From fea6833ea00efefec5dccd2ee85656e759726168 Mon Sep 17 00:00:00 2001
From: Roman Fomin <rfomin@gmail.com>
Date: Wed, 20 Dec 2023 14:09:01 +0700
Subject: [PATCH] update DRS parameters

---
 src/d_main.c   | 16 ++++++----------
 src/doomstat.h |  2 --
 src/i_video.c  | 40 ++++++++++++++++++++++------------------
 src/i_video.h  | 10 ++++++----
 4 files changed, 34 insertions(+), 34 deletions(-)

diff --git a/src/d_main.c b/src/d_main.c
index ad289eeb..0d5fdf59 100644
--- a/src/d_main.c
+++ b/src/d_main.c
@@ -210,7 +210,6 @@ void D_ProcessEvents (void)
 gamestate_t    wipegamestate = GS_DEMOSCREEN;
 boolean        screen_melt = true;
 extern int     showMessages;
-boolean        enable_drs;
 
 void D_Display (void)
 {
@@ -246,10 +245,14 @@ void D_Display (void)
     }
   }
 
-  enable_drs = true;
-
   redrawsbar = false;
 
+  // save the current screen if about to wipe
+  if ((wipe = gamestate != wipegamestate) && NOTSTRICTMODE(screen_melt))
+    wipe_StartScreen(0, 0, video.unscaledw, SCREENHEIGHT);
+  else
+    I_DynamicResolution();
+
   if (setsizeneeded)                // change the view size if needed
     {
       R_ExecuteSetViewSize();
@@ -257,13 +260,6 @@ void D_Display (void)
       borderdrawcount = 3;
     }
 
-  // save the current screen if about to wipe
-  if ((wipe = gamestate != wipegamestate) && NOTSTRICTMODE(screen_melt))
-    {
-      enable_drs = false;
-      wipe_StartScreen(0, 0, video.unscaledw, SCREENHEIGHT);
-    }
-
   if (gamestate == GS_LEVEL && gametic)
     HU_Erase();
 
diff --git a/src/doomstat.h b/src/doomstat.h
index 6f30d5f7..8bccef38 100644
--- a/src/doomstat.h
+++ b/src/doomstat.h
@@ -368,8 +368,6 @@ extern  boolean precache;
 //  to force a wipe on the next draw
 extern  gamestate_t     wipegamestate;
 
-extern  boolean         enable_drs;
-
 extern  int             mouseSensitivity_horiz; // killough
 extern  int             mouseSensitivity_vert;
 extern  int             mouseSensitivity_horiz_strafe; // [FG] strafe
diff --git a/src/i_video.c b/src/i_video.c
index 3f3c903d..9377ccea 100644
--- a/src/i_video.c
+++ b/src/i_video.c
@@ -479,7 +479,7 @@ static int targetrefresh;
 static void ResetResolution(int height);
 static void ResetLogicalSize(void);
 
-static void DynamicResolution(void)
+void I_DynamicResolution(void)
 {
     if (resolution_mode != RES_DRS || frametime_withoutpresent == 0 ||
         frametime_withoutpresent > 1000000 / 15)
@@ -494,9 +494,10 @@ static void DynamicResolution(void)
     double actualpercent = actual / target;
 
     #define DRS_MIN_HEIGHT 400
-    #define DRS_DELTA 0.5
+    #define DRS_DELTA 0.01
     #define DRS_GREATER (1 + DRS_DELTA)
     #define DRS_LESS (1 - DRS_DELTA)
+    #define DRS_STEP (SCREENHEIGHT / 2)
 
     int newheight = 0;
     int oldheight = video.height;
@@ -516,6 +517,15 @@ static void DynamicResolution(void)
         return;
     }
 
+    int mul = (newheight + (DRS_STEP - 1)) / DRS_STEP; // integer round
+
+    newheight = mul * DRS_STEP;
+
+    if (newheight > native_height_adjusted)
+    {
+        newheight -= DRS_STEP;
+    }
+
     if (newheight == oldheight)
     {
         return;
@@ -563,8 +573,8 @@ void I_FinishUpdate(void)
 
         time = frametime_start - last_time;
 
-        // Update FPS counter every second
-        if (time >= 1000000)
+        // Update FPS counter every 10th of second
+        if (time >= 100000)
         {
             fps = (frame_counter * 1000000) / time;
             frame_counter = 0;
@@ -590,11 +600,6 @@ void I_FinishUpdate(void)
         I_ResetScreen();
         need_reset = false;
     }
-    else if (enable_drs)
-    {
-        DynamicResolution();
-        enable_drs = false;
-    }
 
     if (need_resize)
     {
@@ -966,14 +971,16 @@ static void ResetResolution(int height)
 {
     int w, h;
 
+    int unscaled_ah = use_aspect ? ACTUALHEIGHT : SCREENHEIGHT;
+
     actualheight = use_aspect ? (int)(height * 1.2) : height;
     video.height = height;
 
     switch (widescreen)
     {
         case RATIO_ORIG:
-            w = 4;
-            h = 3;
+            w = SCREENWIDTH;
+            h = unscaled_ah;
             break;
         case RATIO_MATCH_SCREEN:
             w = native_width;
@@ -1004,14 +1011,11 @@ static void ResetResolution(int height)
         aspect_ratio = 2.4;
     }
 
-    video.unscaledw = (int)(ACTUALHEIGHT * aspect_ratio);
-    video.width = (int)(actualheight * aspect_ratio);
+    video.unscaledw = (int)(unscaled_ah * aspect_ratio);
 
-    // width and height shoud be even
-    video.unscaledw = (video.unscaledw  + 1) & ~1;
-    video.width     = (video.width + 1) & ~1;
-    video.height    = (video.height + 1) & ~1;
-    actualheight    = (actualheight + 1) & ~1;
+    double vertscale = (double)actualheight / (double)unscaled_ah;
+    video.width = (int)(video.unscaledw * vertscale);
+    video.width = (video.width + 1) & ~1;
 
     video.deltaw = (video.unscaledw - NONWIDEWIDTH) / 2;
 
diff --git a/src/i_video.h b/src/i_video.h
index 2b6b01d4..8a564916 100644
--- a/src/i_video.h
+++ b/src/i_video.h
@@ -51,20 +51,22 @@ typedef enum
 // determines the hardware configuration
 // and sets up the video mode
 
-void I_InitGraphics (void);
+void I_InitGraphics(void);
 void I_ShutdownGraphics(void);
 
 // Takes full 8 bit values.
-void I_SetPalette (byte* palette);
+void I_SetPalette(byte* palette);
 
-void I_FinishUpdate (void);
+void I_FinishUpdate(void);
 
-void I_ReadScreen (byte* scr);
+void I_ReadScreen(byte* dst);
 
 void I_ResetScreen(void);   // killough 10/98
 void I_ResetTargetRefresh(void);
 void I_ToggleVsync(void); // [JN] Calls native SDL vsync toggle
 
+void I_DynamicResolution(void);
+
 extern boolean use_vsync;  // killough 2/8/98: controls whether vsync is called
 extern boolean disk_icon;  // killough 10/98
 extern resolution_mode_t resolution_mode, default_resolution_mode;