Mon Mar 01, 2010 9:10 pm
Fourspriter: Sprite Engine from the Mojon Twins
As I promissed, here I am with an adaptation for the Mojon Twins "Fourspriter". Well, in fact I promissed just the opposite (skip this one and post the other sprite routine I'm working in), but I think this one is more suited to a basic enviroment and the other one is just great for a crap game (see my game Colour Clash of the Titans in the CSSCGC 2010 thread within the WoS games forum) but not so good if you plan to do a polished game.
The engine itself comes in assembler, and all you have to do is POKE the right adresses to configure and move your sprites (up to 4). All I have done is adding 3 subroutines to make easier the poking part, and 4 labes so you can call the different subroutines of the engine via gosub.
Here goes the code you have to include in your library folder (I called it fourspriter.bas):
The subroutines are the following:
1) Define your sprites:
fsprite (n,a,b,c,d) ; where n is the sprite number (0 to 3) and a-d are the UDGs number that compose the sprite (0-21)
2) Set the atributes for each of the sprite's UDG:
fspriteattr (n,a,b,c,d) ; n=sprite number ; a-d=attr of each UDG
3) Set the initial coords for your spries:
fspritecoord (n,y,x) ; n= sprite number ; y=vertical coord ; x=horizontal coord
The labels to be called via gosub are:
borrasprites ; this will erase the sprites, restoring the background.
initsprites ; this will select wether a sprite will be printed or not. If you don't want a sprite to be printed, you have to poke 99 into the first value of the sprite udg (i.e. fsprite (1,99,0,0,0) won't print sprite 1)
drawsprites ; this will draw the sprites on the screen
updatecoordinates ; this will update the current coordinates of each sprite, while storing the old ones so you can restore the background.
The engine itself comes in assembler, and all you have to do is POKE the right adresses to configure and move your sprites (up to 4). All I have done is adding 3 subroutines to make easier the poking part, and 4 labes so you can call the different subroutines of the engine via gosub.
Here goes the code you have to include in your library folder (I called it fourspriter.bas):
- Code:
SUB fsprite (n as uByte, a as uByte, b as uByte, c as uByte, d as uByte) 'Initialite Sprite: n (sprite number 0-3);a,b,c,d (UDG number 0-20,99 means the sprite won't be printed)
POKE @fourspriter+48*n,a
POKE @fourspriter+1+48*n,b
POKE @fourspriter+2+48*n,c
POKE @fourspriter+3+48*n,d
END sub
SUB fspritecoord (n as uByte, x as uByte, y as uByte) 'Set sprite coords: n (sprite number);x,y (vertical,horizontal coords)
POKE @fourspriter+4+48*n,x
POKE @fourspriter+5+48*n,y
POKE @fourspriter+6+48*n,x
POKE @fourspriter+7+48*n,y
END SUB
SUB fspriteattr (n as uByte, attra as uByte, attrb as uByte, attrc as uByte, attrd as uByte) 'Set sprite attrs: n (sprite number);a,b,c,d (UDG attrs)
POKE @fourspriter+40+48*n,attra
POKE @fourspriter+41+48*n,attrb
POKE @fourspriter+42+48*n,attrc
POKE @fourspriter+43+48*n,attrd
END SUB
fourspriter:
ASM
;; 16x16 Sprites moving a character each frame
;; Copyleft 2009 The Mojon Twins.
;; Pergreñado por na_th_an
;; Uses UDGs (it reads the address from the system variables).
;; It moves up to 4 sprites, preserving the backgrounds.
datap: ; each block is 40 bytes long.
;; Sprite 1
udgs1: defb 0, 0, 0, 0 ; Four UDGs of the first sprite.
x_pos1: defb 0 ; X position in chars.
y_pos1: defb 0 ; Y position in chars.
cx_pos1: defb 0 ; Previous X position in chars.
cy_pos1: defb 0 ; Previous Y position in chars.
buffer1: defb 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 ; Gfx buffer.
