Allow Record Attack in modified games

Replays now store & validate the add-on list before loading them. Custom characters can now be allowed in Record Attack.

src/d_netcmd.c

@@ -1643,9 +1643,14 @@ static void Command_Playdemo_f(void)
 {
 	char name[256];
 
-	if (COM_Argc() != 2)
+	if (COM_Argc() < 2)
 	{
-		CONS_Printf(M_GetText("playdemo <demoname>: playback a demo\n"));
+		CONS_Printf("playdemo <demoname> [-addfiles / -force]:\n");
+		CONS_Printf(M_GetText(
+					"Play back a demo file. The full path from your SRB2 directory must be given.\n\n"
+
+					"* With \"-addfiles\", any required files are added from a list contained within the demo file.\n"
+					"* With \"-force\", the demo is played even if the necessary files have not been added.\n"));
 		return;
 	}
 
@@ -1667,6 +1672,16 @@ static void Command_Playdemo_f(void)
 
 	CONS_Printf(M_GetText("Playing back demo '%s'.\n"), name);
 
+	demofileoverride = DFILE_OVERRIDE_NONE;
+	if (strcmp(COM_Argv(2), "-addfiles") == 0)
+	{
+		demofileoverride = DFILE_OVERRIDE_LOAD;
+	}
+	else if (strcmp(COM_Argv(2), "-force") == 0)
+	{
+		demofileoverride = DFILE_OVERRIDE_SKIP;
+	}
+
 	// Internal if no extension, external if one exists
 	// If external, convert the file name to a path in SRB2's home directory
 	if (FIL_CheckExtension(name))

src/f_finale.c

@@ -3509,6 +3509,7 @@ void F_TitleScreenTicker(boolean run)
 		}
 
 		titledemo = true;
+		demofileoverride = DFILE_OVERRIDE_NONE;
 		G_DoPlayDemo(dname);
 	}
 }

src/g_demo.c

@@ -39,6 +39,7 @@
 #include "v_video.h"
 #include "lua_hook.h"
 #include "md5.h" // demo checksums
+#include "d_netfil.h" // G_CheckDemoExtraFiles
 
 boolean timingdemo; // if true, exit with report on completion
 boolean nodrawers; // for comparative timing purposes
@@ -49,6 +50,7 @@ static char demoname[64];
 boolean demorecording;
 boolean demoplayback;
 boolean titledemo; // Title Screen demo can be cancelled by any key
+demo_file_override_e demofileoverride;
 static UINT8 *demobuffer = NULL;
 static UINT8 *demo_p, *demotime_p;
 static UINT8 *demoend;
@@ -95,7 +97,7 @@ demoghost *ghosts = NULL;
 // DEMO RECORDING
 //
 
-#define DEMOVERSION 0x000f
+#define DEMOVERSION 0x0010
 #define DEMOHEADER  "\xF0" "SRB2Replay" "\x0F"
 
 #define DF_GHOST        0x01 // This demo contains ghost data too!
@@ -1413,6 +1415,10 @@ void G_BeginRecording(void)
 	char name[MAXCOLORNAME+1];
 	player_t *player = &players[consoleplayer];
 
+	char *filename;
+	UINT8 totalfiles;
+	UINT8 *m;
+
 	if (demo_p)
 		return;
 	memset(name,0,sizeof(name));
@@ -1435,23 +1441,43 @@ void G_BeginRecording(void)
 	M_Memcpy(demo_p, mapmd5, 16); demo_p += 16;
 
