This value is needed for vulkan to properly allocate a surface, and would benefit OpenGL to move more of its initialization code into here rather than in `emulator.cpp`.
Headlessly creates a new vulkan instance, with conditional MacOS
support, and enables the `VK_EXT_debug_utils` instance-extension with a
debug-messenger to hook onto validation layer messages.
A lot of the architecture of the emulator here does not allow for vulkan
to initialize easily since it involves a bit of data to be exchanged
between SDL and Vulkan. This commit just adds the foundational linkage
and library code for vulkan support.
`config` was being consumed much too early before it has a chance to
call `load`. This caused GPU to read weird uninitialized data, and then
`load` called, and then further initialization to occur based on default
data and the data inside of `config.toml`. `EmulatorConfig` needs to be
loaded in first before any sort of initialization happens, by adding a
new constructor so that it can be initialized sooner.
There are still some initialization errors to work through, such as
config not being initialized properly by the time GPU tries to utilize
it too. Also some life-time issues. But manually forcing it to use the
Null backnd successfully works and allows games to be "played"
headlessly.
Rather than declaring a big C++ literal for these strings, they are now
proper `.vert` and `.frag` files that will become embedded into the
application at build-time. It also allows for clang-format to format the
glsl files the same as our C++ code. CMake will also automatically track
and re-embed the file if it detects that the glsl source files have
changed since the last build. Ex, making a change to
`opengl_display.frag` and compiling will automatically recompile and
link the resource-target that it is associated with.
