From 7d56311152068f6bb7a62546c91898ddf058c692 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@zdoom.fake>
Date: Sun, 23 Jun 2013 18:45:17 +0200
Subject: [PATCH] - added Ryan Cordell's A_CheckRange submission.

---
 src/thingdef/thingdef_codeptr.cpp | 62 +++++++++++++++++++++++++++++++
 wadsrc/static/actors/actor.txt    |  1 +
 2 files changed, 63 insertions(+)

diff --git a/src/thingdef/thingdef_codeptr.cpp b/src/thingdef/thingdef_codeptr.cpp
index e7b26cb49..be91cdf2c 100644
--- a/src/thingdef/thingdef_codeptr.cpp
+++ b/src/thingdef/thingdef_codeptr.cpp
@@ -2501,6 +2501,68 @@ DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_CheckSightOrRange)
 	ACTION_JUMP(jump);
 }
 
+//===========================================================================
+//
+// A_CheckRange
+// Jumps if this actor is out of range of all players.
+//
+//===========================================================================
+static bool DoCheckRange(AActor *self, AActor *camera, double range)
+{
+	if (camera == NULL)
+	{
+		return false;
+	}
+	// Check distance first, since it's cheaper than checking sight.
+	double dx = self->x - camera->x;
+	double dy = self->y - camera->y;
+	double dz;
+	fixed_t eyez = (camera->z + camera->height - (camera->height>>2));	// same eye height as P_CheckSight
+	if (eyez > self->z + self->height){
+		dz = self->z + self->height - eyez;
+	}
+	else if (eyez < self->z){
+		dz = self->z - eyez;
+	}
+	else{
+		dz = 0;
+	}
+	if ((dx*dx) + (dy*dy) + (dz*dz) <= range){
+		// Within range
+		return true;
+	}
+	return false;
+}
+
+DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_CheckRange)
+{
+	ACTION_PARAM_START(2);
+	double range = EvalExpressionF(ParameterIndex+0, self);
+	ACTION_PARAM_STATE(jump, 1);
+
+	ACTION_SET_RESULT(false);	// Jumps should never set the result for inventory state chains!
+
+	range = range * range * (double(FRACUNIT) * FRACUNIT);		// no need for square roots
+	for (int i = 0; i < MAXPLAYERS; ++i)
+	{
+		if (playeringame[i])
+		{
+			// Always check from each player.
+			if (DoCheckRange(self, players[i].mo, range))
+			{
+				return;
+			}
+			// If a player is viewing from a non-player, check that too.
+			if (players[i].camera != NULL && players[i].camera->player == NULL &&
+				DoCheckRange(self, players[i].camera, range))
+			{
+				return;
+			}
+		}
+	}
+	ACTION_JUMP(jump);
+}
+
 
 //===========================================================================
 //
diff --git a/wadsrc/static/actors/actor.txt b/wadsrc/static/actors/actor.txt
index 12c625596..c2fa8a0c7 100644
--- a/wadsrc/static/actors/actor.txt
+++ b/wadsrc/static/actors/actor.txt
@@ -302,6 +302,7 @@ ACTOR Actor native //: Thinker
 	action native A_SetDamageType(name damagetype);
 
 	action native A_CheckSightOrRange(float distance, state label);
+	action native A_CheckRange(float distance, state label);
 
 	action native A_RearrangePointers(int newtarget, int newmaster = AAPTR_DEFAULT, int newtracer = AAPTR_DEFAULT, int flags=0);
 	action native A_TransferPointer(int ptr_source, int ptr_recepient, int sourcefield, int recepientfield=AAPTR_DEFAULT, int flags=0);