From d853f9b355d4bdd411191966de738a5f5ec37cf9 Mon Sep 17 00:00:00 2001
From: Hugo Locurcio <hugo.locurcio@hugo.pro>
Date: Thu, 21 Sep 2023 03:52:19 +0200
Subject: [PATCH] Use velocity to detect teleports in `am_path` drawing

---
 src/am_map.cpp | 11 +++++++----
 src/am_map.h   |  3 +++
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/src/am_map.cpp b/src/am_map.cpp
index d6916b27d5..9caac9b1b0 100644
--- a/src/am_map.cpp
+++ b/src/am_map.cpp
@@ -1846,9 +1846,10 @@ void DAutomap::collectPath ()
 		constexpr int MIN_DISTANCE_BETWEEN_POINTS = 32;
 		if (abs(last_line.b.x - pos.X) >= MIN_DISTANCE_BETWEEN_POINTS || abs(last_line.b.y - pos.Y) >= MIN_DISTANCE_BETWEEN_POINTS)
 		{
-			// If the distance between two points is very high, the player has likely teleported so no path should be drawn between the points.
-			constexpr int MAX_DISTANCE_BETWEEN_TICKS = 100;
-			if (abs(last_line.b.x - pos.X) >= MAX_DISTANCE_BETWEEN_TICKS || abs(last_line.b.y - pos.Y) >= MAX_DISTANCE_BETWEEN_TICKS)
+			// If the player's velocity is lower than the distance between the last two ticks (with some tolerance),
+			// the player has likely teleported so no path should be drawn between the points.
+			constexpr float EPSILON = 10.0;
+			if ((pos - last_tick_pos).Length() > (players[consoleplayer].camera->VelXYToSpeed() + EPSILON))
 			{
 				ml.a.x = pos.X;
 				ml.a.y = pos.Y;
@@ -1862,7 +1863,7 @@ void DAutomap::collectPath ()
 			ml.b.x = pos.X;
 			ml.b.y = pos.Y;
 
-			if (path_history.Size() > am_pathlength)
+			if (path_history.Size() > uint32_t(am_pathlength))
 			{
 				// Path is too long; remove the oldest lines.
 				path_history.Delete(0);
@@ -1879,6 +1880,8 @@ void DAutomap::collectPath ()
 		ml.b.y = pos.Y;
 		path_history.Push(ml);
 	}
+
+	last_tick_pos = players[consoleplayer].camera->InterpolatedPosition(r_viewpoint.TicFrac);
 }
 
 //=============================================================================
diff --git a/src/am_map.h b/src/am_map.h
index 3665e44383..306e19611b 100644
--- a/src/am_map.h
+++ b/src/am_map.h
@@ -44,6 +44,9 @@ public:
 	// called instead of view drawer if automap active.
 	virtual void Drawer(int bottom) = 0;
 
+	// Used for am_path drawing to calculate distance between ticks.
+	DVector2 last_tick_pos;
+
 	virtual void NewResolution() = 0;
 	virtual void LevelInit() = 0;
 	virtual void UpdateShowAllLines() = 0;