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.
Instead of storing all block width, height and depths in their shifted
form:
block_width = 1U << block_shift;
Store them like they are provided by the emulated hardware (their
block_shift form). This way we can avoid doing the costly
Common::AlignUp operation to align texture sizes and drop CPU integer
divisions with bitwise logic (defined in Common::AlignBits).
This was reduced due to happening on most games and at such constant
rate that it affected performance heavily for the end user. In general,
we are well aware of the assert and an implementation is already
planned.
Avoids inlining destruction logic where applicable, and also makes
forward declarations not cause unexpected compilation errors depending
on where the State class is used.
Lessens the amount of code that needs to be read, and gets rid of the
need to introduce an indexing variable. Instead, we just operate on the
objects directly.
std::memset is used to clear the entire register structure, which
requires that the Regs struct be trivially copyable (otherwise undefined
behavior is invoked). This prevents the case where a non-trivial type is
potentially added to the struct.
Fernando Sahmkow