NScumm.Scumm.ScummEngine.CheckXYInBoxBounds C# (CSharp) Метод

        internal bool CheckXYInBoxBounds(int boxnum, Point p)
        {
            // Since this method is called by many other methods that take params
            // from e.g. script opcodes, but do not validate the boxnum, we
            // make a check here to filter out invalid boxes.
            // See also bug #1599113.
            if (boxnum < 0 || boxnum == InvalidBox)
                return false;

            var box = GetBoxCoordinates(boxnum);

            // Quick check: If the x (resp. y) coordinate of the point is
            // strictly smaller (bigger) than the x (y) coordinates of all
            // corners of the quadrangle, then it certainly is *not* contained
            // inside the quadrangle.
            if (p.X < box.UpperLeft.X && p.X < box.UpperRight.X && p.X < box.LowerRight.X && p.X < box.LowerLeft.X)
                return false;

            if (p.X > box.UpperLeft.X && p.X > box.UpperRight.X && p.X > box.LowerRight.X && p.X > box.LowerLeft.X)
                return false;

            if (p.Y < box.UpperLeft.Y && p.Y < box.UpperRight.Y && p.Y < box.LowerRight.Y && p.Y < box.LowerLeft.Y)
                return false;

            if (p.Y > box.UpperLeft.Y && p.Y > box.UpperRight.Y && p.Y > box.LowerRight.Y && p.Y > box.LowerLeft.Y)
                return false;

            // Corner case: If the box is a simple line segment, we consider the
            // point to be contained "in" (or rather, lying on) the line if it
            // is very close to its projection to the line segment.
            if ((box.UpperLeft == box.UpperRight && box.LowerRight == box.LowerLeft) ||
                (box.UpperLeft == box.LowerLeft && box.UpperRight == box.LowerRight))
            {
                Point tmp;
                tmp = ScummMath.ClosestPtOnLine(box.UpperLeft, box.LowerRight, p);
                if (p.SquareDistance(tmp) <= 4)
                    return true;
            }

            // Finally, fall back to the classic algorithm to compute containment
            // in a convex polygon: For each (oriented) side of the polygon
            // (quadrangle in this case), compute whether p is "left" or "right"
            // from it.

            if (!ScummMath.CompareSlope(box.UpperLeft, box.UpperRight, p))
                return false;

            if (!ScummMath.CompareSlope(box.UpperRight, box.LowerRight, p))
                return false;

            if (!ScummMath.CompareSlope(box.LowerRight, box.LowerLeft, p))
                return false;

            if (!ScummMath.CompareSlope(box.LowerLeft, box.UpperLeft, p))
                return false;

            return true;
        }