attrs1: defb 7, 7, 7, 7 ; Sprite ATTRs
buffatrs1: defb 0,0,0, 0 ; Attr's buffer
;; Sprite 2
udgs2: defb 0, 0, 0, 0 ;
x_pos2: defb 0 ;
y_pos2: defb 0 ;
cx_pos2: defb 0 ;
cy_pos2: defb 0 ;
buffer2: defb 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 ;
attrs2: defb 7, 7, 7, 7 ;
buffatrs2: defb 0,0,0, 0 ;
;; Sprite 3
udgs3: defb 0, 0, 0, 0 ;
x_pos3: defb 0 ;
y_pos3: defb 0 ;
cx_pos3: defb 0 ;
cy_pos3: defb 0 ;
buffer3: defb 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 ;
attrs3: defb 7, 7, 7, 7 ;
buffatrs3: defb 0,0,0, 0 ;
;; Sprite 4
udgs4: defb 0, 0, 0, 0 ;
x_pos4: defb 0 ;
y_pos4: defb 0 ;
cx_pos4: defb 0 ;
cy_pos4: defb 0 ;
buffer4: defb 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 ;
attrs4: defb 7, 7, 7, 7 ;
buffatrs4: defb 0,0,0, 0 ;
;; General use coordinates
xpos: defb 0
ypos: defb 0
cxpos: defb 0
cypos: defb 0
;; Sprite control is done writing a certain number
;; in the Sprite's first UDG
;; If the first UDG is 99, it won't be printed
;;
;; Routine to save the background to the buffer
end asm
initsprites:
asm
init_sprites:
; pointer = datap
; for (i = 0; i < 4; i ++) {
; X = *(pointer + 4); // A
; Y = *(pointer + 5);
; scr_address = get_scr_address (X, Y); // B
; for (j = 0; j < 8; j ++) {
; *(pointer + 8 + j) = *scraddress;
; scraddress += 256;
; }
; scr_address = get_scr_address (X+1, Y); // C
; for (j = 0; j < 8; j ++) {
; *(pointer + 16 + j) = *scraddress;
; scraddress += 256;
; }
; scr_address = get_scr_address (X, Y+1); // D
; for (j = 0; j < 8; j ++) {
; *(pointer + 24 + j) = *scraddress;
; scraddress += 256;
; }
; scr_address = get_scr_address (X+1, Y+1); // E
; for (j = 0; j < 8; j ++) {
; *(pointer + 32 + j) = *scraddress;
; scraddress += 256;
; }
; pointer = pointer + 40;
; }
ld de, datap ;
ld b, 4 ;
i4chars: push bc
;;
ld a, (de)
cp 99
jr z, nxt1
;; A
inc de
inc de
inc de
inc de
;
ld a, (de)
ld hl, xpos
ld (hl), a
inc de
;
ld a, (de)
ld hl, ypos
ld (hl), a
inc de
inc de
inc de
;; B
;
call copia_char
; xpos++
ld hl, xpos
inc (hl)
;; C
;
call copia_char
; xpos --
ld hl, xpos
ld a, (hl)
dec a
ld (hl), a
; ypos ++
ld hl, ypos
inc (hl)
;; D
;
call copia_char
; xpos++
ld hl, xpos
inc (hl)
;; E
;
call copia_char
;; Now we point to the ATTR buffer,adding 4:
inc de
inc de
inc de
inc de
;;
; xpos --
ld hl, xpos
ld a, (hl)
dec a
ld (hl), a
; ypos --
ld hl, ypos
ld a, (hl)
dec a
ld (hl), a
;
call get_attr_address
;
ld l, c
ld h, b
ld bc, 31
ld a, (hl)
ld (de), a ; Primer carácter
inc hl
inc de
ld a, (hl)
ld (de), a ; Segundo carácter
add hl, bc
inc de
ld a, (hl)
ld (de), a ; Tercer carácter
inc hl
inc de
ld a, (hl)
ld (de), a ; Cuarto carácter
inc de
; Fin del bucle
nxt1: pop bc
djnz i4chars
ret
copia_char:
call get_scr_address ;
ld l, c
ld h, b ;
ld a, (hl)
ld (de), a
inc h
inc de
ld a, (hl)
ld (de), a
inc h
inc de
ld a, (hl)
ld (de), a
inc h
inc de
ld a, (hl)
ld (de), a
inc h
inc de
ld a, (hl)
ld (de), a
inc h
inc de
ld a, (hl)
ld (de), a
inc h
inc de
ld a, (hl)
ld (de), a
inc h
inc de
ld a, (hl)
ld (de), a
inc h
inc de
ret
;; Routine to move the sprites:
end asm
updatesprite:
asm
update_sprites:
halt
call borra_sprites ; Erase the sprites
call init_sprites ; Save background
call draw_sprites ; print sprites
call update_coordinates ; update coordinates :)
ret
;; Routine to erase the sprites:
end asm
borrasprites:
asm
borra_sprites:
; pointer = datap
; for (i = 0; i < 4; i ++) {
; CX = *(pointer + 6)
; CY = *(pointer + 7)
