[stella] Useless Information Department

[Christopher Tumber <christophertumber@xxxxxxxxxx>]

FWIW, you can use the sprite replication trick (sta RESP0/sta RESP1/sta RESP0) with the Missiles.

Why you would ever want to do this when the bitmaps available through the Player objects is much more usefull, I don't know (perhaps to preserve the Player's vertical positioning if you only need a very simple pattern?)

At any rate, maybe somebody, someday finds a use for this info...


Chris...

;BEWARE! NO STACK!!
	processor 6502
	include vcs.h

	org $F000








Start

;	SEI  ; Disable interrupts, if there are any.
;	CLD  ; Clear BCD math bit.

;	LDX  #$FF
;	TXS  ; Set stack to beginning.

;	LDA #0
;B1    STA 0,X
;	DEX
;	BNE B1




      lda #0
      sta PF0
      sta PF1
      sta PF2
      STA COLUBK
      sta CTRLPF
      STA COLUPF  
      sta GRP0
      sta GRP1
      sta HMCLR

      lda #14
      sta COLUP0
      sta COLUP1

      lda #1
      sta NUSIZ0                           ;3 Cycles
      sta NUSIZ1                           ;3 Cycles


DrawLogo

	LDX  #0
	LDA  #2

	STA  VSYNC ;Begin vertical sync.
	STA  WSYNC ; First line of VSYNC
	STA  WSYNC ; Second line of VSYNC.

	LDA  #41
	STA  TIM64T
	LDA #0
	STA CXCLR
	STA  WSYNC ; Third line of VSYNC.
	STA  VSYNC ; (0)

DrawScreen
	LDA INTIM
	BNE DrawScreen ; Whew!
	STA WSYNC
	STA VBLANK  ;End the VBLANK period with a zero.

      lda #255
      sta ENAM0 ;GRP0
      sta ENAM1 ;GRP1

      ldy #100
nextmissiledemo:
      sta WSYNC
      nop
      nop
      nop
      nop
      nop
      nop
      nop
      nop
      nop
      sta RESM0
      sta RESM1
      sta RESM0
      sta RESM1
      sta RESM0
      sta RESM1
      sta RESM0
      sta RESM1
      sta RESM0
      sta RESM1

      dey
      bne nextmissiledemo

      lda #0
      sta ENAM0 ;GRP0
      sta ENAM1 ;GRP1

      sta WSYNC



      ldy #96
nextblankline:
      sta WSYNC
      dey
      bne nextblankline


	STA VBLANK ; Make TIA output invisible,
      lda #35
      sta TIM64T
OverscanWait:
      lda     INTIM
      bne     OverscanWait

      JMP  DrawLogo      ;Continue forever.





	org $FFFC
	.word Start
	.word Start

Attachment: MultiMissile.bin
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