Added SPF_(NO)FACECAMERA flagst for specifying camera facing on particles and visual thinkers.

- This also adds ensures facing camera is applied to these via the option menu.

Author: MajorCooke

src/playsim/p_effect.h

@@ -66,6 +66,8 @@ enum EParticleFlags
 	SPF_NO_XY_BILLBOARD			= 1 << 8,
 	SPF_LOCAL_ANIM				= 1 << 9,
 	SPF_NEGATIVE_FADESTEP		= 1 << 10,
+	SPF_FACECAMERA				= 1 << 11,
+	SPF_NOFACECAMERA			= 1 << 12,
 };
 
 class DVisualThinker;

src/rendering/hwrenderer/scene/hw_sprites.cpp

@@ -400,8 +400,9 @@ bool HWSprite::CalculateVertices(HWDrawInfo* di, FVector3* v, DVector3* vp)
 		&& (gl_billboard_mode == 1 || (actor && actor->renderflags & RF_FORCEXYBILLBOARD))));
 
 	const bool drawBillboardFacingCamera = hw_force_cambbpref ? gl_billboard_faces_camera :
-		(gl_billboard_faces_camera && (actor && !(actor->renderflags2 & RF2_BILLBOARDNOFACECAMERA)))
-		|| !!(actor && actor->renderflags2 & RF2_BILLBOARDFACECAMERA);
+		gl_billboard_faces_camera
+		&& ((actor && (!(actor->renderflags2 & RF2_BILLBOARDNOFACECAMERA) || (actor->renderflags2 & RF2_BILLBOARDFACECAMERA)))
+		|| (particle && particle->texture.isValid() && (!(particle->flags & SPF_NOFACECAMERA) || (particle->flags & SPF_FACECAMERA))));
 
 	// [Nash] has +ROLLSPRITE
 	const bool drawRollSpriteActor = (actor != nullptr && actor->renderflags & RF_ROLLSPRITE);

wadsrc/static/zscript/constants.zs

@@ -715,6 +715,8 @@ enum EParticleFlags
 	SPF_NO_XY_BILLBOARD			= 1 << 8,
 	SPF_LOCAL_ANIM				= 1 << 9,
 	SPF_NEGATIVE_FADESTEP		= 1 << 10,
+	SPF_FACECAMERA				= 1 << 11,
+	SPF_NOFACECAMERA			= 1 << 12,
 
 	SPF_RELATIVE				= SPF_RELPOS|SPF_RELVEL|SPF_RELACCEL|SPF_RELANG
 };