; scr_address = get_scr_address (CX, CY);
; for (j = 0; j < 8; j ++) {
; *scr_address = *(pointer + 8 + j);
; scr_address += 256;
; }
; scr_address = get_scr_address (CX+1, CY);
; for (j = 0; j < 8; j ++) {
; *scr_address = *(pointer + 16 + j);
; scr_address += 256;
; }
; scr_address = get_scr_address (CX, CY+1);
; for (j = 0; j < 8; j ++) {
; *scr_address = *(pointer + 24 + j);
; scr_address += 256;
; }
; scr_address = get_scr_address (CX+1, CY+1);
; for (j = 0; j < 8; j ++) {
; *scr_address = *(pointer + 32 + j);
; scr_address += 256;
; }
; pointer += 40;
; }
ld de, datap ;
ld b, 4 ;
i4chars2: push bc
;;
ld a, (de)
cp 99
jr z, nxt2
;; A
inc de
inc de
inc de
inc de
inc de
inc de
; Obtenemos xpos = CX
ld a, (de)
ld hl, xpos
ld (hl), a
inc de
; Obtenemos ypos = CY
ld a, (de)
ld hl, ypos
ld (hl), a
inc de
;; B
; Pintamos el primer char
call borra_char
; xpos++
ld hl, xpos
inc (hl)
;; C
; Pintamos el segundo char
call borra_char
; xpos --
ld hl, xpos
ld a, (hl)
dec a
ld (hl), a
; ypos ++
ld hl, ypos
inc (hl)
;; D
; Pintamos el tercer char
call borra_char
; xpos++
ld hl, xpos
inc (hl)
;; E
; Pintamos el cuarto char
call borra_char
;; attr
inc de
inc de
inc de
inc de
;;
; xpos --
ld hl, xpos
ld a, (hl)
dec a
ld (hl), a
; ypos --
ld hl, ypos
ld a, (hl)
dec a
ld (hl), a
;
call get_attr_address
;
call copyattrs
;
nxt2: pop bc
djnz i4chars2
ret
borra_char:
call get_scr_address ;
ld l, c
ld h, b ;
ld a, (de)
ld (hl), a
inc h
inc de
ld a, (de)
ld (hl), a
inc h
inc de
ld a, (de)
ld (hl), a
inc h
inc de
ld a, (de)
ld (hl), a
inc h
inc de
ld a, (de)
ld (hl), a
inc h
inc de
ld a, (de)
ld (hl), a
inc h
inc de
ld a, (de)
ld (hl), a
inc h
inc de
ld a, (de)
ld (hl), a
inc h
inc de
ret
;; Print sprites routine
;; UDGs are labeled from 0 to 21. The addres of the UDG is:
;; *(23675) + 256 * *(23676) + 8 * N
bufchars: defb 0,0,0, 0 ;
end asm
drawsprites:
asm
draw_sprites:
ld de, datap ;
ld b, 4 ;
i4chars3: push bc
;;
ld a, (de)
cp 99
jr z, nxt3
;; copiar aquí "de" a un buffer
call charsabuff
; Obtenemos xpos
ld a, (de)
ld hl, xpos
ld (hl), a
inc de
; Obtenemos ypos
ld a, (de)
ld hl, ypos
ld (hl), a
inc de
inc de
inc de
push de
;;
ld hl, bufchars
call getde
;;
call docopy
; xpos++
ld hl, xpos
inc (hl)
; Dirección del gráfico
ld hl, bufchars
inc hl
call getde
; Pintamos el segundo char
call docopy
; xpos--
ld hl, xpos
ld a, (hl)
dec a
ld (hl), a
; ypos ++
ld hl, ypos
inc (hl)
; Dirección del gráfico
ld hl, bufchars
inc hl
inc hl
call getde
; Pintamos el tercer char
call docopy
; xpos ++
ld hl, xpos
inc (hl)
; Dirección del gráfico
ld hl, bufchars
inc hl
inc hl
inc hl
call getde
; Pintamos el cuarto char
call docopy
pop de
; de = de + 32
ld bc, 32
ld h, d
ld l, e
add hl, bc
ld d, h
ld e, l
;; attr
; xpos --
ld hl, xpos
ld a, (hl)
dec a
ld (hl), a
; ypos --
ld hl, ypos
ld a, (hl)
dec a
ld (hl), a
;
call get_attr_address
;
call copyattrs
inc de
inc de
inc de
inc de ;
nxt3: pop bc
djnz i4chars3
ret
charsabuff: ld hl, bufchars
ld a, (de)
ld (hl), a
inc de
inc hl
ld a, (de)
ld (hl), a
inc de
inc hl
ld a, (de)
ld (hl), a
inc de
inc hl
ld a, (de)
ld (hl), a
inc de
inc hl
ret
copyattrs: ld l, c
ld h, b
ld bc, 31
ld a, (de)
ld (hl), a ; Primer carácter
inc hl
inc de
ld a, (de)
ld (hl), a ; Segundo carácter
add hl, bc
inc de
ld a, (de)
ld (hl), a ; Tercer carácter
inc hl
inc de
ld a, (de)
ld (hl), a ; Cuarto carácter
inc de ; Ahora de apunta a datap+48, o sea, al siguiente sprite.
