Android Open Source - BounceMe Sling

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Back to project page BounceMe.

License

The source code is released under:

MIT License

Java Source Code

package com.cse3345.f13.martin;
/*from ww  w .  j a v a2 s  . c o m*/
import java.util.Random;


import android.graphics.Canvas;
import android.graphics.Paint;
import android.util.Log;

public class Sling {
  public static int canvasWidth;
  private Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
  private int leftX, rightX, Y;
  private int midX, midY, midX2, midY2;
  private int x, y;
  private int startX;
  private boolean left = true;
  private int width;
  private double bounce = .0025;
  boolean above = true;
  boolean forced = false;
  private Type[] types = {new Type(canvasWidth/7, .006, 0xFF4989C8), 
              new Type(canvasWidth/4, .004, 0xFFF2642F), 
              new Type(canvasWidth/7, .006, 0xFF000000), 
              new Type(canvasWidth/9, .006, 0xFF000000)};
  private Type type;
  private int typeNum;
  private int speed;

  public Sling(int x, int y, int num) {
    typeNum = num;
    type = types[typeNum];
    width = type.width;
    bounce = type.bounce;
    mPaint.setColor(type.color);
    
    midX = midX2= this.x = startX = x;
    Y = midY = midY2 = this.y  =  y;
    leftX = midX - width / 2;
    rightX = midX + width / 2;
    
      Random randomGenerator = new Random();
      speed = randomGenerator.nextInt(5) + 1;
      
    mPaint.setStrokeWidth(canvasWidth/200);
  }

  public void draw(Canvas can) {
    //Log.d("OUTPUT", "left:(" + midX + "," + midY + ")");
    //Log.d("OUTPUT", "right:(" + midX2 + "," + midY2 + ")");
    can.drawLine(leftX, Y, midX, midY, mPaint);
    can.drawLine(midX2, midY2, rightX, Y, mPaint);
    //can.drawCircle(leftX, Y, 10, mPaint);
    //can.drawCircle(rightX, Y, 10, mPaint);
  }

  public boolean update(Ball ball){
    if(typeNum == 2){
      if(x < startX - 100){
        left = false;
      }else if(x > startX + 100){
        left = true;
      }
      
      if(left){
        x -= 1;
        midX -= 1;
        midX2 -= 1;
        leftX -= 1;
        rightX -= 1;
      }else{
        x += 1;
        midX += 1;
        midX2 += 1;
        leftX += 1;
        rightX += 1;
      }
    }else if(typeNum == 3){
      if(rightX < 0){
          Random randomGenerator = new Random();
          int rand = randomGenerator.nextInt(100) + 100;
          y = randomGenerator.nextInt(400) + 200;
        rand = randomGenerator.nextInt(100) + 100;
        x = 1300 + rand;
        
        midX = midX2 = x;
        Y = midY = midY2 =  y;
        leftX = midX - width / 2;
        rightX = midX + width / 2;
        
        speed = randomGenerator.nextInt(2) + 2;
      }
      
      x -= speed;
      midX -= speed;
      midX2 -= speed;
      leftX -= speed;
      rightX -= speed;
    }
    
    int radius = ball.getRadius() - 2;
    int centerX = ball.getX();
    int centerY = ball.getY();
    double a1, a2, d1, d2;
    a1 =  a2 = d1 = d2 = 0;
    
    //detecting if the ball is above the sling
    if (centerY + radius < Y + 20){
      above = true;
    }else{
      above = false;
    }
    
    
    if(centerY + radius > Y){
      if((centerX > leftX && centerX < rightX) || forced){
        if(forced || above){
          forced = true;
          
          //Mathematical logic for physics on the sling can be found here - "http://www.emanueleferonato.com/2007/08/13/throw-a-ball-with-a-sling-physics-flash-tutorial/"
                  double x1 = centerX - leftX;
          double y1 = centerY - Y;
          double x2 = rightX - centerX;
          double y2 = Y - centerY;
          
          
          d1 = Math.sqrt(x1*x1 + y1*y1);
          d2 = Math.sqrt(x2*x2 + y2*y2);
          
          a1 = Math.atan2(y1, x1);
          a2 = Math.atan2(y2, x2);
          
          midX = (int) (centerX + Math.cos(a1 + Math.PI/2)*radius);
          midY = (int) (centerY + Math.sin(a1 + Math.PI/2)*radius);
          midX2 = (int) (centerX + Math.cos(a2 + Math.PI/2)*radius);
          midY2 = (int) (centerY + Math.sin(a2 + Math.PI/2)*radius);
          
          a1 += Math.sin(radius/d1);
          a2 += Math.sin(radius/d2)*-1.0;
        }
      }
    }else{
      forced = false;
      midX = midX2 = x;
      midY = midY2 = y;
    }
    
    double xacc = 0;
    double yacc = 0;
    
    if(forced){
      Log.d("OUPUT", "into acc change");
      xacc += d1*Math.sin(a2)*bounce;
          yacc -= d1*Math.cos(a1)*bounce;
          xacc += d2*Math.sin(a1)*bounce;
          yacc -= d2*Math.cos(a2)*bounce;
          
          Log.d("OUPUT", "(" + xacc + "," + yacc + ")");
          ball.setAcc(xacc, yacc);
    }
    
    return true;
  }
  
  public class Type{
    public int width;
    public double bounce;
    public int color;
    
    public Type(int w, double b, int green){
      width = w;
      bounce = b;
      color = green;
    }
  }
}

Java Source Code List

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