Android Open Source - BulletsForever Draw Object

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Back to project page BulletsForever.
License

The source code is released under:
GNU General Public License
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Java Source Code

package com.bulletsforever.bullets;
// w w  w .  j  a va  2 s.c o  m
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;

/**
 * This is DrawWorld's drawable objects
 * This should be created throughout a GameMain session
 * Multiple instances should be added and removed from DrawWorld
 * Don't forget to call super.nextFrame() if the object has motion
 */
public abstract class DrawObject {

  // For debugging
  protected static Paint debugCirclePaint;
  protected static Paint debugRectPaint;
  
  // For info and details
  public DrawWorld dw;
  public Bitmap bitmap;
  
  // Tracking progress
  public int frame;
  
  // Public accessible path info
  public float x, y; // Its faster for direct access than using unnecessary get/set methods
  public float v, a; // absolute velocity and acceleration per frame
  public float gx, gy; // absolute gravity per frame
  public float angle; // out of 360* for easy understanding
  public float angle_v; // angular velocity per frame
  public float dx, dy; // change in x and y per frame, calculated based on velocity and angle
  
  // Private calculated path info
  private float dgx, dgy;
  private float rad; // angle * pi / 180 - for internal calculations
  
  // Hitbox
  public float hitboxHalfWidth, hitboxHalfHeight;
  public float drawOffsetX, drawOffsetY;
  
  // Initializer
  public DrawObject(
    DrawWorld dw,
    float x, float y, float v, float a, float gx, float gy, float angle, float angle_v,
    float hitboxHalfWidth, float hitboxHalfHeight
    ) {
    // For access
    this.dw = dw;
    
    // Start object's individual frame counter at 0
    this.frame = 0;
    
    // Setup public info
    this.x = x;
    this.y = y;
    this.v = v;
    this.a = a;
    this.gx = gx;
    this.gy = gy;
    this.angle = angle;
    this.angle_v = angle_v;
    this.hitboxHalfWidth = hitboxHalfWidth;
    this.hitboxHalfHeight = hitboxHalfHeight;
    this.drawOffsetX = hitboxHalfWidth;
    this.drawOffsetY = hitboxHalfHeight;
    
    calcAngle();
  }// GOOD THINKING PHIL.
  
  // Canvas-specific drawing
  public abstract void draw(Canvas canvas);
  
  // Call this to draw a small circle at the centre and box indicating hitbox
  public void drawDebug(Canvas canvas) {
    if (debugCirclePaint == null) {
      debugCirclePaint = new Paint();
      debugCirclePaint.setColor(Color.RED);
      debugCirclePaint.setAlpha(128);
    }
    if (debugRectPaint == null) {
      debugRectPaint = new Paint();
      debugRectPaint.setColor(Color.BLUE);
      debugRectPaint.setAlpha(128);
    }
    canvas.drawRect(
        x - hitboxHalfWidth, y - hitboxHalfHeight, x + hitboxHalfWidth, y + hitboxHalfHeight,
        debugRectPaint
        );
    canvas.drawCircle(x, y, 5f, debugCirclePaint);
  }
  
  public void calcAngle() {
    // Calculate initial velocity
    rad = angle * (float)Math.PI / 180f;
    dx = (float)(v * Math.sin(rad));
    dy = (float)(v * Math.cos(rad));
  }
  
  // Update coords, etc.
  // Synchronous frame by frame - no skipping!
  public void nextFrame() {
    // Next frame
    frame++;

    // Apply acceleration
    if (a != 0f) {
      v += a;
    }
    
    // Apply angular velocity
    if (angle_v != 0f) {
      // Recalculate angles
      angle_v *= 0.95f; // decay to allow for spiraling
      angle += angle_v;
      calcAngle();
    }
    
    // Apply gravity
    if (gx != 0f || gy != 0f) {
      if (angle_v != 0f) { // If dx/dy was recalculated
        dgx += gx;
        dgy += gy;
        dx += dgx;
        dy += dgy;
      } else { // If no angular velocity
        dx += gx;
        dy += gy;
      }
    }
    
    // Update x/y coords
    x += dx;
    y += dy;
    
  }
  
  // Collision check
  /*
  public boolean hasCollided(DrawObject object) {
    return (object.x > x - hitboxHalfWidth &&
        object.x < x + hitboxHalfWidth &&
        object.y > y - hitboxHalfHeight &&
        object.y < y + hitboxHalfHeight);
  }
  */
  
  // Call on collisions
  public abstract void onCollision(DrawObject object);
  
}
Java Source Code List