 	WRITEUINT8(demo_p,demoflags);
+
+	// file list
+	m = demo_p;/* file count */
+	demo_p += 1;
+
+	totalfiles = 0;
+	for (i = mainwads; ++i < numwadfiles; )
+	{
+		if (wadfiles[i]->important)
+		{
+			nameonly(( filename = va("%s", wadfiles[i]->filename) ));
+			WRITESTRINGL(demo_p, filename, MAX_WADPATH);
+			WRITEMEM(demo_p, wadfiles[i]->md5sum, 16);
+
+			totalfiles++;
+		}
+	}
+
+	WRITEUINT8(m, totalfiles);
+
 	switch ((demoflags & DF_ATTACKMASK)>>DF_ATTACKSHIFT)
 	{
-	case ATTACKING_NONE: // 0
-		break;
-	case ATTACKING_RECORD: // 1
-		demotime_p = demo_p;
-		WRITEUINT32(demo_p,UINT32_MAX); // time
-		WRITEUINT32(demo_p,0); // score
-		WRITEUINT16(demo_p,0); // rings
-		break;
-	case ATTACKING_NIGHTS: // 2
-		demotime_p = demo_p;
-		WRITEUINT32(demo_p,UINT32_MAX); // time
-		WRITEUINT32(demo_p,0); // score
-		break;
-	default: // 3
-		break;
+		case ATTACKING_NONE: // 0
+			break;
+		case ATTACKING_RECORD: // 1
+			demotime_p = demo_p;
+			WRITEUINT32(demo_p,UINT32_MAX); // time
+			WRITEUINT32(demo_p,0); // score
+			WRITEUINT16(demo_p,0); // rings
+			break;
+		case ATTACKING_NIGHTS: // 2
+			demotime_p = demo_p;
+			WRITEUINT32(demo_p,UINT32_MAX); // time
+			WRITEUINT32(demo_p,0); // score
+			break;
+		default: // 3
+			break;
 	}
 
 	WRITEUINT32(demo_p,P_GetInitSeed());
@@ -1590,6 +1616,177 @@ void G_BeginMetal(void)
 	oldmetal.angle = mo->angle>>24;
 }
 
