Date sent: Thu, 19 Jun 1997 00:50:03 +0200 (MET DST) From: Patrik Haggblad To: azure@hamburg.roses.de ; ; Wind/Network contribution for the Starfield-bytesize-compo on #amycoders: ; ; My first try was at about 140-150 bytes, but now it's on 108 bytes... ; ; ; please note that anyone can use this source provided he at least changes ; something meaningfull, such as adding colors, shading, rotation, etc.... ; if you wanna use it as-is, you should credit me, oki? ; ; Wind/Network ; network@redestb.es ; ; Antonio Vargas ; Relator 67, 1 ; 41003 Sevilla ; Spain (spain.... wasn't it in africa or smthng??? ;) ; ********************* *********************** ****** . . ****** **** . . . Init & Exit code . ? **** *** ' . ???????????????? . *** ** . . . . . ? . . ** ** ? written in a hurry for . . ** *** . : . . ?????????????????????? . *** **** #Amycoders' starfield compo by **** ****** . ??????????????????????????? morbid ********************* *********************** ************* stuff for cheking codesize check equ 0 ; 108 ifne check move.l #codesize,d0 rts endc ************* bsr CloseWB ; Flush view and disable multitasking bsr OpenScreen ; Set pointers and sync jsr Starfield_init ;Init starfield ** ************************************************************ ************************************************************ ** ** >>> M A I N <<< ** Main btst #6,$bfe001 beq Exit ************************************************************ bsr DisplayScreen jsr Starfield ;call starfield (a0=Bitplane) bra Main ** ************************************************************ ** ** Flush view & disable system ** CloseWB movea.l 4.w,a6 ; exec base jsr -132(a6) ; Forbid jsr -120(a6) ; Disable lea GfxName(pc),a1 ; graphics.library moveq #0,d0 ; whatever verision jsr -552(a6) ; open it ! move.l d0,GfxBase ; store gfxbase movea.l d0,a6 ; gfxbase in a6 move.l $22(a6),OldView ; store system view move.l $26(a6),OldCop ; store system copper sub.l a1,a1 jsr -222(a6) ; flush view (LoadView) jsr -270(a6) ; WaitTOF jsr -270(a6) ; twice for interlaced views move.w $dff002,OldDMAcon ; store old dma control register ori.w #$8000,OldDMAcon ; set bit #15 move.w #$7fff,$dff096 move.w #$8380,$dff096 rts GfxName dc.b 'graphics.library',0 even GfxBase dc.l 0 OldView dc.l 0 OldCop dc.l 0 OldDMAcon dc.w 0 cnop 0,4 ** ************************************************************* ** ** Display Screen ** DisplayScreen movem.l d0-d1,-(sp) move.b $bfe801,d0 .wait cmp.b $bfe801,d0 beq.b .wait move.l screen_logical(pc),d0 move.l screen_physical(pc),screen_logical move.l d0,screen_physical lea copper_bpl,a0 move.w d0,6(a0) ; lower part of bpl address swap d0 move.w d0,2(a0) ; higher word movea.l screen_logical(pc),a0 moveq #0,d0 move.l #(320/32)*256-1,d1 .clear move.l d0,(a0)+ ; clear logical screen dbf d1,.clear lea -(320/8)*256(a0),a0 movem.l (sp)+,d0-d1 rts screen_physical dc.l 0 screen_logical dc.l 0 ** ************************************************************* ** ** Open Screen ** OpenScreen lea $dff000,a5 move.l #Copper,$80(a5) move.w #$2c81,$08e(a5) ; display window start pos move.w #$2cc1,$090(a5) ; display window stop pos move.w #$0038,$092(a5) ; data fetch start pos move.w #$00d0,$094(a5) ; data fetch stop pos move.l #ScreenA,screen_logical move.l #ScreenB,screen_physical bsr DisplayScreen rts ** ************************************************************** ** ** Open WB ** Exit lea $dff000,a5 move.w #$7fff,$96(a5) ; clear dmacon move.w OldDMAcon(pc),$96(a5) ; set old bits move.l GfxBase(pc),a6 ; gfxbase in a6 move.l OldCop(pc),$80(a5) ; restart old copperlist move.l OldView(pc),a1 jsr -222(a6) ; Load system view move.l a6,a1 move.l 4.w,a6 jsr -414(a6) ; close graphics.library jsr -126(a6) ; Enable jsr -138(a6) ; Permit rts ************************************************************************ section screens,bss_c ScreenA ds.b (320*256)/8 ScreenB ds.b (320*256)/8 ************************************************************************ section copperlist,data_c Copper dc.l $01001000 ; bplcon0 dc.l $01080000 ; bpl1mod dc.l $010a0000 ; bpl2mod dc.l $01800000 ; colour 0 = black dc.l $01820fff ; colour 1 = white copper_bpl dc.l $00e00000 ; bpl1pth dc.l $00e20000 ; bpl1ptl dc.l $fffffffe ************************************************************************** ************************************************************************** ** ** ** Your starfield code starts here ** ** ************************************************************************** ************************************************************************** section code,code ;put your code here ********************************************* ** Do all initialisations here ********************************************* Starfield_init: a lea vars,a6 move.w #(512*3)-1,d7 .init1 bsr.b dorandom move.w d6,(a6)+ dbra d7,.init1 rts dorandom add.l d1,d6 ; cool random number generator eor.w d6,d1 b rts ********************************************* ** This routine is called once a frame ** ** The destination Bitplane is given in a0 ********************************************* ; ; please note there ALWAYS are 512 stars on screen ; c limit1 dc.w -160,159 limit2 dc.w -128,127 nopaint ; new pixel is generated when one is out of bounds sub.w d6,-(a6) ; Z bsr.b dorandom add.l d1,-(a6) ; new X & Y bra.b starloop Starfield: lea vars,a6 eor.l d5,d5 ; d5 = $00000000 not.w d5 ; d5 = $0000ffff moveq.l #40,d4 lea limit1(pc),a5 lea limit2(pc),a4 move.w #511,d7 starloop movem.w (a6)+,d0/d1 sub.w d4,(a6) ; speed = 40 move.w (a6)+,d2 ble.b nopaint ; new star if z<=0 divs.w d2,d0 ; perspective divs.w d2,d1 cmp2.w (a5),d0 ; check X border bcs.b nopaint cmp2.w (a4),d1 ; check Y border bcs.b nopaint sub.w (a5),d0 ; x-(-160) sub.w (a4),d1 ; y-(-128) mulu.w d4,d1 ; y*40 and.l d5,d0 ; fix X offset (clear high word) bfset (a0,d1.l){d0:1} ; plot pixel using bitfield dbra d7,starloop d rts codesize equ (d-c)+(b-a) section bss,bss ;put your tables heres vars ds.l (512*3) ;stars .