Rework bot skin randomisation

- Instead of picking over numskins and adjust the number if it picks an already used skin, build and shuffle a list of allowed skins and pick over that instead.
- Fixes some issues with increased weighting towards the skins immediately after your rivals' skins.
- Use PR_RULESCRAMBLE instead of PR_UNDEFINED.
- Why am I doing it in this branch? I'm getting re-acquainted with how bots are handled between matches in advance of disabling them for bonus events without losing or corrupting data.

src/k_grandprix.c

@@ -96,14 +96,14 @@ INT16 K_CalculateGPRankPoints(UINT8 position, UINT8 numplayers)
 }
 
 /*--------------------------------------------------
-	SINT8 K_BotDefaultSkin(void)
+	UINT8 K_BotDefaultSkin(void)
 
 		See header file for description.
 --------------------------------------------------*/
-SINT8 K_BotDefaultSkin(void)
+UINT8 K_BotDefaultSkin(void)
 {
 	const char *defaultbotskinname = "eggrobo";
-	SINT8 defaultbotskin = R_SkinAvailable(defaultbotskinname);
+	INT32 defaultbotskin = R_SkinAvailable(defaultbotskinname);
 
 	if (defaultbotskin == -1)
 	{
@@ -111,7 +111,7 @@ SINT8 K_BotDefaultSkin(void)
 		defaultbotskin = 0;
 	}
 
-	return defaultbotskin;
+	return (UINT8)defaultbotskin;
 }
 
 /*--------------------------------------------------
@@ -121,7 +121,7 @@ SINT8 K_BotDefaultSkin(void)
 --------------------------------------------------*/
 void K_InitGrandPrixBots(void)
 {
-	const SINT8 defaultbotskin = K_BotDefaultSkin();
+	const UINT8 defaultbotskin = K_BotDefaultSkin();
 
 	const UINT8 startingdifficulty = K_BotStartingDifficulty(grandprixinfo.gamespeed);
 	UINT8 difficultylevels[MAXPLAYERS];
@@ -132,7 +132,9 @@ void K_InitGrandPrixBots(void)
 	UINT8 numplayers = 0;
 	UINT8 competitors[MAXSPLITSCREENPLAYERS];
 
-	boolean skinusable[MAXSKINS];
+	UINT8 usableskins;
+	UINT8 grabskins[MAXSKINS];
+
 	UINT8 botskinlist[MAXPLAYERS];
 	UINT8 botskinlistpos = 0;
 
@@ -142,17 +144,10 @@ void K_InitGrandPrixBots(void)
 	memset(competitors, MAXPLAYERS, sizeof (competitors));
 	memset(botskinlist, defaultbotskin, sizeof (botskinlist));
 
-	// init usable bot skins list
+	// Init usable bot skins list
-	for (i = 0; i < MAXSKINS; i++)
+	for (usableskins = 0; usableskins < numskins; usableskins++)
 	{
-		if (i < numskins)
+		grabskins[usableskins] = usableskins;
-		{
-			skinusable[i] = true;
-		}
-		else
-		{
-			skinusable[i] = false;
-		}
 	}
 
 #if MAXPLAYERS != 16
@@ -192,7 +187,7 @@ void K_InitGrandPrixBots(void)
 			if (numplayers < MAXSPLITSCREENPLAYERS && !players[i].spectator)
 			{
 				competitors[numplayers] = i;
-				skinusable[players[i].skin] = false;
+				grabskins[players[i].skin] = MAXSKINS;
 				numplayers++;
 			}
 			else
@@ -219,52 +214,42 @@ void K_InitGrandPrixBots(void)
 			{
 				player_t *p = &players[competitors[j]];
 				char *rivalname = skins[p->skin].rivals[i];
-				SINT8 rivalnum = R_SkinAvailable(rivalname);
+				INT32 rivalnum = R_SkinAvailable(rivalname);
 
-				if (rivalnum != -1 && skinusable[rivalnum])
+				// Intentionally referenced before (currently dummied out) unlock check. Such a tease!
+				if (rivalnum != -1 && grabskins[(UINT8)rivalnum] != MAXSKINS)
 				{
-					botskinlist[botskinlistpos] = rivalnum;
+					botskinlist[botskinlistpos++] = (UINT8)rivalnum;
-					skinusable[rivalnum] = false;
+					grabskins[(UINT8)rivalnum] = MAXSKINS;
 					botskinlistpos++;
 				}
 			}
 		}
 	}
 
+	// Rearrange usable bot skins list to prevent gaps for randomised selection
+	for (i = 0; i < usableskins; i++)
+	{
+		if (grabskins[i] != MAXSKINS /*&& !K_SkinLocked(usableskins)*/)
+			continue;
+		grabskins[i] = grabskins[--usableskins];
+	}
+
 	// Pad the remaining list with random skins if we need to
 	if (botskinlistpos < wantedbots)
 	{
-		for (i = botskinlistpos; i < wantedbots; i++)
+		while (botskinlistpos < wantedbots)
 		{
-			UINT8 val = M_RandomKey(numskins);
+			UINT8 skinnum = defaultbotskin;
-			UINT8 loops = 0;
 
