This allows us to avoid updating uniforms if that is not necessary. This
in turn allows us to sometimes reuse the same draw op by just extending the
vertex array size we draw rather than doing a separate glDraw call.
For example, in the fishbowl demo, all the icons added at the same
time will have the same time and size, so we emit single draw calls
with 100s of triangles instead of 100s of draw calls with 2 triangles.
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.
Track what we really need to send for inset shadows, which are used
as a border replacement in many cases.
Fishbowl says I can draw around 200-300 more switches per frame like
this too.
This is similar to how we share texture atlases. Some added complexity
in that the program state also needed to be shared, so it had to move to
the shared Programs object.
With this change realization of additional GskRenderers when opening
popups went from ~60msec to ~35 msec on average.
Instead of copying the (rather large) RenderOp to the GArray, we can
simply set the fields directly in the allocated space for the struct.
In most cases, there wont be any allocations to make as the array size
is kept in tact across frame renderings.
This adds debug groups in various places, including the debug
nodes if those are in use. This makes the traces in tools like
renderdoc much easier to read.
So we can check that the currently set clip is the first one and now
intersect with it. This first clip is always the entire viewport or the
entire render_area and we don't want to end up drawing things to a
texture because of it.
Instead of getting the translation x/y everytime we use the modelview,
get it once, when extracting the metadata. Do the same with the scale.
And save if the matrix is "simple" at all, i.e. if it only consists of a
translation and/or scale. This will be helpful later when we start
drawing transformed nodes on textures.
We do this for every single node, which is a little costly, especially
since the common case for the modelview matrix these days is a simple
translation. So, check whether the new modelview matrix is only a
translation matrix and if so, don't do a full matrix multiplication per
node.