+static void G_LoadDemoExtraFiles(UINT8 **pp)
+{
+	UINT8 totalfiles;
+	char filename[MAX_WADPATH];
+	UINT8 md5sum[16];
+	filestatus_t ncs;
+	boolean toomany = false;
+	boolean alreadyloaded;
+	UINT8 i, j;
+
+	totalfiles = READUINT8((*pp));
+	for (i = 0; i < totalfiles; ++i)
+	{
+		if (toomany)
+			SKIPSTRING((*pp));
+		else
+		{
+			strlcpy(filename, (char *)(*pp), sizeof filename);
+			SKIPSTRING((*pp));
+		}
+		READMEM((*pp), md5sum, 16);
+
+		if (!toomany)
+		{
+			alreadyloaded = false;
+
+			for (j = 0; j < numwadfiles; ++j)
+			{
+				if (memcmp(md5sum, wadfiles[j]->md5sum, 16) == 0)
+				{
+					alreadyloaded = true;
+					break;
+				}
+			}
+
+			if (alreadyloaded)
+				continue;
+
+			if (numwadfiles >= MAX_WADFILES)
+				toomany = true;
+			else
+				ncs = findfile(filename, md5sum, false);
+
+			if (toomany)
+			{
+				CONS_Alert(CONS_WARNING, M_GetText("Too many files loaded to add anymore for demo playback\n"));
+				if (!CON_Ready())
+					M_StartMessage(M_GetText("There are too many files loaded to add this demo's addons.\n\nDemo playback may desync.\n\nPress ESC\n"), NULL, MM_NOTHING);
+			}
+			else if (ncs != FS_FOUND)
+			{
+				if (ncs == FS_NOTFOUND)
+					CONS_Alert(CONS_NOTICE, M_GetText("You do not have a copy of %s\n"), filename);
+				else if (ncs == FS_MD5SUMBAD)
+					CONS_Alert(CONS_NOTICE, M_GetText("Checksum mismatch on %s\n"), filename);
+				else
+					CONS_Alert(CONS_NOTICE, M_GetText("Unknown error finding file %s\n"), filename);
+
+				if (!CON_Ready())
+					M_StartMessage(M_GetText("There were errors trying to add this demo's addons. Check the console for more information.\n\nDemo playback may desync.\n\nPress ESC\n"), NULL, MM_NOTHING);
+			}
+			else
+			{
+				P_AddWadFile(filename);
+			}
+		}
+	}
+}
+
+static void G_SkipDemoExtraFiles(UINT8 **pp)
+{
+	UINT8 totalfiles;
+	UINT8 i;
+
+	if (demoversion < 0x0010)
+	{
+		// demo has no file list
+		return;
+	}
+
+	totalfiles = READUINT8((*pp));
+	for (i = 0; i < totalfiles; ++i)
+	{
+		SKIPSTRING((*pp));// file name
+		(*pp) += 16;// md5
+	}
+}
+
+// G_CheckDemoExtraFiles: checks if our loaded WAD list matches the demo's.
+// Enabling quick prevents filesystem checks to see if needed files are available to load.
+static UINT8 G_CheckDemoExtraFiles(UINT8 **pp, boolean quick)
+{
+	UINT8 totalfiles, filesloaded, nmusfilecount;
+	char filename[MAX_WADPATH];
+	UINT8 md5sum[16];
+	boolean toomany = false;
+	boolean alreadyloaded;
+	UINT8 i, j;
+	UINT8 error = DFILE_ERROR_NONE;
+
+	if (demoversion < 0x0010)
+	{
+		// demo has no file list
+		return DFILE_ERROR_NONE;
+	}
+
+	totalfiles = READUINT8((*pp));
+	filesloaded = 0;
+	for (i = 0; i < totalfiles; ++i)
+	{
+		if (toomany)
+			SKIPSTRING((*pp));
+		else
+		{
+			strlcpy(filename, (char *)(*pp), sizeof filename);
+			SKIPSTRING((*pp));
+		}
+		READMEM((*pp), md5sum, 16);
+
+		if (!toomany)
+		{
+			alreadyloaded = false;
+			nmusfilecount = 0;
+
+			for (j = 0; j < numwadfiles; ++j)
+			{
+				if (wadfiles[j]->important && j > mainwads)
+					nmusfilecount++;
+				else
+					continue;
+
+				if (memcmp(md5sum, wadfiles[j]->md5sum, 16) == 0)
+				{
+					alreadyloaded = true;
+
+					if (i != nmusfilecount-1 && error < DFILE_ERROR_OUTOFORDER)
+						error |= DFILE_ERROR_OUTOFORDER;
+
+					break;
+				}
+			}
+
+			if (alreadyloaded)
+			{
+				filesloaded++;
+				continue;
+			}
+
+			if (numwadfiles >= MAX_WADFILES)
+				error = DFILE_ERROR_CANNOTLOAD;
+			else if (!quick && findfile(filename, md5sum, false) != FS_FOUND)
+				error = DFILE_ERROR_CANNOTLOAD;
+			else if (error < DFILE_ERROR_INCOMPLETEOUTOFORDER)
+				error |= DFILE_ERROR_NOTLOADED;
+		} else
+			error = DFILE_ERROR_CANNOTLOAD;
+	}
+
+	// Get final file count
+	nmusfilecount = 0;
+
+	for (j = 0; j < numwadfiles; ++j)
+		if (wadfiles[j]->important && j > mainwads)
+			nmusfilecount++;
+
+	if (!error && filesloaded < nmusfilecount)
+		error = DFILE_ERROR_EXTRAFILES;
+
+	return error;
+}
+
 void G_SetDemoTime(UINT32 ptime, UINT32 pscore, UINT16 prings)
 {
 	if (!demorecording || !demotime_p)
@@ -1645,7 +1842,7 @@ UINT8 G_CmpDemoTime(char *oldname, char *newname)
 	p += 2; // gamemap
 	p += 16; // map md5
 	flags = READUINT8(p); // demoflags
-
+	G_SkipDemoExtraFiles(&p);
 	aflags = flags & (DF_RECORDATTACK|DF_NIGHTSATTACK);
 	I_Assert(aflags);
 	if (flags & DF_RECORDATTACK)
@@ -1710,6 +1907,7 @@ UINT8 G_CmpDemoTime(char *oldname, char *newname)
 		p += 2; // gamemap
 	p += 16; // mapmd5
 	flags = READUINT8(p);
+	G_SkipDemoExtraFiles(&p);
 	if (!(flags & aflags))
 	{
 		CONS_Alert(CONS_NOTICE, M_GetText("File '%s' not from same game mode. It will be overwritten.\n"), oldname);
@@ -1871,6 +2069,73 @@ void G_DoPlayDemo(char *defdemoname)
 	demo_p += 16; // mapmd5
 
