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Upload literally everything from the pokecrystal16 expand-move-ID branch

home/video.asm

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+; Functions dealing with VRAM.
+
+DMATransfer::
+; Return carry if the transfer is completed.
+
+	ldh a, [hDMATransfer]
+	and a
+	ret z
+
+; Start transfer
+	ldh [rHDMA5], a
+
+; Execution is halted until the transfer is complete.
+
+	xor a
+	ldh [hDMATransfer], a
+	scf
+	ret
+
+UpdateBGMapBuffer::
+; Copy [hBGMapTileCount] 16x8 tiles from wBGMapBuffer
+; to bg map addresses in wBGMapBufferPointers.
+
+; [hBGMapTileCount] must be even since this is done in pairs.
+
+; Return carry on success.
+
+	ldh a, [hBGMapUpdate]
+	and a
+	ret z
+
+	ldh a, [rVBK]
+	push af
+
+; Relocate the stack pointer to wBGMapBufferPointers
+	ld [hSPBuffer], sp
+	ld hl, wBGMapBufferPointers
+	ld sp, hl
+
+; We can now pop the addresses of affected spots on the BG Map
+
+	ld hl, wBGMapPalBuffer
+	ld de, wBGMapBuffer
+
+.next
+; Copy a pair of 16x8 blocks (one 16x16 block)
+
+rept 2
+; Get our BG Map address
+	pop bc
+
+; Palettes
+	ld a, 1
+	ldh [rVBK], a
+
+	ld a, [hli]
+	ld [bc], a
+	inc c
+	ld a, [hli]
+	ld [bc], a
+	dec c
+
+; Tiles
+	xor a
+	ldh [rVBK], a
+
+	ld a, [de]
+	inc de
+	ld [bc], a
+	inc c
+	ld a, [de]
+	inc de
+	ld [bc], a
+endr
+
+; We've done 2 16x8 blocks
+	ldh a, [hBGMapTileCount]
+	dec a
+	dec a
+	ldh [hBGMapTileCount], a
+
+	jr nz, .next
+
+; Restore the stack pointer
+	ldh a, [hSPBuffer]
+	ld l, a
+	ldh a, [hSPBuffer + 1]
+	ld h, a
+	ld sp, hl
+
+	pop af
+	ldh [rVBK], a
+
+	xor a
+	ldh [hBGMapUpdate], a
+	scf
+	ret
+
+WaitTop::
+; Wait until the top third of the BG Map is being updated.
+
+	ldh a, [hBGMapMode]
+	and a
+	ret z
+
+	ldh a, [hBGMapThird]
+	and a
+	jr z, .done
+
+	call DelayFrame
+	jr WaitTop
+
+.done
+	xor a
+	ldh [hBGMapMode], a
+	ret
+
+UpdateBGMap::
+; Update the BG Map, in thirds, from wTilemap and wAttrmap.
+
+	ldh a, [hBGMapMode]
+	and a ; 0
+	ret z
+
+; BG Map 0
+	dec a ; 1
+	jr z, .Tiles
+	dec a ; 2
+	jr z, .Attr
+
+; BG Map 1
+	dec a ; useless
+
+	ldh a, [hBGMapAddress]
+	ld l, a
+	ldh a, [hBGMapAddress + 1]
+	ld h, a
+	push hl
+
+	xor a ; LOW(vBGMap1)
+	ldh [hBGMapAddress], a
+	ld a, HIGH(vBGMap1)
+	ldh [hBGMapAddress + 1], a
+
+	ldh a, [hBGMapMode]
+	push af
+	cp 3
+	call z, .Tiles
+	pop af
+	cp 4
+	call z, .Attr
+
+	pop hl
+	ld a, l
+	ldh [hBGMapAddress], a
+	ld a, h
+	ldh [hBGMapAddress + 1], a
+	ret
+
+.Attr:
+	ld a, 1
+	ldh [rVBK], a
+
+	hlcoord 0, 0, wAttrmap
+	call .update
+
+	xor a
+	ldh [rVBK], a
+	ret
+
+.Tiles:
+	hlcoord 0, 0
+
+.update
+	ld [hSPBuffer], sp
+
+; Which third?
