A GskGLShader is an abstraction of a GLSL fragment shader that
can produce pixel values given inputs:
* N (currently max 4) textures
* Current arguments for the shader uniform
Uniform types are: float,(u)int,bool,vec234)
There is also a builder for the uniform arguments which are
passed around as immutable GBytes in the built form.
A GskGLShaderNode is a render node that renders a GskGLShader inside a
specified rectangular bounds. It renders its child nodes as textures
and passes those as texture arguments to the shader. You also pass it
a uniform arguments object.
The introspection scanner tries to match a type name with a get_type()
function, in order to correctly identify a type as a class.
If the function is not available, we have two choices:
- add some special case inside the introspection scanner, similar to
how GParamSpec subclasses are handled in GObject
- add a simple get_type() function
The latter is the simplest approach, and we don't need to change that
much, since we still register all render nodes at once.
Language bindings—especially ones based on introspection—cannot deal
with custom type hiearchies. Luckily for us, GType has a derivable type
with low overhead: GTypeInstance.
By turning GskRenderNode into a GTypeInstance, and creating derived
types for each class of node, we can provide an introspectable API to
our non-C API consumers, with no functional change to the C API itself.
When attaching renderer-specific data, we need to
make sure that we key it off the renderer that is
in use, and cope with the absence of render data.
This fixes recording nodes in the inspector.
This is a quick implementation that avoids many
glyph cache lookups. We keep an array of direct
pointers in the text render node, and throw those
cached pointers away whenever any atlases have
been dropped (since that may invalidate the cached
glyphs).
The code didn't change, it was just shuffled around to make the
with_bounds() versions of the text rendering unnecessary and instead
pass through the generic append_node() path.
And of course, gsk_render_node_get_name() is gone, too.
The replacement is of course debug nodes.
As a side effect, GskRenderNode is now *really* immutable.
We pulled out the bounds calculation for performance reasons, but the
caller can't know how to properly compute them. Inside gtk+, we can do
that but it's not good enough for public API.
... and gsk_render_node_can_diff(). Those are vfuncs to compute a region
containing all the pixels that differ between the two nodes.
This is just the plumbing that chains into node classes. No node
implements it yet.
Rename the surface getter to peek, following other render
node getters, and make the surface-based constructor private,
since it is not something we want to encourage.
Update all callers.
This commit takes several steps towards rendering text
like we want to.
The creation of the cairo surface and texture is moved
to the backend (in GskVulkanRenderer). We add a mask
shader that is used in the next text pipeline to use
the texture as a mask, like cairo_mask_surface does.
There is a separate color text pipeline that uses the
already existing blend shaders to use the texture as
a source, like cairo_paint does.
The text node api is simplified to have just a single
offset, which determines the left end of the text baseline,
like all our other text drawing APIs.
This node essentially implements the feColorMatrix SVG filter. I got the
idea yesterday after looking at the opacity implementation.
It can be used for opacity (not sure if we want to) and to implement a
bunch of the CSS filters.
Note: We interpolate premultiplied colors as per the CSS spec. This i
different from Cairo, which interpolates unpremultiplied.
So in testcases with translucent gradients, it's actually Cairo that is
wrong.
This does a conversion to/from GBytes and is intended for writing tests.
It's really crude but it works.
And that probably means Alex will (ab)use it for broadway.
Instead of a separate allocation for any arrays in the render node
we allocate these as part of the render node itself, using C99
flexible arrays.
This leads to less allocations, which is nice, but the major reason
for this is that it allows us to change the allocation scheme further
in the future. For instance, we want to do stack-like allocation so
that all the render-nodes for an entire frame are allocated in one
(or a few) chunks.
Instead of constantly recalculating this (especially recursively for
parents!) we do it only on construction, because everything is
immutable anyway. Also, most nodes had a bounds already and can
use the new parent member instead.
We also do direct access to the node bounds rather than calling
gsk_render_node_get_bounds in various places, which means
we do less copying.
... and make the icon rendering code use it.
This requires moving even more shadow renering code into GSK, but so be
it. At least the "shadows not implemented" warning is now gone!
The node draws a solid CSS border, which can be used to cover everything
but dashed and dotted borders (double, groove, inset, ...).
For different border styles, we overlay multiple nodes and set their
colors to transparent for sides with non-matching styles.
Instead of having a setter for the transform, have a GskTransformNode.
Most of the oprations that GTK does do not require a transform, so it
doesn't make sense to have it as a primary attribute.
Also, changing the transform requires updating the uniforms of the GL
renderer, so we're happy if we can avoid that.
