Add some new optional parameters to A_SprayDecal:

- useBloodColor: when true, the sprayed decal will be shaded to match the calling actor's blood color.
- decalColor: when defined, the sprayed decal will be shaded to the specified color. Note that this will take precedence over useBloodColor. It is recommended to use only one parameter.

Note that due to how decals work in the engine, the "decalColor" parameter will only properly colorize the decal if the image is grayscale.

src/playsim/a_decals.cpp

@@ -831,7 +831,7 @@ DBaseDecal *DImpactDecal::CloneSelf (const FDecalTemplate *tpl, double ix, doubl
 //
 //----------------------------------------------------------------------------
 
-void SprayDecal(AActor *shooter, const char *name, double distance, DVector3 offset, DVector3 direction)
+void SprayDecal(AActor *shooter, const char *name, double distance, DVector3 offset, DVector3 direction, bool useBloodColor, uint32_t decalColor)
 {
 	//just in case
 	if (!shooter)
@@ -859,12 +859,14 @@ void SprayDecal(AActor *shooter, const char *name, double distance, DVector3 off
 	else
 		dir = direction;
 
+	uint32_t bloodTrans = useBloodColor ? shooter->BloodTranslation : 0;
+	PalEntry entry = !useBloodColor ? (PalEntry)decalColor : shooter->BloodColor;
 
 	if (Trace(off, shooter->Sector, dir, distance, 0, ML_BLOCKEVERYTHING, shooter, trace, TRACE_NoSky))
 	{
 		if (trace.HitType == TRACE_HitWall)
 		{
-			DImpactDecal::StaticCreate(shooter->Level, name, trace.HitPos, trace.Line->sidedef[trace.Side], NULL);
+			DImpactDecal::StaticCreate(shooter->Level, name, trace.HitPos, trace.Line->sidedef[trace.Side], NULL, entry, bloodTrans);
 		}
 	}
 }