Fix UT player swimming physics.

zscript/utcommon.zsc

@@ -305,9 +305,9 @@ Class UTPlayer : DoomPlayer
 		if ( InStateSequence(CurState,FindState("See",true)) )
 			SetStateLabel("See2");
 		if ( !player || (player.mo != self) ) return;
-		if ( (waterlevel >= 2) && (lastwaterlevel < 2) )
+		if ( waterlevel && !lastwaterlevel )
 			PlaySplash(1.);
-		else if ( (waterlevel < 2) && (lastwaterlevel >= 2) )
+		else if ( !waterlevel && lastwaterlevel )
 			PlaySurface();
 		if ( (waterlevel >= 3) && !underwatersnd )
 		{
@@ -522,7 +522,80 @@ Class UTPlayer : DoomPlayer
 			}
 		}
 		last_sm = sm;
-		if ( !bNoGravity && player.onground && (waterlevel < 3) )
+		if ( (bFly && bFlyCheat) || (player.cheats&CF_NOCLIP2) )
+		{
+			// fly cheat has infinite friction (player stops moving when movement keys are released)
+			Vector3 dir = (0,0,0);
+			if ( vel.length() > double.epsilon ) dir = vel.unit();
+			Vector3 x, y;
+			[x, y] = dt_Utility.GetAxes(angle,pitch,0);
+			acceleration3 = x*player.cmd.forwardmove+y*player.cmd.sidemove;
+			if ( player.cmd.buttons&BT_JUMP ) acceleration3.z = 0x500;
+			else if ( player.cmd.buttons&BT_CROUCH ) acceleration3.z = -0x500;
+			if ( acceleration3.length() <= double.epsilon ) vel *= 0;
+			else
+			{
+				Vector3 acceldir = acceleration3.unit();
+				acceleration3 = acceldir*Min(acceleration3.length(),accelrate/TICRATE);
+				vel = vel-(dir-acceldir)*vel.length();
+			}
+			vel = vel+acceleration3/TICRATE;
+			double maxvel;
+			if ( flak_doomspeed ) maxvel = groundspeed_doomish/TICRATE;
+			else maxvel = groundspeed/TICRATE;
+			maxvel *= fs;
+			if ( vel.length() > maxvel ) vel = vel.unit()*maxvel;
+			player.vel *= .8;
+			player.jumptics = -2;
+			if ( !(player.cheats & CF_PREDICTING) ) PlayIdle();
+		}
+		else if ( (waterlevel || bNoGravity) && !player.GetClassicFlight() )
+		{
+			// swimming is pretty much like ground movement, but with much reduced friction and lower speed
+			friction *= fluidfriction/groundfriction;
+			Vector3 dir = (0,0,0);
+			if ( vel.length() > double.epsilon ) dir = vel.unit();
+			double doomfriction = clamp(GetFriction()/ORIG_FRICTION,0.0,1.0);
+			Vector3 x, y;
+			[x, y] = dt_Utility.GetAxes(angle,pitch,0);
+			acceleration3 = x*player.cmd.forwardmove+y*player.cmd.sidemove;
+			if ( player.cmd.buttons&BT_JUMP ) acceleration3.z = 0x500;
+			else if ( player.cmd.buttons&BT_CROUCH ) acceleration3.z = -0x500;
+			if ( acceleration3.length() <= double.epsilon )
+			{
+				Vector3 oldvel = vel;
+				vel = vel-(2*dir)*vel.length()*friction/TICRATE;
+				if ( oldvel dot vel < 0.0 ) vel *= 0;
+			}
+			else
+			{
+				Vector3 acceldir = acceleration3.unit();
+				acceleration3 = acceldir*Min(acceleration3.length(),accelrate/TICRATE);
+				vel = vel-(dir-acceldir)*vel.length()*friction/TICRATE;
+			}
+			vel = vel+acceleration3/TICRATE;
+			double maxvel;
+			if ( bNoGravity )	// flying uses ground speed
+			{
+				if ( flak_doomspeed ) maxvel = groundspeed_doomish/TICRATE;
+				else maxvel = groundspeed/TICRATE;
+			}
+			else
+			{
+				if ( flak_doomspeed ) maxvel = swimspeed_doomish/TICRATE;
+				else maxvel = swimspeed/TICRATE;
+			}
+			maxvel *= fs*doomfriction;
+			if ( vel.length() > maxvel ) vel = vel.unit()*maxvel;
+			player.vel = player.vel*.8+vel.xy*.2;
+			player.jumptics = -2;
+			if ( !(player.cheats & CF_PREDICTING) )
+			{
+				if ( acceleration3.length() <= double.epsilon ) PlayIdle();
+				else PlayRunning();
+			}
+		}
+		else if ( player.onground )
 		{
 			if ( flak_tapdodge && (dodge.length() > 0) && !tempslide )
 			{
@@ -586,7 +659,7 @@ Class UTPlayer : DoomPlayer
