diff options
Diffstat (limited to 'home/vcopy.asm')
| -rw-r--r-- | home/vcopy.asm | 89 |
1 files changed, 47 insertions, 42 deletions
diff --git a/home/vcopy.asm b/home/vcopy.asm index d42293d9..3fe19745 100644 --- a/home/vcopy.asm +++ b/home/vcopy.asm @@ -1,7 +1,7 @@ ; this function seems to be used only once ; it store the address of a row and column of the VRAM background map in hl ; INPUT: h - row, l - column, b - high byte of background tile map address in VRAM -GetRowColAddressBgMap:: ; 1cdd (0:1cdd) +GetRowColAddressBgMap:: xor a srl h rr a @@ -18,7 +18,7 @@ GetRowColAddressBgMap:: ; 1cdd (0:1cdd) ; clears a VRAM background map with blank space tiles ; INPUT: h - high byte of background tile map address in VRAM -ClearBgMap:: ; 1cf0 (0:1cf0) +ClearBgMap:: ld a," " jr .next ld a,l @@ -33,32 +33,35 @@ ClearBgMap:: ; 1cf0 (0:1cf0) jr nz,.loop ret -; When the player takes a step, a row or column of 2x2 tile blocks at the edge -; of the screen toward which they moved is exposed and has to be redrawn. -; This function does the redrawing. -RedrawExposedScreenEdge:: ; 1d01 (0:1d01) - ld a,[H_SCREENEDGEREDRAW] +; This function redraws a BG row of height 2 or a BG column of width 2. +; One of its main uses is redrawing the row or column that will be exposed upon +; scrolling the BG when the player takes a step. Redrawing only the exposed +; row or column is more efficient than redrawing the entire screen. +; However, this function is also called repeatedly to redraw the whole screen +; when necessary. It is also used in trade animation and elevator code. +RedrawRowOrColumn:: + ld a,[hRedrawRowOrColumnMode] and a ret z ld b,a xor a - ld [H_SCREENEDGEREDRAW],a + ld [hRedrawRowOrColumnMode],a dec b jr nz,.redrawRow .redrawColumn - ld hl,wScreenEdgeTiles - ld a,[H_SCREENEDGEREDRAWADDR] + ld hl,wRedrawRowOrColumnSrcTiles + ld a,[hRedrawRowOrColumnDest] ld e,a - ld a,[H_SCREENEDGEREDRAWADDR + 1] + ld a,[hRedrawRowOrColumnDest + 1] ld d,a - ld c,18 ; screen height + ld c,SCREEN_HEIGHT .loop1 ld a,[hli] ld [de],a inc de ld a,[hli] ld [de],a - ld a,31 + ld a,BG_MAP_WIDTH - 1 add e ld e,a jr nc,.noCarry @@ -72,23 +75,24 @@ RedrawExposedScreenEdge:: ; 1d01 (0:1d01) dec c jr nz,.loop1 xor a - ld [H_SCREENEDGEREDRAW],a + ld [hRedrawRowOrColumnMode],a ret .redrawRow - ld hl,wScreenEdgeTiles - ld a,[H_SCREENEDGEREDRAWADDR] + ld hl,wRedrawRowOrColumnSrcTiles + ld a,[hRedrawRowOrColumnDest] ld e,a - ld a,[H_SCREENEDGEREDRAWADDR + 1] + ld a,[hRedrawRowOrColumnDest + 1] ld d,a push de - call .drawHalf ; draw upper half + call .DrawHalf ; draw upper half pop de - ld a,32 ; width of VRAM background map + ld a,BG_MAP_WIDTH ; width of VRAM background map add e ld e,a - ; draw lower half -.drawHalf - ld c,10 + ; fall through and draw lower half + +.DrawHalf + ld c,SCREEN_WIDTH / 2 .loop2 