 	demoflags = READUINT8(demo_p);
+
+	if (demoversion < 0x0010)
+	{
+		; // Don't do anything with files.
+	}
+	else if (titledemo)
+	{
+		// Titledemos should always play and ought to always be compatible with whatever wadlist is running.
+		G_SkipDemoExtraFiles(&demo_p);
+	}
+	else if (demofileoverride == DFILE_OVERRIDE_LOAD)
+	{
+		G_LoadDemoExtraFiles(&demo_p);
+	}
+	else if (demofileoverride == DFILE_OVERRIDE_SKIP)
+	{
+		G_SkipDemoExtraFiles(&demo_p);
+	}
+	else
+	{
+		UINT8 error = G_CheckDemoExtraFiles(&demo_p, false);
+
+		if (error)
+		{
+			switch (error)
+			{
+				case DFILE_ERROR_NOTLOADED:
+					snprintf(msg, 1024,
+						M_GetText("Required files for this demo are not loaded.\n\nUse\n\"playdemo %s -addfiles\"\nto load them and play the demo.\n"),
+					pdemoname);
+					break;
+
+				case DFILE_ERROR_OUTOFORDER:
+					snprintf(msg, 1024,
+						M_GetText("Required files for this demo are loaded out of order.\n\nUse\n\"playdemo %s -force\"\nto play the demo anyway.\n"),
+					pdemoname);
+					break;
+
+				case DFILE_ERROR_INCOMPLETEOUTOFORDER:
+					snprintf(msg, 1024,
+						M_GetText("Required files for this demo are not loaded, and some are out of order.\n\nUse\n\"playdemo %s -addfiles\"\nto load needed files and play the demo.\n"),
+					pdemoname);
+					break;
+
+				case DFILE_ERROR_CANNOTLOAD:
+					snprintf(msg, 1024,
+						M_GetText("Required files for this demo cannot be loaded.\n\nUse\n\"playdemo %s -force\"\nto play the demo anyway.\n"),
+					pdemoname);
+					break;
+
+				case DFILE_ERROR_EXTRAFILES:
+					snprintf(msg, 1024,
+						M_GetText("You have additional files loaded beyond the demo's file list.\n\nUse\n\"playdemo %s -force\"\nto play the demo anyway.\n"),
+					pdemoname);
+					break;
+			}
+
+			CONS_Alert(CONS_ERROR, "%s", msg);
+			M_StartMessage(msg, NULL, MM_NOTHING);
+			Z_Free(pdemoname);
+			Z_Free(demobuffer);
+			demoplayback = false;
+			titledemo = false;
+			return;
+		}
+	}
+
 	modeattacking = (demoflags & DF_ATTACKMASK)>>DF_ATTACKSHIFT;
 	CON_ToggleOff();
 
@@ -2026,6 +2291,91 @@ void G_DoPlayDemo(char *defdemoname)
 	demo_start = true;
 }
 
