This commit implements gl_ViewportIndex and gl_Layer in vertex and
geometry shaders. In the case it's used in a vertex shader, it requires
ARB_shader_viewport_layer_array. This extension is available on AMD and
Nvidia devices (mesa and proprietary drivers), but not available on
Intel on any platform. At the moment of writing this description I don't
know if this is a hardware limitation or a driver limitation.
In the case that ARB_shader_viewport_layer_array is not available,
writes to these registers on a vertex shader are ignored, with the
appropriate logging.
Given the offset is assigned a fixed value in the constructor, we can
just assign it directly and get rid of the need to write the name of the
variable again in the constructor initializer list.
Given the disk shader cache contains non-trivial types, we should
default it in the cpp file in order to prevent inlining of the
complex destruction logic.
We don't need to load the code into a vector and then construct a string
over the data. We can just create a string with the necessary size ahead
of time, and read the data directly into it, getting rid of an
unnecessary heap allocation.
std::move does nothing when applied to a const variable. Resources can't
be moved if the object is immutable. With this change, we don't end up
making several unnecessary heap allocations and copies.
Booleans don't have a guaranteed size, but we still want to have them
integrate into the disk cache system without needing to actually use a
different type. We can do this by supplying non-template overloads for
the bool type.
Non-template overloads always have precedence during function
resolution, so this is safe to provide.
This gets rid of the need to smatter ternary conditionals, as well as
the need to use u8 types to store the value in.
Instead of asserting on already stored shader variants, silently skip them.
This shouldn't be happening but when a shader is invalidated and it is
not stored in the shader cache, this assert would hit and save that
shader anyways when the asserts are disabled.
