public static List <Point> ASSearch(IPathfinderContext context, Point start, Point end, bool *concreteMatrix)
{
int startX = start.X, startY = start.Y;
int endX = end.X, endY = end.Y;
int width = context.Width;
int height = context.Height;
//validate context
if (!(context is ASContext) || context == null)
{
throw new Exception("Invalid A* search context!");
}
ASContext ctx = context as ASContext;
//verify start/end is not collidable!
bool startCollide = *(concreteMatrix + (startY * width) + startX);
bool endCollide = *(concreteMatrix + (endY * width) + endX);
if (startCollide || endCollide)
{
bool resolved = false;
/*attempt to resolve the collision*/
if (startCollide)
{
resolved = ResolveCollision(ref start, end, width, height, concreteMatrix);
}
if (endCollide)
{
resolved = ResolveCollision(ref end, start, width, height, concreteMatrix);
}
//not resolved?
if (!resolved)
{
return(new List <Point>());
}
startX = start.X; startY = start.Y;
endX = end.X; endY = end.Y;
}
//already there?
if (startX == endX && startY == endY)
{
return(new List <Point>());
}
//reset the context
ASNode *nodeMatrix = ctx.reset(
concreteMatrix,
endX,
endY);
//get the node at the start and end
ASNode *startNode = nodeMatrix + (startY * width) + startX;
ASNode *endNode = nodeMatrix + (endY * width) + endX;
//search
bool found = ctx.search(startNode, endNode);
if (!found)
{
return(new List <Point>());
}
//cycle back from the end point all the way back to the start
//adding each node location on the way.
//note: since we have done this backwards, just reverse the list
ASNode * current = endNode;
List <Point> buffer = new List <Point>();
buffer.Add(end);
while (current != startNode)
{
//get the X/Y from the pointer.
short x = (short)((current - nodeMatrix) % width);
short y = (short)((current - nodeMatrix) / width);
buffer.Add(new Point(x, y));
//resolve the parent
ASNode *parent = nodeMatrix + ((*current).ParentY * width) + (*current).ParentX;
current = parent;
}
buffer.Add(start);
buffer.Reverse();
return(buffer);
}