-			while (!skinusable[val])
+			if (usableskins > 0)
 			{
-				if (loops >= numskins)
+				UINT8 index = M_RandomKey(usableskins);
-				{
+				skinnum = grabskins[index];
-					// no more skins
+				grabskins[index] = grabskins[--usableskins];
-					break;
-				}
-
-				val++;
-
-				if (val >= numskins)
-				{
-					val = 0;
-				}
-
-				loops++;
 			}
 
-			if (loops >= numskins)
+			botskinlist[botskinlistpos++] = skinnum;
-			{
-				// leave the rest of the table as the default skin
-				break;
-			}
-
-			botskinlist[i] = val;
-			skinusable[val] = false;
 		}
 	}
 
@@ -519,10 +504,11 @@ void K_IncreaseBotDifficulty(player_t *bot)
 --------------------------------------------------*/
 void K_RetireBots(void)
 {
-	const SINT8 defaultbotskin = K_BotDefaultSkin();
+	const UINT8 defaultbotskin = K_BotDefaultSkin();
 	SINT8 newDifficulty;
 
-	boolean skinusable[MAXSKINS];
+	UINT8 usableskins;
+	UINT8 grabskins[MAXSKINS];
 
 	UINT8 i;
 
@@ -532,25 +518,29 @@ void K_RetireBots(void)
 		return;
 	}
 
-	// init usable bot skins list
+	// Init usable bot skins list
-	for (i = 0; i < MAXSKINS; i++)
+	for (usableskins = 0; usableskins < numskins; usableskins++)
 	{
-		if (i < numskins)
+		grabskins[usableskins] = usableskins;
-		{
-			skinusable[i] = true;
-		}
-		else
-		{
-			skinusable[i] = false;
-		}
 	}
 
+	// Exclude player skins
 	for (i = 0; i < MAXPLAYERS; i++)
 	{
-		if (playeringame[i] && !players[i].spectator)
+		if (!playeringame[i])
-		{
+			continue;
-			skinusable[players[i].skin] = false;
+		if (players[i].spectator)
-		}
+			continue;
+
+		grabskins[players[i].skin] = MAXSKINS;
+	}
+
+	// Rearrange usable bot skins list to prevent gaps for randomised selection
+	for (i = 0; i < usableskins; i++)
+	{
+		if (grabskins[i] != MAXSKINS /*&& !K_SkinLocked(usableskins)*/)
+			continue;
+		grabskins[i] = grabskins[--usableskins];
 	}
 
 	if (!grandprixinfo.gp) // Sure, let's let this happen all the time :)
@@ -590,35 +580,15 @@ void K_RetireBots(void)
 
 		if (bot->pflags & PF_NOCONTEST)
 		{
-			UINT8 skinnum = P_RandomKey(PR_UNDEFINED, numskins);
+			UINT8 skinnum = defaultbotskin;
-			UINT8 loops = 0;
 
-			while (!skinusable[skinnum])
+			if (usableskins > 0)
 			{
-				if (loops >= numskins)
+				UINT8 index = P_RandomKey(PR_RULESCRAMBLE, usableskins);
-				{
+				skinnum = grabskins[index];
-					// no more skins
+				grabskins[index] = grabskins[--usableskins];
-					break;
-				}
-
-				skinnum++;
-
-				if (skinnum >= numskins)
-				{
-					skinnum = 0;
-				}
-
-				loops++;
 			}
 
-			if (loops >= numskins)
-			{
-				// Use default skin
-				skinnum = defaultbotskin;
-			}
-
-			skinusable[skinnum] = false;
-
 			bot->botvars.difficulty = newDifficulty;
 			bot->botvars.diffincrease = 0;
 

src/k_grandprix.h

@@ -63,13 +63,13 @@ INT16 K_CalculateGPRankPoints(UINT8 position, UINT8 numplayers);
 
 
 /*--------------------------------------------------
-	SINT8 K_BotDefaultSkin(void);
+	UINT8 K_BotDefaultSkin(void);
 
 		Returns the skin number of the skin the game
 		uses as a fallback option.
 --------------------------------------------------*/
 
-SINT8 K_BotDefaultSkin(void);
+UINT8 K_BotDefaultSkin(void);
 
 
 /*--------------------------------------------------

src/m_random.h

@@ -47,7 +47,7 @@ typedef enum
 	PR_PLAYERSTARTS, // Player starts
 	PR_VOICES, // Player voice sounds
 
-	PR_RULESCRAMBLE, // Netgame rule scrambing events
+	PR_RULESCRAMBLE, // Rule scrambing events
 
 	PR_ITEM_ROULETTE, // Item results
 	PR_ITEM_RINGS, // Flung ring/bumper/player (on death)