diff options
Diffstat (limited to 'engine/overworld/map_sprite_functions1.asm')
| -rw-r--r-- | engine/overworld/map_sprite_functions1.asm | 390 |
1 files changed, 0 insertions, 390 deletions
diff --git a/engine/overworld/map_sprite_functions1.asm b/engine/overworld/map_sprite_functions1.asm deleted file mode 100644 index 2ad923fb..00000000 --- a/engine/overworld/map_sprite_functions1.asm +++ /dev/null @@ -1,390 +0,0 @@ -_UpdateSprites: - ld h, wSpriteStateData1 / $100 - inc h - ld a, $e ; (wSpriteStateData2 + $0e) & $ff -.spriteLoop - ld l, a - sub $e - ld c, a - ld [H_CURRENTSPRITEOFFSET], a - ld a, [hl] - and a - jr z, .skipSprite ; tests $c2Xe - push hl - push de - push bc - call .updateCurrentSprite - pop bc - pop de - pop hl -.skipSprite - ld a, l - add $10 ; move to next sprite - cp $e ; test for overflow (back at $0e) - jr nz, .spriteLoop - ret -.updateCurrentSprite - ld a, [H_CURRENTSPRITEOFFSET] - and a - jp z, UpdatePlayerSprite - cp $f0 ; pikachu - jp z, SpawnPikachu - ld a, [hl] - -UpdateNonPlayerSprite: - dec a - swap a - ld [$ff93], a ; $10 * sprite# - ld a, [wNPCMovementScriptSpriteOffset] ; some sprite offset? - ld b, a - ld a, [H_CURRENTSPRITEOFFSET] - cp b - jr nz, .unequal - jp DoScriptedNPCMovement -.unequal - jp UpdateNPCSprite - -; This detects if the current sprite (whose offset is at H_CURRENTSPRITEOFFSET) -; is going to collide with another sprite by looping over the other sprites. -; The current sprite's offset will be labelled with i (e.g. $c1i0). -; The loop sprite's offset will labelled with j (e.g. $c1j0). -; -; Note that the Y coordinate of the sprite (in [$c1k4]) is one of the following -; 9 values when the sprite is aligned with the grid: $fc, $0c, $1c, $2c, ..., $7c. -; The reason that 4 is added below to the coordinate is to make it align with a -; multiple of $10 to make comparisons easier. -DetectCollisionBetweenSprites: - ; nop - - ld h, wSpriteStateData1 / $100 - ld a, [H_CURRENTSPRITEOFFSET] - ld l, a - - ld a, [hl] ; a = [$c1i0] (picture) (0 if slot is unused) - and a ; is this sprite slot slot used? - ret z ; return if not used - - ld a, l - add 3 - ld l, a - - ld a, [hli] ; a = [$c1i3] (delta Y) (-1, 0, or 1) - call SetSpriteCollisionValues - - ld a, [hli] ; a = [$C1i4] (Y screen coordinate) - add 4 ; align with multiple of $10 - -; The effect of the following 3 lines is to -; add 7 to a if moving south or -; subtract 7 from a if moving north. - add b - and $f0 - or c - - ld [$ff90], a ; store Y coordinate adjusted for direction of movement - - ld a, [hli] ; a = [$c1i5] (delta X) (-1, 0, or 1) - call SetSpriteCollisionValues - ld a, [hl] ; a = [$C1i6] (X screen coordinate) - -; The effect of the following 3 lines is to -; add 7 to a if moving east or -; subtract 7 from a if moving west. - add b - and $f0 - or c - - ld [$ff91], a ; store X coordinate adjusted for direction of movement - - ld a, l - add 7 - ld l, a - - xor a - ld [hld], a ; zero [$c1id] XXX what's [$c1id] for? - ld [hld], a ; zero [$c1ic] (directions in which collisions occurred) - - ld a, [$ff91] - ld [hld], a ; [$c1ib] = adjusted X coordinate - ld a, [$ff90] - ld [hl], a ; [$c1ia] = adjusted Y coordinate - - xor a ; zero the loop counter - -.loop - ld [$ff8f], a ; store loop counter - swap a - ld e, a - ld a, [H_CURRENTSPRITEOFFSET] - cp e ; does the loop sprite match the current sprite? - jp z, .next ; go to the next sprite if they match - - ld d, h - ld a, [de] ; a = [$c1j0] (picture) (0 if slot is unused) - and a ; is this sprite slot slot used? - jp z, .next ; go the next sprite if not used - - inc e - inc e - ld a, [de] ; a = [$c1j2] ($ff means the sprite is offscreen) - inc a - jp z, .next ; go the next sprite if offscreen - - ld a, [H_CURRENTSPRITEOFFSET] - add 10 - ld l, a - - inc e - ld a, [de] ; a = [$c1j3] (delta Y) - call SetSpriteCollisionValues - - inc e - ld a, [de] ; a = [$C1j4] (Y screen coordinate) - add 4 ; align with multiple of $10 - -; The effect of the following 3 lines is to -; add 7 to a if moving south or -; subtract 7 from a if moving north. - add b - and $f0 - or c - - sub [hl] ; subtract the adjusted Y coordinate of sprite i ([$c1ia]) from that of sprite j - -; calculate the absolute value of the difference to get the distance - jr nc, .noCarry1 - cpl - inc a -.noCarry1 - ld [$ff90], a ; store the distance between the two sprites' adjusted Y values - -; Use the carry flag set by the above subtraction to determine which sprite's -; Y coordinate is larger. This information is used later to set [$c1ic], -; which stores which direction the collision occurred in. -; The following 5 lines set the lowest 2 bits of c, which are later shifted left by 2. -; If sprite i's Y is larger, set lowest 2 bits of c to 10. -; If sprite j's Y is larger or both are equal, set lowest 2 bits of c to 01. - push af - rl c - pop af - ccf - rl c - -; If sprite i's delta Y is 0, then b = 7, else b = 9. - ld b, 7 - ld a, [hl] ; a = [$c1ia] (adjusted Y coordinate) - and $f - jr z, .next1 - ld b, 9 - -.next1 - ld a, [$ff90] ; a = distance between adjusted Y coordinates - sub b - ld [$ff92], a ; store distance adjusted using sprite i's direction - ld a, b - ld [$ff90], a ; store 7 or 9 depending on sprite i's delta Y - jr c, .checkXDistance - -; If sprite j's delta Y is 0, then b = 7, else b = 9. - ld b, 7 - dec e - ld a, [de] ; a = [$c1j3] (delta Y) - inc e - and a - jr z, .next2 - ld b, 9 - -.next2 - ld a, [$ff92] ; a = distance adjusted using sprite i's direction - sub b ; adjust distance using sprite j's direction - jr z, .checkXDistance - jr nc, .next ; go to next sprite if distance is still positive after both adjustments - -.checkXDistance - inc e - inc l - ld a, [de] ; a = [$c1j5] (delta X) - - push bc - - call SetSpriteCollisionValues - inc e - ld a, [de] ; a = [$c1j6] (X screen coordinate) - -; The effect of the following 3 lines is to -; add 7 to a if moving east or -; subtract 7 from a if moving west. - add b - and $f0 - or c - - pop bc - - sub [hl] ; subtract the adjusted X coordinate of sprite i ([$c1ib]) from that of sprite j - -; calculate the absolute value of the difference to get the distance - jr nc, .noCarry2 - cpl - inc a -.noCarry2 - ld [$ff91], a ; store the distance between the two sprites' adjusted X values - -; Use the carry flag set by the above subtraction to determine which sprite's -; X coordinate is larger. This information is used later to set [$c1ic], -; which stores which direction the collision occurred in. -; The following 5 lines set the lowest 