ret
end asm
updatecoordinates:
asm
update_coordinates:
ld de, datap ; Apuntamos a la zona de datos
ld hl, datap ; idem
ld b, 4 ; 4 iteraciones
i4chars4: push bc
;; Para cada sprite hay que hacer:
;; *(datap + 6) = *(datap + 4)
;; *(datap + 7) = *(datap + 5)
inc de
inc de
inc de
inc de
ld a, (de) ; a = X
inc hl
inc hl
inc hl
inc hl
inc hl
inc hl
ld (hl), a ; CX = a
inc de
ld a, (de) ; a = Y
inc hl
ld (hl), a ; CY = a
inc hl
;; hl = hl + 40
ld bc, 40
add hl, bc
;; de = hl
ld d, h
ld e, l
pop bc
djnz i4chars4
ret
;; Esta función calcula la posición en memoria del UDG apuntado por
;; el número que está en la dirección hl.
getde: ld a, (hl)
ld d, a
ld hl, 23676
ld a, (hl)
ld e, a
ld hl, 23675
ld a, (hl)
ld l, a
ld a, e
ld h, a
;; HL = *(23675) + 256 * *(23676)
ld a, d
rlca
rlca
rlca ; a = N * 8
ld d, 0
ld e, a
add hl, de
ld d, h
ld e, l
ret
docopy:
call get_scr_address ; Dirección (xpos, ypos) en BC
ld l, c
ld h, b ; Dirección (xpos, ypos) en HL
ld a, (de)
ld (hl), a
inc h
inc de
ld a, (de)
ld (hl), a
inc h
inc de
ld a, (de)
ld (hl), a
inc h
inc de
ld a, (de)
ld (hl), a
inc h
inc de
ld a, (de)
ld (hl), a
inc h
inc de
ld a, (de)
ld (hl), a
inc h
inc de
ld a, (de)
ld (hl), a
inc h
inc de
ld a, (de)
ld (hl), a
inc h
inc de
ret
;; Esta función devuelve en bc la dirección de memoria
;; de la posición (xpos, ypos) en carácteres. Extraído de código
;; por BloodBaz.
get_scr_address:
push de
ld a, (xpos)
and 31
ld c, a
ld a, (ypos)
ld d, a
and 24
add a, 64
ld b, a
ld a, d
and 7
rrca
rrca
rrca
or c
ld c, a
pop de
ret
;; Esta función devuelve en bc la dirección de memoria
;; de la posición (xpos, ypos) dentro del archivo de atributos.
;; Adaptado de código por Jonathan Cauldwell.
;; 010110YY YYYXXXXX
get_attr_address:
ld a, (ypos) ; Cogemos y
rrca
rrca
rrca ; La multiplicamos por 32
ld c, a ; nos lo guardamos en c
and 3 ; ponemos una mascarita 00000011
add a, 88 ; 88 * 256 = 22528, aquí empieza el tema
ld b, a ; Hecho el bite superior.
ld a, c ; Nos volvemos a traer y * 32
and 224 ; Mascarita 11100000
ld c, a ; Lo volvemos a poner en c
ld a, (xpos) ; Cogemos x
add a, c ; Le sumamos lo que teníamos antes.
ld c, a ; Listo. Ya tenemos en BC la dirección.
ret
spare: defb 85,85,85,85,85,85,85, 85
end asm
The subroutines are the following:
1) Define your sprites:
fsprite (n,a,b,c,d) ; where n is the sprite number (0 to 3) and a-d are the UDGs number that compose the sprite (0-21)
2) Set the atributes for each of the sprite's UDG:
fspriteattr (n,a,b,c,d) ; n=sprite number ; a-d=attr of each UDG
3) Set the initial coords for your spries:
fspritecoord (n,y,x) ; n= sprite number ; y=vertical coord ; x=horizontal coord
The labels to be called via gosub are:
borrasprites ; this will erase the sprites, restoring the background.
initsprites ; this will select wether a sprite will be printed or not. If you don't want a sprite to be printed, you have to poke 99 into the first value of the sprite udg (i.e. fsprite (1,99,0,0,0) won't print sprite 1)
drawsprites ; this will draw the sprites on the screen
updatecoordinates ; this will update the current coordinates of each sprite, while storing the old ones so you can restore the background.
Last edited by apenao on Mon Mar 01, 2010 9:15 pm, edited 1 time in total.
