Add demo rewinding

Preview is fairly basic, and only shows players
rewinding. Full state is restored via reloading
the replay and jumping to the timestamp once
the rewind is done.

src/d_main.c

@@ -568,6 +568,9 @@ static void D_Display(void)
 		V_DrawScaledPatch(viewwindowx + (BASEVIDWIDTH - SHORT(patch->width))/2, py, 0, patch);
 	}
 
+	if (demo.rewinding)
+		V_DrawFadeScreen(TC_RAINBOW, (leveltime & 0x20) ? SKINCOLOR_PASTEL : SKINCOLOR_MOONSLAM);
+
 	// vid size change is now finished if it was on...
 	vid.recalc = 0;
 

src/g_game.c

@@ -5875,6 +5875,168 @@ void G_GhostTicker(void)
 	}
 }
 
+// Demo rewinding functions
+typedef struct rewindinfo_s {
+	tic_t leveltime;
+
+	struct {
+		boolean ingame;
+		player_t player;
+		mobj_t mobj;
+	} playerinfo[MAXPLAYERS];
+
+	struct rewindinfo_s *prev;
+} rewindinfo_t;
+
+static tic_t currentrewindnum;
+static rewindinfo_t *rewindhead = NULL; // Reverse chronological order
+
+void G_InitDemoRewind(void)
+{
+	while (rewindhead)
+	{
+		rewindinfo_t *p = rewindhead->prev;
+		Z_Free(rewindhead);
+		rewindhead = p;
+	}
+
+	currentrewindnum = 0;
+}
+
+void G_StoreRewindInfo(void)
+{
+	static UINT8 timetolog = 8;
+	rewindinfo_t *info;
+	size_t i;
+
+	if (timetolog-- > 0)
+		return;
+	timetolog = 8;
+
+	info = Z_Calloc(sizeof(rewindinfo_t), PU_STATIC, NULL);
+
+	for (i = 0; i < MAXPLAYERS; i++)
+	{
+		if (!playeringame[i] || players[i].spectator)
+		{
+			info->playerinfo[i].ingame = false;
+			continue;
+		}
+
+		info->playerinfo[i].ingame = true;
+		memcpy(&info->playerinfo[i].player, &players[i], sizeof(player_t));
+		if (players[i].mo)
+			memcpy(&info->playerinfo[i].mobj, players[i].mo, sizeof(mobj_t));
+	}
+
+	info->leveltime = leveltime;
+	info->prev = rewindhead;
+	rewindhead = info;
+}
+
+void G_PreviewRewind(tic_t previewtime)
+{
+	size_t i, j;
+	fixed_t tweenvalue = 0;
+	rewindinfo_t *info = rewindhead, *next_info = rewindhead;
+	while (info->leveltime > previewtime && info->prev)
+	{
+		next_info = info;
+		info = info->prev;
+	}
+	if (info != next_info)
+		tweenvalue = FixedDiv(previewtime - info->leveltime, next_info->leveltime - info->leveltime);
+
+	for (i = 0; i < MAXPLAYERS; i++)
+	{
+		if (!playeringame[i] || players[i].spectator)
+		{
+			if (info->playerinfo[i].player.mo)
+			{
+				//@TODO spawn temp object to act as a player display
+			}
+
+			continue;
+		}
+
+		if (!info->playerinfo[i].ingame || !info->playerinfo[i].player.mo)
+		{
+			if (players[i].mo)
+				players[i].mo->flags2 |= MF2_DONTDRAW;
+
+			continue;
+		}
+
+		if (!players[i].mo)
+			continue; //@TODO spawn temp object to act as a player display
+
+		players[i].mo->flags2 &= ~MF2_DONTDRAW;
+
+		P_UnsetThingPosition(players[i].mo);
+#define TWEEN(pr) info->playerinfo[i].mobj.pr + FixedMul((INT32) (next_info->playerinfo[i].mobj.pr - info->playerinfo[i].mobj.pr), tweenvalue)
+		players[i].mo->x = TWEEN(x);
