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;; This is the player code that gets re-used on all scrolling examples. This
;; will show a meta-sprite made up of four sprites that make up diskun. You can
;; move this player with the arrows, and the movement will be pretty basic (1
;; pixel each time). Furthermore, the sprite handles collision with background
;; elements (TODO), which is shared across all the scrolling examples.
;;
;; The sprite is stored in OAM memory $200-$20F, and the $30 and $31 memory
;; addresses are used for keeping up with the screen coordinates.
.scope Player
m_screen_x = $30
m_screen_y = $31
.proc init
lda #40
sta m_screen_x
sta m_screen_y
lda #$01
sta $201
lda #$02
sta $205
lda #$11
sta $209
lda #$12
sta $20D
lda #0
sta $202
sta $206
sta $20A
sta $20E
rts
.endproc
.proc update
jsr update_coordinates
jsr update_sprites
rts
.endproc
.proc update_coordinates
lda #Joypad::BUTTON_UP
and Joypad::m_buttons1
beq @check_down
dec m_screen_y
jmp @check_left
@check_down:
lda #Joypad::BUTTON_DOWN
and Joypad::m_buttons1
beq @check_left
inc m_screen_y
@check_left:
lda #Joypad::BUTTON_LEFT
and Joypad::m_buttons1
beq @check_right
dec m_screen_x
rts
@check_right:
lda #Joypad::BUTTON_RIGHT
and Joypad::m_buttons1
beq @end
inc m_screen_x
;; TODO: move scroll
@end:
rts
.endproc
.proc update_sprites
lda m_screen_x
sta $203
sta $20B
clc
adc #8
sta $207
sta $20F
lda m_screen_y
sta $200
sta $204
clc
adc #8
sta $208
sta $20C
rts
.endproc
.endscope
|
