private bool IsIntersection(int i, int j, ref byte[] rgbValues, PixelFormat imgPixelFormat, int bmpDataStride, int width, int height)
{
var hasUp = false;
var hasRight = false;
var hasDown = false;
var hasLeft = false;
if (j - 1 >= 0)
{
if (BitmapReader.IsPixel(i, j - 1, ref rgbValues, imgPixelFormat, bmpDataStride))
{
hasUp = true;
}
}
if (i + 1 < width)
{
if (BitmapReader.IsPixel(i + 1, j, ref rgbValues, imgPixelFormat, bmpDataStride))
{
hasRight = true;
}
}
if (j + 1 < height)
{
if (BitmapReader.IsPixel(i, j + 1, ref rgbValues, imgPixelFormat, bmpDataStride))
{
hasDown = true;
}
}
if (i - 1 >= 0)
{
if (BitmapReader.IsPixel(i - 1, j, ref rgbValues, imgPixelFormat, bmpDataStride))
{
hasLeft = true;
}
}
return(AtLeastThree(hasUp, hasRight, hasDown, hasLeft) || ChangeInDirection(hasUp, hasRight, hasDown, hasLeft));
}
public IntersectionMazeImage CreateIntersectionMaze(string filePath)
{
var img = new Bitmap(filePath);
PixelFormat pixelFormat = img.PixelFormat;
// Lock the bitmap's bits.
var rect = new Rectangle(0, 0, img.Width, img.Height);
BitmapData bmpData = img.LockBits(rect, ImageLockMode.ReadWrite, pixelFormat);
var newMaze = new IntersectionMazeImage();
var hasSeenWallInJ = false;
var hasSeenWallInI = new bool[img.Width];
var previousIIntersection = new IntersectionPoint[img.Width];
var previousJIntersection = new IntersectionPoint();
var newMazePoints = new List <IntersectionPoint>();
var hasSetStartConnector = false;
var lastSeenEndConnector = new IntersectionPoint();
IntersectionPoint currentPoint;
// Get the address of the first line.
IntPtr ptr = bmpData.Scan0;
// Declare an array to hold the bytes of the bitmap.
int bytes = Math.Abs(bmpData.Stride) * img.Height;
var rgbValues = new byte[bytes];
// Copy the RGB values into the array.
System.Runtime.InteropServices.Marshal.Copy(ptr, rgbValues, 0, bytes);
for (var index = 0; index < img.Width; index++)
{
if (BitmapReader.IsPixel(index, 0, ref rgbValues, pixelFormat, bmpData.Stride))
{
newMaze.StartPoint = new IntersectionPoint()
{
ICoord = index,
JCoord = 0
};
}
if (BitmapReader.IsPixel(index, img.Height - 1, ref rgbValues, pixelFormat, bmpData.Stride))
{
newMaze.EndPoint = new IntersectionPoint()
{
ICoord = index,
JCoord = img.Height - 1
};
}
if (newMaze.StartPoint != null && newMaze.EndPoint != null)
{
break;
}
}
if (newMaze.StartPoint == null || newMaze.EndPoint == null)
{
throw new Exception("Could not find start and endpoint");
}
var i = 1;
var j = 0;
var height = img.Height;
var width = img.Width - 1;
var hasSquares = true;
while (hasSquares)
{
if (BitmapReader.IsPixel(i, j, ref rgbValues, pixelFormat, bmpData.Stride))
{
if (IsIntersection(i, j, ref rgbValues, pixelFormat, bmpData.Stride, img.Width, img.Height))
{
currentPoint = new IntersectionPoint()
{
HasVisited = false,
ICoord = i,
JCoord = j
};
if (!hasSetStartConnector && i == newMaze.StartPoint.ICoord)
{
hasSetStartConnector = true;
newMaze.StartPoint.ConnectedIntersections.Add(currentPoint);
currentPoint.ConnectedIntersections.Add(newMaze.StartPoint);
}
if (i == newMaze.EndPoint.ICoord)
{
lastSeenEndConnector = currentPoint;
}
if (!hasSeenWallInJ)
{
currentPoint.ConnectedIntersections.Add(previousJIntersection);
previousJIntersection.ConnectedIntersections.Add(currentPoint);
}
if (!hasSeenWallInI[j] && previousIIntersection[j] != null)
{
currentPoint.ConnectedIntersections.Add(previousIIntersection[j]);
previousIIntersection[j].ConnectedIntersections.Add(currentPoint);
}
newMazePoints.Add(currentPoint);
hasSeenWallInJ = false;
hasSeenWallInI[j] = false;
previousJIntersection = currentPoint;
previousIIntersection[j] = currentPoint;
}
}
else
{
hasSeenWallInJ = true;
hasSeenWallInI[j] = true;
}
j++;
if (j >= height)
{
i++;
j = 0;
}
if (i >= width)
{
hasSquares = false;
}
}
lastSeenEndConnector.ConnectedIntersections.Add(newMaze.EndPoint);
newMaze.EndPoint.ConnectedIntersections.Add(lastSeenEndConnector);
newMaze.Points = newMazePoints.ToArray();
return(newMaze);
}