+		players[i].mo->y = TWEEN(y);
+		players[i].mo->z = TWEEN(z);
+		players[i].mo->angle = TWEEN(angle);
+#undef TWEEN
+		P_SetThingPosition(players[i].mo);
+
+		players[i].frameangle = info->playerinfo[i].player.frameangle + FixedMul((INT32) (next_info->playerinfo[i].player.frameangle - info->playerinfo[i].player.frameangle), tweenvalue);
+
+		players[i].mo->sprite = info->playerinfo[i].mobj.sprite;
+		players[i].mo->frame = info->playerinfo[i].mobj.frame;
+
+		players[i].realtime = info->playerinfo[i].player.realtime;
+		for (j = 0; j < NUMKARTSTUFF; j++)
+			players[i].kartstuff[j] = info->playerinfo[i].player.kartstuff[j];
+	}
+
+	for (i = splitscreen+1; i > 0; i--)
+		P_ResetCamera(&players[(*G_GetDisplayplayerPtr(i))], P_GetCameraPtr(i));
+}
+
+void G_ConfirmRewind(tic_t rewindtime)
+{
+	tic_t i;
+	boolean oldmenuactive = menuactive, oldsounddisabled = sound_disabled, olddigitaldisabled = digital_disabled;
+
+	INT32 olddp1 = displayplayer, olddp2 = secondarydisplayplayer, olddp3 = thirddisplayplayer, olddp4 = fourthdisplayplayer;
+	UINT8 oldss = splitscreen;
+
+	cv_renderview.value = 0;
+
+	menuactive = false; // Prevent loops
+	sound_disabled = /*digital_disabled =*/ true; // Prevent sound spam
+	demo.rewinding = true; // may not need later
+	G_DoPlayDemo(NULL); // Restart the current demo
+
+	for (i = 0; i < rewindtime && leveltime < rewindtime; i++)
+	{
+		//TryRunTics(1);
+		G_Ticker((i % NEWTICRATERATIO) == 0);
+	}
+
+	demo.rewinding = false;
+	menuactive = oldmenuactive; // Bring the menu back up
+	sound_disabled = oldsounddisabled; // Re-enable SFX
+	digital_disabled = olddigitaldisabled;
+
+	wipegamestate = gamestate; // No fading back in!
+
+	cv_renderview.value = 1;
+
+	splitscreen = oldss;
+	displayplayer = olddp1;
+	secondarydisplayplayer = olddp2;
+	thirddisplayplayer = olddp3;
+	fourthdisplayplayer = olddp4;
+	R_ExecuteSetViewSize();
+	G_ResetViews();
+
+	for (i = splitscreen+1; i > 0; i--)
+		P_ResetCamera(&players[(*G_GetDisplayplayerPtr(i))], P_GetCameraPtr(i));
+}
+
 void G_ReadMetalTic(mobj_t *metal)
 {
 	UINT8 ziptic;
@@ -6842,9 +7004,19 @@ void G_DoPlayDemo(char *defdemoname)
 	boolean spectator;
 	UINT8 slots[MAXPLAYERS], kartspeed[MAXPLAYERS], kartweight[MAXPLAYERS], numslots = 0;
 
+	G_InitDemoRewind();
+
 	skin[16] = '\0';
 	color[16] = '\0';
 
+	// No demo name means we're restarting the current demo
+	if (defdemoname == NULL)
+	{
+		demo_p = demobuffer;
+		pdemoname = ZZ_Alloc(1); // Easier than adding checks for this everywhere it's freed
+	}
+	else
+	{
 		n = defdemoname+strlen(defdemoname);
 		while (*n != '/' && *n != '\\' && n != defdemoname)
 			n--;
@@ -6883,6 +7055,7 @@ void G_DoPlayDemo(char *defdemoname)
 			skiperrors = true; // SRB2Kart: Don't print warnings for staff ghosts, since they'll inevitably happen when we make bugfixes/changes...
 #endif
 		}
+	}
 
