Back face culling

Steps:

1. Find cross product of B - A, C - A and do normalization, in order to get N
2. find camera ray: camera position substract A
3. Doing dot product: (camera ray . N)

If the face dot product result is < 0,

> then camera ray and N are not the same direction, don't display the face

Else

> display the face

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Before:

After:

Resources: pikuma course