Add sector flags to disable equation slope physics

doc/specs/udmf_srb2.txt

@@ -228,6 +228,8 @@ Sonic Robo Blast 2 defines the following standardized fields:
       ropehang           = <bool>;     // Sector is a rope hang. Must be applied to a 3D floor.
       jumpflip           = <bool>;     // Sector flips the gravity of players who jump from it.
       gravityoverride    = <bool>;     // Reverse gravity effect is only applied when an object is in the sector.
+      nophysics_floor    = <bool>;     // Disables floor slope physics if created through a plane equation.
+      nophysics_ceiling  = <bool>;     // Disables ceiling slope physics if created through a plane equation.
 
       friction            = <float>;   // Sector's friction factor.
       gravity             = <float>;   // Sector's gravity. Default is 1.0.

extras/conf/udb/Includes/SRB222_misc.cfg

@@ -78,6 +78,8 @@ sectorflags
 	ropehang = "Rope Hang";
 	jumpflip = "Flip Gravity on Jump";
 	gravityoverride = "Make Reverse Gravity Temporary";
+	nophysics_floor = "Disable Floor Slope Physics";
+	nophysics_ceiling = "Disable Ceiling Slope Physics";
 	flipspecial_nofloor = "No Trigger on Floor Touch";
 	flipspecial_ceiling = "Trigger on Ceiling Touch";
 	triggerspecial_touch = "Trigger on Edge Touch";
@@ -114,6 +116,8 @@ sectorflagscategories
 	ropehang = "special";
 	jumpflip = "special";
 	gravityoverride = "special";
+	nophysics_floor = "special";
+	nophysics_ceiling = "special";
 	flipspecial_nofloor = "trigger";
 	flipspecial_ceiling = "trigger";
 	triggerspecial_touch = "trigger";

src/p_setup.c

@@ -1816,6 +1816,10 @@ static void ParseTextmapSectorParameter(UINT32 i, const char *param, const char
 		sectors[i].specialflags |= SSF_JUMPFLIP;
 	else if (fastcmp(param, "gravityoverride") && fastcmp("true", val))
 		sectors[i].specialflags |= SSF_GRAVITYOVERRIDE;
+	else if (fastcmp(param, "nophysics_floor") && fastcmp("true", val))
+		sectors[i].specialflags |= SSF_NOPHYSICSFLOOR;
+	else if (fastcmp(param, "nophysics_ceiling") && fastcmp("true", val))
+		sectors[i].specialflags |= SSF_NOPHYSICSCEILING;
 	else if (fastcmp(param, "friction"))
 		sectors[i].friction = FLOAT_TO_FIXED(atof(val));
 	else if (fastcmp(param, "gravity"))
@@ -2954,13 +2958,17 @@ static void P_LoadTextmap(void)
 		{
 			sc->f_slope = P_MakeSlopeViaEquationConstants(textmap_planefloor.a, textmap_planefloor.b, textmap_planefloor.c, textmap_planefloor.d);
 			sc->hasslope = true;
+			if (sc->specialflags & SSF_NOPHYSICSFLOOR)
+				sc->f_slope->flags |= SL_NOPHYSICS;
 		}
 
 		if (textmap_planeceiling.defined == (PD_A|PD_B|PD_C|PD_D))
 		{
 			sc->c_slope = P_MakeSlopeViaEquationConstants(textmap_planeceiling.a, textmap_planeceiling.b, textmap_planeceiling.c, textmap_planeceiling.d);
 			sc->hasslope = true;
-		}
+			if (sc->specialflags & SSF_NOPHYSICSCEILING)
+				sc->c_slope->flags |= SL_NOPHYSICS;
+        }
 
 		TextmapFixFlatOffsets(sc);
 	}

src/r_defs.h

@@ -405,6 +405,8 @@ typedef enum
 	SSF_ROPEHANG = 1<<18,
 	SSF_JUMPFLIP = 1<<19,
 	SSF_GRAVITYOVERRIDE = 1<<20, // combine with MSF_GRAVITYFLIP
+	SSF_NOPHYSICSFLOOR = 1<<21,
+	SSF_NOPHYSICSCEILING = 1<<22,
 } sectorspecialflags_t;
 
 typedef enum