XO chip documentation and keyboard bugfix (#59)

* Update XO documentation and XO fixes.

* Add more games testing to the readme.

* Add compatibility notes, bump version number to build.

* Update single line in README to describe octo compatibility.

Author: craigthomas

README.md

@@ -12,7 +12,7 @@ plugins {
 }
 
 group = 'ca.craigthomas'
-version = '1.0.1'
+version = '2.0.0'
 
 mainClassName = 'ca.craigthomas.chip8java.emulator.runner.Runner'
 

build.gradle

@@ -976,7 +976,7 @@ private void drawNormalSprite(int xPos, int yPos, int numBytes, int bitplane, in
     protected void skipIfKeyPressed() {
         int x = (operand & 0x0F00) >> 8;
         int keyToCheck = v[x];
-        if (keyboard.getCurrentKey() == keyToCheck) {
+        if (keyboard.isKeyPressed(keyToCheck)) {
             pc += 2;
             if (memory.read(pc - 2) == 0xF0 && memory.read(pc - 1) == 0x00) {
                 pc += 2;
@@ -993,7 +993,7 @@ protected void skipIfKeyPressed() {
     protected void skipIfKeyNotPressed() {
         int x = (operand & 0x0F00) >> 8;
         int keyToCheck = v[x];
-        if (keyboard.getCurrentKey() != keyToCheck) {
+        if (!keyboard.isKeyPressed(keyToCheck)) {
             pc += 2;
             if (memory.read(pc - 2) == 0xF0 && memory.read(pc - 1) == 0x00) {
                 pc += 2;

src/main/java/ca/craigthomas/chip8java/emulator/components/CentralProcessingUnit.java

@@ -141,7 +141,7 @@ public Emulator(
         }
 
         cpuCycleTime = cycleTime;
-        keyboard = new Keyboard(this);
+        keyboard = new Keyboard();
         memory = new Memory(memSize4k);
         screen = new Screen(scale, converted_color0, converted_color1, converted_color2, converted_color3);
         cpu = new CentralProcessingUnit(memory, keyboard, screen);

src/main/java/ca/craigthomas/chip8java/emulator/components/Emulator.java

@@ -14,7 +14,7 @@
 public class Keyboard extends KeyAdapter
 {
     // Map from a keypress event to key values
-    public static final int[] sKeycodeMap = {
+    public static final int[] keycodeMap = {
             KeyEvent.VK_X, // 0x0
             KeyEvent.VK_1, // 0x1
             KeyEvent.VK_2, // 0x2
@@ -33,6 +33,10 @@ public class Keyboard extends KeyAdapter
             KeyEvent.VK_V, // 0xF
     };
 
+    public boolean [] keypressMap = {
+        false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false
+    };
+
     // The current key being pressed, -1 if no key
     protected int currentKeyPressed = -1;
 
@@ -42,17 +46,27 @@ public class Keyboard extends KeyAdapter
     // The key to quit the emulator
     protected static final int CHIP8_QUIT = KeyEvent.VK_ESCAPE;
 
-    public Keyboard(Emulator emulator) {}
+    public Keyboard() {}
 
     @Override
     public void keyPressed(KeyEvent e) {
         rawKeyPressed = e.getKeyCode();
+        for (int x = 0; x < 16; x++) {
+            if (rawKeyPressed == keycodeMap[x]) {
+                keypressMap[x] = true;
+            }
+        }
         currentKeyPressed = mapKeycodeToChip8Key(rawKeyPressed);
     }
 
     @Override
     public void keyReleased(KeyEvent e) {
-        currentKeyPressed = -1;
+        rawKeyPressed = e.getKeyCode();
+        for (int x = 0; x < 16; x++) {
+            if (rawKeyPressed == keycodeMap[x]) {
+                keypressMap[x] = false;
+            }
+        }
     }
 
