heron-language - Google Code

Source Path: svn/ trunk/ input/ balls.hrn

‹ r31 r47

/*
	TODO: 
	- seperate this into multiple domains
	- add interfaces
	- add support for tags
	- add some basic type-inference
	- increase usage of immutability 
		- mutable or immutable tags?
	- add verification phase
	- add bridge operations and domains
	- support "auto" transitions	
	- provide built-in support for "KeyEvents"
*/


domain Demo {

  imports {
    Math;
    Drawing2D;
    Keyboard;
  }

  attributes {
    painter : Painter;
    shooter : Shooter;
    walls : Collection<Wall>;
    balls : Collection<Ball>;
  }

  operations {
    initialize() {
      var x0 : int = 100;
      var y0 : int = 100;
      var x1 : int = 300;
      var y1 : int = 300;
      walls = new Collection<Wall>();
      balls = new Collection<Ball>();
      shooter = new Shooter(0, 10, 10);
      walls.add(new Wall(x0,y0,x1,y0));
      walls.add(new Wall(x1,y0,x1,y1));
      walls.add(new Wall(x1,y1,x0,y1));
      walls.add(new Wall(x0,y1,x0,y0));
      balls.add(new Ball(new Point(200,200), new Vector(200,120), 10));
      balls.add(new Ball(new Point(150,150), new Vector(100,60), 15));
      balls.add(new Ball(new Point(250,150), new Vector(-50,-5), 20));
      balls.add(new Ball(new Point(250,250), new Vector(-100,0), 25));
      balls.add(new Ball(new Point(150,250), new Vector(0,100), 30));
      painter = new Painter();
      painter.generateNextEvent();
    }

    distance(first : Point, second : Point) : Real {
      return sqrt(sqr(first.x - second.x) + sqr(first.y - second.y));
    }
    sqrt(x : Real) : Real {
      return Math.sqrt(x);
    }
    sqr(x : Real) : Real {
      return x * x;
    }
    acos(x : Real) : Real {
      return Math.acos(x);
    }
    min(x : Real, y : Real) : Real {
      return Math.min(x, y);
    }
    floor(x : Real) : int {
      return (int)Math.floor(x);
    }
    updateBallPositions(elapsedMSec : Real) {
      foreach (ball : Ball in Demo.balls) {
        ball.updatePosition(elapsedMSec);
      }
    }
  }

  classes {
    class Wall {
      attributes {
        line : Line;
      }
      operations {
        constructor(x0 : Real, y0 : Real, x1 : Real, y1 : Real) {
          line = new Line(x0, y0, x1, y1);
        }
      }
    }
    
    class Shooter {
	  attributes {
	    angle : Real; 
	    length : Real;
	    width : Real;
	  }	  	  
	  operations {
	    construct(angle : Real, length : Real, width : Real) {
	      this.angle = angle;
	      this.length = length;
	      this.width = width;
	    }	    
	    getPoints() : Collection<Point> {
		  var result = new Collection<Point>();
		  var pt1 : Point = new Point(-(width / 2), length / 2));
		  var pt2 : Point = new Point(width / 2, length / 2);
		  var pt3 : Point = new Point(0, -(length / 2));		  
		  result.Add(pt1);
		  result.Add(pt2);
		  result.Add(pt3);
		  return result;
	    }
    }
    
    class Ball {
      attributes {
        pos : Point;
        vec : Vector;
        radius : Real;
      }
      operations {
        constructor(pos : Point, vec : Vector, radius : Real) {
          this.pos = pos;
          this.vec = vec;
          this.radius = radius;
        }
        computeWallCollisionEvent(wall : Wall) : BallWallCollisionEvent {
          var x0 : Real = pos.x;
          var y0 : Real = pos.y;
          var xt : Real = vec.x;
          var yt : Real = vec.y;
          var x1 : Real = wall.line.begin.x;
          var y1 : Real = wall.line.begin.y;
          var x2 : Real = wall.line.end.x;
          var y2 : Real = wall.line.end.y;
          var den : Real = Demo.sqrt(Demo.sqr(x2 - x1) + Demo.sqr(y2 - y1));
          var dx : Real = x2 - x1;
          var dy : Real = y2 - y1;

          var t1 : Real = ((radius * den) - (dx * y1) + (dx * y0) + (dy * x1) - (dy * x0)) / (-dx * yt + dy * xt);
          var t2 : Real = (-(radius * den) - (dx * y1) + (dx * y0) + (dy * x1) - (dy * x0)) / (-dx * yt + dy * xt);
          var t : Real = Demo.min(t1, t2);
          if (t1 <= 0.0) {
            if (t2 <= 0.0) {
              return null;
            }
            else {
              t = t2;
            }
          }
          else {
            if (t2 < 0) {
              t = t1;
            }
            else {
              t = Demo .min (t1 , t2 ) ;
            }
          }
          return new CollisionEvent(Demo.floor(t * 1000), this, wall);
        }
        computeCollisionEvents() : Collection<CollisionEvent> {
          var result : Collection<CollisionEvent> = new Collection<CollisionEvent>();
          foreach (wall : Wall in Demo.walls) {
            CollisionEvent collision = computeCollisionEvent(wall);
            if (collision != null) {
              result.add(collision);
            }
          }
          return result;
        }
        bounceOffWall(wall : Wall) {
            var w : Vector = new Vector(wall.line);
            var n : Vector = w.normal();
            var pn : Vector = vec.proj(n);
            var pw : Vector = vec.proj(w);
            var r : Vector = pn.scale(-1.0).add(pw);
            vec.x = r.x;
            vec.y = r.y;
        }
        // Alternatively, this could be implemented as a state.         
        updatePosition(elapsedMSec : Real) {
          pos = pos.translate(vec.scale(elapsedMSec / 1000.0));
        }
      }
    }
    
