******************************************************************** * * Voxelspace_Calc * * calculation routines for Voxelspace (68K version) * * assemble with: * phxass Voxelspace_Calc.s to Voxelspace_Calc.o smallcode * * link with smalldata and smallcode enabled * * Note: this is extremely heavily optimized. Don't try to * understand everything (or anything? :). Documentation is * unsufficient. * * © 1997 HAAGE&PARTNER Computer GmbH * ******************************************************************** include graphics/gfx.i include Voxelspace.i ;// XREF / XDEF xref ChunkyBuffer xref TempBuffer xref HiddenBitmap xref ViewCircle xref ViewCirclePtr xref ViewAngle xref Perspective xref HeightData xref MapFile xref ActualHeight xref StartHeight xref ViewDistance xref MinRange xref MaxRange xref PixCount xref Pix_Count xref PixelCount xref Ray_Count xref Direction xref RayCount xref Angle xref PosXDet xref PosYDet xref Pic_Mask2 xref ColumnCount xref HRotActual xref BitmapWidth xref AreaHeight xref DispHeight xref SkyPos xref SkyScroll xref SkyBuffer xref SkyData xref SkyHeight xref SkyWidth xref SkyWidth2 xref DestOffset xref ChunkyPtr xdef Calculation_T xdef Calculation_T_A xdef Calculation2_T xdef Calculation2_T_A xdef Calculation4 xdef Calculation4_A xdef ChunkyToPlanar ;;/ section "Voxelspace_Calc",code mc68020 ;// Calculation_T (calculates one voxelspace frame - column width 1) ****************************************************************************** * * Calculation_T * * calculates one voxelspace frame with column width = 1 * the results are written into the chunkybuffer * optimized for direct rendering into GfxRAM * ****************************************************************************** Calculation_T movem.l d0-a6,-(sp) move.l HeightData,a0 ;a0 -> place for online persp. move StartHeight,d0 sub ActualHeight,d0 ;calc difference to standard muls ViewDistance,d0 ;perspective muls AreaHeight,d0 ;dh * z * AreaHeight moveq #0,d5 move MinRange,d5 moveq #0,d1 move.b PixCount,d1 lsl.l d1,d5 ;pix count * min. range moveq #0,d3 move Pix_Count,d7 subq #1,d7 .calc move.l d3,d4 move MaxRange,d2 sub MinRange,d2 mulu d2,d4 add.l d5,d4 divu Pix_Count,d4 ;calc actual x position move d4,d6 add ViewDistance,d4 ;x + z ext.l d4 move.l d0,d1 divsl.l d4,d1 ;dh * z / (x + z) * AreaHeight divs DispHeight,d1 ;d1 / Dispheight move d1,(a0)+ ;store value addq #1,d3 dbra d7,.calc move.l MapFile+FILE_ADDRESS,a2 ;a2 -> map move.l ChunkyBuffer,a3 ;a3 -> chunky buffer move AreaHeight,d0 subq #1,d0 moveq #0,d1 move BitmapWidth,d1 move.l d1,a6 mulu d1,d0 add.l d0,a3 ;a3 -> last line in chunky buf. move.l a3,ChunkyPtr move.l TempBuffer,a3 move.l ViewCircle,a0 move.l ViewAngle,a5 move Direction,d0 moveq #0,d1 move Ray_Count,d1 move d1,d2 subq #1,d2 mulu Angle,d1 divu #360*2,d1 ;subtract half angle from dir. sub d1,d0 ;d0 = starting ray and d2,d0 ;wrap around ext.l d0 lsl.l #4,d0 ext.l d2 lsl.l #4,d2 moveq #0,d4 move ActualHeight,d4 ;get actual height moveq #0,d3 move.b SkyScroll,d3 divu d3,d4 ;calc sky scroll value sub SkyPos,d4 ;subtract offset neg d4 swap d4 move.l a6,DestOffset move.l SkyData,a1 ;a1 -> sky definition moveq #9,d7 move.l PosXDet,d5 lsl.l d7,d5 move.l PosYDet,d6 lsl.l d7,d6 move ColumnCount,d7 ;number of columns subq #1,d7 .loop movem.l d2/d3/d5/d6/a0/a3,-(sp) add.l (a5)+,d0 ;jump to next ray and.l d2,d0 ;mask out add.l d0,a0 ;a0 -> new view circle add.l (a0)+,d6 add.l (a0)+,d5 move.l (a0)+,d3 move.l (a0)+,d1 movem.l d0/a0/a5,-(sp) move.l d3,a0 move.l Perspective,a5 ;a5 -> perspective move.l HeightData,a6 ;a1 -> online perspective moveq #0,d3 move HRotActual,d3 ;hor. rotation value ext.l d3 asl.l #8,d3 moveq #0,d0 move ColumnCount,d0 lsr #1,d0 divsl.l d0,d3 ;/ half column count move d7,d4 neg d4 add d0,d4 add d4,d4 subq #1,d4 move d4,d2 ext.l d2 muls.l d2,d3 ;* actual x value moveq #17,d2 asr.l d2,d3 move d3,a4 move #0,d4 ;old height swap d7 move PixelCount,d7 ;number of pixels subq #1,d7 .loop2 move.l d6,d2 move.l d5,d0 lsr.l #16-_PICSIZE,d2 swap d0 and.l #(((1<<_PICSIZE)-1)<<_PICSIZE),d2 and.l #(1<<_PICSIZE)-1,d0 or.l d0,d2 moveq #0,d3 move.b 0(a2,d2.l*2),d3 ;read pixel height from map add.l a0,d6 add.l d1,d5 move 0(a5,d3.w*2),d0 ;calc perspective height lea 256(a5),a5 ;new tab for new distance sub a4,d0 ;subtract HRot offset add (a6)+,d0 ;add online perspective value sub d4,d0 ;calc height difference ble.b .loopend add d0,d4 ;calc new height move.b 1(a2,d2.l*2),d3 ;read pixel color from map subq #1,d0 ;now draw the vertical bar .copy move.b d3,(a3) addq.l #4,a3 dbra d0,.copy .loopend dbra d7,.loop2 .colOK sub AreaHeight,d4 neg d4 ;area height - actual height move d4,d0 ;d0 = sky height to draw move #-1,SKY_COUNT(a1) subq #1,d0 bmi.b .jump ;no sky to draw -> jump swap d4 move d4,d3 ;get sky offset sub a4,d3 ;subtract hor. rotation value add SkyHeight,d3 sub AreaHeight,d3 ;calc real sky offset muls SkyWidth2,d3 ;mulitply by sky width move.l d3,SKY_SOURCE(a1) ;write sky offset move d0,SKY_COUNT(a1) ;write sky height swap d4 .jump movem.l (sp)+,d0/a0/a5 movem.l (sp)+,d2/d3/d5/d6/a0/a3 addq.l #1,a3 ;next column lea SKY_SIZE(a1),a1 ;next sky definition swap d7 move d7,d4 andi #$3,d4 bne.w .loopend2 