added sources for Slick

Former-commit-id: 1647fa32ef6894bd7db44f741f07c2f4dcdf9054
Former-commit-id: 0e5810dcfbe1fd59b13e7cabe9f1e93c5542da2d

lib/slick-source/org/newdawn/slick/geom/Circle.java

@@ -0,0 +1,234 @@
+package org.newdawn.slick.geom;
+
+/**
+ * A simple Circle geometry
+ * 
+ * @author Kevin Glass
+ */
+public strictfp class Circle extends Ellipse {
+	/** The radius of the circle */
+	public float radius;
+	
+	/**
+	 * Create a new circle based on its radius
+	 * 
+	 * @param centerPointX The x location of the center of the circle
+	 * @param centerPointY The y location of the center of the circle
+	 * @param radius The radius of the circle
+	 */
+	public Circle(float centerPointX, float centerPointY, float radius) {
+        this(centerPointX, centerPointY, radius, DEFAULT_SEGMENT_COUNT);
+	}
+
+	/**
+	 * Create a new circle based on its radius
+	 * 
+	 * @param centerPointX The x location of the center of the circle
+	 * @param centerPointY The y location of the center of the circle
+	 * @param radius The radius of the circle
+	 * @param segmentCount The number of segments to build the circle out of
+	 */
+	public Circle(float centerPointX, float centerPointY, float radius, int segmentCount) {
+        super(centerPointX, centerPointY, radius, radius, segmentCount);
+        this.x = centerPointX - radius;
+        this.y = centerPointY - radius;
+        this.radius = radius;
+        boundingCircleRadius = radius;
+	}
+	
+	/** 
+	 * Get the x coordinate of the centre of the circle
+	 * 
+	 * @return The x coordinate of the centre of the circle
+	 */
+	public float getCenterX() {
+		return getX() + radius;
+	}
+	
+	/** 
+	 * Get the y coordinate of the centre of the circle
+	 * 
+	 * @return The y coordinate of the centre of the circle
+	 */
+	public float getCenterY() {
+		return getY() + radius;
+	}
+
+	/** 
+	 * Get the coordinates of the center of the circle
+	 * 
+	 * @return 2-element array with the center of the circle.
+	 */
+	@Override
+	public float[] getCenter() {
+		return new float[] { getCenterX(), getCenterY() };
+	}
+	
+	/**
+	 * Set the radius of this circle
+	 * 
+	 * @param radius The radius of this circle
+	 */
+	public void setRadius(float radius) {
+		if (radius != this.radius) {
+	        pointsDirty = true;
+			this.radius = radius;
+	        setRadii(radius, radius);
+		}
+	}
+	
+	/**
+	 * Get the radius of the circle
+	 * 
+	 * @return The radius of the circle
+	 */
+	public float getRadius() {
+		return radius;
+	}
+	
+	/**
+	 * Check if this circle touches another
+	 * 
+	 * @param shape The other circle
+	 * @return True if they touch
+	 */
+	public boolean intersects(Shape shape) {
+        if(shape instanceof Circle) {
+            Circle other = (Circle)shape;
+    		float totalRad2 = getRadius() + other.getRadius();
+    		
+    		if (Math.abs(other.getCenterX() - getCenterX()) > totalRad2) {
+    			return false;
+    		}
+    		if (Math.abs(other.getCenterY() - getCenterY()) > totalRad2) {
+    			return false;
+    		}
+    		
+    		totalRad2 *= totalRad2;
+    		
+    		float dx = Math.abs(other.getCenterX() - getCenterX());
+    		float dy = Math.abs(other.getCenterY() - getCenterY());
+    		
+    		return totalRad2 >= ((dx*dx) + (dy*dy));
+        }
+        else if(shape instanceof Rectangle) {
+            return intersects((Rectangle)shape);
+        }
+        else {
+            return super.intersects(shape);
+        }
+	}
+	
+	/**
+	 * Check if a point is contained by this circle
+	 * 
+	 * @param x The x coordinate of the point to check
+	 * @param y The y coorindate of the point to check
+	 * @return True if the point is contained by this circle
+	 */
+    public boolean contains(float x, float y) 
+    { 
+        float xDelta = x - getCenterX(), yDelta = y - getCenterY();
+        return xDelta * xDelta + yDelta * yDelta < getRadius() * getRadius();
+    }
+    
+    /**
+     * Check if circle contains the line 
+     * @param line Line to check against 
+     * @return True if line inside circle 
+     */ 
+    private boolean contains(Line line) { 
+         return contains(line.getX1(), line.getY1()) && contains(line.getX2(), line.getY2()); 
+    }
+    
+	/**
+	 * @see org.newdawn.slick.geom.Ellipse#findCenter()
+	 */
+    protected void findCenter() {
+        center = new float[2];
+        center[0] = x + radius;
+        center[1] = y + radius;
+    }
+
+    /**
+     * @see org.newdawn.slick.geom.Ellipse#calculateRadius()
+     */
+    protected void calculateRadius() {
+        boundingCircleRadius = radius;
+    }
+
+    /**
+	 * Check if this circle touches a rectangle
+	 * 
+	 * @param other The rectangle to check against
+	 * @return True if they touch
+	 */
+	private boolean intersects(Rectangle other) {
+		Rectangle box = other;
+		Circle circle = this;
+		
+		if (box.contains(x+radius,y+radius)) {
+			return true;
+		}
+		
+		float x1 = box.getX();
+		float y1 = box.getY();
+		float x2 = box.getX() + box.getWidth();
+		float y2 = box.getY() + box.getHeight();
+		
+		Line[] lines = new Line[4];
+		lines[0] = new Line(x1,y1,x2,y1);
+		lines[1] = new Line(x2,y1,x2,y2);
+		lines[2] = new Line(x2,y2,x1,y2);
+		lines[3] = new Line(x1,y2,x1,y1);
+		
+		float r2 = circle.getRadius() * circle.getRadius();
+		
+		Vector2f pos = new Vector2f(circle.getCenterX(), circle.getCenterY());
+		
+		for (int i=0;i<4;i++) {
+			float dis = lines[i].distanceSquared(pos);
+			if (dis < r2) {
+				return true;
+			}
+		}
+		
+		return false;
+	}
+	
+	/** 
+     * Check if circle touches a line. 
+     * @param other The line to check against 
+     * @return True if they touch 
+     */ 
+    private boolean intersects(Line other) { 
+        // put it nicely into vectors 
+        Vector2f lineSegmentStart = new Vector2f(other.getX1(), other.getY1()); 
+        Vector2f lineSegmentEnd = new Vector2f(other.getX2(), other.getY2()); 
+        Vector2f circleCenter = new Vector2f(getCenterX(), getCenterY()); 
+
+        // calculate point on line closest to the circle center and then 
+        // compare radius to distance to the point for intersection result 
+        Vector2f closest; 
+        Vector2f segv = lineSegmentEnd.copy().sub(lineSegmentStart); 
+        Vector2f ptv = circleCenter.copy().sub(lineSegmentStart); 
+        float segvLength = segv.length(); 
+        float projvl = ptv.dot(segv) / segvLength; 
+        if (projvl < 0) 
+        { 
+            closest = lineSegmentStart; 
+        } 
+        else if (projvl > segvLength) 
+        { 
+            closest = lineSegmentEnd; 
+        } 
+        else 
+        { 
+            Vector2f projv = segv.copy().scale(projvl / segvLength); 
+            closest = lineSegmentStart.copy().add(projv); 
+        } 
+        boolean intersects = circleCenter.copy().sub(closest).lengthSquared() <= getRadius()*getRadius(); 
+        
+        return intersects; 
+    } 
+}