iigs-game-engine/demos/shell/Actions.s
2021-08-26 16:24:46 -05:00

230 lines
6.7 KiB
ArmAsm

MoveLeft
clc
adc StartX ; Increment the virtual X-position
jsl SetBG0XPos
lda StartX
lsr
jsl SetBG1XPos
jsl Render
rts
MoveRight
pha
lda StartX
sec
sbc 1,s
bpl *+5
lda #0
jsl SetBG0XPos
lda StartX
lsr
jsl SetBG1XPos
jsl Render
pla
rts
MoveUp
clc
adc StartY ; Increment the virtual Y-position
pha
lda #240 ; virtual play field height
sec
sbc ScreenHeight
tax
cmp 1,s
bcc *+4
lda 1,s
jsl SetBG0YPos
pla
; lda StartY
; lsr
; jsl SetBG1YPos
jsl Render
rts
MoveDown
pha
lda StartY
sec
sbc 1,s
bpl *+5
lda #0
jsl SetBG0YPos
; lda StartY
; lsr
; jsl SetBG1YPos
jsl Render
pla
rts
; Very simple, scroll as fast as possible
oldOneSecondCounter ds 2
frameCount ds 2
lastTick ds 2
Demo
ldal OneSecondCounter
sta oldOneSecondCounter
stz frameCount
; Every 3 ticks (20 fps) cycle some colors
lda #DoColorCycle
ldx #^DoColorCycle
ldy #3
jsl AddTimer
:loop
PushLong #0
_GetTick
pla
plx
cmp lastTick ; Throttle to 60 fps
beq :loop
tax ; Calculate the increment
sec
sbc lastTick
stx lastTick
; jsr _DoTimers
; lda #1
; jsr MoveLeft
jsr UpdateBG1Rotation
; jsr DoColorCycle
jsl Render
inc frameCount
ldal KBD_STROBE_REG
bit #$0080
beq :nokey
and #$007F
cmp #'s'
bne :nokey
rts
:nokey
ldal OneSecondCounter
cmp oldOneSecondCounter
beq :loop
sta oldOneSecondCounter
lda ScreenWidth
cmp #150
bcs :loop
lda #FPSStr
ldx #0 ; top-left corner
ldy #$7777
jsr DrawString
lda frameCount
ldx #4*4
jsr DrawWord
stz frameCount
bra :loop
FPSStr str 'FPS'
; Move some colors around color (6 - 11) address 12 - 22
DoColorCycle
ldal $E19E0C
pha
ldal $E19E0E
pha
ldal $E19E10
pha
ldal $E19E12
pha
ldal $E19E14
pha
ldal $E19E16
stal $E19E0C
pla
stal $E19E16
pla
stal $E19E14
pla
stal $E19E12
pla
stal $E19E10
pla
stal $E19E0E
rts
; Triggered timer to sway the background
UpdateBG1Offset
lda BG1OffsetIndex
inc
inc
cmp #32 ; 16 entries x 2 for indexing
bcc *+5
sbc #32
sta BG1OffsetIndex
rts
AngleUp
lda angle
inc
cmp #64
bcc *+5
sbc #64
sta angle
jsr _ApplyAngle
jsl Render
rts
AngleDown
lda angle
dec
bpl *+6
clc
adc #64
sta angle
jsr _ApplyAngle
jsl Render
rts
angle dw 0
UpdateBG1Rotation
jsr _ApplyAngle
; Increment the angle
lda angle
inc
cmp #64
bcc *+5
lda #0
sta angle
rts
x_angles EXT
y_angles EXT
_ApplyAngle
lda angle ; debug with angle = 0
asl
tax
ldal x_angles,x ; load the address of addressed for this angle
tay
phx
jsl ApplyBG1XPosAngle
plx
ldal y_angles,x ; load the address of addresses for this angle
tay
jsl ApplyBG1YPosAngle
rts