MouseEventQueue.java

/*
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 *   its contributors may be used to endorse or promote products derived
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package org.lwjgl.opengl;

/**
 * An AWT implementation of a LWJGL compatible Mouse event queue.
 * @author elias_naur
 */

import java.awt.Component;
import java.awt.Point;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.awt.event.MouseWheelEvent;
import java.awt.event.MouseWheelListener;
import java.nio.ByteBuffer;
import java.nio.IntBuffer;

import org.lwjgl.input.Mouse;

class MouseEventQueue extends EventQueue implements MouseListener, MouseMotionListener, MouseWheelListener {
	private static final int WHEEL_SCALE = 120;
	public static final int NUM_BUTTONS = 3;

	private final Component component;

	private boolean grabbed;

	/** The accumulated mouse deltas returned by poll() */
	private int accum_dx;
	private int accum_dy;
	private int accum_dz;

	/** The last mouse position */
	private int last_x;
	private int last_y;

	/** Saved control key state for ctrl-click right button emulation */
	private boolean saved_control_state;

	/** Event scratch array */
	private final ByteBuffer event = ByteBuffer.allocate(Mouse.EVENT_SIZE);

	/** Buttons array */
	private final byte[] buttons = new byte[NUM_BUTTONS];

	MouseEventQueue(Component component) {
		super(Mouse.EVENT_SIZE);
		this.component = component;
	}

	public synchronized void register() {
		resetCursorToCenter();
        if (component != null) {
            component.addMouseListener(this);
            component.addMouseMotionListener(this);
            component.addMouseWheelListener(this);
        }
	}

	public synchronized void unregister() {
        if (component != null) {
            component.removeMouseListener(this);
            component.removeMouseMotionListener(this);
            component.removeMouseWheelListener(this);
        }
	}

	protected Component getComponent() {
		return component;
	}

	public synchronized void setGrabbed(boolean grabbed) {
		this.grabbed = grabbed;
		resetCursorToCenter();
	}

	public synchronized boolean isGrabbed() {
		return grabbed;
	}

	protected int transformY(int y) {
        if (component != null) {
            return component.getHeight() - 1 - y;
        }
        return y;
	}

	protected void resetCursorToCenter() {
		clearEvents();
		accum_dx = accum_dy = 0;
        if (component != null) {
            Point cursor_location = AWTUtil.getCursorPosition(component);
            if (cursor_location != null) {
                last_x = cursor_location.x;
                last_y = cursor_location.y;
            }
        }
	}

	private void putMouseEvent(byte button, byte state, int dz, long nanos) {
		if (grabbed)
			putMouseEventWithCoords(button, state, 0, 0, dz, nanos);
		else
			putMouseEventWithCoords(button, state, last_x, last_y, dz, nanos);
	}

	protected void putMouseEventWithCoords(byte button, byte state, int coord1, int coord2, int dz, long nanos) {
		event.clear();
		event.put(button).put(state).putInt(coord1).putInt(coord2).putInt(dz).putLong(nanos);
		event.flip();
		putEvent(event);
	}

	public synchronized void poll(IntBuffer coord_buffer, ByteBuffer buttons_buffer) {
		if ( grabbed ) {
			coord_buffer.put(0, accum_dx);
			coord_buffer.put(1, accum_dy);
		} else {
			coord_buffer.put(0, last_x);
			coord_buffer.put(1, last_y);
		}
		coord_buffer.put(2, accum_dz);
		accum_dx = accum_dy = accum_dz = 0;
		int old_position = buttons_buffer.position();
		buttons_buffer.put(buttons, 0, buttons.length);
		buttons_buffer.position(old_position);
	}

	private void setCursorPos(int x, int y, long nanos) {
		y = transformY(y);
		if ( grabbed )
			return;
		int dx = x - last_x;
		int dy = y - last_y;
		addDelta(dx, dy);
		last_x = x;
		last_y = y;
		putMouseEventWithCoords((byte)-1, (byte)0, x, y, 0, nanos);
	}

	protected void addDelta(int dx, int dy) {
		accum_dx += dx;
		accum_dy += dy;
	}

	public void mouseClicked(MouseEvent e) {
	}

	public void mouseEntered(MouseEvent e) {
	}

	public void mouseExited(MouseEvent e) {
	}

	private void handleButton(MouseEvent e) {
		byte state;
		switch (e.getID()) {
			case MouseEvent.MOUSE_PRESSED:
				state = 1;
				break;
			case MouseEvent.MOUSE_RELEASED:
				state = 0;
				break;
			default:
				throw new IllegalArgumentException("Not a valid event ID: " + e.getID());
		}
		byte button;
		switch (e.getButton()) {
			case MouseEvent.NOBUTTON:
				// Nothing to do, so return
				return;
			case MouseEvent.BUTTON1:
				// Emulate right click if ctrl is down
				if (state == 1)
					saved_control_state = e.isControlDown();
				if (saved_control_state) {
					if (buttons[1] == state)
						return; // ignore
					button = (byte)1;
				} else {
					button = (byte)0;
				}
				break;
			case MouseEvent.BUTTON2:
				button = (byte)2;
				break;
			case MouseEvent.BUTTON3:
				if (buttons[1] == state)
					return; // ignore
				button = (byte)1;
				break;
			default:
				throw new IllegalArgumentException("Not a valid button: " + e.getButton());
		}
		setButton(button, state, e.getWhen()*1000000);
	}

	public synchronized void mousePressed(MouseEvent e) {
		handleButton(e);
	}

	private void setButton(byte button, byte state, long nanos) {
		buttons[button] = state;
		putMouseEvent(button, state, 0, nanos);
	}

	public synchronized void mouseReleased(MouseEvent e) {
		handleButton(e);
	}

	private void handleMotion(MouseEvent e) {
		if (grabbed) {
			updateDeltas(e.getWhen()*1000000);
		} else {
			setCursorPos(e.getX(), e.getY(), e.getWhen()*1000000);
		}
	}

	public synchronized void mouseDragged(MouseEvent e) {
		handleMotion(e);
	}

	public synchronized void mouseMoved(MouseEvent e) {
		handleMotion(e);
	}

	private void handleWheel(int amount, long nanos) {
		accum_dz += amount;
		putMouseEvent((byte)-1, (byte)0, amount, nanos);
	}

	protected void updateDeltas(long nanos) {
	}

	public synchronized void mouseWheelMoved(MouseWheelEvent e) {
		int wheel_amount = -e.getWheelRotation() * WHEEL_SCALE;
		handleWheel(wheel_amount, e.getWhen()*1000000);
	}
}