m3gcanvas.java

一个3D游戏的实例

import javax.microedition.lcdui.Graphics;
import javax.microedition.lcdui.game.GameCanvas;
import javax.microedition.m3g.Camera;
import javax.microedition.m3g.Graphics3D;
import javax.microedition.m3g.Light;
import javax.microedition.m3g.Loader;
import javax.microedition.m3g.Object3D;
import javax.microedition.m3g.Transform;
import javax.microedition.m3g.World;

public class M3GCanvas
extends GameCanvas
implements Runnable {
    // Thread-control
    boolean running = false;
    boolean done = true;
    
    // If the game should end
    public static boolean gameOver = false;
    
    // Rendering hints
    public static final int STRONG_RENDERING_HINTS = Graphics3D.ANTIALIAS | Graphics3D.TRUE_COLOR | Graphics3D.DITHER;
    public static final int WEAK_RENDERING_HINTS = 0;
    public static int RENDERING_HINTS = STRONG_RENDERING_HINTS;
    
    // Key array
    boolean[] key = new boolean[5];
    
    // Key constants
    public static final int FIRE = 0;
    public static final int UP = FIRE + 1;
    public static final int DOWN = UP + 1;
    public static final int LEFT = DOWN + 1;
    public static final int RIGHT = LEFT + 1;
    
    // Global identity matrix
    Transform identity = new Transform();
    
    // Global Graphics3D object
    Graphics3D g3d = null;
    
    // The global world object
    World world = null;
    
    // The global camera object
    Camera cam = null;
    
    // Camera rotation
    float camRot = 0.0f;
    double camSine = 0.0f;
    double camCosine = 0.0f;
    
    // Head bobbing
    float headDeg = 0.0f;
    
    /** Constructs the canvas
     */
    public M3GCanvas(int fps)
    {
        // We don't want to capture keys normally
        super(true);
        
        // We want a fullscreen canvas
        setFullScreenMode(true);
        
        // Load our world
        loadWorld();
        
        // Load our camera
        loadCamera();
    }
    
    /** When fullscreen mode is set, some devices will call
     * this method to notify us of the new width/height.
     * However, we don't really care about the width/height
     * in this tutorial so we just let it be
     */
    public void sizeChanged(int newWidth, int newHeight)
    {
        
    }
    
    /** Loads our camera */
    private void loadCamera()
    {
        // BAD!
        if(world == null)
            return;
        
        // Get the active camera from the world
        cam = world.getActiveCamera();
        
        // Create a light
        Light l = new Light();
        
        // Make sure it's AMBIENT
        l.setMode(Light.AMBIENT);
        
        // We want a little higher intensity
        l.setIntensity(3.0f);
        
        // Add it to our world
        world.addChild(l);
    }
    
    /** Loads our world */
    private void loadWorld()
    {
        try
        {
            // Loading the world is very simple. Note that I like to use a
            // res-folder that I keep all files in. If you normally just put your
            // resources in the project root, then load it from the root.
            Object3D[] buffer = Loader.load("/res/map.m3g");
            
            // Find the world node, best to do it the "safe" way
            for(int i = 0; i < buffer.length; i++)
            {
                if(buffer[i] instanceof World)
                {
                    world = (World)buffer[i];
                    break;
                }
            }
            
            // Clean objects
            buffer = null;
        }
        catch(Exception e)
        {
            // ERROR!
            System.out.println("Loading error!");
            reportException(e);
        }
    }

    /** Draws to screen
     */
    private void draw(Graphics g)
    {
        // Envelop all in a try/catch block just in case
        try
        {
            // Move the camera around
            moveCamera();
            
            // Get the Graphics3D context
            g3d = Graphics3D.getInstance();
            
	        // First bind the graphics object. We use our pre-defined rendering hints.
	        g3d.bindTarget(g, true, RENDERING_HINTS);
	        
	        // Now, just render the world. Simple as pie!
	        g3d.render(world);
        }
        catch(Exception e)
        {
            reportException(e);
        }
        finally
        {
            // Always remember to release!
            g3d.releaseTarget();
        }
    }
    
    /**
     * 
     */
    private void moveCamera() {
        // Check controls
        if(key[LEFT])
        {
            camRot += 5.0f;
        }
        else if(key[RIGHT])
        {
            camRot -= 5.0f;
        }
        
        // Set the orientation
        cam.setOrientation(camRot, 0.0f, 1.0f, 0.0f);
        
        // Calculate trigonometry for camera movement
        double rads = Math.toRadians(camRot);
        camSine = Math.sin(rads);
        camCosine = Math.cos(rads);
        
        if(key[UP])
        {
            // Move forward
            cam.translate(-2.0f * (float)camSine, 0.0f, -2.0f * (float)camCosine);
            
            // Bob head
            headDeg += 0.5f;
            
            // A simple way to "bob" the camera as the user moves
            cam.translate(0.0f, (float)Math.sin(headDeg) / 3.0f, 0.0f);
        }
        else if(key[DOWN])
        {
            // Move backward
            cam.translate(2.0f * (float)camSine, 0.0f, 2.0f * (float)camCosine);
            
            // Bob head
            headDeg -= 0.5f;
            
            // A simple way to "bob" the camera as the user moves
            cam.translate(0.0f, (float)Math.sin(headDeg) / 3.0f, 0.0f);
        }
        
        // If the user presses the FIRE key, let's quit
        if(key[FIRE])
            M3GMidlet.die();
    }

    /** Starts the canvas by firing up a thread
     */
    public void start() {
        Thread myThread = new Thread(this);
        
        // Make sure we know we are running
        running = true;
        done = false;
        
        // Start
        myThread.start();
    }
    
    /** Run, runs the whole thread. Also keeps track of FPS
     */
    public void run() {
        while(running) {
            try {                
                // Call the process method (computes keys)
                process();
                
                // Draw everything
                draw(getGraphics());
                flushGraphics();
                
                // Sleep to prevent starvation
                try{ Thread.sleep(30); } catch(Exception e) {}
            }
            catch(Exception e) {
                reportException(e);
            }
        }
        
        // Notify completion
        done = true;
    }
    
    /**
     * @param e
     */
    private void reportException(Exception e) {
        System.out.println(e.getMessage());
        System.out.println(e);
        e.printStackTrace();
    }

    /** Pauses the game
     */
    public void pause() {}
    
    /** Stops the game
     */
    public void stop() { running = false; }
    
    /** Processes keys
     */
    protected void process()
    {
        int keys = getKeyStates();
        
        if((keys & GameCanvas.FIRE_PRESSED) != 0)
            key[FIRE] = true;
        else
            key[FIRE] = false;
        
        if((keys & GameCanvas.UP_PRESSED) != 0)
            key[UP] = true;
        else
            key[UP] = false;
        
        if((keys & GameCanvas.DOWN_PRESSED) != 0)
            key[DOWN] = true;
        else
            key[DOWN] = false;
        
        if((keys & GameCanvas.LEFT_PRESSED) != 0)
            key[LEFT] = true;
        else
            key[LEFT] = false;
        
        if((keys & GameCanvas.RIGHT_PRESSED) != 0)
            key[RIGHT] = true;
        else
            key[RIGHT] = false;
    }
    
    /** Checks if thread is running
     */
    public boolean isRunning() { return running; }
    
    /** checks if thread has finished its execution completely
     */
    public boolean isDone() { return done; }
}