Catch the error when it happens, so that we can emit a specific and more
helpful error message.
Also verify that all branches in the code now do indeed set a proper
GError when they fail, so that the final catch-all is no longer needed.
Instead, assert that the error is set so that we catch future code
additions early that do not set the GError.
glFrameBufferTexture maps to all faces of a cube and that is not needed
here. Additionally, texture_id is not deleted after we use the additional
flipped texture, but should be.
We're caching two things, either a node itself being rendered, or a
parent storing a cached version of a child as rendered to an offscreen
the size and location of the parent.
If both the parent and child uses the cache this will cause a conflict in
the cache as it is currently use keying of a node pointer which will have
the same value for the node-as-itself and the child-node-of-the-parent.
We fix this by adding another part to the key "pointer_is_child" which means
we can have the same node pointer twice in the cache.
Additionally, in the child-is-rendered-offscreen case the offscreen
result actually depends on the position and size of the parent viewport,
so we need to store the parent bounds in that case.
For vulkan/broadway this just means to ignore it, but for the gl
backend we support (with up to 4 texture inputs, which is similar to
what shadertoy does, so should be widely supported).
There is no real reason to have this on the side indexed via the
index, as it is stored next to each other anyway. Plus, storing them
together lets use use `Program` structures not in the array.
Do custom uploads rather than using gdk_cairo_surface_upload_to_gl(),
because this way we avoids a roundtrip (memcpy and possibly conversion)
to the cairo image surface format.
We need to include both the scale and the filtering
in the key for the texture cache, since those affect
the texture.
This fixes misrendering in the recorder in the inspector
whenever transforms are involved. An example where this
was showing up is testrevealer's swing transition.
When rendering to an offscreen because of transforms,
check if transforming the bounds of the node results
in a non-axis-aligned quad. If it doesn't, we want
GL_NEAREST interpolation to get sharp edges. Otherwise,
we use GL_LINEAR to get better results for things
that are actually transformed.
