Hexen uncapped framerate (#854)

* Bind crispy_uncapped in Hexen

* Minimal uncapped framerate implementation

* Implement uncapped quake

* Implement uncapped sector height change

* Interpolate moving polyobjects

* Improve interpolation of moving polyobjects

Fixes out-of-sync polyobjects on Griffin Chapel. Thanks to @JNechaevsky
for letting me know about that particular stress test.

* Polyobject movment interpolation take 3

Handle interpolation in a more straightforward way.
Fix synchronization issues.
Add comments.

This could probably be handled better, but perfect is the enemy of done!

* Interpolate rotating polyobjects

* Properly adjust seg angles for rotating polys

No surprise, this greatly improves the smoothness of rotating poly
objects.

* Improve smoothness of poly movement interpolation

Fix logic error which was causing interpolation to terminate early,
resulting in stutter.

Improve handling of the first frame after starting a new gametic.

Fix dx and dy not being properly initialized. This would sometimes cause
polyobjects to shake when stopped.

* Poly movement refactor

Make the poly movement code mirror the poly rotation code. We now move
vertices, calculate the bounding boxes and then undo the movement if
interpolating.

Exit PO_InterpolatePolyObjects immediately if not interpolating.

* Remove some obsolete conditions

* Implement smooth wall texture scrolling

* Implement smooth flat scrolling

Thanks to @JNechaevsky for figuring out the trick with using the
ds_*frac values!

* Fix flat scrolling hitch when pausing

* Add uncapped framerate option to Crispness menu

src/hexen/g_game.c

@@ -1097,6 +1097,9 @@ void G_Ticker(void)
         inventory = false;
         cmd->arti = 0;
     }
+
+    oldleveltime = leveltime; // [crispy] Track if game is running
+
 //
 // do main actions
 //

src/hexen/h2_main.c

@@ -198,6 +198,7 @@ void D_BindVariables(void)
     M_BindIntVariable("crispy_smoothscaling",   &crispy->smoothscaling);
     M_BindIntVariable("crispy_vsync",           &crispy->vsync);
     M_BindIntVariable("crispy_widescreen",      &crispy->widescreen);
+    M_BindIntVariable("crispy_uncapped",        &crispy->uncapped);
 }
 
 // Set the default directory where hub savegames are saved.

src/hexen/h2def.h

@@ -222,6 +222,16 @@ typedef struct mobj_s
     short tid;                  // thing identifier
     byte special;               // special
     byte args[5];               // special arguments
+
+    // [AM] If true, ok to interpolate this tic.
+    int                 interp;
+
+    // [AM] Previous position of mobj before think.
+    //      Used to interpolate between positions.
+    fixed_t		oldx;
+    fixed_t		oldy;
+    fixed_t		oldz;
+    angle_t		oldangle;
 } mobj_t;
 
 // each sector has a degenmobj_t in it's center for sound origin purposes
@@ -567,6 +577,10 @@ typedef struct player_s
     int morphTics;              // player is a pig if > 0
     unsigned int jumpTics;      // delay the next jump for a moment
     unsigned int worldTimer;    // total time the player's been playing
+
+    // [AM] Previous position of viewz before think.
+    //      Used to interpolate between camera positions.
+    angle_t		oldviewz;
 } player_t;
 
 #define CF_NOCLIP		1

src/hexen/mn_menu.c

@@ -112,6 +112,7 @@ static boolean SCNetCheck(int option);
 static void CrispyHires(int option);
 static void CrispyToggleWidescreen(int option);
 static void CrispySmoothing(int option);
+static void CrispyUncapped(int option);
 static void CrispyVsync(int option);
 static void SCNetCheck2(int option);
 static void SCLoadGame(int option);
@@ -301,13 +302,14 @@ static MenuItem_t CrispnessItems[] = {
     {ITT_LRFUNC, "HIGH RESOLUTION RENDERING:", CrispyHires, 0, MENU_NONE},
     {ITT_LRFUNC, "ASPECT RATIO:", CrispyToggleWidescreen, 0, MENU_NONE},
     {ITT_LRFUNC, "SMOOTH PIXEL SCALING:", CrispySmoothing, 0, MENU_NONE},
+    {ITT_LRFUNC, "UNCAPPED FRAMERATE:", CrispyUncapped, 0, MENU_NONE},
     {ITT_LRFUNC, "ENABLE VSYNC:", CrispyVsync, 0, MENU_NONE}
 };
 
 static Menu_t CrispnessMenu = {
     68, 40,
     DrawCrispnessMenu,
-    4, CrispnessItems,
+    5, CrispnessItems,
     0,
     MENU_OPTIONS
 };
@@ -1253,6 +1255,11 @@ static void CrispySmoothing(int option)
     crispy->smoothscaling = !crispy->smoothscaling;
 }
 
