Godot migration tutorial: matrices and the vertex shader

[clayjohn]

Currently the tutorial focuses on the fragment shader, especially regarding the book of shaders and shadertoy. However, there are some important differences in how Godot handles conversion of models into NDC. Specifically it would be valuable to explain when and how Godot multiples the Vertex by various matrices, and how you can avoid those conversions.

For example, by default Godot presents VERTEX in model space, then after vertex() runs it converts from model space into view space. Setting skip_vertex_transform avoids the model to view space transform but Godot still applies the view to clip space transform.

I think the migration tutorial may be the place for this, however it may be better to add a tutorial under the shading section call 'Vertex shaders' and then explain it in detail there, any thoughts?