FF7: Replace field load model built-in atoi

Instead of blindly converting all the buffer, as the model size can't be bigger than 4096, use always only the first 4 bytes.

Fixes #295

Author: julianxhokaxhiu

src/ff7.h

@@ -1933,6 +1933,7 @@ struct ff7_externals
 	uint32_t menu_sub_6CDC09;
 	uint32_t menu_sub_7212FB;
 	uint32_t load_save_file;
+	uint32_t field_load_models_atoi;
 };
 
 uint32_t ff7gl_load_group(uint32_t group_num, struct matrix_set *matrix_set, struct p_hundred *hundred_data, struct p_group *group_data, struct polygon_data *polygon_data, struct ff7_polygon_set *polygon_set, struct ff7_game_obj *game_object);

src/ff7/defs.h

@@ -58,7 +58,7 @@ void ff7_limit_fps();
 void ff7_handle_ambient_playback();
 BOOL ff7_write_save_file(char slot);
 DWORD ff7_sub_404D80();
-
+int ff7_field_load_models_atoi(const char* str);
 
 // field
 void field_load_textures(struct ff7_game_obj *game_object, struct struc_3 *struc_3);

src/ff7/misc.cpp

@@ -543,16 +543,26 @@ BOOL ff7_write_save_file(char slot)
 	return ret;
 }
 
+// The function that load the model size sometimes gets a buffer that is non-null terminated, returning weird values.
+// Replace the native `atoi` call with a custom function that always uses the first 4 bytes to convert the buffer to int
+int ff7_field_load_models_atoi(const char* str)
+{
+	std::string buf(str, 4);
+
+	return std::stol(buf);
+}
+
 //#########################
 // steam achievement hooks
 //#########################
 
 // Replaced this function only in credits main loop
-DWORD ff7_sub_404D80(){ // NOT TESTED
+DWORD ff7_sub_404D80() // NOT TESTED
+{
 	if (trace_all || trace_achievement)
         ffnx_trace("%s - unlock end of game progress\n", __func__);
 
 	g_FF7SteamAchievements.unlockGameProgressAchievement(END_OF_GAME);
 
-	return ((DWORD(*)()) ff7_externals.sub_404D80)(); 
+	return ((DWORD(*)()) ff7_externals.sub_404D80)();
 }

src/ff7_data.h

@@ -551,7 +551,7 @@ void ff7_find_externals(struct ff7_game_obj* game_object)
 	ff7_externals.menu_shop_loop = get_relative_call(ff7_externals.menu_sub_71FF95, 0x84);
 	ff7_externals.get_materia_gil = get_relative_call(ff7_externals.menu_shop_loop, 0x327B);
 	ff7_externals.menu_sub_6CBCB9 = get_relative_call(ff7_externals.menu_shop_loop, 0x353B);
-	
+
 	ff7_externals.credits_main_loop = credits_main_loop;
 	ff7_externals.sub_404D80 = get_relative_call(ff7_externals.credits_main_loop, 0x211);
 
@@ -567,6 +567,8 @@ void ff7_find_externals(struct ff7_game_obj* game_object)
 	uint32_t menu_sub_722393 = get_relative_call(menu_sub_6CBD65, 0x4);
 	ff7_externals.menu_sub_7212FB = get_relative_call(menu_sub_722393, 0x8B);
 	ff7_externals.load_save_file = get_relative_call(ff7_externals.menu_sub_7212FB, 0xE9D);
+
+	ff7_externals.field_load_models_atoi = ff7_externals.field_load_models + 0x262;
 }
 
 void ff7_data(struct ff7_game_obj* game_object)

src/ff7_opengl.cpp

@@ -57,6 +57,9 @@ void ff7_init_hooks(struct game_obj *_game_object)
 	game_object->d3d2_flag = 1;
 	game_object->nvidia_fix = 0;
 
+	// Load Models atoi function
+	replace_call_function(ff7_externals.field_load_models_atoi, ff7_field_load_models_atoi);
+
 	// DirectInput hack, try to reacquire on any error
 	memset_code(ff7_externals.dinput_getdata2 + 0x65, 0x90, 9);
 	memset_code((uint32_t)common_externals.dinput_acquire_keyboard + 0x31, 0x90, 5);
@@ -190,7 +193,6 @@ void ff7_init_hooks(struct game_obj *_game_object)
 	// #####################
 	// battle toggle
 	// #####################
-
 	replace_call_function(ff7_externals.field_battle_toggle, ff7_toggle_battle_field);
 	replace_call_function(ff7_externals.worldmap_battle_toggle, ff7_toggle_battle_worldmap);
 
@@ -225,6 +227,7 @@ void ff7_init_hooks(struct game_obj *_game_object)
 				break;
 		}
 	}
+
 	//###############################
 	// steam achievement unlock calls
 	//###############################