Drop MemoryBarrier from the buffer cache and use Maxwell3D's register
WaitForIdle.
To implement this on OpenGL we just call glMemoryBarrier with the
necessary bits.
Vulkan lacks this synchronization primitive, so we set an event and
immediately wait for it. This is not a pretty solution, but it's what
Vulkan can do without submitting the current command buffer to the queue
(which ends up being more expensive on the CPU).
Using deko3d as reference:
4e47ba0013/source/maxwell/gpu_3d_state.cpp (L42)
We were using bits 3 and 4 to determine depth clamping, but these are
the same both enabled and disabled:
state->depthClampEnable ? 0x101A : 0x181D
The same happens on Nvidia's OpenGL driver, where they do something like
this (default capabilities, GL 4.5 compatibility):
(state & DEPTH_CLAMP) != 0 ? 0x201a : 0x281c
There's always a difference between the first bits in this register, but
bit 11 is consistently disabled on both deko3d/NVN and OpenGL. This
commit changes yuzu's behaviour to use bit 11 to determine depth
clamping.
- Fixes depth issues on Super Mario Odyssey's intro.
On NVN buffers can be enabled but have no size. According to deko3d and
the behavior we see in Animal Crossing: New Horizons these buffers get
the special address of 0x1000 and limit themselves to 0xfff.
Implement buffers without a size by binding a null buffer to OpenGL
without a side.
1d1930beea/source/maxwell/gpu_3d_vbo.cpp (L62-L63)
Layered framebuffer attachments is a feature that allows applications to
write attach layered textures to a single attachment. What layer the
fragments are written to is decided from the shader using gl_Layer.
Instead of waiting immediately for executed commands, defer the query
until the guest CPU reads it. This way we get closer to what the guest
program is doing.
To archive this we have to build a dependency queue, because host APIs
(like OpenGL and Vulkan) use ranged queries instead of counters like
NVN.
Waiting for queries implicitly uses fences and this requires a command
being queued, otherwise the driver will lock waiting until a timeout. To
fix this when there are no commands queued, we explicitly call glFlush.
RASTERIZE_ENABLE is the opposite of GL_RASTERIZER_DISCARD. Implement it
naturally using this.
NVN games expect rasterize to be enabled by default, reflect that in our
initial GPU state.
Fernando Sahmkow