From 3f0ed5d2529b7d6b4870303d28a0c8a22149b563 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <c.oelckers@zdoom.fake>
Date: Tue, 12 Apr 2016 19:44:12 +0200
Subject: [PATCH] - added a distancecheck property to AActor that allows a
 given CVAR to be used as maximum display distance for actors of this type.

This is for WolfenDoom: BOA, which has some scripted sprite distance checks that very negatively affected performance.
---
 src/actor.h                          |  6 ++++++
 src/info.h                           |  2 ++
 src/r_things.cpp                     | 15 +++++++++++++--
 src/thingdef/thingdef_properties.cpp | 22 ++++++++++++++++++++++
 4 files changed, 43 insertions(+), 2 deletions(-)

diff --git a/src/actor.h b/src/actor.h
index 539144ed9..e7fe048ef 100644
--- a/src/actor.h
+++ b/src/actor.h
@@ -804,6 +804,12 @@ public:
 		return bloodcls;
 	}
 
+	double Distance2DSquared(AActor *other, bool absolute = false)
+	{
+		DVector2 otherpos = absolute ? other->Pos() : other->PosRelative(this);
+		return (Pos().XY() - otherpos).LengthSquared();
+	}
+
 	double Distance2D(AActor *other, bool absolute = false)
 	{
 		DVector2 otherpos = absolute ? other->Pos() : other->PosRelative(this);
diff --git a/src/info.h b/src/info.h
index decfd72df..285894dc7 100644
--- a/src/info.h
+++ b/src/info.h
@@ -53,6 +53,7 @@ struct Baggage;
 class FScanner;
 struct FActorInfo;
 class FArchive;
+class FIntCVar;
 
 // Sprites that are fixed in position because they can have special meanings.
 enum
@@ -259,6 +260,7 @@ public:
 
 	DDropItem *DropItems;
 	FString SourceLumpName;
+	FIntCVar *distancecheck;
 
 	// Old Decorate compatibility stuff
 	bool DontHurtShooter;
diff --git a/src/r_things.cpp b/src/r_things.cpp
index 2033423e8..c2fa165db 100644
--- a/src/r_things.cpp
+++ b/src/r_things.cpp
@@ -1246,9 +1246,20 @@ void R_AddSprites (sector_t *sec, int lightlevel, int fakeside)
 	// Handle all things in sector.
 	for (thing = sec->thinglist; thing; thing = thing->snext)
 	{
+		FIntCVar *cvar = thing->GetClass()->distancecheck;
+		if (cvar != NULL && *cvar >= 0)
+		{
+			double dist = thing->Distance2DSquared(camera);
+			double check = (double)**cvar;
+			if (dist >= check * check)
+			{
+				continue;
+			}
+		}
+
 		// find fake level
-		for(int i = 0; i < (int)frontsector->e->XFloor.ffloors.Size(); i++) {
-			rover = frontsector->e->XFloor.ffloors[i];
+		for(auto rover : frontsector->e->XFloor.ffloors) 
+		{
 			if(!(rover->flags & FF_EXISTS) || !(rover->flags & FF_RENDERPLANES)) continue;
 			if(!(rover->flags & FF_SOLID) || rover->alpha != 255) continue;
 			if(!fakefloor)
diff --git a/src/thingdef/thingdef_properties.cpp b/src/thingdef/thingdef_properties.cpp
index c435cd575..3ec4c624d 100644
--- a/src/thingdef/thingdef_properties.cpp
+++ b/src/thingdef/thingdef_properties.cpp
@@ -1523,6 +1523,28 @@ DEFINE_PROPERTY(riplevelmax, I, Actor)
 	defaults->RipLevelMax = id;
 }
 
+//==========================================================================
+//
+//==========================================================================
+DEFINE_PROPERTY(distancecheck, S, Actor)
+{
+	PROP_STRING_PARM(cvar, 0);
+	FBaseCVar *scratch;
+	FBaseCVar *cv = FindCVar(cvar, &scratch);
+	if (cv == NULL)
+	{
+		I_Error("CVar %s not defined", cvar);
+	}
+	else if (cv->GetRealType() == CVAR_Int)
+	{
+		static_cast<PClassActor*>(info)->distancecheck = static_cast<FIntCVar *>(cv);
+	}
+	else
+	{
+		I_Error("CVar %s must of type Int", cvar);
+	}
+}
+
 //==========================================================================
 //
 // Special inventory properties