This adds GSK_GPU_IMAGE_CAN_MIPMAP and GSK_GPU_IMAGE_MIPMAP flags and
support to ensure_image() and image creation functions for creating a
mipmapped image.
Mipmaps are created using the new mipmap op that uses
glGenerateMipmap() on GL and equivalent blit ops on Vulkan.
This is then used to ensure the image is mipmapped when rendering it
with a texture-scale node.
This now uses all the previously added features to allow displaying YUV
images.
Also add a utility function that turns an image into a toggle ref for a
texture. This makes sure that reffing the image also refs the texture
and that ensures that textures stay alive as long as the image is in
use.
Images can now have samplers - meaning they must be rendered with that
sampler. It also means that sampler must be handled as an immutable
sampler in descriptorsets.
These samplers can be created with a samplerYcbcrConversion, so code has
been added to pass that conversion when creating the imageview.
Also add code to GskVulkanFrame to track immutable samplers.
Nobody is making use of this yet.
Define an array with a compile-time-constant variable size for the
immutable samplers.
A bunch of work is necessary to ensure that at least one element is in
the sampler array, because the GLSL code
sampler2D immutable_textures[0];
is invalid.
This allows having different layouts sothat we can support immutable
samplers, whcih are required for multiplane and YUV formats.
We don't use them yet.
Introduce a new GskGpuImageDescriptors object that tracks descriptors
for a set of images that can be managed by the GPU.
Then have each GskGpuShaderOp just reference the descriptors object they are
using, so that the coe can set things up properly.
To reference an image, the ops now just reference their descriptor -
which is the uint32 we've been sending to the shaders since forever.
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
