From 8ad2d5f949df609fa6841525347e30b5fd660360 Mon Sep 17 00:00:00 2001
From: orcephrye <drakethebanditi@yahoo.com>
Date: Mon, 8 Jul 2019 20:13:24 -0500
Subject: [PATCH] [client] autodetect monitor refresh rate for fps limit

---
 client/src/config.c |  4 ++--
 client/src/main.c   | 21 ++++++++++++++++++++-
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/client/src/config.c b/client/src/config.c
index 5f9a8b09..9c683c9c 100644
--- a/client/src/config.c
+++ b/client/src/config.c
@@ -185,10 +185,10 @@ static struct Option options[] =
   {
     .module         = "win",
     .name           = "fpsLimit",
-    .description    = "Frame rate limit (0 = disable - not recommended)",
+    .description    = "Frame rate limit (0 = disable - not recommended, -1 = auto detect)",
     .shortopt       = 'K',
     .type           = OPTION_TYPE_INT,
-    .value.x_int    = 200,
+    .value.x_int    = -1,
   },
   {
     .module         = "win",
diff --git a/client/src/main.c b/client/src/main.c
index 47def566..9ce9384b 100644
--- a/client/src/main.c
+++ b/client/src/main.c
@@ -1000,7 +1000,6 @@ int run()
   state.running   = true;
   state.scaleX    = 1.0f;
   state.scaleY    = 1.0f;
-  state.frameTime = 1e9 / params.fpsLimit;
 
   state.mouseSens = params.mouseSens;
        if (state.mouseSens < -9) state.mouseSens = -9;
@@ -1120,6 +1119,26 @@ int run()
   // ensure renderer viewport is aware of the current window size
   updatePositionInfo();
 
+  //Auto detect active monitor refresh rate for FPS Limit if no FPS Limit was passed.
+  if (params.fpsLimit == -1)
+  {
+      SDL_DisplayMode current;
+      if (SDL_GetCurrentDisplayMode(SDL_GetWindowDisplayIndex(state.window), &current) == 0)
+      {
+          state.frameTime = 1e9 / (current.refresh_rate * 2);
+      }
+      else 
+      {
+          DEBUG_WARN("Unable to capture monitor refresh rate using the default FPS Limit: 200");
+          state.frameTime = 1e9 / 200;
+      }
+  }
+  else 
+  {
+      DEBUG_INFO("Using the FPS Limit from args: %d", params.fpsLimit);
+      state.frameTime = 1e9 / params.fpsLimit;
+  }
+  
   register_key_binds();
 
   // set the compositor hint to bypass for low latency