Z80 Routines:Graphic:put8x8sprite
From WikiTI
The put8xBsprite routine is used to plot a 8xB sized sprite.
Contents
Code
Basic Version
;-----> Draw a sprite ; input: a=x e=y ; b=height of sprite ; ix holds pointer ; output: ; destroys de,hl putSprite8xb: ld h,$00 ld d,h #ifdef faster sla e ;*2 sla e ;*4 #endif ld l,e add hl,de ;*2 faster:*8 add hl,de ;*3 faster:*12 #ifndef faster add hl,hl ;*6 add hl,hl ;*12 #endif ld e,a srl e srl e srl e add hl,de ld de,gbuf add hl,de and 7 ld c,a putSpriteLoop1: ld d,(ix) ld e,$00 ld a,c or a jr z,putSpriteSkip1 putSpriteLoop2: srl d rr e dec a jr nz,putSpriteLoop2 putSpriteSkip1: ld a,(hl) xor d ld (hl),a inc hl ld a,(hl) xor e ld (hl),a ld de,$0B add hl,de inc ix djnz putSpriteLoop1 ret
Masked Version
PutSpriteMask:
; Displays an 8x8 masked sprite
; A = x coordinate
; E = y coordinate
; IX = address of sprite
; IX + 8 = address of mask
LD H, 0
LD D, H
LD E, L
ADD HL, HL
ADD HL, DE
ADD HL, HL
ADD HL, HL
LD E, A
SRL E
SRL E
SRL E
ADD HL, DE
LD DE, PlotSScreen
ADD HL, DE
AND 7
JR Z, _Aligned
LD C, A
LD B,8
_RowLoop:
PUSH BC
LD B, C
LD D, (IX)
LD A, (IX + 8)
LD C, 0
LD E, C
_ShiftLoop:
SRL A
RR C
SRL D
RR E
DJNZ _ShiftLoop
CPL
AND (HL)
XOR D
LD (HL), A
INC HL
LD A, C
CPL
AND (HL)
XOR E
LD (HL), A
LD DE, 12
ADD HL, DE
INC IX
POP BC
DJNZ _RowLoop
RET
_Aligned:
LD DE, 12
_PutLoop
LD A, (IX + 8)
AND (HL)
XOR (IX)
LD (HL), A
INC IX
ADD HL, DE
DJNZ _PutLoop
RET
Full Clipping (vertical and horizontal) Version
ClipSprXOR:
; D = xpos
; E = ypos
; B = height
; IX = image address
; Start by doing vertical clipping
LD A, %11111111 ; Reset clipping mask
LD (clip_mask), A
LD A, E ; If ypos is negative
OR A ; try clipping the top
JP M, ClipTop ;
SUB 64 ; If ypos is >= 64
RET NC ; sprite is off-screen
NEG ; If (64 - ypos) > height
CP B ; don't need to clip
JR NC, VertClipDone ;
LD B, A ; Do bottom clipping by
JR VertClipDone ; setting height to (64 - ypos)
ClipTop:
LD A, B ; If ypos <= -height
NEG ; sprite is off-screen
SUB E ;
RET NC ;
PUSH AF
ADD A, B ; Get the number of clipped rows
LD E, 0 ; Set ypos to 0 (top of screen)
LD B, E ; Advance image data pointer
LD C, A ;
ADD IX, BC ;
POP AF
NEG ; Get the number of visible rows
LD B, A ; and set as height
VertClipDone:
; Now we're doing horizontal clipping
LD C, 0 ; Reset correction factor
LD A, D
CP -7 ; If 0 > xpos >= -7
JR NC, ClipLeft ; clip the left side
CP 96 ; If xpos >= 96
RET NC ; sprite is off-screen
CP 89 ; If 0 <= xpos < 89
JR C, HorizClipDone ; don't need to clip
ClipRight:
AND 7 ; Determine the clipping mask
LD C, A
LD A, %11111111
FindRightMask:
ADD A, A
DEC C
JR NZ, FindRightMask
LD (clip_mask), A
LD A, D
JR HorizClipDone
ClipLeft:
AND 7 ; Determine the clipping mask
LD C, A
LD A, %11111111
FindLeftMask:
ADD A, A
DEC C
JR NZ, FindLeftMask
CPL
LD (clip_mask), A
LD A, D
ADD A, 96 ; Set xpos so sprite will "spill over"
LD C, 12 ; Set correction
HorizClipDone:
; A = xpos
; E = ypos
; B = height
; IX = image address
; Now we can finally display the sprite.
LD H, 0
LD D, H
LD L, E
ADD HL, HL
ADD HL, DE
ADD HL, HL
ADD HL, HL
LD E, A
SRL E
SRL E
SRL E
ADD HL, DE
LD DE, PlotSScreen
ADD HL, DE
LD D, 0 ; Correct graph buffer address
LD E, C ; if clipping the left side
SBC HL, DE ;
AND 7
JR Z, _Aligned
LD C, A
LD DE, 11
_RowLoop:
PUSH BC
LD B, C
LD A, (clip_mask) ; Mask out the part of the sprite
AND (IX) ; to be horizontally clipped
LD C, 0
_ShiftLoop:
SRL A
RR C
DJNZ _ShiftLoop
XOR (HL)
LD (HL), A
INC HL
LD A, C
XOR (HL)
LD (HL), A
ADD HL, DE
INC IX
POP BC
DJNZ _RowLoop
RET
_Aligned:
LD DE, 12
_PutLoop:
LD A, (IX)
XOR (HL)
LD (HL), A
INC IX
ADD HL, DE
DJNZ _PutLoop
RET
clip_mask: .DB 0
Customization
You can suit these routines to your needs by following the following suggestions: - change the input in e to l - replace the logic ("xor" intructions to "or" or "cpl \ and ") - instead of 8xB, you can put a ld b,8 - adapt for each sprite its height/width
.db 3 ; height .db %11111111 .db %11111111 .db %11111111
- take out horizontal/vertical clipping if you don't need it
You will need to change the code yourself. If you understand well assembly it will be a quick task.
Define faster to get more speed with size costs. To use these routines in the TI-85 or TI-86, you need to change not only the address of the graphics buffer but also the multiplication of the x coordinates. (TI-83+ screen is 96x64 instead of 128x64) Later we can provide a TI-85/86 version.
Example
A example using the basic version of PutSprite8xB.
;... ld e,8 ;y ld a,16 ;x ld b,8 ;height ld ix,sprite call putsprite call fastcopy ;... sprite: .db %11111111 .db %10000001 .db %10000001 .db %10000001 .db %10000001 .db %10000001 .db %10000001 .db %11111111
