diff --git a/src/d_clisrv.c b/src/d_clisrv.c
index e654512c0..c8041d431 100644
--- a/src/d_clisrv.c
+++ b/src/d_clisrv.c
@@ -1358,7 +1358,7 @@ static void CL_ReloadReceivedSavegame(void)
 
 	for (i = 0; i < MAXSPLITSCREENPLAYERS; i++)
 	{
-		camera[i].subsector = R_PointInSubsector(camera[i].x, camera[i].y);
+		camera[i].subsector = R_PointInSubsectorFast(camera[i].x, camera[i].y);
 	}
 
 	cl_redownloadinggamestate = false;
diff --git a/src/hardware/hw_main.c b/src/hardware/hw_main.c
index 7d8efb29e..4e8261e68 100644
--- a/src/hardware/hw_main.c
+++ b/src/hardware/hw_main.c
@@ -3076,7 +3076,7 @@ static void HWR_RenderBSPNode(INT32 bspnum)
 		bsp = &nodes[bspnum];
 
 		// Decide which side the view point is on.
-		side = R_PointOnSide(viewx, viewy, bsp);
+		side = R_PointOnSideFast(viewx, viewy, bsp);
 
 		// Recursively divide front space.
 		HWR_RenderBSPNode(bsp->children[side]);
diff --git a/src/p_mobj.c b/src/p_mobj.c
index 566600230..cfc99ad13 100644
--- a/src/p_mobj.c
+++ b/src/p_mobj.c
@@ -3660,7 +3660,7 @@ boolean P_CameraThinker(player_t *player, camera_t *thiscam, boolean resetcalled
 		}
 	}
 
-	thiscam->subsector = R_PointInSubsector(thiscam->x, thiscam->y);
+	thiscam->subsector = R_PointInSubsectorFast(thiscam->x, thiscam->y);
 	thiscam->floorz = tm.floorz;
 	thiscam->ceilingz = tm.ceilingz;
 
@@ -10372,12 +10372,12 @@ void P_PrecipitationEffects(void)
 		for (y = yl; y <= yh; y += RADIUSSTEP)
 			for (x = xl; x <= xh; x += RADIUSSTEP)
 			{
-				if (R_PointInSubsector((fixed_t)x, (fixed_t)y)->sector->ceilingpic == skyflatnum) // Found the outdoors!
-				{
-					newdist = S_CalculateSoundDistance(players[g_localplayers[0]].mo->x, players[g_localplayers[0]].mo->y, 0, (fixed_t)x, (fixed_t)y, 0);
-					if (newdist < closedist)
-						closedist = newdist;
-				}
+				if (R_PointInSubsectorFast((fixed_t)x, (fixed_t)y)->sector->ceilingpic != skyflatnum) // Found the outdoors!
+					continue;
+
+				newdist = S_CalculateSoundDistance(players[g_localplayers[0]].mo->x, players[g_localplayers[0]].mo->y, 0, (fixed_t)x, (fixed_t)y, 0);
+				if (newdist < closedist)
+					closedist = newdist;
 			}
 #undef RADIUSSTEP
 
diff --git a/src/p_setup.c b/src/p_setup.c
index 4f7737b44..094e35602 100644
--- a/src/p_setup.c
+++ b/src/p_setup.c
@@ -8065,7 +8065,7 @@ static void P_SetupCamera(UINT8 pnum, camera_t *cam)
 		cam->y = players[pnum].mo->y;
 		cam->z = players[pnum].mo->z;
 		cam->angle = players[pnum].mo->angle;
-		cam->subsector = R_PointInSubsector(cam->x, cam->y); // make sure camera has a subsector set -- Monster Iestyn (12/11/18)
+		cam->subsector = R_PointInSubsectorFast(cam->x, cam->y); // make sure camera has a subsector set -- Monster Iestyn (12/11/18)
 	}
 	else
 	{
@@ -8082,7 +8082,7 @@ static void P_SetupCamera(UINT8 pnum, camera_t *cam)
 			cam->y = thing->y;
 			cam->z = thing->z;
 			cam->angle = FixedAngle((fixed_t)thing->angle << FRACBITS);
-			cam->subsector = R_PointInSubsector(cam->x, cam->y); // make sure camera has a subsector set -- Monster Iestyn (12/11/18)
+			cam->subsector = R_PointInSubsectorFast(cam->x, cam->y); // make sure camera has a subsector set -- Monster Iestyn (12/11/18)
 		}
 	}
 }
diff --git a/src/p_user.c b/src/p_user.c
index 99443976b..beab7153d 100644
--- a/src/p_user.c
+++ b/src/p_user.c
@@ -2941,7 +2941,7 @@ void P_DemoCameraMovement(camera_t *cam)
 	democam.soundmobj = awayviewmobj_hack;
 
 	// update subsector to avoid crashes;
-	cam->subsector = R_PointInSubsector(cam->x, cam->y);
+	cam->subsector = R_PointInSubsectorFast(cam->x, cam->y);
 }
 
 void P_ResetCamera(player_t *player, camera_t *thiscam)
@@ -2975,7 +2975,7 @@ void P_ResetCamera(player_t *player, camera_t *thiscam)
 	thiscam->aiming = 0;
 	thiscam->relativex = 0;
 
-	thiscam->subsector = R_PointInSubsector(thiscam->x,thiscam->y);
+	thiscam->subsector = R_PointInSubsectorFast(thiscam->x,thiscam->y);
 
 	thiscam->radius = 20*FRACUNIT;
 	thiscam->height = 16*FRACUNIT;
diff --git a/src/r_bsp.cpp b/src/r_bsp.cpp
index ccac34d31..2a93c5d92 100644
--- a/src/r_bsp.cpp
+++ b/src/r_bsp.cpp
@@ -1453,7 +1453,7 @@ void R_RenderBSPNode(INT32 bspnum)
 		bsp = &nodes[bspnum];
 
