Android Game development Collision Detection (rectangular collision, circular collision, pixel collision) _android

Source: Internet
Author: User
Tags drawtext gety pow sleep

This article for everyone to share the Android game development Collision detection, for your reference, the specific content as follows

The principle of rectangular collision : Four kinds of two rectangular positions not in these four cases are collisions

Circular Collision principle: Using the distance between the two centers to determine. When the distance between two centers is less than the radius of the collision.

Pixel Collision principle: Not applicable traversal all pixel detection too much

Multi-Rectangular collision principle: To set up multiple rectangular collision detection areas to detect the position relationship between a collision rectangular array and another colliding rectangular array.

Rectangular Collision Code:

public class Mysurfaceview extends Surfaceview implements Callback, Runnable {private Surfaceholder sfh;
  Private Paint Paint;
  private Thread th;
  Private Boolean flag;
  Private Canvas Canvas;
  private int screenw, screenh;
  Defines a two-rectangle wide-high coordinate private int x1 = ten, y1 =, W1 =, H1 = 40;
  private int x2 = y2 =, W2 =, H2 = 40;

  Easy to see if there is a collision setting an identity bit private Boolean iscollsion;
    /** * Surfaceview initialization function/public Mysurfaceview {super (context);
    SFH = This.getholder ();
    Sfh.addcallback (this);
    Paint = new paint ();
    Paint.setcolor (Color.White);
    Paint.setantialias (TRUE);
  Setfocusable (TRUE); /** * Surfaceview View creation, response to this function/@Override public void surfacecreated (Surfaceholder holder) {screenw = t
    His.getwidth ();
    Screenh = This.getheight ();
    Flag = true;
    instance thread th = new thread (this);
  Start thread Th.start (); /** * Game drawing/public void Mydraw () {try {canvas = Sfh.lockcanvas ();
        if (canvas!= null) {Canvas.drawcolor (color.black);
          if (iscollsion) {paint.setcolor (color.red);
          Paint.settextsize (20); Canvas.drawtext ("collision!
        ", 0, paint);
        else {paint.setcolor (color.white);
        //Draw two rectangular canvas.drawrect (x1, y1, x1 + W1, y1 + h1, paint);
      Canvas.drawrect (x2, y2, x2 + w2, y2 + h2, paint); } catch (Exception e) {//Todo:handle Exception} finally {if (canvas!= null) sfh.unlock
    Canvasandpost (canvas); /** * Touchscreen Event Monitor/@Override public boolean ontouchevent (Motionevent event) {//Let rectangle 1 move with touchscreen position x1 =
    (int) Event.getx ()-w1/2;
    y1 = (int) event.gety ()-h1/2;
    if (Iscollsionwithrect (x1, y1, W1, H1, X2, y2, W2, H2)) {iscollsion = true;
    else {iscollsion = false;
  return true; /** * Button Event Monitor/@Override public boolean onKeyDown (int KeyCode, KeyEvent event) {return Super.onkeydown (KeyCode, event); /** * Game logic/private void logic () {} public boolean iscollsionwithrect (int x1, int y1, int w1, int H1
    , int x2, int y2, int w2, int h2) {if (x1 >= x2 && x1 >= x2 + W2) {return false;
    else if (x1 <= x2 && x1 + W1 <= x2) {return false;
    else if (y1 >= y2 && y1 >= y2 + H2) {return false;
    else if (y1 <= y2 && y1 + h1 <= y2) {return false;
  return true;
      @Override public void Run () {while (flag) {Long start = System.currenttimemillis ();
      Mydraw ();
      Logic ();
      Long end = System.currenttimemillis ();
        try {if (End-start <) {Thread.Sleep (End-start));
      } catch (Interruptedexception e) {e.printstacktrace (); /** * Surfaceview view state changed in response to this function/* @Override public voidSurfacechanged (surfaceholder holder, int format, int width, int height) {}/** * Surfaceview View dies, respond to this function * *
  Override public void surfacedestroyed (Surfaceholder holder) {flag = false;

 }
}

Round Collision Code:

public class Mysurfaceview extends Surfaceview implements Callback, Runnable {private Surfaceholder sfh;
  Private Paint Paint;
  private Thread th;
  Private Boolean flag;
  Private Canvas Canvas;
  private int screenw, screenh;
  Defines two rounded radii with coordinates private int r1 = r2 = 20;
  private int x1 = Y1 = +, x2 = $, y2 = 100;

