TriangleStrip class Null safety
Represents a strip of triangles.
Each triangle uses the last edge of the previous one. The following diagram
shows an example of a triangle strip, with each vertex labeled with its
index in the vertex_index array. (1)-----(3) / \ / \ / \ / \ / \ /
(0)-----(2)-----(4) Vertices may be in either clockwise or counter-clockwise order.