From 12619671e6846fa7831e1814ff75c69421062512 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@users.noreply.github.com>
Date: Mon, 27 Dec 2021 15:33:10 +0100
Subject: [PATCH] - Duke/RR: added fudging to work around aiming randomization
 issues with the pistol when autoaim is off.

Solution is the same as in RedNukem/EDuke32: do one hitscan directly in aiming order and if that hits a sprite, use it as aiming target.
---
 source/core/intvec.h             |  1 +
 source/games/duke/src/inlines.h  |  1 -
 source/games/duke/src/player.cpp | 24 ++++++++++++++++++++----
 3 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/source/core/intvec.h b/source/core/intvec.h
index 11c6f76e6..8e9e45edc 100644
--- a/source/core/intvec.h
+++ b/source/core/intvec.h
@@ -41,6 +41,7 @@ struct vec3_t
     vec3_t operator-(const vec3_t& other) const { return { X - other.X, Y - other.Y, Z - other.Z }; }
     vec3_t& operator+=(const vec3_t& other) { X += other.X; Y += other.Y; Z += other.Z; return *this; };
     vec3_t& operator-=(const vec3_t& other) { X -= other.X; Y -= other.Y; Z += other.Z; return *this; };
+    vec3_t withZOffset(int ofs) { return { X, Y, Z + ofs }; }
 
 };
 
diff --git a/source/games/duke/src/inlines.h b/source/games/duke/src/inlines.h
index e547214f2..91fc329c0 100644
--- a/source/games/duke/src/inlines.h
+++ b/source/games/duke/src/inlines.h
@@ -112,7 +112,6 @@ inline bool isIn(int value, const std::initializer_list<int>& list)
 	return false;
 }
 
-
 // these are mainly here to avoid directly accessing the input data so that it can be more easily refactored later.
 inline bool PlayerInput(int pl, ESyncBits bit)
 {
diff --git a/source/games/duke/src/player.cpp b/source/games/duke/src/player.cpp
index d7219fa28..59739145c 100644
--- a/source/games/duke/src/player.cpp
+++ b/source/games/duke/src/player.cpp
@@ -230,7 +230,7 @@ DDukeActor* aim(DDukeActor* actor, int aang)
 {
 	bool gotshrinker, gotfreezer;
 	int a, k, cans;
-	int aimstats[] = { STAT_PLAYER, STAT_DUMMYPLAYER, STAT_ACTOR, STAT_ZOMBIEACTOR };
+	static const int aimstats[] = { STAT_PLAYER, STAT_DUMMYPLAYER, STAT_ACTOR, STAT_ZOMBIEACTOR };
 	int dx1, dy1, dx2, dy2, dx3, dy3, smax, sdist;
 	int xv, yv;
 
@@ -239,11 +239,27 @@ DDukeActor* aim(DDukeActor* actor, int aang)
 	// Autoaim from DukeGDX.
 	if (actor->spr.picnum == TILE_APLAYER)
 	{
+		auto* plr = &ps[actor->spr.yvel];
 		int autoaim = Autoaim(actor->spr.yvel);
 		if (!autoaim)
 		{
+			// Some fudging to avoid aim randomization when autoaim is off.
+			// This is a reimplementation of how it was solved in RedNukem.
+			if (plr->curr_weapon == PISTOL_WEAPON && !isWW2GI())
+			{
+				int zvel = -plr->horizon.sum().asq16() >> 5;
+
+				HitInfo hit{};
+				hitscan(plr->pos.withZOffset(1024), actor->sector(), { bcos(actor->spr.ang), bsin(actor->spr.ang), zvel }, hit, CLIPMASK1);
+
+				if (hit.actor() != nullptr)
+				{
+					if (isIn(hit.actor()->spr.statnum, { STAT_PLAYER, STAT_DUMMYPLAYER, STAT_ACTOR, STAT_ZOMBIEACTOR }))
+						return hit.actor();
+				}
+			}
 			// The chickens in RRRA are homing and must always autoaim.
-			if (!isRRRA() || ps[actor->spr.yvel].curr_weapon != CHICKEN_WEAPON)
+			if (!isRRRA() || plr->curr_weapon != CHICKEN_WEAPON)
 				return nullptr;
 		}
 		else if (autoaim == 2)
@@ -251,11 +267,11 @@ DDukeActor* aim(DDukeActor* actor, int aang)
 			int weap;
 			if (!isWW2GI())
 			{
-				weap = ps[actor->spr.yvel].curr_weapon;
+				weap = plr->curr_weapon;
 			}
 			else
 			{
-				weap = aplWeaponWorksLike(ps[actor->spr.yvel].curr_weapon, actor->spr.yvel);
+				weap = aplWeaponWorksLike(plr->curr_weapon, actor->spr.yvel);
 			}
 			if (weap > CHAINGUN_WEAPON || weap == KNEE_WEAPON)
 			{