+	ldh a, [hBGMapThird]
+	and a ; 0
+	jr z, .top
+	dec a ; 1
+	jr z, .middle
+	; 2
+
+DEF THIRD_HEIGHT EQU SCREEN_HEIGHT / 3
+
+; bottom
+	ld de, 2 * THIRD_HEIGHT * SCREEN_WIDTH
+	add hl, de
+	ld sp, hl
+
+	ldh a, [hBGMapAddress + 1]
+	ld h, a
+	ldh a, [hBGMapAddress]
+	ld l, a
+
+	ld de, 2 * THIRD_HEIGHT * BG_MAP_WIDTH
+	add hl, de
+
+; Next time: top third
+	xor a
+	jr .start
+
+.middle
+	ld de, THIRD_HEIGHT * SCREEN_WIDTH
+	add hl, de
+	ld sp, hl
+
+	ldh a, [hBGMapAddress + 1]
+	ld h, a
+	ldh a, [hBGMapAddress]
+	ld l, a
+
+	ld de, THIRD_HEIGHT * BG_MAP_WIDTH
+	add hl, de
+
+; Next time: bottom third
+	ld a, 2
+	jr .start
+
+.top
+	ld sp, hl
+
+	ldh a, [hBGMapAddress + 1]
+	ld h, a
+	ldh a, [hBGMapAddress]
+	ld l, a
+
+; Next time: middle third
+	ld a, 1
+
+.start
+; Which third to update next time
+	ldh [hBGMapThird], a
+
+; Rows of tiles in a third
+	ld a, THIRD_HEIGHT
+
+; Discrepancy between wTilemap and BGMap
+	ld bc, BG_MAP_WIDTH - (SCREEN_WIDTH - 1)
+
+.row
+; Copy a row of 20 tiles
+rept SCREEN_WIDTH / 2 - 1
+	pop de
+	ld [hl], e
+	inc l
+	ld [hl], d
+	inc l
+endr
+	pop de
+	ld [hl], e
+	inc l
+	ld [hl], d
+
+	add hl, bc
+	dec a
+	jr nz, .row
+
+	ldh a, [hSPBuffer]
+	ld l, a
+	ldh a, [hSPBuffer + 1]
+	ld h, a
+	ld sp, hl
+	ret
+
+Serve1bppRequest::
+; Only call during the first fifth of VBlank
+
+	ld a, [wRequested1bppSize]
+	and a
+	ret z
+
+; Back out if we're too far into VBlank
+	ldh a, [rLY]
+	cp LY_VBLANK
+	ret c
+	cp LY_VBLANK + 2
+	ret nc
+
+; Copy [wRequested1bppSize] 1bpp tiles from [wRequested1bppSource] to [wRequested1bppDest]
+
+	ld [hSPBuffer], sp
+
+; Source
+	ld hl, wRequested1bppSource
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	ld sp, hl
+
+; Destination
+	ld hl, wRequested1bppDest
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+
+; # tiles to copy
+	ld a, [wRequested1bppSize]
+	ld b, a
+
+	xor a
+	ld [wRequested1bppSize], a
+
+.next
+
+rept 3
+	pop de
+	ld [hl], e
+	inc l
+	ld [hl], e
+	inc l
+	ld [hl], d
+	inc l
+	ld [hl], d
+	inc l
+endr
+	pop de
+	ld [hl], e
+	inc l
+	ld [hl], e
+	inc l
+	ld [hl], d
+	inc l
+	ld [hl], d
+
+	inc hl
+	dec b
+	jr nz, .next
+
+	ld a, l
+	ld [wRequested1bppDest], a
+	ld a, h
+	ld [wRequested1bppDest + 1], a
+
+	ld [wRequested1bppSource], sp
+
+	ldh a, [hSPBuffer]
+	ld l, a
+	ldh a, [hSPBuffer + 1]
+	ld h, a
+	ld sp, hl
+	ret
+
+Serve2bppRequest::
+; Only call during the first fifth of VBlank
+
+	ld a, [wRequested2bppSize]
+	and a
+	ret z
+
+; Back out if we're too far into VBlank
+	ldh a, [rLY]
+	cp LY_VBLANK
+	ret c
+	cp LY_VBLANK + 2
+	ret nc
+	jr _Serve2bppRequest
+
+Serve2bppRequest_VBlank::
+	ld a, [wRequested2bppSize]
+	and a
+	ret z
+
+_Serve2bppRequest::
+; Copy [wRequested2bppSize] 2bpp tiles from [wRequested2bppSource] to [wRequested2bppDest]
+
+	ld [hSPBuffer], sp
+
+; Source
+	ld hl, wRequested2bppSource
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	ld sp, hl
+
+; Destination
+	ld hl, wRequested2bppDest
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+
+; # tiles to copy
+	ld a, [wRequested2bppSize]
+	ld b, a
+
+	xor a
+	ld [wRequested2bppSize], a
+
+.next
+
+rept 7
+	pop de
+	ld [hl], e
+	inc l
+	ld [hl], d
+	inc l
+endr
+	pop de
+	ld [hl], e
+	inc l
+	ld [hl], d
+
+	inc hl
+	dec b
+	jr nz, .next
+
+	ld a, l
+	ld [wRequested2bppDest], a
+	ld a, h
+	ld [wRequested2bppDest + 1], a
+
+	ld [wRequested2bppSource], sp
+
+	ldh a, [hSPBuffer]
+	ld l, a
+	ldh a, [hSPBuffer + 1]
+	ld h, a
+	ld sp, hl
+	ret
+
+AnimateTileset::
+; Only call during the first fifth of VBlank
+
+	ldh a, [hMapAnims]
+	and a
+	ret z
+
+; Back out if we're too far into VBlank
+	ldh a, [rLY]
+	cp LY_VBLANK
+	ret c
+	cp LY_VBLANK + 7
+	ret nc
+
+	ldh a, [hROMBank]
+	push af
+	ld a, BANK(_AnimateTileset)
+	rst Bankswitch
+
+	ldh a, [rSVBK]
+	push af
+	ld a, BANK(wTilesetAnim)
+	ldh [rSVBK], a
+
+	ldh a, [rVBK]
+	push af
+	xor a
+	ldh [rVBK], a
+
+	call _AnimateTileset
+
+	pop af
+	ldh [rVBK], a
+	pop af
+	ldh [rSVBK], a
+	pop af
+	rst Bankswitch
+	ret