How many vertices does a triangle fan use opengl

Question

I am learning openGL, and i have come across triangle fans using vertex buffer objects. If given an array of vertices to render, how does openGL decide how many of those ve

Answer 1

Look here: GL_TRIANGLE FAN Explanation

The more vertices you give to openGL, the more triangles you get. The first vertex will be common to all triangles. First triangle consists of the vertices 1, 2 and 3. Second triangle consists of 1, 3 and 4. And so on. You get n - 2 triangles for n vertices.