; opt c- include hardware.i ; Some library functions: OpenLibrary =-552 CloseLibrary =-414 AllocMem =-198 FreeMem =-210 Forbid =-132 Permit =-138 move.l 4,a6 lea gfxname,a1 ; Open Gfx library moveq.l #0,d0 ; Any version jsr OpenLibrary(a6) move.l d0,gfxbase ; Store its base move.l #256*120,d0 ; Reserve 5 bitplane space move.l #2+(1<<16),d1 ; Chip RAM jsr AllocMem(a6) ; Reserve it tst.l d0 ; Check if available beq quit ; If unavailable quit moveq.l #2,d1 ; d1 = no. of bitplanes -1 lea b1,a0 ; a0 = place to store address of bpl 1 lea b1l,a1 ; a1 = place in copper list to put pointers dobpls move.l d0,(a0)+ ; Store address in b1,b2,b3 or b4 move.w d0,(a1) ; Store address in copper list swap d0 move.w d0,4(a1) swap d0 add.l #256*40,d0 ; Next bpl add.l #8,a1 ; Next part in copper list dbra d1,dobpls jsr Forbid(a6) ; No Multi-tasking lea $dff000,a5 bsr vwait ; Switch off sprites move.w #$20,dmacon(a5) move.w #$8400,dmacon(a5) ; Give blitter priority move.l #copper,cop1lch(a5) ; Strobe our copper list move.w #0,copjmp1(a5) move.w #0,$1fc(a5) wait lea Points,a0 ; a0=address of points table lea NewPoints,a1 ; a1=address to put rotated points lea Angles,a2 ; a2=address of angles (Z, then Y then X) move.l #NoOfPoints-1,d7 ; d7=no. of points-1 bsr CalcPoints ; Calcuate new points lea NewPoints,a0 ; a0=address of rotated points move.l #NoOfPoints-1,d7 ; d7=no. of points-1 bsr SortPoints ; Sort points by Z axis tst.b FirstOne ; Is this the first rotation? beq .loop ; If so, we've got nowt to wipe move.l #NoOfPoints-1,d7 ; d7=no. of points-1 bsr ClearBalls ; Wipe the balls .loop move.b #1,FirstOne ; Next time, we will wipe the balls lea NewPoints,a0 ; a0=address of rotated points move.l #NoOfPoints-1,d7 ; d7=no. of points-1 bsr DisplayBalls ; Display the balls lea Angles,a0 ; a0=address of angles lea AngleIncs,a1 ; a1=address of number to add to angles moveq.l #2,d0 ; 3 angles (-1 for dbra) .loop1 move.w (a1)+,d1 ; d1=number to add to angle add.w d1,(a0) ; Add it to the angle cmp.w #360,(a0) ; Is new angle>359 ? blt .loop2 ; Is so, bring it within 0-359 range sub.w #360,(a0) .loop2 addq.l #2,a0 ; point a0 to next angle dbra d0,.loop1 ; increase (or decrease) other angles btst #6,$bfe001 ; LMB pressed? bne wait move.w #$8020,dmacon(a5) ; Switch on sprites free move.l 4,a6 jsr Permit(a6) ; Enable multi-tasking move.l #256*120,d0 ; 5 bitplanes space move.l b1,a1 ; Free the memory jsr FreeMem(a6) move.l gfxbase,a1 ; Enter old copper list move.l 38(a1),cop1lch(a5) jmp CloseLibrary(a6) ; And close the gfx library vwait cmp.b #255,vhposr(a5) ; Wait for vertical blanking bne.s vwait quit rts bwait btst #14,dmaconr(a5) bne.s bwait rts ******* Calculate x/y positions ; Entry : a0 = Table of original co-ord ; a1 = Space for new table ; a2 = Address of angles (Z,Y,X) ; d7 = No. of points-1 CalcPoints: lea SineTable,a3 ; a2=address of sine table ; Calculate current X,Y and Z positions CalcXYZ: move.w (a0),d2 ; d2=xpos move.w 2(a0),d3 ; d3=ypos bsr CalcNewPos move.w d4,(a1) ; d4=new xpos move.w d5,2(a1) ; d5=new ypos move.w d4,d2 ; d2=xpos move.w 4(a0),d3 ; d3=zpos bsr CalcNewPos move.w d4,(a1) ; d4=new xpos move.w d5,4(a1) ; d5=nw zpos move.w d5,d2 ; d2=zpos move.w 2(a1),d3 ; d3=ypos bsr CalcNewPos move.w d4,4(a1) ; d4=new zpos move.w d5,2(a1) ; d5=new ypos move.w 6(a0),6(a1) ; Copy colour from orig points to new ones addq.l #8,a0 ; a0=address of next original point addq.l #8,a1 ; a1=address of next rotated point subq.l #6,a2 ; Point a2 back to start of angles dbra d7,CalcXYZ rts CalcNewPos: move.w (a2)+,d0 ; Get angle from list ext.l d0 ; make it a long word lsl.l d0 ; Multiply by 2 (sine table in words) move.w (a3,d0),d1 ; d1=sine value for angle ; Cos(X) = Sin (90+X) ; All things added/subtracted are *2 since sine table is in words add.l #180,d0 ; Add 90 to angle cmp.l #720,d0 ; If angle>359, bring it within 0-359 range blt .ok sub.l #720,d0 ; By subtracting 360 from it .ok move.w (a3,d0),d0 ; d0=cos value for angle move.l d2,d4 ; d4=d2 move.l d3,d5 ; d5=d3 muls d0,d4 ; d4=d4 * cos(X) muls d1,d3 ; d3=d3 * sin(X) sub.l d3,d4 ; Subtract d3 from d4 to get first value muls d0,d5 ; d5=d5 * cos(X) muls d1,d2 ; d2=d2 * sin(X) add.l d2,d5 ; Add d2 to d5 to get second value asr.l #7,d4 ; Divide each value by 16384 since each sine asr.l #7,d4 ; number was multiplied by this in the first asr.l #7,d5 ; place asr.l #7,d5 rts ******* Sort points by Z co-ord ; Entry : a0 = address of points ; d7 = no. of points-1 ; Sorted by a simple sort technique (don't know its offical name). Take ; 1st value in list, and see if any values following it are smaller. If ; so, swap the 1st value with smallest value. Go to the second and do ; the same, the third, and so on so that when you get to the last value ; the list is in order. ; In this case the Z co-ord is the one we're interested in, but of course ; we need to swap all of the information for each point (X, Y, Z co-ords ; and colour) SortPoints: subq.l #1,d7 ; On 1st sort, look at (no. of points-1) after 1st, ; -1 for dbra Sort1: move.l d7,d6 ; Keep d7 the same, use d6 instead move.l a0,a1 ; Ditto a0 and a1 addq.l #8,a1 ; Start searching in entry after current one sub.l a2,a2 ; No smaller value found so far move.w 4(a0),d0 ; d0=value to compare each entry with .loop cmp.w 4(a1),d0 ; Is this entry