OpenGL doesn't render to a 2-layer backbuffer like D3D/Vulkan for quad-buffered
stereo, instead drawing twice with the eye selected by glDrawBuffer()
(see OGL::Renderer::RenderXFBToScreen).
This header doesn't actually make use of MathUtil.h within itself, so
this can be removed. Many other source files used VideoCommon.h as an
indirect include to include MathUtil.h, so these includes can also be
adjusted.
While we're at it, we can also migrate valid inclusions of VideoCommon.h
into cpp files where it can feasibly be done to minimize propagating it
via other headers.
Also ensure that all members of the class are initialized on
construction as well. Previously the bool indicating if options are
dirty wouldn't be initialized, which could be read uninitialized if an
instance was constructed and then IsDirty() is called.
On locales that don't use period as a separator this would break us.
For vector values in a configuration, we use comma as a separator which causes the configuration to balloon to massive sizes due to never saving them
correctly. Loading would then break since it would load a million configuration options.
Fixes issue #7569.
This catches most instances of configuration failures that can happen in a post processing shader.
Gives a user a helpful error message that lets them know what they have failed to set up correctly
This class loads all the common PP shader configuration options and passes those options through to a inherited class that OpenGL or D3D will have.
Makes it so all the common code for PP shaders is in VideoCommon instead of duplicating the code across each backend.