+static void CrispyUncapped(int option)
+{
+    crispy->uncapped = !crispy->uncapped;
+}
+
 static void CrispyVsyncHook(void)
 {
     crispy->vsync = !crispy->vsync;
@@ -2034,8 +2041,11 @@ static void DrawCrispnessMenu(void)
     // Smooth pixel scaling
     MN_DrTextA(crispy->smoothscaling ? "ON" : "OFF", 216, 60);
 
+    // Uncapped framerate
+    MN_DrTextA(crispy->uncapped ? "ON" : "OFF", 217, 70);
+
     // Vsync
-    MN_DrTextA(crispy->vsync ? "ON" : "OFF", 167, 70);
+    MN_DrTextA(crispy->vsync ? "ON" : "OFF", 167, 80);
 
     dp_translation = NULL;
 }

src/hexen/p_anim.c

@@ -40,6 +40,8 @@
 #define LIGHTNING_SPECIAL2 	199
 #define SKYCHANGE_SPECIAL 	200
 
+#define TEXTURE_SCROLL_SHIFT    10 // [crispy]
+
 // TYPES -------------------------------------------------------------------
 
 typedef struct
@@ -142,16 +144,28 @@ void P_AnimateSurfaces(void)
         switch (line->special)
         {
             case 100:          // Scroll_Texture_Left
-                sides[line->sidenum[0]].textureoffset += line->arg1 << 10;
+                sides[line->sidenum[0]].basetextureoffset +=
+                    line->arg1 << TEXTURE_SCROLL_SHIFT;
+                sides[line->sidenum[0]].textureoffset =
+                    sides[line->sidenum[0]].basetextureoffset;
                 break;
             case 101:          // Scroll_Texture_Right
-                sides[line->sidenum[0]].textureoffset -= line->arg1 << 10;
+                sides[line->sidenum[0]].basetextureoffset -=
+                    line->arg1 << TEXTURE_SCROLL_SHIFT;
+                sides[line->sidenum[0]].textureoffset =
+                    sides[line->sidenum[0]].basetextureoffset;
                 break;
             case 102:          // Scroll_Texture_Up
-                sides[line->sidenum[0]].rowoffset += line->arg1 << 10;
+                sides[line->sidenum[0]].baserowoffset +=
+                    line->arg1 << TEXTURE_SCROLL_SHIFT;
+                sides[line->sidenum[0]].rowoffset =
+                    sides[line->sidenum[0]].baserowoffset;
                 break;
             case 103:          // Scroll_Texture_Down
-                sides[line->sidenum[0]].rowoffset -= line->arg1 << 10;
+                sides[line->sidenum[0]].baserowoffset -=
+                    line->arg1 << TEXTURE_SCROLL_SHIFT;
+                sides[line->sidenum[0]].rowoffset =
+                    sides[line->sidenum[0]].baserowoffset;
                 break;
         }
     }
@@ -173,6 +187,46 @@ void P_AnimateSurfaces(void)
     }
 }
 
+extern fixed_t fractionaltic; // [crispy]
+
+// [crispy] smooth texture scrolling
+void R_InterpolateTextureOffset(void)
+{
+    const line_t* line;
+    side_t* side;
+    int i;
+
+    if (!(crispy->uncapped && leveltime > oldleveltime))
+    {
+        return;
+    }
+
+    for (i = 0; i < numlinespecials; i++)
+    {
+        line = linespeciallist[i];
+        side = &sides[line->sidenum[0]];
+
+        switch (line->special)
+        {
+            case 100:       // Scroll_Texture_Right
+                side->textureoffset = side->basetextureoffset +
+                    (FixedMul(fractionaltic, line->arg1) << TEXTURE_SCROLL_SHIFT);
+                break;
+            case 101:       // Scroll_Texture_Left
+                side->textureoffset = side->basetextureoffset -
+                    (FixedMul(fractionaltic, line->arg1) << TEXTURE_SCROLL_SHIFT);
+                break;
+            case 102:       // Scroll_Texture_Up
+                side->rowoffset = side->baserowoffset +
+                    (FixedMul(fractionaltic, line->arg1) << TEXTURE_SCROLL_SHIFT);
+                break;
+            case 103:       // Scroll_Texture_Down
+                side->rowoffset = side->baserowoffset -
+                    (FixedMul(fractionaltic, line->arg1) << TEXTURE_SCROLL_SHIFT);
+                break;
+        }
+    }
+}
 //==========================================================================
 //
 // P_LightningFlash

src/hexen/p_floor.c

@@ -41,6 +41,11 @@ result_e T_MovePlane(sector_t * sector, fixed_t speed,
     boolean flag;
     fixed_t lastpos;
 
