Blender Git Loki

Remove attempt at timeline editor version patching

This will never get run, because direct_link_area() already flags/resets
every space type isn't registered, meaning that we don't have any opportunity
to apply our patching.

Dopesheet-Timeline: Removal of Timeline Editor!

This commit removes all references to the old timeline editor.

Unfortuantely, the removal of the Timeline spacetype defining
functions has ended up breaking the version patching code I'd
been working on earlier (as now, the editor gets marked as
"unknown/info" before we get a chance to patch it!)

Fix: Copy and paste error from earlier commit adding message_subscriber callbacks

All of these were previously using the timeline theme, instead of the one
for each respective editor

Dopesheet-Timeline: Somewhat hacky version-patching code to switch old timelines to dopesheet-timelines

After a lot of failed attempts and head banging working trying to find a way to reuse
the standard editor-switching/creation code, I've just hacked in a temporary solution
here so that users can load old files and see the old timeline instances replaced
with Dopesheet-Timelines.

Note: This is not nice code, and copies a lot of the standard initialisation code,
but it works well enough for now. We can revisit this later when the other mode changes
come along.

Fix: Timeline's "Show Cache" options should not get reset on window size change

These were getting set in the init() callback instead of the new(). As a result,
the settings would get reset everytime you resized the window/area - not quite
something you'd really want happening everything the size changes!

Dopesheet-Timeline: Make sure ND_SPACE_TIMELINE notifier gets handled by dopesheet

Dopesheet-Timeline: Channels list now gets hidden automatically when switching to dopesheet-timeline

Add utility to make it easier to get editors/regions to redraw after changing visibility of regions

Previously, there was only an API method to toggle and update, but sometimes you
want to explicitly hide instead of just toggling.

Dopesheet-Timeline: Collapse summary channel by default (so that it's more like default timeline)

TODO: Still can't figure out a way to get the channels region to hide

Fix: Toggling preview range from timeline button didn't update animation editors

Most of these were missing the message bus stuff that now handles the update flushing.

Preview Range: Show preview range using a different color (based on ANIM_ACTIVE)
instead of using "black" curtains

With most editors now showing the start/end range by default, we need a way of
easily distinguishing when preview range is now enabled. By using a different color
(the exact color used is something we can change/adjust later), there is a more distinct
visual difference between them, making it easier to see what's happening.

AnimEditors: Draw start/end frame ranges on all timelines by default

This uses the global scene range, with styling matching the sequencer's start/end
frame drawing.

(The graph editor's "drivers" mode is exempt, as that doesn't really display time
in a linear way, so the start/end frames don't apply)

Move the set start/end frame operators from Timeline to Animation module

Eventually the idea is that they'll get remapped to some more global/generic hotkey
that can get used across all animation editors (see T54728). However, to facilitate
the removal of the timeline editor, it's better we do this now.

Dopesheet-Timeline: Ported over all (missing) notifiers/listeners/etc. from timeline to dopesheet

We already had most of these, but some of these were missing (e.g. pointcache and animplay)
as well as messagebus stuff. Hopefully I didn't miss any!

Cleanup: Remove the "SpaceTime->caches" and "SpaceTimeCache" stuff

These were runtime only data, used in pre 2.8 Blender to make use of GL vertex arrays
to draw these more efficiently. Maybe we might restore these sometime as an optimisation
step, but for now, they're not needing and were confusing.

Dopesheet-Timeline: Ported over cache indicator drawing + settings used to control their visibility

These now live in the action editor/dopesheet related files.

Apart from these, the timeline didn't actually have other settings
of its own that were of any interest to anyone.

Dopesheet-Timeline: First steps towards making the Timeline a mode of the DopeSheet Editor

For many years, animators have been requesting the ability to edit keyframes in the
timeline. However, implementing such tools in the timeline quickly becomes a slippery
slope, where we'll eventually end up having to duplicate all the functionality from the
dopesheet editor.

Discussing with William and Pablo this morning, we realised that perhaps it might be possible
to just make the Timeline a mode of the Dopesheet Editor (and kill off the old standalone
Timeline), meaning that we essentially get all the Dopesheet Editor goodness for free!
Also, with some proposed UI updates (i.e. allowing "submodes" of editors to be part of the
the main editors selector), it might not even matter that there isn't an "actual" timeline
editor anymore.

This commit implements the following changes (which are actually sufficient for supporting
most basic workflows):
* Timeline mode in Dopesheet Editor
* Tweaks to UI code to make the Timeline header/menus show up in Dopesheet editor

TODO:
* Hide channels list when switching to timeline mode
* Port over cache-file indicators
* Add missing timeline-only settings that need a new home in the dopesheet
* Go through fixing all timeline editor operators (e.g. Bind to camera)
* Port over start/end frame shading (and adjust preview range rendering to make the
distinction between these clear)
* Remove old timeline editor, and transfer over any leftover code

Eevee: TAA Reprojection: Initial implementation

This "improve" the viewport experience by reducing the noise from random
sampling effects (SSAO, Contact Shadows, SSR) when moving the viewport or
during playback.

This does not do Anti Aliasing because this would conflict with the outline
pass. We could enable AA jittering in "only render" mode though.

There are many things to improve but this is a solid basis to build upon.

Eevee: TAA Reprojection: Add layer property.

Eevee: Add Velocity pass.

This pass create a velocity buffer which is basically a 2D motion vector
texture. This is not yet used for rendering but will be usefull for motion
blur and temporal reprojection.