By using equation 7 from the paper, we make the surfaces nearest to the
viewpoint appear more "opaque". This gives better sense of ordering than
the previous weighting function that was really not doing anything.
There was a method explained in the Weighted Blended Order-Independent
Transparency paper to support hardware that does not support per render
target blending function.
So now only 2 geometry passes are required instead of 3 (one being the
outline/depth fill pass).
This also fix how the blending is done. There was some premult confusion
in the implementation.
As in Pose Mode, the idea here it to try to reduce viewport complexity
without requiring users to turn off the overlay completely all the time.
For example, a background prop (e.g. a tree with a tyre hanging off it,
or a branch with hand-placed leaves) won't be cluttering the viewport with
its relationship lines all the time, when you're trying to do something else.
When you really do need to see these lines, you can still select the object
in question, and you'll see the lines for which objects are its children
or what its parent is. And to see all lines, you can still always select all
objects.
This patch reduce the branching in the lamp loop, improving compilation time
noticeably (2372ms to 1785ms for the default shader).
This should not change the appearance of the shader.
Performance impact is negligeable.
This mimics the 'spreadsheet' behavior. Columns and/or rows can have
equal sizes, or adapt to their content - but always in a grid way (i.e.
all items in a same column will always have same available width, and
all items in a same row will always have same available height).
Also, you can fill (order) the grid in a row- or column-major way.
Not used anywhere for now.
Differential: https://developer.blender.org/D2395
This fixes the problem that matcaps have when using a very larg FOV in
perspective view.
This was because it was stupidly using the normal direction which can not
aligned with the view vector under perspective.
So to workaround this problem we don't use the normal as is, but compute
how much it's facing the camera.
This changes how matcaps looks in perspective because they now always use
the full range of the matcap (which is expected).