ld a,[hli] ld [de],a @@ -113,9 +117,9 @@ RedrawExposedScreenEdge:: ; 1d01 (0:1d01) ; background per V-blank. It cycles through which third it draws. ; This transfer is turned off when walking around the map, but is turned ; on when talking to sprites, battling, using menus, etc. This is because -; the above function, RedrawExposedScreenEdge, is used when walking to +; the above function, RedrawRowOrColumn, is used when walking to ; improve efficiency. -AutoBgMapTransfer:: ; 1d57 (0:1d57) +AutoBgMapTransfer:: ld a,[H_AUTOBGTRANSFERENABLED] and a ret z @@ -130,7 +134,7 @@ AutoBgMapTransfer:: ; 1d57 (0:1d57) dec a jr z,.transferMiddleThird .transferBottomThird - hlCoord 0, 12 + coord hl, 0, 12 ld sp,hl ld a,[H_AUTOBGTRANSFERDEST + 1] ld h,a @@ -141,7 +145,7 @@ AutoBgMapTransfer:: ; 1d57 (0:1d57) xor a ; TRANSFERTOP jr .doTransfer .transferTopThird - hlCoord 0, 0 + coord hl, 0, 0 ld sp,hl ld a,[H_AUTOBGTRANSFERDEST + 1] ld h,a @@ -150,7 +154,7 @@ AutoBgMapTransfer:: ; 1d57 (0:1d57) ld a,TRANSFERMIDDLE jr .doTransfer .transferMiddleThird - hlCoord 0, 6 + coord hl, 0, 6 ld sp,hl ld a,[H_AUTOBGTRANSFERDEST + 1] ld h,a @@ -163,7 +167,7 @@ AutoBgMapTransfer:: ; 1d57 (0:1d57) ld [H_AUTOBGTRANSFERPORTION],a ; store next portion ld b,6 -TransferBgRows:: ; 1d9e (0:1d9e) +TransferBgRows:: ; unrolled loop and using pop for speed rept 20 / 2 - 1 @@ -197,7 +201,7 @@ TransferBgRows:: ; 1d9e (0:1d9e) ; Copies [H_VBCOPYBGNUMROWS] rows from H_VBCOPYBGSRC to H_VBCOPYBGDEST. ; If H_VBCOPYBGSRC is XX00, the transfer is disabled. -VBlankCopyBgMap:: ; 1de1 (0:1de1) +VBlankCopyBgMap:: ld a,[H_VBCOPYBGSRC] ; doubles as enabling byte and a ret z @@ -302,12 +306,11 @@ VBlankCopyDouble:: VBlankCopy:: -; Copy [H_VBCOPYSIZE] 2bpp tiles +; Copy [H_VBCOPYSIZE] 2bpp tiles (or 16 * [H_VBCOPYSIZE] tile map entries) ; from H_VBCOPYSRC to H_VBCOPYDEST. -; Source and destination addresses -; are updated, so transfer can -; continue in subsequent calls. +; Source and destination addresses are updated, +; so transfer can continue in subsequent calls. ld a, [H_VBCOPYSIZE] and a @@ -380,21 +383,23 @@ UpdateMovingBgTiles:: and a ret z ; no animations if indoors (or if a menu set this to 0) - ld a, [$ffd8] + ld a, [hMovingBGTilesCounter1] inc a - ld [$ffd8], a - cp $14 + ld [hMovingBGTilesCounter1], a + cp 20 ret c - cp $15 + cp 21 jr z, .flower +; water + ld hl, vTileset + $14 * $10 ld c, $10 - ld a, [wd085] + ld a, [wMovingBGTilesCounter2] inc a and 7 - ld [wd085], a + ld [wMovingBGTilesCounter2], a and 4 jr nz, .left @@ -417,14 +422,14 @@ UpdateMovingBgTiles:: ret nc ; if in a cave, no flower animations xor a - ld [$ffd8], a + ld [hMovingBGTilesCounter1], a ret .flower xor a - ld [$ffd8], a + ld [hMovingBGTilesCounter1], a - ld a, [wd085] + ld a, [wMovingBGTilesCounter2] and 3 cp 2 ld hl, FlowerTile1 |