 	// read demo header
 	gameaction = ga_nothing;

src/g_game.h

@@ -43,6 +43,7 @@ struct demovars_s {
 	char titlename[65];
 	boolean recording, playback, timing;
 	boolean title; // Title Screen demo can be cancelled by any key
+	boolean rewinding; // Rewind in progress
 
 	boolean loadfiles, ignorefiles; // Demo file loading options
 	boolean fromtitle; // SRB2Kart: Don't stop the music
@@ -234,6 +235,12 @@ void G_WriteGhostTic(mobj_t *ghost, INT32 playernum);
 void G_ConsAllGhostTics(void);
 void G_ConsGhostTic(INT32 playernum);
 void G_GhostTicker(void);
+
+void G_InitDemoRewind(void);
+void G_StoreRewindInfo(void);
+void G_PreviewRewind(tic_t previewtime);
+void G_ConfirmRewind(tic_t rewindtime);
+
 void G_ReadMetalTic(mobj_t *metal);
 void G_WriteMetalTic(mobj_t *metal);
 void G_SaveMetal(UINT8 **buffer);

src/m_menu.c

@@ -346,6 +346,7 @@ static void M_EnterReplayOptions(INT32 choice);
 static void M_HutStartReplay(INT32 choice);
 
 static void M_DrawPlaybackMenu(void);
+static void M_PlaybackRewind(INT32 choice);
 static void M_PlaybackPause(INT32 choice);
 static void M_PlaybackFastForward(INT32 choice);
 static void M_PlaybackAdvance(INT32 choice);
@@ -569,7 +570,7 @@ static menuitem_t PlaybackMenu[] =
 {
 	{IT_CALL   | IT_STRING, "M_PHIDE",  "Hide Menu", M_SelectableClearMenus, 0},
 
-	{IT_CALL   | IT_STRING, "M_PREW",   "Rewind",        M_SelectableClearMenus, 24},
+	{IT_CALL   | IT_STRING, "M_PREW",   "Rewind",        M_PlaybackRewind,      24},
 	{IT_CALL   | IT_STRING, "M_PPAUSE", "Pause",         M_PlaybackPause,       40},
 	{IT_CALL   | IT_STRING, "M_PRESUM", "Resume",        M_PlaybackPause,       40},
 	{IT_CALL   | IT_STRING, "M_PFFWD",  "Fast-Foward",   M_PlaybackFastForward, 56},
@@ -5713,7 +5714,7 @@ static void M_DrawPlaybackMenu(void)
 	UINT8 *activemap = R_GetTranslationColormap(TC_RAINBOW, SKINCOLOR_GOLD, GTC_MENUCACHE);
 
 	// Toggle items
-	if (paused)
+	if (paused && !demo.rewinding)
 	{
 		PlaybackMenu[playback_pause].status = PlaybackMenu[playback_fastforward].status = IT_DISABLED;
 		PlaybackMenu[playback_resume].status = PlaybackMenu[playback_advanceframe].status = IT_CALL|IT_STRING;
@@ -5768,13 +5769,32 @@ static void M_DrawPlaybackMenu(void)
 	}
 }
 
+static void M_PlaybackRewind(INT32 choice)
+{
+	(void)choice;
+
+	if (!demo.rewinding)
+		demo.rewinding = paused = true;
+	else
+		G_ConfirmRewind(leveltime);
+
+	// temp
+	//G_ConfirmRewind(starttime + 90*TICRATE);
+}
+
 static void M_PlaybackPause(INT32 choice)
 {
 	(void)choice;
 
 	paused = !paused;
 
-	if (paused)
+	if (demo.rewinding)
+	{
+		G_ConfirmRewind(leveltime);
+		paused = true;
+		S_PauseAudio();
+	}
+	else if (paused)
 	{
 		itemOn = playback_resume;
 		S_PauseAudio();
@@ -5792,6 +5812,12 @@ static void M_PlaybackFastForward(INT32 choice)
 {
 	(void)choice;
 
