module CrossHairs (clk, BrightRow, BrightCol, ReadData, vcnt, hcnt, PixelDataOut, LaserPoint);
		
//
// Input
//		
input clk ;
input [7:0] BrightRow ;	//Brightest pixel in the image is in this row
input [7:0] BrightCol ;	//Brightest pixel in the image is in this col
input [7:0] ReadData ;	//pixel data read from memory
input [7:0] vcnt ;		//pixel column read from memory
input [7:0] hcnt ;		//pixel row read from memory
input LaserPoint ;


//
// Output
//
output [7:0] PixelDataOut ;


//
// Output registers
//
reg [7:0] PixelDataOut ;


//
// Basically, this module determines if the current row and 
// column being read from memory has a laser point in it. If
// it does, then white cross-hairs are displayed on the image,
// otherwise the white cross-hairs are not displayed. Also, this
// module implements color mapping. All colors that are white
// (or nearly white, i.e. >250 on a 0->255 scale) are simply
// displayed directly. All other colors are mapped to be
// displayed as black pixels (=0).
//
// Note that there is a one cycle delay from getting the data
// from memory and sending the address to memory. Thus, our
// row and column will be one pixel out of sync. This can be
// fixed at a later date.
//
always @ (posedge clk)
  begin
  		if (LaserPoint)	//There was a laser point detected in this image
  			begin
  				if ((BrightRow == vcnt ) || (BrightCol == hcnt ))  
  					// If the current row == the brightest row in the image, or the current
  					// column == the brightest column in the image, display the pixel as a
  					// white pixel (this will create the cross hairs).
  					PixelDataOut = 255;
  				else
  					// Otherwise, check to see if the original data read from memory is
  					// bright (above a certain threshold, for this application, see if
  					// it is white (=255) or almost white- so check for > 250). If the
  					// pixel is white (>250), then display the pixel. Otherwise, display
  					// the pixel as a black pixel (=0). This effectively filters out all
  					// light except white light (which is the brightest light in the image).
  					if (ReadData > 250)
  						PixelDataOut = ReadData;
  					else
  						PixelDataOut = 0;
  			end
  		else
  		  begin
			// There is no laser point in the image, so don't display any
			// white pixels (this removes the purple cross hairs from being
			// displayed in the image). Also, perform the same check as above
			// to see if the pixel is white or some other (less intense)
			// color. Display the white pixels without modification, and
			// display all other colors and intensities as black pixels (=0).
	  		if (ReadData > 250)
				PixelDataOut = ReadData;
			else
				PixelDataOut = 0;
		  end
  
  end //end always

endmodule