GL_TRIANGLE FAN Explanation

Question

I am trying to "fill" a surface of a sphere that I drew using this algorithm here: http://paulbourke.net/miscellaneous/sphere_cylinder/ , the first method. I know that GL_QUADS is no longer used in OpenGL 3+. SO I used GL_TRIANGLE_FAN . Is it the same thing? The problem here is that my sphere facets are squares. So if I use GL_TRIANGLE then I get a weird "filling", not all the surface is covered. Am I doing it the wrong way? How does GL_TRIANGLE_FAN work exactly?

Answer 1

How does GL_TRIANGLE_FAN works exactly?

The first vertex of a triangle fan acts like a hub. The vertices following connect with the previous non-starting vertex and the hub.

Answer 2

You probably need a triangle strip instead of a fan.

See also this question: gl_triangle_strip vs gl_triangle_fan