Fix Sub Zero Peak opening

Bots adjust their speed caluclations with slopes, so they anticipate moving faster going downhill and will stop sooner. They also EBrake instead reversing when trying to reverse up a hill.

src/k_bot.c

@@ -309,12 +309,29 @@ boolean K_BotCanTakeCut(player_t *player)
 --------------------------------------------------*/
 static fixed_t K_BotSpeedScaled(player_t *player, fixed_t speed)
 {
-	fixed_t friction = player->mo->friction;
+	fixed_t moveFactor = player->mo->movefactor;
 	fixed_t result = speed;
 
-#ifdef SUBZEROFIX // Intended for Subzero Peak's opening, but doesn't work...
+#if 0 // I still think this is a good idea, but it makes them move way slower on ice. Needs investigating.
-	// Going uphill: pretend speed is x0
+	if (moveFactor != FRACUNIT)
-	// Going downhill: pretend speed is x2
+	{
+		if (moveFactor == 0)
+		{
+			moveFactor = 1;
+		}
+
+		// Reverse against friction. Allows for bots to
+		// acknowledge they'll be moving faster on ice,
+		// and to steer harder / brake earlier.
+		moveFactor = FixedDiv(FRACUNIT, moveFactor);
+
+		// The full value is way too strong, reduce it.
+		moveFactor -= (moveFactor - FRACUNIT)*3/4;
+
+		result = FixedMul(result, moveFactor);
+	}
+#endif
+
 	if (player->mo->standingslope != NULL)
 	{
 		const pslope_t *slope = player->mo->standingslope;
@@ -327,23 +344,14 @@ static fixed_t K_BotSpeedScaled(player_t *player, fixed_t speed)
 			if (P_MobjFlip(player->mo) * slope->zdelta < 0)
 				angle ^= ANGLE_180;
 
+			// Going uphill: 0
+			// Going downhill: FRACUNIT*2
 			slopeMul = FRACUNIT + FINECOSINE(angle >> ANGLETOFINESHIFT);
-			result = FixedMul(result, slopeMul);
+
+			// Range: 0.9 to 1.1
+			result = FixedMul(result, (FRACUNIT*9/10) + (slopeMul/10));
 		}
 	}
-#endif
-
-	// Reverse against friction. Allows for bots to
-	// acknowledge they'll be moving faster on ice,
-	// and to steer harder / brake earlier.
-
-	if (friction == 0)
-	{
-		// There isn't really a good value to use in this instance.
-		friction = 1;
-	}
-
-	result = FixedDiv(speed, friction);
 
 	return result;
 }
@@ -737,7 +745,7 @@ static botprediction_t *K_CreateBotPrediction(player_t *player)
 	const INT16 normal = KART_FULLTURN; // "Standard" handling to compare to
 
 	const tic_t futuresight = (TICRATE * normal) / max(1, handling); // How far ahead into the future to try and predict
-	const fixed_t speed = P_AproxDistance(player->mo->momx, player->mo->momy);
+	const fixed_t speed = K_BotSpeedScaled(player, P_AproxDistance(player->mo->momx, player->mo->momy));
 
 	const INT32 startDist = (768 * mapobjectscale) / FRACUNIT;
 	const INT32 distance = ((speed / FRACUNIT) * futuresight) + startDist;
@@ -1294,7 +1302,6 @@ static INT32 K_HandleBotReverse(player_t *player, ticcmd_t *cmd, botprediction_t
 	}
 	else
 	{
-#ifdef SUBZEROFIX
 		fixed_t slopeMul = FRACUNIT;
 
 		if (player->mo->standingslope != NULL)
@@ -1312,19 +1319,19 @@ static INT32 K_HandleBotReverse(player_t *player, ticcmd_t *cmd, botprediction_t
 			}
 		}
 
-
+#define STEEP_SLOPE (FRACUNIT*11/10)
-		if (slopeMul > (FRACUNIT + (FRACUNIT >> 4)))
+		if (slopeMul > STEEP_SLOPE)
 		{
 			// Slope is too steep to reverse -- EBrake.
 			cmd->forwardmove = 0;
 			cmd->buttons |= BT_ACCELERATE|BT_BRAKE;
 		}
 		else
-#endif
 		{
 			cmd->forwardmove = -MAXPLMOVE;
 			cmd->buttons |= BT_BRAKE; //|BT_LOOKBACK
 		}
+#undef STEEP_SLOPE
 
 		if (anglediff < 10)
 		{
@@ -1410,24 +1417,21 @@ void K_BuildBotTiccmd(player_t *player, ticcmd_t *cmd)
 		const fixed_t closeDist = distBase + (distAdjust * (9 - player->kartweight));
 		const fixed_t farDist = closeDist + (distAdjust * 2);
 
+		const tic_t futureSight = (TICRATE >> 1);
+
 		fixed_t distToFinish = K_DistanceOfLineFromPoint(
 			finishBeamLine->v1->x, finishBeamLine->v1->y,
 			finishBeamLine->v2->x, finishBeamLine->v2->y,
 			player->mo->x, player->mo->y
-		) - K_BotSpeedScaled(player, player->speed);
+		) - (K_BotSpeedScaled(player, player->speed) * futureSight);
 
 		// Don't run the spindash code at all until we're in the right place
 		trySpindash = false;
 
-#define QuickDebugPrint(input) \
-	if (player - players == displayplayers[0]) \
-		CONS_Printf(input);
-
 		if (distToFinish < closeDist)
 		{
 			// We're too close, we need to start backing up.
 			turnamt = K_HandleBotReverse(player, cmd, predict, destangle);
-			QuickDebugPrint("Too close\n");
 		}
 		else if (distToFinish < farDist)
 		{
@@ -1460,7 +1464,6 @@ void K_BuildBotTiccmd(player_t *player, ticcmd_t *cmd)
 					}
 				}
 
-				QuickDebugPrint("No one to bully\n");
 				turnamt = K_HandleBotTrack(player, cmd, predict, destangle);
 				cmd->buttons &= ~(BT_ACCELERATE|BT_BRAKE);
 				cmd->forwardmove = 0;
@@ -1468,7 +1471,6 @@ void K_BuildBotTiccmd(player_t *player, ticcmd_t *cmd)
 			}
 			else
 			{
-				QuickDebugPrint("Go get 'em\n");
 				turnamt = bullyTurn;
 
 				trySpindash = false;
@@ -1478,7 +1480,6 @@ void K_BuildBotTiccmd(player_t *player, ticcmd_t *cmd)
 		}
 		else
 		{
-			QuickDebugPrint("Too far\n");
 			// Too far away, we need to just drive up.
 			if (predict == NULL)
 			{