From 9889cd80c5f7644b7a771669d25efd528682c839 Mon Sep 17 00:00:00 2001
From: Lukas Krickl <lukas@krickl.dev>
Date: Mon, 22 Sep 2025 09:53:11 +0200
Subject: [PATCH] collision: wip player movement

---
 src/actor.s     | 34 ++++++++++++++++++++++++++++++++++
 src/player.s    | 22 ++++++++++++++++++++++
 src/rectangle.s |  4 ++++
 src/wram.s      |  4 ++++
 4 files changed, 64 insertions(+)

diff --git a/src/actor.s b/src/actor.s
index 3de0ba1..b0a30cd 100644
--- a/src/actor.s
+++ b/src/actor.s
@@ -125,3 +125,37 @@ actor_despawn:
 	xor a, a
 	ld [de], a
 	ret
+
+	; writes actor default collider
+	; bsed on an input position
+	; writes the collider to dst
+	; e.g. use with actor's real rectangle 
+	; if real collision should be written
+	;	use with tmp_rect for collision tests before moving
+	;	inputs:
+	;		  a: collision mask
+	;		b/c: y/x position of actor
+	;		hl: destination rectangle
+actor_write_default_collider:
+	ld [hl+], a ; mask
+	ld a, b
+	ld [hl+], a ; y pos
+	ld a, c
+	ld [hl+], a ; x pos
+	
+	ld a, 16 ; width/height
+	ld [hl+], a ; height 
+	ld [hl+], a ; width 
+	ret
+	
+	; tests movement against all collision rectangles
+	; inputs:
+	;			     a: collision mask
+	;					de: current actor (this actor is skipped)
+	;		tmp_rect: new collision rectangle
+	; returns:
+	;		a == 0: no collision
+	;		a == 1: collision
+	;		hl: if collided with an actor points to the actor hit, otherwise NULL
+actor_test_movement:
+	ret
diff --git a/src/player.s b/src/player.s
index c71d597..c835f17 100644
--- a/src/player.s
+++ b/src/player.s
@@ -53,6 +53,16 @@ player_update:
 		call player_try_move
 @not_right:
 
+	; write collider for this frame
+	ld a, [player+act_pos_y]
+	ld b, a
+	ld a, [player+act_pos_x]
+	ld c, a
+	ld a, RF_PLAYER
+	ld hl, player+act_rect
+	call actor_write_default_collider
+
+
 	ret
 
 #define PLAYER_SPRITE_IDLE1 0x8D
@@ -124,6 +134,18 @@ player_stage_move_n:
 	; inputs:
 	;		b/c: new y/x position
 player_try_move:
+	; write temporary collider
+	push bc
+	ld a, RF_PLAYER
+	ld hl, tmp_rect
+	call actor_write_default_collider
+	
+	; test collision agains walls and enemies
+	ld a, RF_WALL | RF_ENEMY
+	ld de, player
+	call actor_test_movement
+	pop bc
+
 	ld a, b
 	ld [player+act_pos_y], a
 
diff --git a/src/rectangle.s b/src/rectangle.s
index 63c4580..be67463 100644
--- a/src/rectangle.s
+++ b/src/rectangle.s
@@ -161,6 +161,10 @@ rect_point_test:
 	and a, d
 	; exit if mask is no match
 	jp z, @no_collision_mask_match
+
+	push hl
+	call rect_tr
+	pop hl
 	
 
 	ret
diff --git a/src/wram.s b/src/wram.s
index 5c054d1..243b85c 100644
--- a/src/wram.s
+++ b/src/wram.s
@@ -68,6 +68,10 @@ player: .adv act_size
 actors: .adv act_size * ACTS_MAX 
 map_objs: .adv mo_size * MAP_OBJ_MAX
 rectangles: .adv r_size * RECT_MAX
+	
+	; temporary rectangle used for collision checks 
+	; during movement
+tmp_rect: .adv r_size
 
 	; current row that is being drawn
 map_curr_row: .adv 1
-- 
2.30.2