Dragging will just drag the render node.
Dropping will replace the current contents of the textview with the
dropped node.
Neat side effect: You can drag the node onto itself to do a
deserialize/serialize of the current text.
The primary goal here was to cleanup the current GL renderer to make
maintenance easier going forward. Furthermore, it tracks state to allow
us to implement more advanced renderer features going forward.
Reordering
This renderer will reorder batches by render target to reduce the number
of times render targets are changed.
In the future, we could also reorder by program within the render target
if we can determine that vertices do not overlap.
Uniform Snapshots
To allow for reordering of batches all uniforms need to be tracked for
the programs. This allows us to create the full uniform state when the
batch has been moved into a new position.
Some care was taken as it can be performance sensitive.
Attachment Snapshots
Similar to uniform snapshots, we need to know all of the texture
attachments so that we can rebind them when necessary.
Render Jobs
To help isolate the process of creating GL commands from the renderer
abstraction a render job abstraction was added. This could be extended
in the future if we decided to do tiling.
Command Queue
Render jobs create batches using the command queue. The command queue
will snapshot uniform and attachment state so that it can reorder
batches right before executing them.
Currently, the only reordering done is to ensure that we only visit
each render target once. We could extend this by tracking vertices,
attachments, and others.
This code currently uses an inline array helper to reduce overhead
from GArray which was showing up on profiles. It could be changed to
use GdkArray without too much work, but had roughly double the
instructions. Cycle counts have not yet been determined.
GLSL Programs
This was simplified to use XMACROS so that we can just extend one file
(gskglprograms.defs) instead of multiple places. The programs are added
as fields in the driver for easy access.
Driver
The driver manages textures, render targets, access to atlases,
programs, and more. There is one driver per display, by using the
shared GL context.
Some work could be done here to batch uploads so that we make fewer
calls to upload when sending icon theme data to the GPU. We'd need
to keep a copy of the atlas data for such purposes.
Using GtkCssSection in public headers here may be
ok from the C perspective, since it all ends up in
the same library anyway. But it causes circular
dependency problems for our gir files that are still
split by namespace.
To avoid this problem, copy the GtkCssLocation struct
struct as GskParseLocation, and pass take two of them
instead of a GtkCssSection in the error callback.
Update all users.
Fixes: #2454
Don't install headers for code that we don't build.
And don't include those headers in gsk.h.
Just as we do in gdk, require applications to include
the backend-specific headers they need explicitly.
Update the one affected demo, gtk4-node-editor.
GtkFileChooser's API predates GIO by a few years, so it started off with
filenames and URI as character arrays. After introducing GIO as a
dependency, the API included GFile-based entry points.
It's much more appropriate to use GFile everywhere, as we want to
encourage people to use GIO instead of passing random bytes to low level
POSIX API.
See: #2455
