keeps program from freaking out when ROM file not found, added some command line arguments

Author: garrettgu10

src/org/the429ers/gameboy/Cartridge.java

@@ -11,7 +11,8 @@ static Cartridge fromFile(String fileName) {
         try {
             new FileInputStream(file).read(rom);
         } catch (IOException e) {
-            e.printStackTrace();
+            System.out.println("File not found: " + fileName);
+            return null;
         }
 
         int cartridgeType = rom[0x0147] & 0xff;

src/org/the429ers/gameboy/GameBoy.java

@@ -242,25 +242,6 @@ public void switchRom(String newRom) {
 
     }
 
-    public GameBoy() {
-        super();
-        BufferedImage img = new BufferedImage(160, 144, BufferedImage.TYPE_3BYTE_BGR);
-        gbs = new GameBoyScreen(img);
-        gbs.setDoubleBuffered(true);
-        gbs.setPreferredSize(new Dimension(500, 500));
-        gbs.setFocusable(true);
-        this.add(gbs);
-        this.setMenuBar(new MainMenuBar(this));
-        this.pack();
-        this.setTitle("OOPBoy");
-        this.setVisible(true);
-        this.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
-        this.addWindowListener(listener);
-
-        quickSave = false;
-        quickLoad = false;
-    }
-    
     public GameBoy(String fileName) {
         super();
         this.romFileName = fileName;
@@ -449,6 +430,11 @@ public void pause() {
     }
 
     public void start() {
+        if(mmu.getROM() == null){
+            System.out.println("Invalid cartridge");
+            return;
+        }
+        
         new Thread(() -> {
             paused = false;
 
@@ -466,12 +452,20 @@ public void dispose() {
 
     public static void main(String[] args) throws InterruptedException {
 
-        gb = new GameBoy(DEFAULT_ROM);
-
-        Scanner fin = new Scanner(System.in);
-        if(args.length > 0 && args[0].equals("-d")) {
-            System.out.print("First breakpoint (hex): ");
-            gb.breakPoints.add(fin.nextInt(16));
+        if(args.length > 0) {
+            if(!args[0].equals("-d")) {
+                gb = new GameBoy(args[0]);
+            }else{
+                gb = new GameBoy(DEFAULT_ROM);
+            }
+            
+            if(args[args.length-1].equals("-d")) {
+                Scanner fin = new Scanner(System.in);
+                System.out.print("First breakpoint (hex): ");
+                gb.breakPoints.add(fin.nextInt(16));
+            }
+        }else{
+            gb = new GameBoy(DEFAULT_ROM);
         }
 
         gb.start();

src/org/the429ers/gameboy/MMU.java

@@ -85,14 +85,18 @@ public IPPU getPPU() {
         return this.ppu;
     }
 
+    public Cartridge getROM() {
+        return this.rom;
+    }
+    
     public MMU() {
         //no need to copy boot rom since that is intercepted by readByte
     }
 
     // Load rom from disk
     public MMU(String fileName) {
         this.rom = Cartridge.fromFile(fileName);
-        this.isCGB = rom.isGBC();
+        this.isCGB = rom != null && rom.isGBC();
     }
 
     public void cleanUp() {
@@ -188,11 +192,11 @@ public int readByte(int location) {
         }
 
         if(location < 0x8000){
-            return rom.readByte(location);
+            return rom == null? 0 : rom.readByte(location);
         }
 
         if (location >= 0xA000 && location <= 0xBFFF) {
-            return rom.readByte(location);
+            return rom == null? 0 : rom.readByte(location);
         }
 
         if (location >= 0x8000 && location <= 0x9FFF) {
@@ -271,12 +275,12 @@ public void writeByte(int location, int toWrite){
         }
 
         if(location < 0x7fff){
-            rom.writeByte(location, toWrite);
+            if(rom != null) rom.writeByte(location, toWrite);
             return;
         }
 
         if (location >= 0xA000 && location <= 0xBFFF) {
-            rom.writeByte(location, toWrite);
+            if(rom != null) rom.writeByte(location, toWrite);
             return;
         }