   draw an infinite line
  Hi,How can I draw an infinite line using OpenGL?   
  Find where the line intersects with the edges of your viewport, then draw a line-segment between those points.   ;  in 3D??   ;  Find where the line intersects with the edges of your frustum, then draw a line-segment between those points.   ;  Well, you could also use very large coordinates. Works to some degree. The line will eventually start jumping if the coordinates get too large.You could also approximate sufficiently large coordinates based on the frustum without having to calculate intersections with all 6 sides.What exactly do you need infinite lines for?   ;  It doesn't matter if the line is infinite, there's no point drawing what you can't see. So as Hodgman said, calculate the part that is seen and just draw that.You can describe the line as just Position and Direction. Using this you can calculate where/if it intersects the view frustum any where in the world.   