From: Lukas Krickl <lukas@krickl.dev>
Date: Mon, 22 Sep 2025 15:34:06 +0000 (+0200)
Subject: actor: wip collision code
X-Git-Url: https://git.krickl.dev/?a=commitdiff_plain;h=810e05bd21a7683b2de1cbf7ef78587fa55e7ae3;p=gbrg%2F.git

actor: wip collision code
---

diff --git a/src/actor.s b/src/actor.s
index b0a30cd..026cd26 100644
--- a/src/actor.s
+++ b/src/actor.s
@@ -158,4 +158,43 @@ actor_write_default_collider:
 	;		a == 1: collision
 	;		hl: if collided with an actor points to the actor hit, otherwise NULL
 actor_test_movement:
+	ld [tmp_rect_mask], a
+	; check all static rectangles
+	ld hl, rectangles
+	ld b, RECT_MAX
+	ld de, r_size
+@rect_test_loop:
+		; pre-filter rectangle mask
+		ld a, [tmp_rect_mask]
+		call rect_test_mask
+		jp z,  @skip_rect 
+
+		; test all corners of tmp_rect 
+		push_all
+		
+		push hl
+		call rect_tl ; bc = top left point
+		push de
+		pop bc
+		pop hl ; hl = test rect
+
+		ld a, [tmp_rect_mask]
+		call rect_point_test
+		cp a, 1
+		jp z, @rect_collision
+
+		pop_all
+
+@skip_rect:
+		add hl, de ; next rect (de = r_size)
+		dec b
+		jp nz, @rect_test_loop
+
+
+	xor a, a ; no collision
+	ret
+@rect_collision:
+	pop_all
+	ld hl, NULL
+	ld a, 1
 	ret
diff --git a/src/player.s b/src/player.s
index c835f17..94e2e24 100644
--- a/src/player.s
+++ b/src/player.s
@@ -146,6 +146,11 @@ player_try_move:
 	call actor_test_movement
 	pop bc
 
+	; TODO: handle collision with another actor 
+	; if hl != NULL
+	cp a, 0
+	ret nz
+
 	ld a, b
 	ld [player+act_pos_y], a
 
diff --git a/src/rectangle.s b/src/rectangle.s
index be67463..6e44b1b 100644
--- a/src/rectangle.s
+++ b/src/rectangle.s
@@ -148,28 +148,67 @@ rect_br:
 	ret
 
 	; tests if a point is inside r1
-	;		 a: mask
+	;	 does not perform collision mask test
 	;		bc: y/x point
 	;		hl: rectangle
 	;	returns:
 	;		a == 1: inside
 	;		a == 0: not inside
 rect_point_test:
-	; check collision mask
-	ld d, a
-	ld [hl], a
-	and a, d
-	; exit if mask is no match
-	jp z, @no_collision_mask_match
+	; top left
+	push hl
+	call rect_tl
+	pop hl
 
+	ld a, b ; compare y points
+	cp a, d
+	jp nc, @no_collision
+	ld a, c ; compare x position
+	cp a, e
+	jp nc, @no_collision
+	
+	; bottom left
+	push hl
+	call rect_bl
+	pop hl
+
+	ld a, b ; compare y
+	cp a, d
+	jp c, @no_collision
+	ld a, c ; compare x
+	cp a, e
+	jp c, @no_collision
+
+	; top right
 	push hl
 	call rect_tr
 	pop hl
-	
 
+
+	; bottom right 
+	push hl
+	call rect_br
+	pop hl
+
+
+@collision:
+	ld a, 1
 	ret
-@no_collision_mask_match:
-	xor a, a
+@no_collision:
+	xor a, a ; no collision
+	ret
+	
+	; tests rectangle mask
+	;	inputs:
+	;		a: mask
+	;		hl: rectangle
+	; returns:
+	;		z-flag: != 0 if mask is ok
+	;	uses: a, c 
+rect_test_mask:
+	ld c, a
+	ld a, [hl]
+	and a, c 
 	ret
 	
 	; removes a rectangle
diff --git a/src/wram.s b/src/wram.s
index 243b85c..e16109c 100644
--- a/src/wram.s
+++ b/src/wram.s
@@ -72,6 +72,7 @@ rectangles: .adv r_size * RECT_MAX
 	; temporary rectangle used for collision checks 
 	; during movement
 tmp_rect: .adv r_size
+tmp_rect_mask: .adv 1
 
 	; current row that is being drawn
 map_curr_row: .adv 1