  Defines a collision identifier bit private Boolean iscollision;
    /** * Surfaceview initialization function/public Mysurfaceview {super (context);
    SFH = This.getholder ();
    Sfh.addcallback (this);
    Paint = new paint ();
    Paint.setcolor (Color.White);
    Paint.setantialias (TRUE);
  Setfocusable (TRUE); /** * Surfaceview View creation, response to this function/@Override public void surfacecreated (Surfaceholder holder) {screenw = t
    His.getwidth ();
    Screenh = This.getheight ();
    Flag = true;
    instance thread th = new thread (this);
  Start thread Th.start ();
      /** * Game drawing/public void Mydraw () {try {canvas = Sfh.lockcanvas ();if (canvas!= null) {Canvas.drawcolor (color.black);
          if (iscollision) {paint.setcolor (color.red);
          Paint.settextsize (20);
        Canvas.drawtext ("collision!", 0, paint);
        else {paint.setcolor (color.white);
        } canvas.drawcircle (x1, y1, r1, paint);
      Canvas.drawcircle (x2, y2, r2, paint); } catch (Exception e) {//Todo:handle Exception} finally {if (canvas!= null) sfh.unlock
    Canvasandpost (canvas); 
    /** * Touchscreen Event Monitor/@Override public boolean ontouchevent (Motionevent event) {x1 = (int) event.getx ();
    y1 = (int) event.gety ();
    if (iscollisionwithcircle (x1, y1, x2, y2, R1, R2)) {iscollision = true;
    else {iscollision = false;
  return true;
   /** * Circular collision * @param X1 Circle 1 's Center x coordinate * @param y1 Circle 2 's Center x coordinate * @param x2 Circle 1 's Center y coordinate * @param y2 Circle 2 's Center y-coordinate * @param R1 Circle 1 radius * @param R2 Circle 2 radius *return */Private Boolean iscollisionwithcircle (int x1, int y1, int x2, int y2, int r1, int r2) {//math.sqrt: Open squared 
      Math.pow (double x, double y): X's Y-square if (Math.sqrt (Math.pow (X1-X2, 2) + Math.pow (Y1-y2, 2)) <= R1 + R2) {
    If the center distance of two circles is less than or equal to two circle radius, the collision return true is considered;
  return false; /** * Button Event Monitor/@Override public boolean onKeyDown (int keycode, keyevent event) {return Super.onkeydow
  N (keycode, event); /** * Game logic/private void logic () {} @Override public void Run () {while (flag) {Long STA
      RT = System.currenttimemillis ();
      Mydraw ();
      Logic ();
      Long end = System.currenttimemillis ();
        try {if (End-start <) {Thread.Sleep (End-start));
      } catch (Interruptedexception e) {e.printstacktrace ();  /** * Surfaceview view state changed in response to this function */@Override public void surfacechanged (surfaceholder holder, int ForMat, int width, int height) {}/** * Surfaceview View dies, respond to this function */@Override public void surfacedestroyed (Surf
  Aceholder holder) {flag = false;

 }
}

Multi-Rectangular collision code

public class Mysurfaceview extends Surfaceview implements Callback, Runnable {private Surfaceholder sfh;
  Private Paint Paint;
  private Thread th;
  Private Boolean flag;
  Private Canvas Canvas;
  private int screenw, screenh;
  Defines the wide-high coordinates of two rectangular graphics private int rectX1 = ten, rectY1 = ten, rectW1 =, rectH1 = 40;
  private int rectX2 = RectY2 =, rectW2 =, rectH2 = 40;
  Easy to see if there is a collision setting an identity bit private Boolean iscollsion;
  Defines the rectangular array of collisions for the first rectangle private Rect ClipRect1 = new Rect (0, 0, 15, 15);
  Private Rect ClipRect2 = new Rect (rectw1-15, recth1-15, rectW1, rectH1);
  Private rect[] ArrayRect1 = new rect[] {clipRect1, clipRect2};
  Defines a rectangular array of collisions for the second rectangle private Rect clipRect3 = new Rect (0, 0, 15, 15);
  Private Rect ClipRect4 = new Rect (rectw2-15, recth2-15, rectW2, rectH2);