 		// Decide which side the view point is on.
-		side = R_PointOnSide(viewx, viewy, bsp);
+		side = R_PointOnSideFast(viewx, viewy, bsp);
 		// Recursively divide front space.
 		R_RenderBSPNode(bsp->children[side]);
 
diff --git a/src/r_fps.c b/src/r_fps.c
index dc894dd5f..a60adf520 100644
--- a/src/r_fps.c
+++ b/src/r_fps.c
@@ -184,7 +184,7 @@ void R_InterpolateView(fixed_t frac)
 	viewcos = FINECOSINE(viewangle>>ANGLETOFINESHIFT);
 
 	viewplayer = newview->player;
-	viewsector = R_PointInSubsector(viewx, viewy)->sector;
+	viewsector = R_PointInSubsectorFast(viewx, viewy)->sector;
 
 	R_SetupFreelook(newview->player, newview->sky);
 }
diff --git a/src/r_main.cpp b/src/r_main.cpp
index bb628c543..a80b17f2e 100644
--- a/src/r_main.cpp
+++ b/src/r_main.cpp
@@ -1427,7 +1427,7 @@ static void R_PortalFrame(portal_t *portal)
 	{
 		portalclipline = NULL;
 		portalcullsector = NULL;
-		viewsector = R_PointInSubsector(viewx, viewy)->sector;
+		viewsector = R_PointInSubsectorFast(viewx, viewy)->sector;
 	}
 }
 
diff --git a/src/r_main.h b/src/r_main.h
index b23bdff06..fbf3484f2 100644
--- a/src/r_main.h
+++ b/src/r_main.h
@@ -74,6 +74,15 @@ extern lighttable_t *zlight[LIGHTLEVELS][MAXLIGHTZ];
 #define R_PointOnSide(x,y,node) udmf ? R_PointOnSideUDMF(x,y,node) : R_PointOnSideKart(x,y,node)
 INT32 R_PointOnSideUDMF(fixed_t x, fixed_t y, const node_t *node);
 INT32 R_PointOnSideKart(fixed_t x, fixed_t y, const node_t *node);
+
+// This is not as accurate
+// SHOULD NOT BE USED FOR ANYTHING GAMEPLAY RELATED!!
+FUNCINLINE static ATTRINLINE INT32 R_PointOnSideFast(fixed_t x, fixed_t y, const node_t *node)
+{
+	// use cross product to determine side quickly
+	return ((INT64)y - node->y) * node->dx - ((INT64)x - node->x) * node->dy > 0;
+}
+
 INT32 R_PointOnSegSide(fixed_t x, fixed_t y, const seg_t *line);
 #define R_PointToAngle(x, y) R_PointToAngle2(viewx, viewy, x, y)
 angle_t R_PointToAnglePlayer(player_t *player, fixed_t x, fixed_t y);
@@ -86,6 +95,18 @@ fixed_t R_ScaleFromGlobalAngle(angle_t visangle);
 subsector_t *R_PointInSubsector(fixed_t x, fixed_t y);
 subsector_t *R_PointInSubsectorOrNull(fixed_t x, fixed_t y);
 
+// uses R_PointOnSideFast
+// SHOULD NOT BE USED FOR ANYTHING GAMEPLAY RELATED!!
+FUNCINLINE static ATTRINLINE subsector_t *R_PointInSubsectorFast(fixed_t x, fixed_t y)
+{
+	size_t nodenum = numnodes-1;
+
+	while (!(nodenum & NF_SUBSECTOR))
+		nodenum = nodes[nodenum].children[R_PointOnSideFast(x, y, nodes+nodenum)];
+
+	return &subsectors[nodenum & ~NF_SUBSECTOR];
+}
+
 boolean R_DoCulling(line_t *cullheight, line_t *viewcullheight, fixed_t vz, fixed_t bottomh, fixed_t toph);
 
 void R_GetRenderBlockMapDimensions(fixed_t drawdist, INT32 *xl, INT32 *xh, INT32 *yl, INT32 *yh);
diff --git a/src/s_sound.c b/src/s_sound.c
index 215786b0d..8feb3a3eb 100644
--- a/src/s_sound.c
+++ b/src/s_sound.c
@@ -1100,7 +1100,7 @@ boolean S_AdjustSoundParams(const mobj_t *listener, const mobj_t *source, INT32
 	{
 		fixed_t x, y, yl, yh, xl, xh, newdist;
 
-		if (R_PointInSubsector(listensource.x, listensource.y)->sector->ceilingpic == skyflatnum)
+		if (R_PointInSubsectorFast(listensource.x, listensource.y)->sector->ceilingpic == skyflatnum)
 			approx_dist = 0;
 		else
 		{
@@ -1113,7 +1113,7 @@ boolean S_AdjustSoundParams(const mobj_t *listener, const mobj_t *source, INT32
 			for (y = yl; y <= yh; y += FRACUNIT*64)
 				for (x = xl; x <= xh; x += FRACUNIT*64)
 				{
-					if (R_PointInSubsector(x, y)->sector->ceilingpic == skyflatnum)
+					if (R_PointInSubsectorFast(x, y)->sector->ceilingpic == skyflatnum)
 					{
 						// Found the outdoors!
 						newdist = S_CalculateSoundDistance(listensource.x, listensource.y, 0, x, y, 0);