From 80145d6e6c0513149aa443d5d4f511b0377b2e87 Mon Sep 17 00:00:00 2001
From: Roman Fomin <rfomin@gmail.com>
Date: Mon, 18 Dec 2023 16:06:43 +0700
Subject: [PATCH] working DRS in capped mode, remove newsync uncapped hack
 (#1341)

---
 src/d_loop.c  | 15 +------------
 src/i_video.c | 60 ++++++++++++++++++++++++++++++---------------------
 src/i_video.h |  1 +
 src/m_menu.c  |  8 ++++---
 4 files changed, 43 insertions(+), 41 deletions(-)

diff --git a/src/d_loop.c b/src/d_loop.c
index c7b24558..bd31db2d 100644
--- a/src/d_loop.c
+++ b/src/d_loop.c
@@ -755,20 +755,7 @@ void TryRunTics (void)
 
     if (new_sync)
     {
-        if (uncapped)
-        {
-            // decide how many tics to run
-            if (realtics < availabletics-1)
-                counts = realtics+1;
-            else if (realtics < availabletics)
-                counts = realtics;
-            else
-                counts = availabletics;
-        }
-        else
-        {
-            counts = availabletics;
-        }
+        counts = availabletics;
 
         // [AM] If we've uncapped the framerate and there are no tics
         //      to run, return early instead of waiting around.
diff --git a/src/i_video.c b/src/i_video.c
index 0991bb44..9a3ea3b4 100644
--- a/src/i_video.c
+++ b/src/i_video.c
@@ -89,7 +89,7 @@ static int actualheight;
 static int native_width;
 static int native_height;
 static int native_height_adjusted;
-static int refresh_rate;
+static int native_refresh_rate;
 
 static boolean need_resize;
 
@@ -477,6 +477,7 @@ static void UpdateRender(void)
 }
 
 static uint64_t frametime_withoutpresent;
+static int targetrefresh;
 
 static void ResetResolution(int height);
 static void ResetLogicalSize(void);
@@ -495,7 +496,7 @@ static void DynamicResolution(void)
     }
 
     // 1.25 milliseconds for SDL render present
-    double target = (1.0 / refresh_rate) - 0.00125;
+    double target = (1.0 / targetrefresh) - 0.00125;
     double actual = frametime_withoutpresent / 1000000.0;
 
     double actualpercent = actual / target;
@@ -609,34 +610,32 @@ void I_FinishUpdate(void)
         need_resize = false;
     }
 
-    if (uncapped)
+    if (uncapped && fpslimit >= TICRATE)
     {
-        if (fpslimit >= TICRATE)
+        uint64_t target_time = 1000000ull / targetrefresh;
+
+        while (true)
         {
-            uint64_t target_time = 1000000ull / fpslimit;
-            static uint64_t start_time;
+            uint64_t current_time = I_GetTimeUS();
+            uint64_t elapsed_time = current_time - frametime_start;
+            uint64_t remaining_time = 0;
 
-            while (1)
+            if (elapsed_time >= target_time)
             {
-                uint64_t current_time = I_GetTimeUS();
-                uint64_t elapsed_time = current_time - start_time;
-                uint64_t remaining_time = 0;
-
-                if (elapsed_time >= target_time)
-                {
-                    start_time = current_time;
-                    break;
-                }
-
-                remaining_time = target_time - elapsed_time;
-
-                if (remaining_time > 1000)
-                    I_Sleep((remaining_time - 1000) / 1000);
+                frametime_start = current_time;
+                break;
             }
+
+            remaining_time = target_time - elapsed_time;
+
+            if (remaining_time > 1000)
+                I_Sleep((remaining_time - 1000) / 1000);
         }
     }
-
-    frametime_start = I_GetTimeUS();
+    else
+    {
+        frametime_start = I_GetTimeUS();
+    }
 }
 
 //
@@ -1149,6 +1148,18 @@ static void ResetLogicalSize(void)
     }
 }
 
+void I_ResetTargetRefresh(void)
+{
+    if (uncapped)
+    {
+        targetrefresh = (fpslimit >= TICRATE) ? fpslimit : native_refresh_rate;
+    }
+    else
+    {
+        targetrefresh = TICRATE;
+    }
+}
+
 //
 // killough 11/98: New routine, for setting hires and page flipping
 //
@@ -1161,6 +1172,7 @@ static void I_InitVideoParms(void)
     resolution_mode = default_resolution_mode;
     uncapped = default_uncapped;
     grabmouse = default_grabmouse;
+    I_ResetTargetRefresh();
 
     //!
     // @category video
@@ -1359,7 +1371,7 @@ static void CreateSurfaces(void)
 
     native_width = mode.w;
     native_height = mode.h;
-    refresh_rate = mode.refresh_rate;
+    native_refresh_rate = mode.refresh_rate;
 
     w = native_width;
     h = use_aspect ? (int)(native_height / 1.2) : native_height;
diff --git a/src/i_video.h b/src/i_video.h
index 0040d34a..2b6b01d4 100644
--- a/src/i_video.h
+++ b/src/i_video.h
@@ -62,6 +62,7 @@ void I_FinishUpdate (void);
 void I_ReadScreen (byte* scr);
 
 void I_ResetScreen(void);   // killough 10/98
+void I_ResetTargetRefresh(void);
 void I_ToggleVsync(void); // [JN] Calls native SDL vsync toggle
 
 extern boolean use_vsync;  // killough 2/8/98: controls whether vsync is called
diff --git a/src/m_menu.c b/src/m_menu.c
index 00f9cfcc..6e128f6c 100644
--- a/src/m_menu.c
+++ b/src/m_menu.c
@@ -3773,9 +3773,10 @@ static void M_SetMidiPlayer(void)
   S_RestartMusic();
 }
 
-static void M_EnableDisableFPSLimit(void)
+static void M_ToggleUncapped(void)
 {
   DISABLE_ITEM(!uncapped, gen_settings1[gen1_fpslimit]);
+  I_ResetTargetRefresh();
 }
 
 static void M_ToggleFullScreen(void)
@@ -3792,6 +3793,7 @@ static void M_CoerceFPSLimit(void)
 {
   if (fpslimit < TICRATE)
     fpslimit = 0;
+  I_ResetTargetRefresh();
 }
 
 static void M_ResetScreen(void)
@@ -3820,7 +3822,7 @@ setup_menu_t gen_settings1[] = { // General Settings screen1
   {"", S_SKIP, m_null, M_X, M_Y + gen1_gap2*M_SPC},
 
   {"Uncapped Frame Rate", S_YESNO, m_null, M_X, M_Y+ gen1_uncapped*M_SPC,
-   {"uncapped"}, 0, M_EnableDisableFPSLimit},
+   {"uncapped"}, 0, M_ToggleUncapped},
 
   {"Frame Rate Limit", S_NUM, m_null, M_X,
    M_Y + gen1_fpslimit*M_SPC, {"fpslimit"}, 0, M_CoerceFPSLimit},
@@ -6864,7 +6866,7 @@ void M_ResetSetupMenu(void)
 
 void M_ResetSetupMenuVideo(void)
 {
-  M_EnableDisableFPSLimit();
+  M_ToggleUncapped();
 }
 
 //