+//
+// Check if a replay can be loaded from the menu
+//
+UINT8 G_CheckDemoForError(char *defdemoname)
+{
+	lumpnum_t l;
+	char *n,*pdemoname;
+
+	n = defdemoname+strlen(defdemoname);
+	while (*n != '/' && *n != '\\' && n != defdemoname)
+		n--;
+	if (n != defdemoname)
+		n++;
+	pdemoname = ZZ_Alloc(strlen(n)+1);
+	strcpy(pdemoname,n);
+
+	// Internal if no extension, external if one exists
+	if (FIL_CheckExtension(defdemoname))
+	{
+		//FIL_DefaultExtension(defdemoname, ".lmp");
+		if (!FIL_ReadFile(defdemoname, &demobuffer))
+		{
+			return DFILE_ERROR_NOTDEMO;
+		}
+		demo_p = demobuffer;
+	}
+	// load demo resource from WAD
+	else if ((l = W_CheckNumForName(defdemoname)) == LUMPERROR)
+	{
+		return DFILE_ERROR_NOTDEMO;
+	}
+	else // it's an internal demo
+	{
+		demobuffer = demo_p = W_CacheLumpNum(l, PU_STATIC);
+	}
+
+	// read demo header
+	if (memcmp(demo_p, DEMOHEADER, 12))
+	{
+		return DFILE_ERROR_NOTDEMO;
+	}
+	demo_p += 12; // DEMOHEADER
+
+	demo_p++; // version
+	demo_p++; // subversion
+	demoversion = READUINT16(demo_p);
+	switch(demoversion)
+	{
+	case 0x000d:
+	case 0x000e:
+	case 0x000f:
+	case DEMOVERSION: // latest always supported
+		break;
+#ifdef OLD22DEMOCOMPAT
+	case 0x000c:
+		break;
+#endif
+	// too old, cannot support.
+	default:
+		return DFILE_ERROR_NOTDEMO;
+	}
+	demo_p += 16; // demo checksum
+	if (memcmp(demo_p, "PLAY", 4))
+	{
+		return DFILE_ERROR_NOTDEMO;
+	}
+	demo_p += 4; // "PLAY"
+	demo_p += 2; // gamemap
+	demo_p += 16; // mapmd5
+
+	demo_p++; // demoflags
+
+	// Don't do anything with files.
+	if (demoversion < 0x0010)
+	{
+		return DFILE_ERROR_NONE;
+	}
+	else if (titledemo)
+	{
+		return DFILE_ERROR_NONE;
+	}
+
+	return G_CheckDemoExtraFiles(&demo_p, true);
+}
+
 void G_AddGhost(char *defdemoname)
 {
 	INT32 i;
@@ -2130,6 +2480,9 @@ void G_AddGhost(char *defdemoname)
 		Z_Free(buffer);
 		return;
 	}
+
+	G_SkipDemoExtraFiles(&p); // Don't wanna modify the file list for ghosts.
+
 	switch ((flags & DF_ATTACKMASK)>>DF_ATTACKSHIFT)
 	{
 	case ATTACKING_NONE: // 0

src/g_demo.h

@@ -26,6 +26,15 @@
 extern boolean demoplayback, titledemo, demorecording, timingdemo;
 extern tic_t demostarttime;
 
+typedef enum
+{
+	DFILE_OVERRIDE_NONE = 0, // Show errors normally
+	DFILE_OVERRIDE_LOAD, // Forcefully load demo, add files beforehand
+	DFILE_OVERRIDE_SKIP, // Forcefully load demo, skip file list
+} demo_file_override_e;
+
+extern demo_file_override_e demofileoverride;
+
 // Quit after playing a demo from cmdline.
 extern boolean singledemo;
 extern boolean demo_start;
@@ -53,6 +62,18 @@ typedef enum
 	GHC_RETURNSKIN // ditto
 } ghostcolor_t;
 
+// G_CheckDemoExtraFiles: checks if our loaded WAD list matches the demo's.
+typedef enum
+{
+	DFILE_ERROR_NONE = 0, // No file error
+	DFILE_ERROR_NOTLOADED, // Files are not loaded, but can be without a restart.
+	DFILE_ERROR_OUTOFORDER, // Files are loaded, but out of order.
+	DFILE_ERROR_INCOMPLETEOUTOFORDER, // Some files are loaded out of order, but others are not.
+	DFILE_ERROR_CANNOTLOAD, // Files are missing and cannot be loaded.
+	DFILE_ERROR_EXTRAFILES, // Extra files outside of the replay's file list are loaded.
+	DFILE_ERROR_NOTDEMO = UINT8_MAX, // This replay isn't even a replay...
+} demo_file_error_e;
+
 // Record/playback tics
 void G_ReadDemoTiccmd(ticcmd_t *cmd, INT32 playernum);
 void G_WriteDemoTiccmd(ticcmd_t *cmd, INT32 playernum);
@@ -83,5 +104,6 @@ ATTRNORETURN void FUNCNORETURN G_StopMetalRecording(boolean kill);
 void G_StopDemo(void);
 boolean G_CheckDemoStatus(void);
 INT32 G_ConvertOldFrameFlags(INT32 frame);
+UINT8 G_CheckDemoForError(char *defdemoname);
 
