Rename View matrices in the form world_to_view, etc

[JMS55]

Currently, the View uniform looks like this:

struct View {
    view_proj: mat4x4<f32>,
    unjittered_view_proj: mat4x4<f32>,
    inverse_view_proj: mat4x4<f32>,
    view: mat4x4<f32>,
    inverse_view: mat4x4<f32>,
    projection: mat4x4<f32>,
    inverse_projection: mat4x4<f32>,
    ...
};

There's been much confusion over which of these do what. It would be much better to call, for instance the projection matrix, view_to_clip. We could then put "This is the projection matrix" in a doc comment.

We could also use a doc comment for unjittered_view_proj vs view_proj. The unjittered matrix is basically only useful for calculating motion vectors for TAA, and is equivalent to the view_proj matrix when the motion vector prepass is disabled. Users shouldn't really need to touch the unjittered matrix ever.

[ickk]

In Hotham we eventually settled on y_from_x as the naming convention of transforms, since it composes better than x_to_y;
we have lots of code that looks like:

let global_from_local = global_from_stage * stage_from_local;

let local_from_mesh = local_from_global * global_from_joint * joint_from_mesh;

which is easier to quickly read than

let local_to_global = stage_to_global * local_to_stage;

let mesh_to_local = global_to_local * joint_to_global * mesh_to_joint;

[JMS55]

Good point, I agree :)