From a75833847eed497d65093761b397614c808eda6d Mon Sep 17 00:00:00 2001
From: Andrea Odetti <mariofutire@gmail.com>
Date: Sat, 13 Feb 2021 13:09:55 +0000
Subject: [PATCH] Add cmd line option to switch off vsync.

Useful to profile.

Signed-off-by: Andrea Odetti <mariofutire@gmail.com>
---
 source/frontends/common2/programoptions.cpp |  2 ++
 source/frontends/common2/programoptions.h   |  1 +
 source/frontends/sdl/main.cpp               | 17 +++++++++++------
 3 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/source/frontends/common2/programoptions.cpp b/source/frontends/common2/programoptions.cpp
index a6519f80..0670fd79 100644
--- a/source/frontends/common2/programoptions.cpp
+++ b/source/frontends/common2/programoptions.cpp
@@ -85,6 +85,7 @@ bool getEmulatorOptions(int argc, const char * argv [], const std::string & edit
     ("timer-interval,i", po::value<int>()->default_value(options.timerInterval), "Timer interval in ms")
     ("loose-mutex,l", "Loose mutex")
     ("sdl-driver", po::value<int>()->default_value(options.sdlDriver), "SDL driver")
+    ("gl-swap", po::value<int>()->default_value(options.glSwapInterval), "SDL_GL_SwapInterval")
     ("imgui", "Render with Dear ImGui")
     ("size", po::value<std::string>(), "WxH")
     ;
@@ -114,6 +115,7 @@ bool getEmulatorOptions(int argc, const char * argv [], const std::string & edit
     options.looseMutex = vm.count("loose-mutex");
     options.timerInterval = vm["timer-interval"].as<int>();
     options.sdlDriver = vm["sdl-driver"].as<int>();
+    options.glSwapInterval = vm["gl-swap"].as<int>();
     options.imgui = vm.count("imgui");
 
     if (vm.count("config"))
diff --git a/source/frontends/common2/programoptions.h b/source/frontends/common2/programoptions.h
index 3eb912b7..f92ad526 100644
--- a/source/frontends/common2/programoptions.h
+++ b/source/frontends/common2/programoptions.h
@@ -38,6 +38,7 @@ struct EmulatorOptions
   int sdlDriver = -1; // default = -1 to let SDL choose
   bool imgui = false; // use imgui renderer
   std::pair<int, int> size; // width x height
+  int glSwapInterval = 1; // SDL_GL_SetSwapInterval
 
   std::vector<std::string> registryOptions;
 };
diff --git a/source/frontends/sdl/main.cpp b/source/frontends/sdl/main.cpp
index 74bee6c3..1df98d76 100644
--- a/source/frontends/sdl/main.cpp
+++ b/source/frontends/sdl/main.cpp
@@ -105,6 +105,11 @@ void run_sdl(int argc, const char * argv [])
   frame.reset(new SDLRendererFrame(options));
 #endif
 
+  if (SDL_GL_SetSwapInterval(options.glSwapInterval))
+  {
+    throw std::runtime_error(SDL_GetError());
+  }
+
   SetFrame(frame);
 
   if (options.log)
@@ -131,14 +136,14 @@ void run_sdl(int argc, const char * argv [])
   {
     // we need to switch off vsync, otherwise FPS is limited to 60
     // and it will take longer to run
-    const int res = SDL_GL_SetSwapInterval(0);
-    // if this fails, should we throw, print something or just ignore?
+    if (SDL_GL_SetSwapInterval(0))
+    {
+      throw std::runtime_error(SDL_GetError());
+    }
 
-    const auto redraw = [&frame, res]{
+    const auto redraw = [&frame]{
 			  frame->UpdateTexture();
-			  if (res == 0) {
-			    frame->RenderPresent();
-			  }
+			  frame->RenderPresent();
 			};
 
     const auto refresh = [redraw, &video]{