_draw();
+
+        component_loader_draw(progress);
+
+        rdpq_detach_show();
+    }
+}
+
+
+static void load_emulator_nes_rom (path_t *path, menu_t *menu) {
+
+    if (file_exists(EMULATOR_FOLDER"emu.nes")) { // || neon64bu.rom
+
+        menu->flashcart_error = flashcart_load_rom(EMULATOR_FOLDER"emu.nes", false, draw_progress);
+        /* Combine EMU and ROM before loading. See https://github.com/hcs64/neon64v2/tree/master/pkg */
+         menu->flashcart_error = flashcart_load_file(path_get(path), eum_rom_start_address);
+        if (menu->flashcart_error != FLASHCART_OK) {
+            menu->next_mode = MENU_MODE_FAULT;
+            path_free(path);
+            return;
+        }
+
+        path_ext_replace(path, "sav");
+        menu->flashcart_error = flashcart_load_save(path_get(path), FLASHCART_SAVE_TYPE_SRAM_BANKED);
+        if (menu->flashcart_error != FLASHCART_OK) {
+            menu->next_mode = MENU_MODE_FAULT;
+            path_free(path);
+            return;
+        }
+
+    }
+
+}
+
+static void load_emulator_gameboy_rom (path_t *path, menu_t *menu) {
+
+    if (file_exists(EMULATOR_FOLDER"emu.gb")) { // || gb.v64
+
+        menu->flashcart_error = flashcart_load_rom(EMULATOR_FOLDER"emu.gb", false, draw_progress);
+        /* Combine EMU and ROM before loading. */
+         menu->flashcart_error = flashcart_load_file(path_get(path), eum_rom_start_address);
+        if (menu->flashcart_error != FLASHCART_OK) {
+            menu->next_mode = MENU_MODE_FAULT;
+            path_free(path);
+            return;
+        }
+
+        path_ext_replace(path, "sav");
+        menu->flashcart_error = flashcart_load_save(path_get(path), FLASHCART_SAVE_TYPE_FLASHRAM);
+        if (menu->flashcart_error != FLASHCART_OK) {
+            menu->next_mode = MENU_MODE_FAULT;
+            path_free(path);
+            return;
+        }
+
+    }
+
+}
+
+static void load_emulator_gameboy_color_rom (path_t *path, menu_t *menu) {
+
+    if (file_exists(EMULATOR_FOLDER"emu.gbc")) { // || gbc.v64
+
+        menu->flashcart_error = flashcart_load_rom(EMULATOR_FOLDER"emu.gbc", false, draw_progress);
+        /* Combine EMU and ROM before loading. */
+         menu->flashcart_error = flashcart_load_file(path_get(path), eum_rom_start_address);
+        if (menu->flashcart_error != FLASHCART_OK) {
+            menu->next_mode = MENU_MODE_FAULT;
+            path_free(path);
+            return;
+        }
+
+        path_ext_replace(path, "sav");
+        menu->flashcart_error = flashcart_load_save(path_get(path), FLASHCART_SAVE_TYPE_FLASHRAM);
+        if (menu->flashcart_error != FLASHCART_OK) {
+            menu->next_mode = MENU_MODE_FAULT;
+            path_free(path);
+            return;
+        }
+
+    }
+
+}
+
+
+static void load (menu_t *menu) {
+    menu->next_mode = MENU_MODE_BOOT;
+
+    path_t *path = path_clone(menu->browser.directory);
+    path_push(path, menu->browser.list[menu->browser.selected].name);
+
+    if (file_has_extensions (path_get(path), emu_nes_rom_extensions)) {
+        load_emulator_nes_rom(path, menu);
+    }
+    else if (file_has_extensions (path_get(path), emu_gameboy_rom_extensions)) {
+        load_emulator_gameboy_rom(path, menu);
+    }
+    else if (file_has_extensions (path_get(path), emu_gameboy_color_rom_extensions)) {
+        load_emulator_gameboy_color_rom(path, menu);
+    }
+    else if (file_has_extensions (path_get(path), emu_sega_rom_extensions)) {
+        //load_emulator_sega_rom(path, menu);
+    }
+
+    path_free(path);
+
+    menu->boot_params->device_type = BOOT_DEVICE_TYPE_ROM;
+    menu->boot_params->tv_type = BOOT_TV_TYPE_PASSTHROUGH;
+    menu->boot_params->detect_cic_seed = true;
+}
+
+
+static void process (menu_t *menu) {
+    if (menu->actions.enter) {
+        load_pending = true;
+    } else if (menu->actions.back) {
+        menu->next_mode = MENU_MODE_BROWSER;
+    }
+}
+
+static void draw (menu_t *menu, surface_t *d) {
+    rdpq_attach(d, NULL);
+
+    component_background_draw();
+
+    if (load_pending) {
+        component_loader_draw(0.0f);
+    } else {
+        component_layout_draw();
+
+        component_main_text_draw(
+            ALIGN_CENTER, VALIGN_TOP,
+            "Emulator information\n"
+            "THE EMULATOR\n"
+            "Rom Name\n"
+            "\n"
+            "%s",
+            menu->browser.list[menu->browser.selected].name
+        );
+
+        
+
+        component_actions_bar_text_draw(
+            ALIGN_LEFT, VALIGN_TOP,
+            "A: Load and run Emulator ROM\n"
+            "B: Exit"
+        );
+
+    }
+
+    rdpq_detach_show();
+}
+
+
+void view_load_emulator_init (menu_t *menu) {
+    load_pending = false;
+
+    path_t *path = path_clone(menu->browser.directory);
+    path_push(path, menu->browser.list[menu->browser.selected].name);
+
+    path_free(path);
+}
+
+void view_load_emulator_display (menu_t *menu, surface_t *display) {
+    process(menu);
+    draw(menu, display);
+    if (load_pending) {
+        load_pending = false;
+        load(menu);
+    }
+}

src/menu/views/views.h

@@ -41,6 +41,9 @@ void view_credits_display (menu_t *menu, surface_t *display);
 void view_load_init (menu_t *menu);
 void view_load_display (menu_t *menu, surface_t *display);
 
+void view_load_emulator_init (menu_t *menu);
+void view_load_emulator_display (menu_t *menu, surface_t *display);
+
 void view_error_init (menu_t *menu);
 void view_error_display (menu_t *menu, surface_t *display);