effectimage.java

本代码为java编写的泡泡龙游戏

import java.awt.*;
import java.awt.image.*;

//采用像素的方式，提高图像的处理速度
public class EffectImage {

    public final static int RENDERING_FAST = 0;
    public final static int RENDERING_SMOOTH = 1;
        
    GameApplet applet;

    int[] imageData;
    int imgWidth, imgHeight;
    
    private EffectImage() {}
    
    public EffectImage(GameApplet applet, String sourceImage) {
        this(applet, sourceImage, null);
    }

    
    public EffectImage(GameApplet applet, String sourceImage, String alphaImage) {

        this.applet = applet;
        
        Image img = applet.getGameMedia().loadImage(sourceImage);
        
        imgWidth = img.getWidth(applet);
        imgHeight = img.getHeight(applet);
        
        imageData = new int[imgWidth * imgHeight];
        
        //从指定的范围之中得到相应的像素数据，并保存到一个数组之中
        PixelGrabber pg = new PixelGrabber(img, 0, 0, imgWidth, imgHeight, imageData, 0, imgWidth);
        try {
            pg.grabPixels();
        }
        catch(Exception e) {
            e.printStackTrace();
        }
        
        if (alphaImage != null) {
        
            Image alpha = applet.getGameMedia().loadImage(alphaImage);
            int[] alphaData = new int[imgWidth * imgHeight];
            
            // Alpha is supposed to have same width & height        
            pg = new PixelGrabber(alpha, 0, 0, imgWidth, imgHeight, alphaData, 0, imgWidth);
            try {
                pg.grabPixels();
            }
            catch(Exception e) {
                e.printStackTrace();
            }
            
            //一个像素由32位来表示，24-32表示透明度，16-234表示红色，8-15表示绿色，0-7表示蓝色
            for (int i=0 ; i<imageData.length ; i++) {
                imageData[i] = (imageData[i] & 0xFFFFFF) | ((alphaData[i] & 0xFF0000) << 8);
            }
        }
    }
    
    public Image getRotate(double theta, double x, double y) {
        return getFastRotate(theta, x, y);
    }
    
    public Image getRotate(double theta, double x, double y, int rendering) {
        if (rendering == EffectImage.RENDERING_SMOOTH) {
            //return 
        }
        
        return getFastRotate(theta, x, y);
    }
    
    
    private Image getFastRotate(double theta, double x, double y) {

        int[] output = new int[imageData.length];
                
        // Reusable values
        double cosTheta = Math.cos(-theta);
        double sinTheta = Math.sin(-theta);
        
        double deltaX = x * (1. - cosTheta) + y * sinTheta;
        double deltaY = y * (1. - sinTheta) - y * cosTheta;
        
        // Calculate
        for (int j=0 ; j<imgHeight ; j++) {
            for (int i=0 ; i<imgWidth ; i++) {
                // For each output point
                // Find its origin
                int orX = (int)Math.round(i * cosTheta - j * sinTheta + deltaX);
                int orY = (int)Math.round(i * sinTheta + j * cosTheta + deltaY);
                                
                if (orX < 0 || orX >= imgWidth || orY < 0 || orY >= imgHeight) {
                    // out of scope
                    output[i + j * imgWidth] = 0;
                }
                else {
                    // Compute value
                    output[i + j * imgWidth] = imageData[orX + orY * imgWidth];
                }
            }
        }
        
        return applet.createImage(new MemoryImageSource(imgWidth, imgHeight, output, 0, imgWidth));
    }
}