 #endif // __G_DEMO__

src/m_menu.c

@@ -3500,10 +3500,10 @@ boolean M_Responder(event_t *ev)
 #ifndef DEVELOP
 					// TODO: Replays are scary, so I left the remaining instances of this alone.
 					// It'd be nice to get rid of this once and for all though!
-					if (((currentMenu->menuitems[itemOn].status & IT_CALLTYPE) & IT_CALL_NOTMODIFIED) && (modifiedgame && !savemoddata) && !usedCheats)
+					if (((currentMenu->menuitems[itemOn].status & IT_CALLTYPE) & IT_CALL_NOTMODIFIED) && usedCheats)
 					{
 						S_StartSound(NULL, sfx_skid);
-						M_StartMessage(M_GetText("This cannot be done in a modified game.\n\n(Press a key)\n"), NULL, MM_NOTHING);
+						M_StartMessage(M_GetText("This cannot be done in a cheated game.\n\n(Press a key)\n"), NULL, MM_NOTHING);
 						return true;
 					}
 #endif
@@ -10449,13 +10449,23 @@ static void M_ChooseTimeAttack(INT32 choice)
 	G_DeferedInitNew(false, G_BuildMapName(cv_nextmap.value), (UINT8)(cv_chooseskin.value-1), false, false);
 }
 
+static char ra_demoname[1024];
+
+static void M_StartTimeAttackReplay(INT32 choice)
+{
+	if (choice == 'y' || choice == KEY_ENTER)
+	{
+		M_ClearMenus(true);
+		modeattacking = ATTACKING_RECORD; // set modeattacking before G_DoPlayDemo so the map loader knows
+		G_DoPlayDemo(ra_demoname);
+	}
+}
+
 // Player has selected the "REPLAY" from the time attack screen
 static void M_ReplayTimeAttack(INT32 choice)
 {
 	const char *which;
-	char *demoname;
-	M_ClearMenus(true);
-	modeattacking = ATTACKING_RECORD; // set modeattacking before G_DoPlayDemo so the map loader knows
+	UINT8 error = DFILE_ERROR_NONE;
 
 	if (currentMenu == &SP_ReplayDef)
 	{
@@ -10475,11 +10485,15 @@ static void M_ReplayTimeAttack(INT32 choice)
 			break;
 		case 4: // guest
 			// srb2/replay/main/map01-guest.lmp
-			G_DoPlayDemo(va("%s"PATHSEP"replay"PATHSEP"%s"PATHSEP"%s-guest.lmp", srb2home, timeattackfolder, G_BuildMapName(cv_nextmap.value)));
-			return;
+			snprintf(ra_demoname, 1024, "%s"PATHSEP"replay"PATHSEP"%s"PATHSEP"%s-guest.lmp", srb2home, timeattackfolder, G_BuildMapName(cv_nextmap.value));
+			break;
+		}
+
+		if (choice != 4)
+		{
+			// srb2/replay/main/map01-sonic-time-best.lmp
+			snprintf(ra_demoname, 1024, "%s"PATHSEP"replay"PATHSEP"%s"PATHSEP"%s-%s-%s.lmp", srb2home, timeattackfolder, G_BuildMapName(cv_nextmap.value), skins[cv_chooseskin.value-1].name, which);
 		}
-		// srb2/replay/main/map01-sonic-time-best.lmp
-		G_DoPlayDemo(va("%s"PATHSEP"replay"PATHSEP"%s"PATHSEP"%s-%s-%s.lmp", srb2home, timeattackfolder, G_BuildMapName(cv_nextmap.value), skins[cv_chooseskin.value-1].name, which));
 	}
 	else if (currentMenu == &SP_NightsReplayDef)
 	{
@@ -10495,19 +10509,66 @@ static void M_ReplayTimeAttack(INT32 choice)
 			which = "last";
 			break;
 		case 3: // guest
-			G_DoPlayDemo(va("%s"PATHSEP"replay"PATHSEP"%s"PATHSEP"%s-guest.lmp", srb2home, timeattackfolder, G_BuildMapName(cv_nextmap.value)));
-			return;
+			snprintf(ra_demoname, 1024, "%s"PATHSEP"replay"PATHSEP"%s"PATHSEP"%s-guest.lmp", srb2home, timeattackfolder, G_BuildMapName(cv_nextmap.value));
+			break;
 		}
 