2 bits of c. -; If sprite i's X is larger, set lowest 2 bits of c to 10. -; If sprite j's X is larger or both are equal, set lowest 2 bits of c to 01. - push af - rl c - pop af - ccf - rl c - -; If sprite i's delta X is 0, then b = 7, else b = 9. - ld b, 7 - ld a, [hl] ; a = [$c1ib] (adjusted X coordinate) - and $f - jr z, .next3 - ld b, 9 - -.next3 - ld a, [$ff91] ; a = distance between adjusted X coordinates - sub b - ld [$ff92], a ; store distance adjusted using sprite i's direction - ld a, b - ld [$ff91], a ; store 7 or 9 depending on sprite i's delta X - jr c, .collision - -; If sprite j's delta X is 0, then b = 7, else b = 9. - ld b, 7 - dec e - ld a, [de] ; a = [$c1j5] (delta X) - inc e - and a - jr z, .next4 - ld b, 9 - -.next4 - ld a, [$ff92] ; a = distance adjusted using sprite i's direction - sub b ; adjust distance using sprite j's direction - jr z, .collision - jr nc, .next ; go to next sprite if distance is still positive after both adjustments - -.collision - ld a, l - and $f0 ; collision with pikachu? - jr nz, .asm_4cd9 - xor a - ld [wd434], a - ld a, [$ff8f] - cp $f - jr nz, .asm_4cd9 - call Func_4d0a - jr .asm_4cef -.asm_4cd9 - ld a, [$ff91] ; a = 7 or 9 depending on sprite i's delta X - ld b, a - ld a, [$ff90] ; a = 7 or 9 depending on sprite i's delta Y - inc l - -; If delta X isn't 0 and delta Y is 0, then b = %0011, else b = %1100. -; (note that normally if delta X isn't 0, then delta Y must be 0 and vice versa) - cp b - jr c, .next5 - ld b, %1100 - jr .next6 -.next5 - ld b, %0011 - -.next6 - ld a, c ; c has 2 bits set (one of bits 0-1 is set for the X axis and one of bits 2-3 for the Y axis) - and b ; we select either the bit in bits 0-1 or bits 2-3 based on the calculation immediately above - or [hl] ; or with existing collision direction bits in [$c1ic] - ld [hl], a ; store new value - ld a, c ; useless code because a is overwritten before being used again - -; set bit in [$c1ie] or [$c1if] to indicate which sprite the collision occurred with - inc l - inc l -.asm_4cef - ld a, [$ff8f] ; a = loop counter - ld de, SpriteCollisionBitTable - add a - add e - ld e, a - jr nc, .noCarry3 - inc d -.noCarry3 - ld a, [de] - or [hl] - ld [hli], a - inc de - ld a, [de] - or [hl] - ld [hl], a - -.next - ld a, [$ff8f] ; a = loop counter - inc a - cp $10 - jp nz, .loop - ret - -; takes delta X or delta Y in a -; b = delta X/Y -; c = 0 if delta X/Y is 0 -; c = 7 if delta X/Y is 1 -; c = 9 if delta X/Y is -1 -Func_4d0a: - ld a, [$ff91] - ld b, a - ld a, [$ff90] - inc l - cp b - jr c, .asm_4d17 - ld b, %1100 - jr .asm_4d19 -.asm_4d17 - ld b, %11 -.asm_4d19 - ld a, c - and b - ld [wd434], a - ld a, c - inc l - inc l - ret - -SetSpriteCollisionValues: - and a - ld b, 0 - ld c, 0 - jr z, .done - ld c, 9 - cp -1 - jr z, .ok - ld c, 7 - ld a, 0 -.ok - ld b, a -.done - ret - -SpriteCollisionBitTable: - db %00000000,%00000001 - db %00000000,%00000010 - db %00000000,%00000100 - db %00000000,%00001000 - db %00000000,%00010000 - db %00000000,%00100000 - db %00000000,%01000000 - db %00000000,%10000000 - db %00000001,%00000000 - db %00000010,%00000000 - db %00000100,%00000000 - db %00001000,%00000000 - db %00010000,%00000000 - db %00100000,%00000000 - db %01000000,%00000000 - db %10000000,%00000000 |