Instead of strictly rounding to the given clip rectangle, increase the
rectangle to the next pixel boundary.
Also add docs that the clip_bounds do not influence the actual size of
the returned image.
It's just an object that encapsulates everything needed to create (the
data for) a pattern op.
It also clarifies which code does what, because now the NodeProcessor
and the PatternWriter are 2 different things.
Pretty much a copy of the Vulkan border shader.
A notable change is that the input arguments are changed, because GL
gets confused if you put a mat4 at the end.
when doing get_node_as_image(), that may spawn a new buffer writer that
writes into the samme buffer when rendering an offscreen with patterns.
So as a more or less hacky workaround, we now abort the current buffer
write and restart it once we've created the image.
If creation fails, create an offscreen image instead and draw that as a
texture.
Because offscreens basically always succeed, we can pretty much assume
success everywhere - apart from pattern creation functions that also
create images, because they can run out of shader space.
Frames now carry a timestamp for when they are used.
This is mainly intended to attach timestamps to cached items (textures
or glyphs), but it could in theory also be used when profiling.
We use wallclock time here, not server time, because it's cheaper and
because we're more intereseted in the local machine we're rendering on.
Now we can extend the pattern creation easily - and we can add new
patterns quickly later.
Plus, we need to keep this file in sync with pattern.glsl and it's neat
when those 2 files reference only each other.
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.
