If GskGpuCache has an idea of what time it is, cached items can use that
time to update their last-use time instead of having to carry it around
throught function calls everywhere.
We want to cache textures in the compositing color state, not in their
original color state. However, the compositing color state may change
(think multimonitor setups).
So we additionally keep a cache per colorstate.
That means texture lookup is now a 3-step process:
1. Look up in the compositing colorstate's cache
2. Look up in the general cache
3. Upload
This is for 3 reasons:
1. Separation of concerns
The device is meant to manage the Vulkan/GL device and check stuff
like image sizes.
Caching is not part of that.
2. Refcounting
Images etc want to reference the device, but the cache wants to
reference images. If the cache is the device, that's a refcycle.
3. Flexibility
It's now easier to implement >1 cache, say one per depth or one per
color state.
This function does not use the standard __cdecl calling convention on
Windows, meaning using g_clear_pointer() on it directly will cause
crashes on 32-bit Windows. Just call it directly if the GLsync it uses
exists.
Some maps are used for read only and do not require uploading contents
back to the GPU afterwards. In other cases, we can often upload less than
the fully allocated buffer size.
This ensures both that we signal a semaphore for a dmabuf when we export
an image and that we import semaphores for dmabufs and wait on them.
Fixes Vulkan node-editor displaying the Vulkan renderer in the sidebar.
Make gsk_renderer_render_texture() create a dmabuf texture if that is
possible.
If it isn't (ie if we're not on Linux or if dmabufs are otherwise not
working) fall back to the previous code of creating a memory texture.
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 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
