+ * The graphical representation of each character is derived from a + * character generator ROM image. For this simulation, the Commodore PET + * character generator ROM was chosen, but any character generator ROM + * could be used in its place. + *
+ * It may be convenient to think of this as the View (in the MVC + * pattern sense) to the Crtc's Model and Controller. Whenever the CRTC + * updates state in a way that may require the view to update, it calls + * the deviceStateChange callback on this Window. + */ public class VideoWindow extends JFrame implements DeviceChangeListener { private static final Logger logger = Logger.getLogger(VideoWindow.class.getName()); @@ -56,7 +71,7 @@ public class VideoWindow extends JFrame implements DeviceChangeListener { private int verticalDisplayed; private int scanLinesPerRow; private int cursorBlinkRate; - private boolean showCursor; + private boolean hideCursor; private Dimension dimensions; private Crtc crtc; @@ -64,6 +79,9 @@ public class VideoWindow extends JFrame implements DeviceChangeListener { private ScheduledExecutorService scheduler; private ScheduledFuture cursorBlinker; + /** + * A panel representing the composite video output, with fast Graphics2D painting. + */ private class VideoPanel extends JPanel { @Override public void paintComponent(Graphics g) { @@ -71,7 +89,7 @@ public class VideoWindow extends JFrame implements DeviceChangeListener { int address = crtc.getStartAddress() + i; int originX = (i % horizontalDisplayed) * CHAR_WIDTH; int originY = (i / horizontalDisplayed) * scanLinesPerRow; - image.getRaster().setPixels(originX, originY, CHAR_WIDTH, scanLinesPerRow, getGlyph(i, videoRam[address])); + image.getRaster().setPixels(originX, originY, CHAR_WIDTH, scanLinesPerRow, getGlyph(address)); } Graphics2D g2d = (Graphics2D)g; if (shouldScale) { @@ -92,12 +110,15 @@ public class VideoWindow extends JFrame implements DeviceChangeListener { } + /** + * Runnable task that blinks the cursor. + */ private class CursorBlinker implements Runnable { public void run() { SwingUtilities.invokeLater(new Runnable() { public void run() { if (cursorBlinkRate > 0) { - showCursor = !showCursor; + hideCursor = !hideCursor; repaint(); } } @@ -110,7 +131,7 @@ public class VideoWindow extends JFrame implements DeviceChangeListener { this.scheduler = Executors.newSingleThreadScheduledExecutor(); this.crtc = crtc; - this.charRom = convertCharRom(loadCharRom("/pet.rom"), CHAR_WIDTH); + this.charRom = loadCharRom("/pet.rom"); this.videoRam = crtc.getDmaAccess(); this.scaleX = scaleX; this.scaleY = scaleY; @@ -137,57 +158,22 @@ public class VideoWindow extends JFrame implements DeviceChangeListener { } - private byte[] loadCharRom(String resource) throws IOException { - BufferedInputStream bis = null; - try { - bis = new BufferedInputStream(this.getClass().getResourceAsStream(resource)); - ByteArrayOutputStream bos = new ByteArrayOutputStream(); - while (bis.available() > 0) { - bos.write(bis.read()); - } - bos.flush(); - bos.close(); - return bos.toByteArray(); - } finally { - if (bis != null) { - bis.close(); - } + public void refreshDisplay() { + // TODO: Verify whether this is necessary. Does `repaint()' do anything if the window is not visible? + if (isVisible()) { + repaint(); } } - public void createAndShowUi() { - setTitle("Composite Video"); - - int borderWidth = 20; - int borderHeight = 20; - - JPanel containerPane = new JPanel(); - containerPane.setBorder(BorderFactory.createEmptyBorder(borderHeight, borderWidth, borderHeight, borderWidth)); - containerPane.setLayout(new BorderLayout()); - containerPane.setBackground(Color.black); - - containerPane.add(new VideoPanel(), BorderLayout.CENTER); - - getContentPane().add(containerPane, BorderLayout.CENTER); - setResizable(false); - pack(); - } - - private void buildImage() { - int rasterWidth = CHAR_WIDTH * horizontalDisplayed; - int rasterHeight = scanLinesPerRow * verticalDisplayed; - this.image = new BufferedImage(rasterWidth, rasterHeight, BufferedImage.TYPE_BYTE_BINARY); - this.dimensions = new Dimension(rasterWidth * scaleX, rasterHeight * scaleY); - } - /** * Called by the CRTC on state change. */ public void deviceStateChanged() { - // Certain state boolean repackNeeded = false; + // TODO: I'm not entirely happy with this pattern, and I'd like to make it a bit DRY-er. + if (horizontalDisplayed != crtc.getHorizontalDisplayed()) { horizontalDisplayed = crtc.getHorizontalDisplayed(); repackNeeded = true; @@ -209,6 +195,7 @@ public class VideoWindow extends JFrame implements DeviceChangeListener { if (cursorBlinker != null) { cursorBlinker.cancel(true); cursorBlinker = null; + hideCursor = false; } if (cursorBlinkRate > 0) { @@ -226,26 +213,22 @@ public class VideoWindow extends JFrame implements DeviceChangeListener { } } - /** - * Convert a raw binary Character ROM image into an array of pixel data usable - * by the Raster underlying the display's BufferedImage. - * - * @param rawBytes - * @param charWidth - * @return - */ - private int[] convertCharRom(byte[] rawBytes, int charWidth) { - int[] converted = new int[rawBytes.length * charWidth]; + private void createAndShowUi() { + setTitle("Composite Video"); - int romIndex = 0; - for (int i = 0; i < converted.length;) { - byte charRow = rawBytes[romIndex++]; + int borderWidth = 20; + int borderHeight = 20; - for (int j = 7; j >= 0; j--) { - converted[i++] = ((charRow & (1 << j)) == 0) ? 0 : 0xff; - } - } - return converted; + JPanel containerPane = new JPanel(); + containerPane.setBorder(BorderFactory.createEmptyBorder(borderHeight, borderWidth, borderHeight, borderWidth)); + containerPane.setLayout(new BorderLayout()); + containerPane.setBackground(Color.black); + + containerPane.add(new VideoPanel(), BorderLayout.CENTER); + + getContentPane().add(containerPane, BorderLayout.CENTER); + setResizable(false); + pack(); } /** @@ -253,11 +236,11 @@ public class VideoWindow extends JFrame implements DeviceChangeListener { * Character ROM plus cursor overlay (if any). The cursor overlay simulates an XOR * of the Character Rom output and the 6545 Cursor output. * - * @param position The position within the character field, from 0 to (horizontalDisplayed * verticalDisplayed) - * @param chr The character value within the ROM to display. - * @return + * @param address The address of the character being requested. + * @return An array of integers representing the pixel data. */ - private int[] getGlyph(int position, int chr) { + private int[] getGlyph(int address) { + int chr = videoRam[address]; int romOffset = (chr & 0xff) * (CHAR_HEIGHT * CHAR_WIDTH); int[] glyph = new int[CHAR_WIDTH * scanLinesPerRow]; @@ -267,7 +250,7 @@ public class VideoWindow extends JFrame implements DeviceChangeListener { } // Overlay the cursor - if (showCursor && crtc.isCursorEnabled() && crtc.getCursorPosition() == position) { + if (!hideCursor && crtc.isCursorEnabled() && crtc.getCursorPosition() == address) { int cursorStart = Math.min(glyph.length, crtc.getCursorStartLine() * CHAR_WIDTH); int cursorStop = Math.min(glyph.length, (crtc.getCursorStopLine() + 1) * CHAR_WIDTH); @@ -279,11 +262,54 @@ public class VideoWindow extends JFrame implements DeviceChangeListener { return glyph; } - public void refreshDisplay() { - // TODO: Verify whether this is necessary. Does `repaint()' do anything if the window is not visible? - if (isVisible()) { - repaint(); - } + private void buildImage() { + int rasterWidth = CHAR_WIDTH * horizontalDisplayed; + int rasterHeight = scanLinesPerRow * verticalDisplayed; + this.image = new BufferedImage(rasterWidth, rasterHeight, BufferedImage.TYPE_BYTE_BINARY); + this.dimensions = new Dimension(rasterWidth * scaleX, rasterHeight * scaleY); } + /** + * Load a Character ROM file and convert it into an array of pixel data usable + * by the underlying BufferedImage's Raster. + *
+ * Since the BufferedImage is a TYPE_BYTE_BINARY, the data must be converted + * into a single byte per pixel, 0 for black and 255 for white. + + * @param resource The ROM file resource to load. + * @return An array of glyphs, each ready for insertion. + * @throws IOException + */ + private int[] loadCharRom(String resource) throws IOException { + BufferedInputStream bis = null; + try { + bis = new BufferedInputStream(this.getClass().getResourceAsStream(resource)); + ByteArrayOutputStream bos = new ByteArrayOutputStream(); + while (bis.available() > 0) { + bos.write(bis.read()); + } + bos.flush(); + bos.close(); + + byte[] raw = bos.toByteArray(); + + // Now convert the raw ROM image into a format suitable for + // insertion directly into the BufferedImage. + int[] converted = new int[raw.length * CHAR_WIDTH]; + + int romIndex = 0; + for (int i = 0; i < converted.length;) { + byte charRow = raw[romIndex++]; + + for (int j = 7; j >= 0; j--) { + converted[i++] = ((charRow & (1 << j)) == 0) ? 0 : 0xff; + } + } + return converted; + } finally { + if (bis != null) { + bis.close(); + } + } + } }