Added SPF_ROLLCENTER for particles and visual thinkers.

Author: MajorCooke

src/playsim/p_effect.h

@@ -68,6 +68,7 @@ enum EParticleFlags
 	SPF_NEGATIVE_FADESTEP		= 1 << 10,
 	SPF_FACECAMERA				= 1 << 11,
 	SPF_NOFACECAMERA			= 1 << 12,
+	SPF_ROLLCENTER				= 1 << 13,
 };
 
 class DVisualThinker;

src/rendering/hwrenderer/scene/hw_sprites.cpp

@@ -415,7 +415,7 @@ bool HWSprite::CalculateVertices(HWDrawInfo* di, FVector3* v, DVector3* vp)
 
 	// [Nash] is a flat sprite
 	const bool isWallSprite = (actor != nullptr) && (spritetype == RF_WALLSPRITE);
-	const bool useOffsets = (actor != nullptr) && !(actor->renderflags & RF_ROLLCENTER);
+	const bool useOffsets = ((actor != nullptr) && !(actor->renderflags & RF_ROLLCENTER)) || (particle && !(particle->flags & SPF_ROLLCENTER));
 
 	FVector2 offset = FVector2( offx, offy );
 	float xx = -center.X + x;

wadsrc/static/zscript/constants.zs

@@ -717,6 +717,7 @@ enum EParticleFlags
 	SPF_NEGATIVE_FADESTEP		= 1 << 10,
 	SPF_FACECAMERA				= 1 << 11,
 	SPF_NOFACECAMERA			= 1 << 12,
+	SPF_ROLLCENTER				= 1 << 13,
 
 	SPF_RELATIVE				= SPF_RELPOS|SPF_RELVEL|SPF_RELACCEL|SPF_RELANG
 };