From 64cf7a3d208efa9a8f4e74fb8c1c8198e155b7ee Mon Sep 17 00:00:00 2001
From: Lukas Krickl <lukas@krickl.dev>
Date: Thu, 26 Jun 2025 13:00:45 +0200
Subject: [PATCH] unit: wip sub-tile animation

---
 src/defs.s     | 10 ++++++++--
 src/macros.inc |  3 +--
 src/unit.s     | 14 +++++++++++++-
 3 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/src/defs.s b/src/defs.s
index db3c7ca..008a45a 100644
--- a/src/defs.s
+++ b/src/defs.s
@@ -140,8 +140,14 @@
   ; last collision with actor
   ; set during unit_collision_woth_any_other
 .de act_rt_collided_with, 2
-.de act_rt_subtile_y, 1
-.de act_rt_subtile_x, 1
+
+  ; sub-tile drawing vars
+  ; during this animation the actor is already technically in its new 
+  ; location.
+  ; ab000000: direction bits (a == 0/1 -> up/down; b == 0/1 -> left/right)
+  ; 00nnn000: current tile offset y position
+  ; 00000nnn: currnet tile offset x position
+.de act_rt_sub_tile, 1
 
   ; stats1
 .de act_level, 1
diff --git a/src/macros.inc b/src/macros.inc
index 7237c16..2328adb 100644
--- a/src/macros.inc
+++ b/src/macros.inc
@@ -183,8 +183,7 @@
 
   ; act_rt_collided_with
   dw 0 
-  .db 0  ; y-subtile
-  .db 0  ; x-subtile
+  .db 0  ; act_rt_sub_tile 
 #endmacro
   
   ; defines an actor's stats (1/2)
diff --git a/src/unit.s b/src/unit.s
index 223ffa5..503fd80 100644
--- a/src/unit.s
+++ b/src/unit.s
@@ -310,8 +310,12 @@ unit_collides_with_any_other:
   ; to a movement animation
   ; the animation time is dependant on movement
   ; speed (100-stat_calc_speed)
+  ; the end-state of the move_animation should
+  ; clear rt_sub_tile to 0 
   ; inputs:
   ;   de: actor
+  ;    a: mask for rt_sub_tile
+  ;       rt_subtile |= a
 unit_transition_to_move_animation:
   ret
 
@@ -341,7 +345,9 @@ unit_try_move_up:
 
   dec a 
   ld [hl], a
-
+  
+  ; not bits set
+  ld a, 0b00000000
   call unit_transition_to_move_animation
 
   ret
@@ -360,6 +366,8 @@ unit_try_move_down:
   inc a
   ld [hl], a
 
+  ; set down bit
+  ld a, 0b10000000
   call unit_transition_to_move_animation
   
   ret
@@ -378,6 +386,8 @@ unit_try_move_left:
   dec a
   ld [hl], a
   
+  ; no bits set
+  ld a, 0b00000000
   call unit_transition_to_move_animation
   
   ret
@@ -397,6 +407,8 @@ unit_try_move_right:
   inc a
   ld [hl], a
 
+  ; set right bit
+  ld a, 0b01000000
   call unit_transition_to_move_animation
 
   ret 
-- 
2.30.2