Based on Olivier's suggestion, the text rendering primitive is created
by painting the text onto a temporary HTML canvas
element and binding that to a texture.
The cargo target directory tree is now populated with a cmake package
file and that's also installed into the prefix specified with the cargo
cmake xtask.
As a consequence, the cpptest example can be built by first building the
cmake package:
cargo xtask cmake
or
cargo xtask cmake --release --target some-triplet)
or
cargo xtask cmake --release --prefix /somewhere --install
and then run cmake in the cpptest example with a prefix path:
-DCMAKE_PREFIX_PATH=/where/you/installed/it or simply
-DCMAKE_PREFIX_PATH=../../target/debug for example.
Pending still is the sixtyfps compiler tool installation and discovery.
Use a full prefixed name (sixtyfps_rendering_backend_gl) to ensure that
the created static lib can be installed without file conflicts (libgl is
not a unique name).
This is done by calling cargo with json output to build the libraries,
collect the .a files, extract the native libraries needed for final
linkage and pass all that to a CMake project that cobbles together the
.a files into a propery cmake target with include paths, etc.
The objective is to automatically create a propery cmake module, with a
FindSixtyFPSConfig.cmake, corresponding targets .cmake files, etc. This
should encapsulate the build profile (debug vs. release) and also allow
making the choice of shared vs. static transparent.
Unfortunately it does not seem to be possible to easily combine different
crates into one cdylib crate that can re-export symbols from the
statically linked rust crates (cbindgen generated, as well as manual
extern "C").
That means for the dynamic case (not cared for right now), we're going
to need to create either one cdylib per crate that has public symbols or
manually re-export the symbols.
For the static case, linking just against the "last crate" in the chain
(the gl renderer backend) is sufficient to pull in all needed symbols.
In addition for the static case we need to specify the linkage of some
external libraries. This can be extracted manually via
cargo rustc -p gl -- --print=native-static-libs
for example. For now that's in the changed CMakeLists.txt, but the plan
going forward is to automate this extraction in an xtask, to paste that
into the cmake target.
Finally, both linkage scenarios require access to the headers. This is
for now solved by generating them simply in an include sub-directory of
the build folder ($root/target/${profile}/include).
Remove the Optional from the evaluation context passing for property
evaluation. Unfortunately there are nullptr uses left on the C++ side,
that need to be replaced with passing through.
This introduces a separate rendering preparation step in the main
window. As a consequence, the component becomes a parameter and the
graphicstest example can't use the main window anymore.
The decision whether a new low-level primitive needs to be created or
not is made by comparing the last RenderingPrimitive against the new
one.
On the upside, this means that property changes are now reflected in the
graphics.
Forward the text and color properties to the rendering backend, where
right now we just rendering all the glyphs into a dedicated texture.
Next steps are a glyph atlas texture, blending the specified color with
the alpha of the glyphs, configurable size and family, shaping with
Harfbuzz and may more things.
The source property is a path relative to the path of the executable.
That is still rather inconvenient. It would be more convenient to make
it relative to the source file, but the corresponding proc-macro span
source_file() accessor is not public/stable.
Perhaps there's a way of doing this also through the generated code and
std::file!().
