From 3fd63fd1559c678f0b63ba48d0de211aab1cf591 Mon Sep 17 00:00:00 2001
From: Holger Schemel <info@artsoft.org>
Date: Tue, 29 Sep 2020 21:35:09 +0200
Subject: [PATCH] fixed single-step mode for wrap-around levels in EM engine

This fixes a graphical bug when wrapping around in single-step mode by
drawing wrap-around animation before going to single step pause mode.
---
 src/engines.h        |  2 +-
 src/game_em/game.c   |  9 ++++++--
 src/game_em/global.h |  2 ++
 src/game_em/logic.c  | 51 +++++++++++++++++++++++++++++++++-----------
 src/tools.c          | 10 +++++----
 5 files changed, 54 insertions(+), 20 deletions(-)

diff --git a/src/engines.h b/src/engines.h
index 46cdbf4f..826ad964 100644
--- a/src/engines.h
+++ b/src/engines.h
@@ -33,7 +33,7 @@ boolean isActivePlayer_EM(int);
 
 void PlayLevelSound_EM(int, int, int, int);
 void InitGraphicInfo_EM(void);
-void CheckSingleStepMode_EM(byte action[], int, boolean, boolean, boolean);
+boolean CheckSingleStepMode_EM(byte action[], int, boolean, boolean, boolean);
 
 void SetGfxAnimation_EM(struct GraphicInfo_EM *, int, int, int, int);
 void getGraphicSourceObjectExt_EM(struct GraphicInfo_EM *, int, int, int, int);
diff --git a/src/game_em/game.c b/src/game_em/game.c
index 3115fb5a..8443ff05 100644
--- a/src/game_em/game.c
+++ b/src/game_em/game.c
@@ -108,8 +108,13 @@ void GameActions_EM(byte action[MAX_PLAYERS], boolean warp_mode)
 	ply[i].dynamite_cnt < 5)
       any_player_dropping = TRUE;
 
-  CheckSingleStepMode_EM(action, frame, game_em.any_player_moving,
-			 game_em.any_player_snapping, any_player_dropping);
+  boolean single_step_mode_paused =
+    CheckSingleStepMode_EM(action, frame, game_em.any_player_moving,
+			   game_em.any_player_snapping, any_player_dropping);
+
+  // draw wrapping around before going to single step pause mode
+  if (single_step_mode_paused && logic_check_wrap())
+    logic_move();
 
   RedrawPlayfield_EM(FALSE);
 }
diff --git a/src/game_em/global.h b/src/game_em/global.h
index 3efba447..33b96423 100644
--- a/src/game_em/global.h
+++ b/src/game_em/global.h
@@ -19,6 +19,8 @@ void game_init_cave_buffers(void);
 void play_sound(int, int, int);
 void play_element_sound(int, int, int, int);
 
+boolean logic_check_wrap(void);
+void logic_move(void);
 void logic_init(void);
 void logic(void);
 
diff --git a/src/game_em/logic.c b/src/game_em/logic.c
index 5055be5a..8b759630 100644
--- a/src/game_em/logic.c
+++ b/src/game_em/logic.c
@@ -7381,27 +7381,28 @@ static void handle_tile(int x, int y)
   }
 }
 
-static void logic_players(void)
+boolean logic_check_wrap(void)
 {
-  int start_check_nr;
   int i;
 
-  cave = lev.cave;
-  next = lev.next;
-  boom = lev.boom;
-
-  game_em.any_player_moving = FALSE;
-  game_em.any_player_snapping = FALSE;
-
-  /* must test for death and actually kill separately */
   for (i = 0; i < MAX_PLAYERS; i++)
   {
-    boolean ply_kill = player_killed(&ply[i]);
+    if (!ply[i].alive)
+      continue;
 
-    if (ply[i].alive && ply_kill)
-      kill_player(&ply[i]);
+    /* check for wrap-around movement */
+    if (ply[i].x < lev.left ||
+	ply[i].x > lev.right - 1)
+      return TRUE;
   }
 
+  return FALSE;
+}
+
+void logic_move(void)
+{
+  int i;
+
   for (i = 0; i < MAX_PLAYERS; i++)
   {
     if (!ply[i].alive)
@@ -7425,6 +7426,30 @@ static void logic_players(void)
     ply[i].prev_y = ply[i].y;
     ply[i].anim = PLY_still;
   }
+}
+
+static void logic_players(void)
+{
+  int start_check_nr;
+  int i;
+
+  cave = lev.cave;
+  next = lev.next;
+  boom = lev.boom;
+
+  game_em.any_player_moving = FALSE;
+  game_em.any_player_snapping = FALSE;
+
+  /* must test for death and actually kill separately */
+  for (i = 0; i < MAX_PLAYERS; i++)
+  {
+    boolean ply_kill = player_killed(&ply[i]);
+
+    if (ply[i].alive && ply_kill)
+      kill_player(&ply[i]);
+  }
+
+  logic_move();
 
   start_check_nr = ((game_em.random & 128 ? 0 : 1) * 2 +
 		    (game_em.random & 256 ? 0 : 1));
diff --git a/src/tools.c b/src/tools.c
index 2c30df83..a4199a14 100644
--- a/src/tools.c
+++ b/src/tools.c
@@ -9078,10 +9078,10 @@ static void CheckSaveEngineSnapshot_MM(boolean element_clicked,
   }
 }
 
-void CheckSingleStepMode_EM(byte action[MAX_PLAYERS], int frame,
-			    boolean any_player_moving,
-			    boolean any_player_snapping,
-			    boolean any_player_dropping)
+boolean CheckSingleStepMode_EM(byte action[MAX_PLAYERS], int frame,
+			       boolean any_player_moving,
+			       boolean any_player_snapping,
+			       boolean any_player_dropping)
 {
   if (tape.single_step && tape.recording && !tape.pausing)
     if (frame == 7 && !any_player_dropping)
@@ -9089,6 +9089,8 @@ void CheckSingleStepMode_EM(byte action[MAX_PLAYERS], int frame,
 
   CheckSaveEngineSnapshot_EM(action, frame, any_player_moving,
 			     any_player_snapping, any_player_dropping);
+
+  return tape.pausing;
 }
 
 void CheckSingleStepMode_SP(boolean murphy_is_waiting,
-- 
2.34.1