Indexing primitives
The osg::DrawArrays works fine when reading vertex data straight through the arrays, without any skipping and hopping. However, it tends to be a little inefficient if there are lots of shared vertices. For example, in order to make osg::DrawArrays draw a cube with eight vertices in the GL_TRIANGLES mode, the vertex array should repeat each vertex a couple of times and should increase the array size to 36 (12 triangle faces) at last:
The osg::DrawElementsUInt class, as well as osg::DrawElementsUByte and osg::DrawElementsUShort classes, are used as index arrays in order to solve the above problem. They all derive from osg::PrimitiveSet ...
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