-		demoname = va("%s"PATHSEP"replay"PATHSEP"%s"PATHSEP"%s-%s-%s.lmp", srb2home, timeattackfolder, G_BuildMapName(cv_nextmap.value), skins[cv_chooseskin.value-1].name, which);
+		if (choice != 3)
+		{
+			snprintf(ra_demoname, 1024, "%s"PATHSEP"replay"PATHSEP"%s"PATHSEP"%s-%s-%s.lmp", srb2home, timeattackfolder, G_BuildMapName(cv_nextmap.value), skins[cv_chooseskin.value-1].name, which);
 
 #ifdef OLDNREPLAYNAME // Check for old style named NiGHTS replay if a new style replay doesn't exist.
-		if (!FIL_FileExists(demoname))
-			demoname = va("%s"PATHSEP"replay"PATHSEP"%s"PATHSEP"%s-%s.lmp", srb2home, timeattackfolder, G_BuildMapName(cv_nextmap.value), which);
+			if (!FIL_FileExists(ra_demoname))
+			{
+				snprintf(ra_demoname, 1024, "%s"PATHSEP"replay"PATHSEP"%s"PATHSEP"%s-%s.lmp", srb2home, timeattackfolder, G_BuildMapName(cv_nextmap.value), which);
+			}
 #endif
-
-		G_DoPlayDemo(demoname);
+		}
 	}
+
+	demofileoverride = DFILE_OVERRIDE_NONE;
+	error = G_CheckDemoForError(ra_demoname);
+
+	if (error)
+	{
+		S_StartSound(NULL, sfx_skid);
+
+		switch (error)
+		{
+			case DFILE_ERROR_NOTDEMO:
+				M_StartMessage(M_GetText("An error occurred loading this replay.\n\n(Press a key)\n"), NULL, MM_NOTHING);
+				break;
+
+			case DFILE_ERROR_NOTLOADED:
+				demofileoverride = DFILE_OVERRIDE_LOAD;
+				M_StartMessage(M_GetText("Add-ons for this replay\nhave not been loaded.\n\nAttempt to load files?\n\n(Press 'Y' to confirm)\n"), M_StartTimeAttackReplay, MM_YESNO);
+				break;
+
+			case DFILE_ERROR_OUTOFORDER:
+				demofileoverride = DFILE_OVERRIDE_SKIP;
+				M_StartMessage(M_GetText("Add-ons for this replay\nwere loaded out of order.\n\nAttempt to playback anyway?\n\n(Press 'Y' to confirm)\n"), M_StartTimeAttackReplay, MM_YESNO);
+				break;
+
+			case DFILE_ERROR_INCOMPLETEOUTOFORDER:
+				demofileoverride = DFILE_OVERRIDE_LOAD;
+				M_StartMessage(M_GetText("Add-ons for this replay\nhave not been loaded,\nand some are in the wrong order.\n\nAttempt to load files?\n\n(Press 'Y' to confirm)\n"), M_StartTimeAttackReplay, MM_YESNO);
+				break;
+
+			case DFILE_ERROR_CANNOTLOAD:
+				demofileoverride = DFILE_OVERRIDE_SKIP;
+				M_StartMessage(M_GetText("Add-ons for this replay\ncould not be loaded.\n\nAttempt to playback anyway?\n\n(Press 'Y' to confirm)\n"), M_StartTimeAttackReplay, MM_YESNO);
+				break;
+
+			case DFILE_ERROR_EXTRAFILES:
+				demofileoverride = DFILE_OVERRIDE_SKIP;
+				M_StartMessage(M_GetText("You have more files loaded\nthan the replay does.\n\nAttempt to playback anyway?\n\n(Press 'Y' to confirm)\n"), M_StartTimeAttackReplay, MM_YESNO);
+				break;
+		}
+
+		return;
+	}
+
+	M_StartTimeAttackReplay(KEY_ENTER);
 }
 
 static void M_EraseGuest(INT32 choice)