    class BallBallCollisionEvent {
      attributes {
        timeElapsed : Real;
        ball1 : Ball;
        ball2 : Ball;
      }
      operations {
        constructor(timeElapsed : Real, ball1 : Ball, ball2 : Ball) {
          this.timeElapsed = timeElapsed;
          this.ball1 = ball1;
          this.ball2 = ball2;
        }
      }
    }
    
    class BallWallCollisionEvent {
      attributes {
        timeElapsed : Real;
        ball : Ball;
        wall : Wall;
      }
      operations {
        constructor(timeElapsed : Real, ball : Ball, wall : Wall) {
          this.timeElapsed = timeElapsed;
          this.ball = ball;
          this.wall = wall;
        }
      }
    }


    class PaintEvent {
      attributes {
        timeElapsed : Real;
      }
      operations {
        constructor(timeElapsed : Real) {
          this.timeElapsed = timeElapsed;
        }
      }
    }
    
    class EventGenerator {
    }

    class Painter {
      attributes {
        paintFrequency : Real;
        timeToNextPaint : Real;
      }
      operations {
        constructor() {
          paintFrequency = 50.0;
          timeToNextPaint = paintFrequency;
        }
        generateNextEvent()  {
          generateNextEvent(null, null);
        }
        generateNextEvent(lastBall : Ball, lastWall : Wall)  {
          var next : CollisionEvent;
          var q : Collection<CollisionEvent> = new Collection<CollisionEvent>();

          // Compute all possible CollisionEvents
          q.clear();
          foreach (ball : Ball in Demo.balls) {
            q.concat(ball.computeCollisionEvents());
          }

          // Exclude last ball/wall CollisionEvent
          q.filter((x : CollisionEvent)
            => { return (x.ball != lastBall) || (x.wall != lastWall); });

          // Get the next earliest CollisionEvent
          next = q.min((x : CollisionEvent) => { return x.timeElapsed; });

          if (next != null) {
            if (next.timeElapsed < timeToNextPaint) {
              timeToNextPaint = timeToNextPaint - next.timeElapsed;
              this.sendIn(next, (int)next.timeElapsed);
            }
            else {
              this.sendIn(new PaintEvent(timeToNextPaint), (int)timeToNextPaint);
            }
          }
          else {
            Demo.error("could not compute next collision");
          }
        }
        drawShooter() {
          // Note: a "fold" function would be more elegant
          var pts : Collection<Point> = Demo.shooter.getPoints();
          var i : int = 1;
          while (i < pts.Count) {
            var pt1 : Point = pts.getAt(i - 1);
            var pt2 : Point = pts.getAt(i);              
            Demo.drawLine(pt1.x, pt1.y, pt2.x, pt2.y);
            ++i;
          }
          if (pts.Count > 0) {
            var pt1 : Point = pts.getAt(0);
            Demo.drawLine(
          }
        }
      }
      states {
        initial() {
          transitions {
            BallWallCollisionEvent -> onBallWallCollision;
            BallBallCollisionEvent -> onBallBallCollsion;
            PaintEvent -> onPaint;
            KeyboardEvent -> onKeyboard;
          }
        }
        onCollision(col : CollisionEvent) {
          entry {
            Demo.updateBallPositions(col.timeElapsed);
            col.ball.bounceOffWall(col.wall);
            generateNextEvent(col.ball, col.wall);
          }
          transitions {
			auto -> initial;
          }
        }
        onPaint(evt : PaintEvent)  {
          entry {
            timeToNextPaint = paintFrequency;
            Demo.clear();
            Demo.updateBallPositions(evt.timeElapsed);

            foreach (wall : Wall in Demo.walls) {
              Demo.drawLine(wall.line.begin.x, wall.line.begin.y, wall.line.end.x, wall.line.end.y);
            }

            foreach (ball : Ball in Demo.balls) {
              Demo.drawCircle(ball.pos.x, ball.pos.y, ball.radius);
            }
            
			drawShooter();            
            Demo.render();
            generateNextEvent();
          }
          transitions {
            auto -> initial;
          }
        }
        onKey(evt : KeyEvent) {
          entry {
            if (evt.Key == Keys.LeftArrow) {
              Demo.shooter.TurnLeft();
            }
            else if (evt.Key == Keys.RightArrow) {
              Demo.shooter.TurnRight();
            }
            else if (evt.Key == Keys.Space) {
              Demo.shooter.Shoot();
            }            
          }
          transitions {
		    auto -> initial;
          }
        }
      }
    }
  }
}

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Change log

r43 by cdiggins on Mar 25, 2008 Diff

Improved C++ compliance of YARD library.
Started using unit tests again. Made a
bunch of improvements.

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Older revisions

r31 by cdiggins on Feb 19, 2008 Diff

Now works as an applet.

r29 by cdiggins on Feb 19, 2008 Diff

OMG it works!!

r28 by cdiggins on Feb 18, 2008 Diff

Drawing and movement but no collision
yet. Still working on that.

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