From: Lukas Krickl <lukas@krickl.dev>
Date: Mon, 12 Jan 2026 13:38:58 +0000 (+0100)
Subject: player: Added basic movement and wall collisions
X-Git-Url: https://git.krickl.dev/?a=commitdiff_plain;h=7ef5da51f84785f4011d0be5eb32188dacb3c8bd;p=gbrg%2F.git

player: Added basic movement and wall collisions
---

diff --git a/src/actor.s b/src/actor.s
index 3b4a447..cc22617 100644
--- a/src/actor.s
+++ b/src/actor.s
@@ -319,3 +319,72 @@ act_load_attr_table:
 	; bc = attribute table
 
 	ret
+
+	; attempts to move an actor
+	; to a new y/x position.
+	; aborts the move if the position 
+	; is inside a wall tile or the tile is already occupied
+	; unsets t_act on current tile. sets t_act on new tile
+	; inputs:
+	;		de: actor ptr
+	;		bc: new position
+	;	returns:
+	;		a: 0 -> moved
+	;		a: 1 -> not moved 
+	;		col_tile: ptr to new tile
+act_move_to:
+	ld hl, act_pos_y
+	add hl, de
+
+	push hl
+	push bc
+	
+	call map_get_tile
+	; write col tile
+	ld a, h
+	ld [col_tile], a
+	ld a, l
+	ld [col_tile+1], a
+
+	; hl = tile
+	push hl
+
+	; check flags
+	ld de, t_flags0
+	add hl, de
+	ld a, [hl]
+	; if wall flag do not move
+	and a, TF0_WALL
+	jp nz, @hit
+	pop hl
+
+	; check actor ptr
+	ld de, t_act
+	add hl, de
+
+	; if not NULL do not move
+	ld a, [hl+]
+	or a, [hl]
+	jp nz, @hit
+
+
+	pop bc
+	pop de ; de = actor ptr
+	
+
+	; write new position
+	ld a, b
+	ld [de], a
+	inc de
+	ld a, c
+	ld [de], a
+
+	ld a, 0
+	ret
+@hit:
+	; clean up stack
+	pop de
+	pop de 
+	pop de
+	ld a, 1
+	ret
diff --git a/src/map.s b/src/map.s
index d632449..10f4e21 100644
--- a/src/map.s
+++ b/src/map.s
@@ -33,9 +33,12 @@ map_load:
 	call vblank_wait
 	call enableinterrupts
 	
+	call map_uncover
+
 	call map_full_draw
 	call update_render
 
+
 	ret
 	
 	; loads all map related data that 
@@ -478,8 +481,14 @@ map_full_draw:
 	call update_render
 	ret
 	
+	; uncovers tiles starting at player position
+	; and moving in all non-uncovered tiles until walls are hit
+map_uncover:
+	ret
+	
 	; nop map rotuine
 map_r_nop:
 	ret
 
 
+
diff --git a/src/player.s b/src/player.s
index 375a7f7..9c96a46 100644
--- a/src/player.s
+++ b/src/player.s
@@ -2,7 +2,7 @@
 
 	; sets up the player actor
 player_init:
-	xor a, a
+	ld a, 2
 	ld [player+act_pos_y], a
 	ld [player+act_pos_x], a
 
@@ -107,8 +107,18 @@ player_handle_move:
 	jr z, @not_left REL
 		ld a, [player+act_pos_x]
 		dec a
-		ld [player+act_pos_x], a
-		call map_full_draw
+		ld c, a
+
+		ld a, [player+act_pos_y]
+		ld b, a
+
+
+		ld de, player
+		call act_move_to
+
+		cp a, 0
+		jp z, player_moved
+		jp player_collided
 @not_left:
 
 	ld b, DIRRIGHT
@@ -116,8 +126,17 @@ player_handle_move:
 	jr z, @not_right REL
 		ld a, [player+act_pos_x]
 		inc a
-		ld [player+act_pos_x], a
-		call map_full_draw
+		ld c, a
+
+		ld a, [player+act_pos_y]
+		ld b, a
+
+		ld de, player
+		call act_move_to
+		
+		cp a, 0
+		jp z, player_moved
+		jp player_collided
 @not_right:
 
 	ld b, DIRUP
@@ -125,8 +144,17 @@ player_handle_move:
 	jr z, @not_up REL
 		ld a, [player+act_pos_y]
 		dec a
-		ld [player+act_pos_y], a
-		call map_full_draw
+		ld b, a
+
+		ld a, [player+act_pos_x]
+		ld c, a
+
+		ld de, player
+		call act_move_to
+
+		cp a, 0
+		jp z, player_moved
+		jp player_collided
 @not_up:
 
 	ld b, DIRDOWN
@@ -134,8 +162,48 @@ player_handle_move:
 	jr z, @not_down REL
 		ld a, [player+act_pos_y]
 		inc a
-		ld [player+act_pos_y], a
-		call map_full_draw
+		ld b, a
+		
+		ld a, [player+act_pos_x]
+		ld c, a
+		
+		ld de, player
+		call act_move_to
+
+		cp a, 0
+		jp z, player_moved
+		jp player_collided
 @not_down:
 	ret
 	
+	; code to run when player has collided
+player_collided:
+	ld a, [col_tile]
+	ld d, a
+	ld a, [col_tile+1]
+	ld e, a
+	; de = collision tile
+
+	ld a, [de] 
+	cp a, TT_DOOR ; if its a door run special code
+	jp z, @open_door
+	
+	ret
+@open_door:
+	ld a, TT_FLOOR
+	ld [de], a
+
+	ld hl, t_flags0
+	add hl, de 
+	; clear all flags
+	xor a, a
+	ld [hl], a
+
+	call map_uncover
+	call map_full_draw
+	ret
+
+	; code to run when player has moved
+player_moved:
+	call map_full_draw
+	ret
diff --git a/src/wram.s b/src/wram.s
index 0e8da63..085e22b 100644
--- a/src/wram.s
+++ b/src/wram.s
@@ -116,6 +116,9 @@ combat: .adv combat_size
 
 render_buffer: .adv RENDER_BUF_TILES
 
+col_actor: .adv 2
+col_tile: .adv 2
+
 #ifdef DEBUG_CANARY
 render_canary: .adv 4
 #endif