Exemple #1
0
        /// <summary>
        /// Check to see if two Rotated Rectangls have collided
        /// </summary>
        /// <param name="theRectangle"></param>
        /// <returns></returns>
        public bool Intersects(RotatedRectangle theRectangle)
        {
            //Calculate the Axis we will use to determine if a collision has occurred
            //Since the objects are rectangles, we only have to generate 4 Axis (2 for
            //each rectangle) since we know the other 2 on a rectangle are parallel.
            List<Vector2> aRectangleAxis = new List<Vector2>();
            aRectangleAxis.Add(UpperRightCorner() - UpperLeftCorner());
            aRectangleAxis.Add(UpperRightCorner() - LowerRightCorner());
            aRectangleAxis.Add(theRectangle.UpperLeftCorner() - theRectangle.LowerLeftCorner());
            aRectangleAxis.Add(theRectangle.UpperLeftCorner() - theRectangle.UpperRightCorner());

            //Cycle through all of the Axis we need to check. If a collision does not occur
            //on ALL of the Axis, then a collision is NOT occurring. We can then exit out
            //immediately and notify the calling function that no collision was detected. If
            //a collision DOES occur on ALL of the Axis, then there is a collision occurring
            //between the rotated rectangles. We know this to be true by the Seperating Axis Theorem
            foreach (Vector2 aAxis in aRectangleAxis)
            {
                if (!IsAxisCollision(theRectangle, aAxis))
                {
                    return false;
                }
            }

            return true;
        }
Exemple #2
0
        /// <summary>
        /// Determines if a collision has occurred on an Axis of one of the
        /// planes parallel to the Rectangle
        /// </summary>
        /// <param name="theRectangle"></param>
        /// <param name="aAxis"></param>
        /// <returns></returns>
        private bool IsAxisCollision(RotatedRectangle theRectangle, Vector2 aAxis)
        {
            //Project the corners of the Rectangle we are checking on to the Axis and
            //get a scalar value of that project we can then use for comparison
            List<int> aRectangleAScalars = new List<int>();
            aRectangleAScalars.Add(GenerateScalar(theRectangle.UpperLeftCorner(), aAxis));
            aRectangleAScalars.Add(GenerateScalar(theRectangle.UpperRightCorner(), aAxis));
            aRectangleAScalars.Add(GenerateScalar(theRectangle.LowerLeftCorner(), aAxis));
            aRectangleAScalars.Add(GenerateScalar(theRectangle.LowerRightCorner(), aAxis));

            //Project the corners of the current Rectangle on to the Axis and
            //get a scalar value of that project we can then use for comparison
            List<int> aRectangleBScalars = new List<int>();
            aRectangleBScalars.Add(GenerateScalar(UpperLeftCorner(), aAxis));
            aRectangleBScalars.Add(GenerateScalar(UpperRightCorner(), aAxis));
            aRectangleBScalars.Add(GenerateScalar(LowerLeftCorner(), aAxis));
            aRectangleBScalars.Add(GenerateScalar(LowerRightCorner(), aAxis));

            //Get the Maximum and Minium Scalar values for each of the Rectangles
            int aRectangleAMinimum = aRectangleAScalars.Min();
            int aRectangleAMaximum = aRectangleAScalars.Max();
            int aRectangleBMinimum = aRectangleBScalars.Min();
            int aRectangleBMaximum = aRectangleBScalars.Max();

            //If we have overlaps between the Rectangles (i.e. Min of B is less than Max of A)
            //then we are detecting a collision between the rectangles on this Axis
            if (aRectangleBMinimum <= aRectangleAMaximum && aRectangleBMaximum >= aRectangleAMaximum)
            {
                return true;
            }
            else if (aRectangleAMinimum <= aRectangleBMaximum && aRectangleAMaximum >= aRectangleBMaximum)
            {
                return true;
            }

            return false;
        }