 				else player.vel = player.vel*.8+vel.xy*.2;
 			}
 		}
-		else if ( !bNoGravity && (waterlevel < 1) )
+		else
 		{
 			// air acceleration when falling
 			float maxaccel = accelrate/TICRATE;
@@ -617,79 +690,6 @@ Class UTPlayer : DoomPlayer
 			player.jumptics = -2;
 			if ( !(player.cheats & CF_PREDICTING) ) PlayIdle();
 		}
-		else if ( (bFly && bFlyCheat) || (player.cheats&CF_NOCLIP2) )
-		{
-			// fly cheat has infinite friction (player stops moving when movement keys are released)
-			Vector3 dir = (0,0,0);
-			if ( vel.length() > double.epsilon ) dir = vel.unit();
-			Vector3 x, y;
-			[x, y] = dt_Utility.GetAxes(angle,pitch,0);
-			acceleration3 = x*player.cmd.forwardmove+y*player.cmd.sidemove;
-			if ( player.cmd.buttons&BT_JUMP ) acceleration3.z = 0x500;
-			else if ( player.cmd.buttons&BT_CROUCH ) acceleration3.z = -0x500;
-			if ( acceleration3.length() <= double.epsilon ) vel *= 0;
-			else
-			{
-				Vector3 acceldir = acceleration3.unit();
-				acceleration3 = acceldir*Min(acceleration3.length(),accelrate/TICRATE);
-				vel = vel-(dir-acceldir)*vel.length();
-			}
-			vel = vel+acceleration3/TICRATE;
-			double maxvel;
-			if ( flak_doomspeed ) maxvel = groundspeed_doomish/TICRATE;
-			else maxvel = groundspeed/TICRATE;
-			maxvel *= fs;
-			if ( vel.length() > maxvel ) vel = vel.unit()*maxvel;
-			player.vel *= .8;
-			player.jumptics = -2;
-			if ( !(player.cheats & CF_PREDICTING) ) PlayIdle();
-		}
-		else
-		{
-			// swimming is pretty much like ground movement, but with much reduced friction and lower speed
-			friction *= fluidfriction/groundfriction;
-			Vector3 dir = (0,0,0);
-			if ( vel.length() > double.epsilon ) dir = vel.unit();
-			double doomfriction = clamp(GetFriction()/ORIG_FRICTION,0.0,1.0);
-			Vector3 x, y;
-			[x, y] = dt_Utility.GetAxes(angle,pitch,0);
-			acceleration3 = x*player.cmd.forwardmove+y*player.cmd.sidemove;
-			if ( player.cmd.buttons&BT_JUMP ) acceleration3.z = 0x500;
-			else if ( player.cmd.buttons&BT_CROUCH ) acceleration3.z = -0x500;
-			if ( acceleration3.length() <= double.epsilon )
-			{
-				Vector3 oldvel = vel;
-				vel = vel-(2*dir)*vel.length()*friction/TICRATE;
-				if ( oldvel dot vel < 0.0 ) vel *= 0;
-			}
-			else
-			{
-				Vector3 acceldir = acceleration3.unit();
-				acceleration3 = acceldir*Min(acceleration3.length(),accelrate/TICRATE);
-				vel = vel-(dir-acceldir)*vel.length()*friction/TICRATE;
-			}
-			vel = vel+acceleration3/TICRATE;
-			double maxvel;
-			if ( waterlevel < 2 )	// flying uses ground speed
-			{
-				if ( flak_doomspeed ) maxvel = groundspeed_doomish/TICRATE;
-				else maxvel = groundspeed/TICRATE;
-			}
-			else
-			{
-				if ( flak_doomspeed ) maxvel = swimspeed_doomish/TICRATE;
-				else maxvel = swimspeed/TICRATE;
-			}
-			maxvel *= fs*doomfriction;
-			if ( vel.length() > maxvel ) vel = vel.unit()*maxvel;
-			player.vel = player.vel*.8+vel.xy*.2;
-			player.jumptics = -2;
-			if ( !(player.cheats & CF_PREDICTING) )
-			{
-				if ( acceleration3.length() <= double.epsilon ) PlayIdle();
-				else PlayRunning();
-			}
-		}
 		if ( player.cheats & CF_REVERTPLEASE )
 		{
 			player.cheats &= ~CF_REVERTPLEASE;
@@ -765,40 +765,7 @@ Class UTPlayer : DoomPlayer
 			return;
 		// unreal physics while dead
 		double friction = FrictionToUnreal();
-		if ( !bNoGravity && player.onground && (waterlevel < 3) )
+		if ( waterlevel )
-		{
-			// Hook in Unreal physics
-			Vector2 dir = (0,0);
-			if ( vel.xy.length() > double.epsilon ) dir = vel.xy.unit();
-			double doomfriction = clamp(GetFriction()/ORIG_FRICTION,0.0,1.0);
-			Vector2 oldvel = vel.xy;
