Fixes#90017Fixes#90030Fixes#98044
This PR makes the following changes:
# Force processing of GPU commands for frame_count frames
The variable `frames_pending_resources_for_processing` is added to track
this.
The ticket #98044 suggested to use `_flush_and_stall_for_all_frames()`
while minimized.
Technically this works and is a viable solution.
However I noticed that this issue was happening because Logic/Physics
continue to work "business as usual" while minimized(\*). Only Graphics
was being deactivated (which caused commands to accumulate until window
is restored).
To continue this behavior of "business as usual", I decided that GPU
work should also "continue as usual" by buffering commands in a double
or triple buffer scheme until all commands are done processing (if they
ever stop coming). This is specially important if the app specifically
intends to keep processing while minimized.
Calling `_flush_and_stall_for_all_frames()` would fix the leak, but it
would make Godot's behavior different while minimized vs while the
window is presenting.
\* `OS::add_frame_delay` _does_ consider being minimized, but it just
throttles CPU usage. Some platforms such as Android completely disable
processing because the higher level code stops being called when the app
goes into background. But this seems like an implementation-detail that
diverges from the rest of the platforms (e.g. Windows, Linux & macOS
continue to process while minimized).
# Rename p_swap_buffers for p_present
**This is potentially a breaking change** (if it actually breaks
anything, I ignore. But I strongly suspect it doesn't break anything).
"Swap Buffers" is a concept carried from OpenGL, where a frame is "done"
when `glSwapBuffers()` is called, which basically means "present to the
screen".
However it _also_ means that OpenGL internally swaps its internal
buffers in a double/triple buffer scheme (in Vulkan, we do that
ourselves and is tracked by `RenderingDevice::frame`).
Modern APIs like Vulkan differentiate between "submitting GPU work" and
"presenting".
Before this PR, calling `RendererCompositorRD::end_frame(false)` would
literally do nothing. This is often undesired and the cause of the leak.
After this PR, calling `RendererCompositorRD::end_frame(false)` will now
process commands, swap our internal buffers in a double/triple buffer
scheme **but avoid presenting to the screen**.
Hence the rename of the variable from `p_swap_buffers` to `p_present`
(which slightly alters its behavior).
If we want `RendererCompositorRD::end_frame(false)` to do nothing, then
we should not call it at all.
This PR reflects such change: When we're minimized **_and_**
`has_pending_resources_for_processing()` returns false, we don't call
`RendererCompositorRD::end_frame()` at all.
But if `has_pending_resources_for_processing()` returns true, we will
call it, but with `p_present = false` because we're minimized.
There's still the issue that Godot keeps processing work (logic,
scripts, physics) while minimized, which we shouldn't do by default. But
that's work for follow up PR.
Thaddeus Crews
smix8
Dario
Rémi Verschelde
Rémi Verschelde
Matias N. Goldberg
Pāvels Nadtočajevs
Mikael Hermansson
Yuri Rubinsky