I am making an addon to create this type of primitive in openFrameworks https://threejs.org/docs/#api/en/geometries/LatheGeometry
Let’s say that I want to create a mesh, where the triangles composing it are re-using some vertices.
So, instead of having 9 vertices as in the left side of the picture, I have 5, as in the right side of the picture.
Let’s also say that this triangle strip does not lay on a flat plane, where all the normals look in the same direction, but it covers a curved surface, like in the Lathe Geometry in the threejs example.
I assume that the normal for the vertex C in the picture on the left is just an interpolation between the normal of A and the normal of E, and I think this is what is happening in threejs https://github.com/mrdoob/three.js/blob/master/src/geometries/LatheGeometry.js#L166.
Is this the way to go? are there any complication that could arise, whenever I want to make the geometries created by this addon instance of a class that inherits from ofPrimitive? ofBoxPrimitive, for example, is not re-using vertices.
In general I am wondering about any complication of having a mesh that re-use vertices and has interpolated normals, and I am considering of keeping things simpler and go for the classical approach on the left side of the image.