Merged https://github.com/ZDoom/gzdoom/pull/1960 (Bounce virtual)

src/playsim/actor.h

@@ -842,6 +842,11 @@ public:
 	// (virtual on the script side only)
 	int SpecialMissileHit (AActor *victim);
 
+	// Called when bouncing to allow for custom behavior.
+	// Returns -1 for normal behavior, 0 to stop, and 1 to keep going.
+	// (virtual on the script side only)
+	int SpecialBounceHit(AActor* bounceMobj, line_t* bounceLine, secplane_t* bouncePlane);
+
 	// Returns true if it's okay to switch target to "other" after being attacked by it.
 	bool CallOkayToSwitchTarget(AActor *other);
 	bool OkayToSwitchTarget (AActor *other);

src/playsim/p_map.cpp

@@ -3518,6 +3518,16 @@ bool FSlide::BounceWall(AActor *mo)
 	}
 	line = bestslideline;
 
+	if (mo->flags & MF_MISSILE)
+	{
+		switch (mo->SpecialBounceHit(nullptr, line, nullptr))
+		{
+			case 1:		return true;
+			case 0:		return false;
+			default:	break;
+		}
+	}
+
 	if (line->special == Line_Horizon || ((mo->BounceFlags & BOUNCE_NotOnSky) && line->hitSkyWall(mo)))
 	{
 		mo->SeeSound = mo->BounceSound = NO_SOUND;	// it might make a sound otherwise
@@ -3608,6 +3618,13 @@ bool P_BounceActor(AActor *mo, AActor *BlockingMobj, bool ontop)
 			case 0:		return false;
 			default:	break;
 		}
+
+		switch (mo->SpecialBounceHit(BlockingMobj, nullptr, nullptr))
+		{
+			case 1:		return true;
+			case 0:		return false;
+			default:	break;
+		}
 	}
 
 	//Don't go through all of this if the actor is reflective and wants things to pass through them.

src/playsim/p_mobj.cpp

@@ -1528,6 +1528,17 @@ void AActor::PlayBounceSound(bool onfloor)
 
 bool AActor::FloorBounceMissile (secplane_t &plane)
 {
+	if (flags & MF_MISSILE)
+	{
+		switch (SpecialBounceHit(nullptr, nullptr, &plane))
+		{
+			// This one is backwards for some reason...
+			case 1:		return false;
+			case 0:		return true;
+			default:	break;
+		}
+	}
+
 	// [ZZ] if bouncing missile hits a damageable sector(plane), it dies
 	if (P_ProjectileHitPlane(this, -1) && bouncecount > 0)
 	{
@@ -3178,6 +3189,21 @@ int AActor::SpecialMissileHit (AActor *victim)
 	else return -1;
 }
 
+// This virtual method only exists on the script side.
+int AActor::SpecialBounceHit(AActor* bounceMobj, line_t* bounceLine, secplane_t* bouncePlane)
+{
+	IFVIRTUAL(AActor, SpecialBounceHit)
+	{
+		VMValue params[4] = { (DObject*)this, bounceMobj, bounceLine, bouncePlane };
+		VMReturn ret;
+		int retval;
+		ret.IntAt(&retval);
+		VMCall(func, params, 4, &ret, 1);
+		return retval;
+	}
+	else return -1;
+}
+
 bool AActor::AdjustReflectionAngle (AActor *thing, DAngle &angle)
 {
 	if (flags2 & MF2_DONTREFLECT) return true;

wadsrc/static/zscript/actors/actor.zs

@@ -543,6 +543,12 @@ class Actor : Thinker native
 		return -1;
 	}
 
+	// This is called when a missile bounces off something.
+	virtual int SpecialBounceHit(Actor bounceMobj, Line bounceLine, SecPlane bouncePlane)
+	{
+		return -1;
+	}
+
 	// Called when the player presses 'use' and an actor is found, except if the
 	// UseSpecial flag is set. Use level.ExecuteSpecial to call action specials
 	// instead.