From 3aa759714acef0b7ddf3bffcc8b412a70902e3b9 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@zdoom.fake>
Date: Sat, 7 Apr 2012 12:48:56 +0000
Subject: [PATCH] - added DavidPH's A_FaceTarget with pitch submission.

SVN r3528 (trunk)
---
 src/p_enemy.cpp                | 73 ++++++++++++++++++++++++++++------
 src/p_enemy.h                  |  2 +-
 src/tables.h                   |  4 ++
 wadsrc/static/actors/actor.txt |  6 +--
 4 files changed, 68 insertions(+), 17 deletions(-)

diff --git a/src/p_enemy.cpp b/src/p_enemy.cpp
index 5cb1ce673b..796480c9c6 100644
--- a/src/p_enemy.cpp
+++ b/src/p_enemy.cpp
@@ -2726,7 +2726,7 @@ void A_Chase(AActor *self)
 // A_FaceTracer
 //
 //=============================================================================
-void A_Face (AActor *self, AActor *other, angle_t max_turn)
+void A_Face (AActor *self, AActor *other, angle_t max_turn, angle_t max_pitch)
 {
 	if (!other)
 		return;
@@ -2773,6 +2773,50 @@ void A_Face (AActor *self, AActor *other, angle_t max_turn)
 		self->angle = other_angle;
 	}
 
+	// [DH] Now set pitch. In order to maintain compatibility, this can be
+	// disabled and is so by default.
+	if (max_pitch <= ANGLE_180)
+	{
+		// [DH] Don't need to do proper fixed->double conversion, since the
+		// result is only used in a ratio.
+		double dist_x = self->target->x - self->x;
+		double dist_y = self->target->y - self->y;
+		double dist_z = self->target->z - self->z;
+		double dist = sqrt(dist_x*dist_x + dist_y*dist_y + dist_z*dist_z);
+
+		angle_t other_pitch = rad2bam(asin(dist_z / dist));
+
+		if (max_pitch && (max_pitch < (angle_t)abs(self->pitch - other_pitch)))
+		{
+			if (self->pitch > other_pitch)
+			{
+				if (self->pitch - other_pitch < ANGLE_180)
+				{
+					self->pitch -= max_pitch;
+				}
+				else
+				{
+					self->pitch += max_pitch;
+				}
+			}
+			else
+			{
+				if (other_pitch - self->pitch < ANGLE_180)
+				{
+					self->pitch += max_pitch;
+				}
+				else
+				{
+					self->pitch -= max_pitch;
+				}
+			}
+		}
+		else
+		{
+			self->pitch = other_pitch;
+		}
+	}
+
 	// This will never work well if the turn angle is limited.
 	if (max_turn == 0 && (self->angle == other_angle) && other->flags & MF_SHADOW && !(self->flags6 & MF6_SEEINVISIBLE) )
     {
@@ -2780,43 +2824,46 @@ void A_Face (AActor *self, AActor *other, angle_t max_turn)
     }
 }
 
-void A_FaceTarget (AActor *self, angle_t max_turn)
+void A_FaceTarget (AActor *self, angle_t max_turn, angle_t max_pitch)
 {
-	A_Face(self, self->target, max_turn);
+	A_Face(self, self->target, max_turn, max_pitch);
 }
 
-void A_FaceMaster (AActor *self, angle_t max_turn)
+void A_FaceMaster (AActor *self, angle_t max_turn, angle_t max_pitch)
 {
-	A_Face(self, self->master, max_turn);
+	A_Face(self, self->master, max_turn, max_pitch);
 }
 
-void A_FaceTracer (AActor *self, angle_t max_turn)
+void A_FaceTracer (AActor *self, angle_t max_turn, angle_t max_pitch)
 {
-	A_Face(self, self->tracer, max_turn);
+	A_Face(self, self->tracer, max_turn, max_pitch);
 }
 
 DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_FaceTarget)
 {
-	ACTION_PARAM_START(1);
+	ACTION_PARAM_START(2);
 	ACTION_PARAM_ANGLE(max_turn, 0);
+	ACTION_PARAM_ANGLE(max_pitch, 1);
 
-	A_FaceTarget(self, max_turn);
+	A_FaceTarget(self, max_turn, max_pitch);
 }
 
 DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_FaceMaster)
 {
-	ACTION_PARAM_START(1);
+	ACTION_PARAM_START(2);
 	ACTION_PARAM_ANGLE(max_turn, 0);
+	ACTION_PARAM_ANGLE(max_pitch, 1);
 
-	A_FaceMaster(self, max_turn);
+	A_FaceMaster(self, max_turn, max_pitch);
 }
 
 DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_FaceTracer)
 {
-	ACTION_PARAM_START(1);
+	ACTION_PARAM_START(2);
 	ACTION_PARAM_ANGLE(max_turn, 0);
+	ACTION_PARAM_ANGLE(max_pitch, 1);
 
-	A_FaceTracer(self, max_turn);
+	A_FaceTracer(self, max_turn, max_pitch);
 }
 
 //===========================================================================
diff --git a/src/p_enemy.h b/src/p_enemy.h
index 343ba27e94..ff40c7003b 100644
--- a/src/p_enemy.h
+++ b/src/p_enemy.h
@@ -72,7 +72,7 @@ DECLARE_ACTION(A_FreezeDeathChunks)
 DECLARE_ACTION(A_BossDeath)
 
 void A_Chase(AActor *self);
-void A_FaceTarget (AActor *actor, angle_t max_turn = 0);
+void A_FaceTarget (AActor *actor, angle_t max_turn = 0, angle_t max_pitch = ANGLE_270);
 
 bool A_RaiseMobj (AActor *, fixed_t speed);
 bool A_SinkMobj (AActor *, fixed_t speed);
diff --git a/src/tables.h b/src/tables.h
index aeb2c6991d..929fabf808 100644
--- a/src/tables.h
+++ b/src/tables.h
@@ -109,5 +109,9 @@ inline double bam2rad(angle_t ang)
 {
 	return double(ang >> 1) * (PI / ANGLE_90);
 }
+inline angle_t rad2bam(double ang)
+{
+	return angle_t(ang * (double(1<<30) / PI)) << 1;
+}
 
 #endif // __TABLES_H__
diff --git a/wadsrc/static/actors/actor.txt b/wadsrc/static/actors/actor.txt
index 7e7a591e1a..eb27583ab3 100644
--- a/wadsrc/static/actors/actor.txt
+++ b/wadsrc/static/actors/actor.txt
@@ -69,9 +69,9 @@ ACTOR Actor native //: Thinker
 	action native A_XScream();
 	action native A_Look();
 	action native A_Chase(state melee = "*", state missile = "none", int flags = 0);
-	action native A_FaceTarget(float max_turn = 0);
-	action native A_FaceTracer(float max_turn = 0);
-	action native A_FaceMaster(float max_turn = 0);
+	action native A_FaceTarget(float max_turn = 0, float max_pitch = 270);
+	action native A_FaceTracer(float max_turn = 0, float max_pitch = 270);
+	action native A_FaceMaster(float max_turn = 0, float max_pitch = 270);
 	action native A_PosAttack();
 	action native A_Scream();
 	action native A_SPosAttack();