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.
Now that the GskRenderNode subclasses are recognised as proper
sub-types, we can annotate the constructors with their type. The C API
remains the same.
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.
Compute the pattern matrix directly instead of transforming the cairo_t.
This ensures that when node_size / texture_size is some obscure floating
point value, we don't get rounding issues from scaling by it once we
draw the texture_size rectangle.
I have no actual failure where this comes in handy, but I had written
the code anyway, so decided to keep it.
We currently disable when draw()ing nodes using the cairo fallback path,
which means we can't just use cairo_paint(). Use a proper rectangle
instead.
Fixes#2431
We're not in the business of adding Cairo APIs. That's Cairo's job.
Also, we don't need this API anywhere like the original commit claimed,
so there's no need to make it available in any way.
This reverts commit afa6cc2369.
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).
