Step 10 : Point View and Angles Tricks

Dealing with angles is not a piece of cake. In the last step, we have seen than angles are circular data so angles should be wrapped or corrected:

If an Angle gets bigger than 2*PI then Angle=Angle - 2*Math.PI;

If an Angle gets negative then Angle=Angle + 2*Math.PI;

This should be taken into account when computing the distances to the walls according to a given Point of View :

The starting angle is : startangle=POVrad-this.HalfFOVrad;

	
				// wrap around if necessary
				if (startangle < 0)
				{
					startangle=2*Math.PI + startangle;
				}

The ending angle is : var endangle=POVrad+this.HalfFOVrad;

	
				// wrap around if necessary
				if (endangle>=2*Math.PI){
					endangle-=2*Math.PI;
				}

A ray should be cast for all angles between the start angle and then end angle

	
				var rayangle=startangle;	
				for (var i=0; i<this.nbangles; i++)
				{	
					var d=this.ComputeOneBestWallIntersection(xunitplayer,yunitplayer,rayangle,draw,0);
					
					this.distancesToWalls[i]=d;
					rayangle=rayangle+this.AngleRadByColumn;
					// wrap around if necessary	
					if (rayangle>=2*Math.PI){
						rayangle-=2*Math.PI;
					}
				}

All Together


			ComputeBestWallIntersections : function(xunitplayer,yunitplayer,POVrad,debug,draw)
			{
			
				var startangle=POVrad-this.HalfFOVrad;
				
				// wrap around if necessary
				if (startangle < 0)
				{
					startangle=2*Math.PI + startangle;
				}
				
				
				var endangle=POVrad+this.HalfFOVrad;
				// wrap around if necessary
				if (endangle>=2*Math.PI){
					endangle-=2*Math.PI;
				}
				
				var str="";
				var rayangle=startangle;
				
				for (var i=0; i<this.nbangles; i++)
				{	
					var d=this.ComputeOneBestWallIntersection(xunitplayer,yunitplayer,rayangle,draw,0);
					
					this.distancesToWalls[i]=d;
					rayangle=rayangle+this.AngleRadByColumn;
					// wrap around if necessary	
					if (rayangle>=2*Math.PI){
						rayangle-=2*Math.PI;
					}
				}
				
				return 1;
			},
			
			

		


		
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