OpenGL : curved lines

Newbie & Debugging Questions
#1

Hello

Still with my OpenGL experimentation for my tile based 2D game, I now want to draw curved lines.

I want to border a zone of any shape made of entire tiles with a line following the tiles’ edges. It’s not difficult do do it with GL_LINE_LOOP but I would like it to look better by “rounding” corners. Tiles are square so line angles are always 90 degrees.

How would you do it ? GL Evaluators ?

Thanks

#2

Bezier curves are an easy and effective way of generating curves. You’d just have to generate a list of coordinates from the relavent control points from the equation.

Picking the control points would be the only tricky bit, but if you’re starting with tiles then you could simply use the edges of the tiles at the start and end directions.

Have a look at the cubic form here: http://www.cl.cam.ac.uk/Teaching/2000/AGraphHCI/SMEG/node3.html