-			vel.xy = vel.xy - (2 * dir) * vel.xy.length() * friction/TICRATE;
-			if ( oldvel dot vel.xy < 0.0 ) vel.xy *= 0;
-			double maxvel;
-			if ( flak_doomspeed ) maxvel = groundspeed_doomish/TICRATE;
-			else maxvel = groundspeed/TICRATE;
-			maxvel *= doomfriction;
-			if ( vel.xy.length() > maxvel ) vel.xy = vel.xy.unit()*maxvel;
-			player.vel *= 0;
-		}
-		else if ( !bNoGravity && (waterlevel < 1) )
-		{
-			// air acceleration when falling
-			Vector2 dir = (0,0);
-			if ( vel.xy.length() > double.epsilon ) dir = vel.xy.unit();
-			double maxvel;
-			if ( flak_doomspeed ) maxvel = groundspeed_doomish/TICRATE;
-			else maxvel = groundspeed/TICRATE;
-			// if new velocity is higher than ground speed, steer but don't increase it
-			if ( vel.xy.length() > maxvel )
-			{
-				double vsiz = vel.xy.length();
-				vel.xy = vel.xy.unit()*vsiz;
-			}
-			if ( vel.length() > terminalvelocity/TICRATE ) vel = vel.unit()*(terminalvelocity/TICRATE);
-			player.vel *= 0;
-		}
-		else
 		{
 			// swimming is pretty much like ground movement, but with much reduced friction and lower speed
 			friction *= fluidfriction/groundfriction;
@@ -815,6 +782,61 @@ Class UTPlayer : DoomPlayer
 			if ( vel.length() > maxvel ) vel = vel.unit()*maxvel;
 			player.vel *= 0;
 		}
+		else if ( player.onground )
+		{
+			// Hook in Unreal physics
+			Vector2 dir = (0,0);
+			if ( vel.xy.length() > double.epsilon ) dir = vel.xy.unit();
+			double doomfriction = clamp(GetFriction()/ORIG_FRICTION,0.0,1.0);
+			Vector2 oldvel = vel.xy;
+			vel.xy = vel.xy - (2 * dir) * vel.xy.length() * friction/TICRATE;
+			if ( oldvel dot vel.xy < 0.0 ) vel.xy *= 0;
+			double maxvel;
+			if ( flak_doomspeed ) maxvel = groundspeed_doomish/TICRATE;
+			else maxvel = groundspeed/TICRATE;
+			maxvel *= doomfriction;
+			if ( vel.xy.length() > maxvel ) vel.xy = vel.xy.unit()*maxvel;
+			player.vel *= 0;
+		}
+		else
+		{
+			// air acceleration when falling
+			Vector2 dir = (0,0);
+			if ( vel.xy.length() > double.epsilon ) dir = vel.xy.unit();
+			double maxvel;
+			if ( flak_doomspeed ) maxvel = groundspeed_doomish/TICRATE;
+			else maxvel = groundspeed/TICRATE;
+			// if new velocity is higher than ground speed, steer but don't increase it
+			if ( vel.xy.length() > maxvel )
+			{
+				double vsiz = vel.xy.length();
+				vel.xy = vel.xy.unit()*vsiz;
+			}
+			if ( vel.length() > terminalvelocity/TICRATE ) vel = vel.unit()*(terminalvelocity/TICRATE);
+			player.vel *= 0;
+		}
+	}
+
+	// backported from DEMOLITIONIST, needed to fix quirks in swimming behavior
+	override void FallAndSink( double grav, double oldfloorz )
+	{
+		if ( !flak_utmovement || !player || (player.mo != self) || (player.cheats&(CF_FROZEN|CF_TOTALLYFROZEN)) )
+		{
+			Super.FallAndSink(grav,oldfloorz);
+			return;
+		}
+		// do nothing if standing on ground or "floating"
+		if ( player.onground || bNOGRAVITY ) return;
+		// ensure we don't pass terminal velocity just from falling
+		if ( vel.z < -50 ) return;
+		// we don't care about "the doom way" here, gravity is
+		// ALWAYS in effect when not standing on solid ground
+		if ( waterlevel > 1 )
+		{
+			// UT buoyancy, reduces gravity in water by 99%
+			grav *= .01;
+		}
+		vel.z -= grav;
 	}
 
 	virtual void PlayFootstep( double vol )
@@ -971,7 +993,7 @@ Class UTPlayer : DoomPlayer
 				|| InStateSequence(CurState,FindState("Turn")) )
 				SetStateLabel("See2");
 		}
-		else if ( !bNoGravity && (waterlevel < 1) && abs(pos.z-floorz) > maxstepheight )
+		else if ( !bNoGravity && (waterlevel < 1) && (abs(pos.z-floorz) > maxstepheight) )
 		{
 			// Falling
 			if ( InStateSequence(CurState,FindState("Spawn"))