     /**
@@ -65,8 +79,8 @@ public void keyReleased(KeyEvent e) {
      * @return The Chip 8 key value for the specified keycode
      */
     public int mapKeycodeToChip8Key(int keycode) {
-        for (int i = 0; i < sKeycodeMap.length; i++) {
-            if (sKeycodeMap[i] == keycode) {
+        for (int i = 0; i < keycodeMap.length; i++) {
+            if (keycodeMap[i] == keycode) {
                 return i;
             }
         }
@@ -82,6 +96,20 @@ public int getCurrentKey() {
         return currentKeyPressed;
     }
 
+    /**
+     * Returns true if the specified key in the keymap is currently reported
+     * as being pressed.
+     *
+     * @param key the key number in the keymap to check for
+     * @return true if the key is pressed
+     */
+    public boolean isKeyPressed(int key) {
+        if (key >= 0 && key < 16) {
+            return keypressMap[key];
+        }
+        return false;
+    }
+
     /**
      * Returns the currently pressed debug key. Will return 0 if no debug key was
      * pressed.

src/main/java/ca/craigthomas/chip8java/emulator/components/Keyboard.java

@@ -705,6 +705,9 @@ public void testReadRegistersFromMemoryIndexQuirks() {
 
     @Test
     public void testSkipIfKeyPressedSkipsCorrectly() {
+        Keyboard keyboard = new Keyboard();
+        keyboard.keypressMap[9] = true;
+        cpu = new CentralProcessingUnit(memory, keyboard, screen);
         for (int register = 0; register < 0xF; register++) {
             cpu.v[register] = 9;
             cpu.operand = register << 8;
@@ -738,6 +741,9 @@ public void testSkipIfKeyNotPressedSkipsCorrectly() {
 
     @Test
     public void testSkipIfKeyNotPressedDoesNotSkipIfPressed() {
+        Keyboard keyboard = new Keyboard();
+        cpu = new CentralProcessingUnit(memory, keyboard, screen);
+        keyboard.keypressMap[9] = true;
         for (int register = 0; register < 0xF; register++) {
             cpu.v[register] = 9;
             cpu.operand = register << 8;

src/test/java/ca/craigthomas/chip8java/emulator/components/CentralProcessingUnitTest.java

@@ -25,15 +25,14 @@ public class KeyboardTest
 
     @Before
     public void setUp() {
-        emulator = Mockito.mock(Emulator.class);
-        keyboard = new Keyboard(emulator);
+        keyboard = new Keyboard();
         event = mock(KeyEvent.class);
     }
 
     @Test
     public void testMapKeycodeToChip8Key() {
-        for (int index = 0; index < Keyboard.sKeycodeMap.length; index++) {
-            assertEquals(index, keyboard.mapKeycodeToChip8Key(Keyboard.sKeycodeMap[index]));
+        for (int index = 0; index < Keyboard.keycodeMap.length; index++) {
+            assertEquals(index, keyboard.mapKeycodeToChip8Key(Keyboard.keycodeMap[index]));
         }
     }
 
@@ -54,16 +53,19 @@ public void testGetDebugKey() {
     }
 
     @Test
-    public void testKeyReleased() {
-        keyboard.currentKeyPressed = 1;
-        keyboard.keyReleased(null);
-        assertEquals(-1, keyboard.currentKeyPressed);
+    public void testKeyPressedWorksCorrectly() {
+        when(event.getKeyCode()).thenReturn(KeyEvent.VK_2);
+        keyboard.keyPressed(event);
+        assertEquals(2, keyboard.currentKeyPressed);
     }
 
     @Test
-    public void testKeyPressedWorksCorrectly() {
+    public void testKeyReleased() {
         when(event.getKeyCode()).thenReturn(KeyEvent.VK_2);
         keyboard.keyPressed(event);
-        assertEquals(2, keyboard.currentKeyPressed);
+        assertTrue(keyboard.isKeyPressed(2));
+
+        keyboard.keyReleased(event);
+        assertFalse(keyboard.isKeyPressed(2));
     }
 }