+	if (demo.rewinding)
+	{
+		G_ConfirmRewind(leveltime);
+		paused = false;
+		S_ResumeAudio();
+	}
 	CV_SetValue(&cv_playbackspeed, cv_playbackspeed.value == 1 ? 4 : 1);
 }
 

src/p_setup.c

@@ -2829,7 +2829,7 @@ boolean P_SetupLevel(boolean skipprecip)
 
 	// Encore mode fade to pink to white
 	// This is handled BEFORE sounds are stopped.
-	if (rendermode != render_none && encoremode && !prevencoremode)
+	if (rendermode != render_none && encoremode && !prevencoremode && !demo.rewinding)
 	{
 		tic_t locstarttime, endtime, nowtime;
 
@@ -2881,7 +2881,7 @@ boolean P_SetupLevel(boolean skipprecip)
 
 	// Let's fade to white here
 	// But only if we didn't do the encore startup wipe
-	if (rendermode != render_none && !ranspecialwipe)
+	if (rendermode != render_none && !ranspecialwipe && !demo.rewinding)
 	{
 		F_WipeStartScreen();
 		V_DrawFill(0, 0, BASEVIDWIDTH, BASEVIDHEIGHT, levelfadecol);

src/p_tick.c

@@ -591,7 +591,15 @@ void P_Ticker(boolean run)
 
 	// Check for pause or menu up in single player
 	if (paused || P_AutoPause())
+	{
+		if (demo.rewinding && leveltime > 0)
+		{
+			leveltime = (leveltime-1) & ~3;
+			G_PreviewRewind(leveltime);
+		}
+
 		return;
+	}
 
 	postimgtype = postimgtype2 = postimgtype3 = postimgtype4 = postimg_none;
 
@@ -768,6 +776,9 @@ void P_Ticker(boolean run)
 
 	P_MapEnd();
 
+	if (demo.playback)
+		G_StoreRewindInfo();
+
 //	Z_CheckMemCleanup();
 }
 

src/s_sound.c

@@ -1733,7 +1733,7 @@ void S_ShowMusicCredit(void)
 {
 	musicdef_t *def = musicdefstart;
 
-	if (!cv_songcredits.value)
+	if (!cv_songcredits.value || demo.rewinding)
 		return;
 
 	if (!def) // No definitions
@@ -1920,6 +1920,7 @@ void S_ChangeMusic(const char *mmusic, UINT16 mflags, boolean looping)
 #endif
 
 	if (S_MusicDisabled()
+		|| demo.rewinding // Don't mess with music while rewinding!
 		|| demo.title) // SRB2Kart: Demos don't interrupt title screen music
 		return;
 
@@ -1955,6 +1956,7 @@ void S_ChangeMusic(const char *mmusic, UINT16 mflags, boolean looping)
 void S_StopMusic(void)
 {
 	if (!I_SongPlaying()
+		|| demo.rewinding // Don't mess with music while rewinding!
 		|| demo.title) // SRB2Kart: Demos don't interrupt title screen music
 		return;
 

src/v_video.c

@@ -1234,7 +1234,10 @@ void V_DrawFadeScreen(UINT16 color, UINT8 strength)
 #endif
 
     {
-        const UINT8 *fadetable = ((color & 0xFF00) // Color is not palette index?
+        const UINT8 *fadetable =
+			(color > 0xFFF0) // Grab a specific colormap palette?
+			? R_GetTranslationColormap(color | 0xFFFF0000, strength, GTC_CACHE)
+			: ((color & 0xFF00) // Color is not palette index?
 			? ((UINT8 *)colormaps + strength*256) // Do COLORMAP fade.
 			: ((UINT8 *)transtables + ((9-strength)<<FF_TRANSSHIFT) + color*256)); // Else, do TRANSMAP** fade.
         const UINT8 *deststop = screens[0] + vid.rowbytes * vid.height;