Because GL flips its shit sometimes (ie when it's the framebuffer),
pass the height of the target as the flip variable, so commands
that need to operate on the pixels can flip the y axis around this value.
This is again mostly a copy of the Vulkan renderer.
It's a bit awkward codewise with the new invalidation framework,
because we need to cache the previous values individually now,
but it's a lot more finegrained, and we don't emit globals multiple
times when clips are nested.
... and use it to initialize the "proper" projection matrix to use in
shaders.
The resulting viewport will go from top left (0,0) to bottom right
(width, height) and the z clipping plane will go from -10000 to 10000.
This heaves over an inital chunk of code from the Vulkan renderer to
execute shaders.
The only shader that exists for now is a shader that draws a single
texture.
We use that to replace the blit op we were doing before.
For now, it just renders using cairo, uploads the result to the GPU,
blits it onto the framebuffer and then is happy.
But it can do that using Vulkan and using GL (no idea which version).
The most important thing still missing is shaders.
It also has a bunch of copy/paste from the Vulkan renderer that isn't
used yet.
But I didn't want to rip it out and then try to copy it back later
We want to introduce a new one next.
Technically, this breaks API, because gsk_vulkan_renderer_new() is going
away, but practically, we're gonna bring it back once we introduce that
renderer in a few commits.
These are not usable outside of GTK, so lets not burden bindings
with them.
I'll keep the get_child() function exposed, since it is needed to
iterate over node trees containing subsurface nodes.
asan randomly failed when this almost correct code wasn't quite correct.
Hopefully this is the correct incantation to compute the size.
Related: glib#205
This is mostly untested and a result of reading the code.
The main effect here happens when a node was drawn that didn't start on
an integer boundary, which is very rare.
However, with specially crafted tests and when using fractional scaling,
this can happen.
This happened most often when clipping by the node bounds to restrict a
push_group() call. Enlarge that rectangle to fall on a pixel boundary.
Testcase included
The code was writing invalid memory, so this might not have always
crashed, but I did my best to write the test so it causes a SEGV.
Also included is a fix for the testsuite where the expected result was
wrong.
These 2 rectangles used to intersect fine:
0 0 50 50 / 50 0
0 0 50 50 / 0 50
But the computed result was:
0 0 50 50 / 50
which is not a valid rectangle, because the corners overlap.
Make sure such rectangles return NOT_REPRESENTABLE.
The above rectangle has been added to the testsuite.
After discussion on IRC about debug messages:
- FALLBACK is meant to be used for printing stuff about fallbacks
(Cairo, offscreens, conversion when uploading, etc)
- CAIRO is for overdrawing everything drawn with Cairo
When hilighting Cairo nodes, use a different hilight color than when
hilighting other nodes.
This allows differentiating application use of Cairo (via nodes) from
renderer use of Cairo (via fallback).
Use it to overlay an error pattern over all Cairo drawing done by
renderers.
This has 2 purposes:
1. It allows detecting fallbacks in GPU renderers.
2. Application code can use it to detect where it is using Cairo
drawing.
As such, it is meant to trigger both with cairo nodes as well as when
renderers fallback for regular nodes.
The old use of the debug flag - which were 2 not very useful print
statements - was removed.
Mask nodes are transparent outside of the intersection of source and
mask, unless the mask ode is inverted alpha.
Set the bounds accordingly.
Tests have been updated accordingly.