+    // [AM] Store old sector heights for interpolation.
+    sector->oldfloorheight = sector->floorheight;
+    sector->oldceilingheight = sector->ceilingheight;
+    sector->oldgametic = gametic;
+
     switch (floorOrCeiling)
     {
         case 0:                // FLOOR

src/hexen/p_mobj.c

@@ -1055,6 +1055,27 @@ static void PlayerLandedOnThing(mobj_t * mo, mobj_t * onmobj)
 void P_MobjThinker(mobj_t * mobj)
 {
     mobj_t *onmo;
+
+    // [crispy] suppress interpolation of player missiles for the first tic
+    if (mobj->interp == -1)
+    {
+        mobj->interp = false;
+    }
+    else
+    // [AM] Handle interpolation unless we're an active player.
+    if (!(mobj->player != NULL && mobj == mobj->player->mo))
+    {
+        // Assume we can interpolate at the beginning
+        // of the tic.
+        mobj->interp = true;
+
+        // Store starting position for mobj interpolation.
+        mobj->oldx = mobj->x;
+        mobj->oldy = mobj->y;
+        mobj->oldz = mobj->z;
+        mobj->oldangle = mobj->angle;
+    }
+
 /*
 	// Reset to not blasted when momentums are gone
 	if((mobj->flags2&MF2_BLASTED) && (!(mobj->momx)) && (!(mobj->momy)))
@@ -1246,6 +1267,15 @@ mobj_t *P_SpawnMobj(fixed_t x, fixed_t y, fixed_t z, mobjtype_t type)
         mobj->floorclip = 0;
     }
 
+    // [AM] Do not interpolate on spawn.
+    mobj->interp = false;
+
+    // [AM] Just in case interpolation is attempted...
+    mobj->oldx = mobj->x;
+    mobj->oldy = mobj->y;
+    mobj->oldz = mobj->z;
+    mobj->oldangle = mobj->angle;
+
     mobj->thinker.function = P_MobjThinker;
     P_AddThinker(&mobj->thinker);
     return (mobj);
@@ -2283,6 +2313,10 @@ mobj_t *P_SpawnPlayerMissile(mobj_t * source, mobjtype_t type)
         MissileMobj->y += (MissileMobj->momy >> 1);
         MissileMobj->z += (MissileMobj->momz >> 1);
     }
+
+    // [crispy] suppress interpolation of player missiles for the first tic
+    MissileMobj->interp = -1;
+
     if (!P_TryMove(MissileMobj, MissileMobj->x, MissileMobj->y))
     {                           // Exploded immediately
         P_ExplodeMissile(MissileMobj);

src/hexen/p_setup.c

@@ -297,6 +297,16 @@ void P_LoadSectors(int lump)
         ss->tag = SHORT(ms->tag);
         ss->thinglist = NULL;
         ss->seqType = SEQTYPE_STONE;    // default seqType
+
+        // [AM] Sector interpolation.  Even if we're
+        //      not running uncapped, the renderer still
+        //      uses this data.
+        ss->oldfloorheight = ss->floorheight;
+        ss->interpfloorheight = ss->floorheight;
+        ss->oldceilingheight = ss->ceilingheight;
+        ss->interpceilingheight = ss->ceilingheight;
+        // [crispy] inhibit sector interpolation during the 0th gametic
+        ss->oldgametic = -1;
     }
     W_ReleaseLumpNum(lump);
 }
@@ -691,6 +701,7 @@ void P_SetupLevel(int episode, int map, int playermask, skill_t skill)
 
     P_InitThinkers();
     leveltime = 0;
+    oldleveltime = 0;  // [crispy] Track if game is running
 
     M_snprintf(lumpname, sizeof(lumpname), "MAP%02d", map);
     lumpnum = W_GetNumForName(lumpname);

src/hexen/p_user.c

@@ -603,6 +603,17 @@ void P_PlayerThink(player_t * player)
     int floorType;
     mobj_t *pmo;
 
+    // [AM] Assume we can interpolate at the beginning
+    //      of the tic.
+    player->mo->interp = true;
+
+    // [AM] Store starting position for player interpolation.
+    player->mo->oldx = player->mo->x;
+    player->mo->oldy = player->mo->y;
+    player->mo->oldz = player->mo->z;
+    player->mo->oldangle = player->mo->angle;
+    player->oldviewz = player->viewz;
+
     // No-clip cheat
     if (player->cheats & CF_NOCLIP)
     {