  Private rect[] ArrayRect2 = new rect[] {clipRect3, clipRect4};
    /** * Surfaceview initialization function/public Mysurfaceview {super (context);
    SFH = This.getholder ();Sfh.addcallback (this);
    Paint = new paint ();
    Paint.setcolor (Color.White);
    Paint.setantialias (TRUE);
  Setfocusable (TRUE); /** * Surfaceview View creation, response to this function/@Override public void surfacecreated (Surfaceholder holder) {screenw = t
    His.getwidth ();
    Screenh = This.getheight ();
    Flag = true;
    instance thread th = new thread (this);
  Start thread Th.start ();
      /** * Game drawing/public void Mydraw () {try {canvas = Sfh.lockcanvas ();
        if (canvas!= null) {Canvas.drawcolor (color.black);
        Paint.setcolor (Color.White);
        Paint.setstyle (Style.fill);
          if (iscollsion) {paint.settextsize (20); Canvas.drawtext ("collision!
        ", 0, paint);
        //Draw two rectangular canvas.drawrect (rectX1, rectY1, rectX1 + rectW1, rectY1 + rectH1, paint);
        Canvas.drawrect (rectX2, rectY2, rectX2 + rectW2, rectY2 + rectH2, paint); ---Draw the collision area using a paint.setstyle and set the brush color white (style.stroke);
        Paint.setcolor (color.red);  Draws all rectangular collision areas for the first rectangle for (int i = 0; i < arrayrect1.length i++) {canvas.drawrect (Arrayrect1[i].left + THIS.RECTX1, Arrayrect1[i].top + this.recty1, Arrayrect1[i].right + this.rectx1, Arrayrect1[i].bottom + thi
        S.recty1, paint); ///Draw all rectangular collision areas for the second rectangle for (int i = 0; i < arrayrect2.length i++) {canvas.drawrect (arrayRect2
              [I].left + this.rectx2, Arrayrect2[i].top + this.recty2, Arrayrect2[i].right + this.rectx2, ArrayRect2[i].bottom
        + rectY2, paint); (Exception e) {//Todo:handle Exception} finally {if (Canvas!= null) SF
    H.unlockcanvasandpost (canvas); /** * Touchscreen Event Monitor/@Override public boolean ontouchevent (Motionevent event) {//Let rectangle 1 move with touchscreen position Rectx
    1 = (int) event.getx ()-rectw1/2;
    rectY1 = (int) event.gety ()-recth1/2; if (Iscollsionwithrect (ArrayRect1, Arrayrect2)) {iscollsion = true;
    else {iscollsion = false;
  return true; /** * Button Event Monitor/@Override public boolean onKeyDown (int keycode, keyevent event) {return Super.onkeydow
  N (keycode, event);      }/** * Game logic/private void logic () {}//rect class four properties top bottom left right//respectively indicates the top and bottom of this rectangle
    Left and right public boolean iscollsionwithrect (rect[] Rectarray, rect[] rect2array) {Rect Rect = null;
    Rect rect2 = null;
      for (int i = 0; i < rectarray.length; i++) {//to sequentially remove each rectangular instance of the first rectangular array rect = rectarray[i];
      Gets the property value int x1 = rect.left + this.rectx1 for each rectangle element in the first rectangular array;
      int y1 = rect.top + this.recty1;
      int w1 = Rect.right-rect.left;
      int h1 = Rect.bottom-rect.top;
        for (int j = 0; J < Rect2array.length; J +) {//to sequentially remove each rectangular instance of the second rectangular array rect2 = rect2array[j];
        Gets the property value int x2 = rect2.left + this.rectx2 for each rectangle element in the second rectangular array; int y2 = Rect2.top + This.recty2;
        int w2 = Rect2.right-rect2.left;
        int h2 = Rect2.bottom-rect2.top; Loop through two rectangular collisions. The position relationship between all elements of an array if (x1 >= x2 && x1 >= x2 + w2) {} else if (x1 <= x2 &&am P x1 + W1 <= x2) {} else if (y1 >= y2 && y1 >= y2 + h2) {} else if (y1 <= y2 &&amp ;
        Y1 + h1 <= y2) {} else {//As long as there is a collision between a colliding rectangular array and another colliding rectangular array, the collision is considered to be true;
  }} return false;
      @Override public void Run () {while (flag) {Long start = System.currenttimemillis ();
      Mydraw ();
      Logic ();
      Long end = System.currenttimemillis ();
        try {if (End-start <) {Thread.Sleep (End-start));
      } catch (Interruptedexception e) {e.printstacktrace ();  /** * Surfaceview view state changed in response to this function */@Override public void surfacechanged (surfaceholder holder, int format, int Width, int height) {}/** * Surfaceview View dies, respond to this function */@Override public void surfacedestroyed (Surfaceholder hol
  Der) {flag = false;

 }
}

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