Remove unused function

src/collision.s

@@ -2,49 +2,8 @@ INCLUDE "oam.inc"
 
 SECTION "Collision", ROMX
 
-; Check whether a 16x16 metasprite collides with the background
-; @param a The index of the first (top left) OAM entry of the sprite
-; @destroy hl
-; note: doesn't work atm (use srl, not sra?)
-sprite16x16_bg_collides::
-    ; compute oam entry address (_OAM + a * 4)
-    ; a is guaranteed not to overflow since l = $00 and a < 40
-    ld hl, _OAM
-    sla a
-    sla a
-    add l
-    ld l, a
-
-    ; top left (x,y)
-    ld a, [hl+]
-    sra a
-    sra a
-    sra a
-    ld c, [hl]
-    sra c
-    sra c
-    sra c
-    call can_move_to
-    ret nz
-
-    ; other three sprites
-    REPT 3
-        ld a, [hl+]
-        sra a
-        sra a
-        sra a
-        ld c, [hl]
-        sra c
-        sra c
-        sra c
-        call can_move_to
-        ret nz
-    ENDR
-
-    ret
-
 player_bg_collides::
-    ; c = x/8
+    ; c = x % 8 == 0 ? x/8 : x/8 + 1
     ld hl, PLAYER_X
     ld a, [hl]
     ld c, a
@@ -58,7 +17,7 @@ player_bg_collides::
     srl c
     srl c
 
-    ; b = y/8
+    ; b = y % 8 == 0 ? y/8 : y/8 + 1
     inc hl
     ld a, [hl]
     ld b, a