Keeps associated data together. It also eliminates the possibility of out
parameters not being initialized properly. For example, consider the
following example:
-- some FramebufferManager implementation --
void FBMgrImpl::GetTargetSize(u32* width, u32* height) override
{
// Do nothing
}
-- somewhere else where the function is used --
u32 width, height;
framebuffer_manager_instance->GetTargetSize(&width, &height);
if (texture_width != width) <-- Uninitialized variable usage
{
...
}
It makes it much more obvious to spot any initialization issues, because
it requires something to be returned, as opposed to allowing an
implementation to just not do anything.
Should we ever introduce anything else that has to be done when a command
buffer is executed (e.g. invalidating constants from previous commit), we
don't have to update all the callers.
There's not a lot of point in passing these around or storing them
(texture cache/state tracker mainly) as there will only ever be a single
instance of the class.
Also adds downcast helpers such as Vulkan::Renderer::GetInstance().