Chapter 4
Results of different primitive types
The OpenGL documentation and some web tutorials can explain them clearly: http://www.opengl.org/sdk/docs/man/xhtml/glBegin.xml.
There is also an osggeometry example in the OSG source code, located at examples\osggeometry.
Optimizing indexed geometries
If you are drawing in GL_TRIANGLES mode without indexing, there will be up to 24 vertices allocated. GL_TRIANGLE_STRIPS works fine while triangles are connected in groups. For the case of representing an octahedron, we could use a triangle strip primitive set (2, 5, 3, 4, 1, 0, 2, 3, as shown in the figure in the Drawing an octahedron section) and two single triangles (4, 0, 3, and 5, 2, 1) to implement the same result.
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