From 1dff22d5768d6860ef6ed6ee8ad3a353bbea0093 Mon Sep 17 00:00:00 2001
From: Dentomologist <dentomologist@gmail.com>
Date: Wed, 8 Nov 2023 18:43:00 -0800
Subject: [PATCH] Movie: Fix crash when starting input recording on OpenGL
 single-core

Use RunOnCPUThread instead of RunAsCPUThread in BeginRecordingInput.

Most OpenGL functions require an OpenGL context to have been created on
that thread before calling the function; when that isn't the case they
return invalid results which can cause crashes when passed into other
functions.

Dolphin creates the OpenGL context in the EmuThread which then becomes
either the CPU-GPU thread or the Video thread for single and dual core
respectively. OpenGL functions must therefore be called from that
thread.

Movie::BeginRecordingInput is called from the Host thread and runs a
block of code which ultimately creates a savestate, which in turn embeds
the framebuffer which requires calling various OpenGL functions.

In single core the use of RunAsCPUThread leads to this all happening on
the Host thread, eventually leading to invalid OpenGL calls and a crash.

In Dual core the crash is avoided because VideoBackendBase::DoState uses
the AsyncRequests::DO_SAVE_STATE event which causes VideoCommon_DoState
and its subsequent OpenGL calls to safely run on the Video thread.

This commit uses RunOnCPUThread instead of RunAsCPUThread, which causes
the subsequent code to run on the CPU-GPU thread in single core which
has the valid OpenGL context and so doesn't crash.
---
 Source/Core/Core/Movie.cpp | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/Source/Core/Core/Movie.cpp b/Source/Core/Core/Movie.cpp
index 152f5617b2..5b66b707ea 100644
--- a/Source/Core/Core/Movie.cpp
+++ b/Source/Core/Core/Movie.cpp
@@ -545,7 +545,7 @@ bool BeginRecordingInput(const ControllerTypeArray& controllers,
       (controllers == ControllerTypeArray{} && wiimotes == WiimoteEnabledArray{}))
     return false;
 
-  Core::RunAsCPUThread([controllers, wiimotes] {
+  const auto start_recording = [controllers, wiimotes] {
     s_controllers = controllers;
     s_wiimotes = wiimotes;
     s_currentFrame = s_totalFrames = 0;
@@ -615,7 +615,8 @@ bool BeginRecordingInput(const ControllerTypeArray& controllers,
 
     if (Core::IsRunning())
       Core::UpdateWantDeterminism();
-  });
+  };
+  Core::RunOnCPUThread(start_recording, true);
 
   Core::DisplayMessage("Starting movie recording", 2000);
   return true;