When transforming back from a complex transform to a simpler transform,
the resulting clip might turn out to clip everything, because clips can
grow while transforming, but the scissor rect won't. So when this
process happens, we can end up with an empty clip by transforming:
1. Set a clip that also sets the scissor
2. transform in a way that grows the clip, say rotate(45)
3. modify the clip to shrink it
4. transform in a way that simplifies the transform, say another
rotate(45)
5. Figure out that this clip and the scissor rect do no longer overlap
Catch this case and avoid drawing anything.
Add a new GskShadow2 struct that has a GdkColor instead of
a GdkRGBA, and a new constructor and getter to go along with
it.
With this commit, my_color_get_depth is no longer used and
has been dropped.
We know it at begin_frame() time, so if we pass it there instead of
end_frame(), we can use it then to make decisions about opacity.
For example, we could notice that the whole surface is opaque and choose
an RGBx format.
We don't do that yet, but now we could.
This is poking into the surface directly, so not a good idea.
And I want to hide that struct in the priv member.
Technically, this code should look at the opaque region, but I am lazy
and the GL renderer is on its way out, so I think it's not worth doing.
Make sure both GL renderers don't leave their contexts alive via the
current context, but ensure they dispose of them properly.
Fixes issues when the corresponding GL resources in the surfaces they
were attached to go away.
GLContexts marked as surface_attached are always attached to the surface
in make_current().
Other contexts continue to only get attached to their surface between
begin_frame() and end_frame().
All our renderer use surface-attached contexts now.
Public API only gives out non-surface-attached contexts.
The benefit here is that we can now choose whenever we want to
call make_current() because it will not cause a re-make_current() if we
call it outside vs inside the begin/end_frame() region.
Or in other words: I want to call make_current() before begin_frame()
without a performance penalty, and now I can.
... and pass the opaque region of the node.
We don't do anything with it yet, this is just the plumbing.
The original function still exists, it passes NULL which is the value
for no opaque region at all.
If we apply a rounded clip, we might change the clip in a way that makes
it intersectable with the scissor again, if both had diverged before.
So try and intersect with the clip.
In the case of no offloading, we want to pass through to the child
(which is likely a big texture doing occlusion).
In the case of punching a hole, we want to punch the hole and not draw
anything behind it, so we start an occlusion pass with transparency.
And in the final case with offloading active, we don't draw anything,
so we don't draw anything.
This should fix concerns about drawing the background behind the video
as mentioned for example in
https://github.com/Rafostar/clapper/issues/343#issuecomment-1445425004
Container nodes save their opaque region, so it's quick to access. Use
that to check if the largest opaque region even qualifies for culling -
and if not, just exit.
Speeds up walking node trees by a lot.
Now that we can specify the min size for an occlusion pass, we can
specify that we want the full clip rect to be occluded for occlusion to
trigger.
The benefit of this is that for partial redraws we almost
always get the background color to cover the redrawn rectangle, so
occlusion will kick in.
When trying to cull, try culling from the largest rectangle of the
remaining draw region first. That region has the biggest chance of
containing a large area to skip.
As a side effect, we can stop trying to cull once the largest rectangle
isn't big enough anymore to contain anything worth culling.
When querying clip bounds, also check the scissor rect, because
sometimes that one is tighter than the clip bounds, because the clip
bounds need to track some larger rounded corners.
Makes a few tests harder to break.
Instead of requiring an occlusion pass to cover the whole given scissor
rect, allow using a smaller rect to start the pass.
When starting such a pass, we adjust the scissor rect to the size of
that pass and do not grow it again until the pass is done.
The rectangle subtraction at the end will then take care of subtraction
that rectangle from the remaining pixels.
To not end up with lots of tiny occlusion passes, add a limit for how
small such a pass may be.
For now that limit is arbitrarily chosen at 100k pixels.
gsk_gpu_node_processor_rect_to_device() is a useful function to have,
even if it has to return FALSE sometimes when there is no simple 1:1
mapping - ie when the modelview contains a rotation.
Instead of just iterating over all the rectangles of the region,
always draw the first rectangle of the region and subtract it when done.
This sounds more complicated, but it will allow us to modify the
rectangle in future commits.
