Quad Function

gistfile1.txt

	public double angleWith(Edge otherEdge) {
        double angle1 = Math.atan2(getPoint1().getY() - getPoint2().getY(),
                                   getPoint1().getX() - getPoint2().getX());
        
        double angle2 = Math.atan2(otherEdge.getPoint1().getY() - otherEdge.getPoint2().getY(),
        						   otherEdge.getPoint1().getX() - otherEdge.getPoint2().getX());
        
        double resultRadians = angle1 - angle2;
        double resultDegrees = resultRadians * (180 / Math.PI);
        
        if (resultDegrees < 0)
        	resultDegrees = 360 + resultDegrees;
        
        return resultDegrees;
    }


	public static boolean quadIsConvex(Triangle t1, Triangle t2, Edge sharedEdge) {
		
		if (t1 == t2)
			return false;
		
		Edge leftTopLine = t1.getEdge(2, sharedEdge);
		Edge leftBottomLine = t1.getEdge(3, sharedEdge);
	
		Edge rightTopLine = t2.getEdge(2, sharedEdge);
		Edge rightBottomLine = t2.getEdge(3, sharedEdge);
	
		double angle1 = leftTopLine.angleWith(leftBottomLine);
		if (angle1 < 180) return false;
		
		double angle = leftTopLine.angleWith(rightTopLine);
		if (angle < 180) return false;

		angle = rightTopLine.angleWith(rightBottomLine);
		if (angle < 180) return false;

		angle = rightBottomLine.angleWith(leftBottomLine);
		if (angle < 180) return false;
		
		return true;
	}