movem.l d0/d2/d5-d7,-(sp) move.l ChunkyPtr,a4 addq.l #4,ChunkyPtr subq.l #4,a3 move AreaHeight,d4 subq #2,d4 move -4*SKY_SIZE+SKY_COUNT(a1),d2 move -3*SKY_SIZE+SKY_COUNT(a1),d5 move -2*SKY_SIZE+SKY_COUNT(a1),d1 move -SKY_SIZE+SKY_COUNT(a1),d3 move.l DestOffset,d0 move d3,d6 cmp d6,d1 bge.b .cmp1 move d1,d6 .cmp1 cmp d6,d5 bge.b .cmp2 move d5,d6 .cmp2 cmp d6,d2 bge.b .cmp3 move d2,d6 .cmp3 sub d4,d6 neg d6 tst d6 bmi.b .nodraw .copycol move.l (a3)+,(a4) sub.l d0,a4 dbra d6,.copycol .nodraw movem.l (sp)+,d0/d2/d5-d7 move.l TempBuffer,a3 .loopend2 dbra d7,.loop sub.l a3,a3 move.l DestOffset,d5 move SkyWidth2,a3 move.l SkyBuffer,a1 ;a1 -> sky graphics move Direction,d7 ;get direction mulu SkyWidth2,d7 divu Ray_Count,d7 ;calc sky hor. position cmp SkyWidth,d7 ;check for overflow blt.b .cont sub SkyWidth,d7 .cont add d7,a1 ;a1 -> sky start pos move.l a1,d2 move.l SkyData,a0 ;a0 -> sky definition move.l ChunkyBuffer,a2 ;a2 -> chunky buffer move.l a2,d4 move ColumnCount,d7 subq #1,d7 .loop3 move.l SKY_SOURCE(a0),d0 ;get sky source offset move.l d2,a1 move.l d4,a2 add.l d0,a1 ;a1 -> sky start pos cmp #3,d7 blt.w .normal cmp.l SKY_SOURCE+SKY_SIZE(a0),d0 ;next offset equal? bne.w .normal ;no -> normal draw cmp.l SKY_SOURCE+2*SKY_SIZE(a0),d0 ;next offset equal? bne.w .normal ;no -> normal draw cmp.l SKY_SOURCE+3*SKY_SIZE(a0),d0 ;next offset equal? bne.w .normal ;no -> normal draw subq #3,d7 movem.l d0/d2/d4/d7,-(sp) move SKY_COUNT(a0),d6 move SKY_COUNT+SKY_SIZE(a0),d3 move SKY_COUNT+2*SKY_SIZE(a0),d1 move SKY_COUNT+3*SKY_SIZE(a0),d0 move d6,d2 cmp d2,d3 bge.b .scmp1 move d3,d2 .scmp1 cmp d2,d1 bge.b .scmp2 move d1,d2 .scmp2 cmp d2,d0 bge.b .scmp3 move d0,d2 .scmp3 tst d2 bmi.b .ssingle1 sub d2,d6 sub d2,d3 sub d2,d1 sub d2,d0 subq #1,d6 subq #1,d3 subq #1,d1 subq #1,d0 .drawsky4 move.l (a1),(a2) ;draw 4 columns at once add.l d5,a2 add.l a3,a1 dbra d2,.drawsky4 .ssingle1 tst d6 bmi.b .ssingle2 move.l a1,d4 move.l a2,d7 .ssloop1 move.b (a1),(a2) add.l d5,a2 add.l a3,a1 dbra d6,.ssloop1 move.l d4,a1 move.l d7,a2 .ssingle2 tst d3 bmi.b .ssingle3 move.l a1,d4 move.l a2,d7 .ssloop2 move.b 1(a1),1(a2) add.l d5,a2 add.l a3,a1 dbra d3,.ssloop2 move.l d4,a1 move.l d7,a2 .ssingle3 tst d1 bmi.b .ssingle4 move.l a1,d4 move.l a2,d7 .ssloop3 move.b 2(a1),2(a2) add.l d5,a2 add.l a3,a1 dbra d1,.ssloop3 move.l d4,a1 move.l d7,a2 .ssingle4 tst d0 bmi.b .ssingle5 move.l a1,d4 move.l a2,d7 .ssloop4 move.b 3(a1),3(a2) add.l d5,a2 add.l a3,a1 dbra d0,.ssloop4 move.l d4,a1 move.l d7,a2 .ssingle5 movem.l (sp)+,d0/d2/d4/d7 addq.l #4,d2 ;increase by 4 columns addq.l #4,d4 lea SKY_SIZE*4(a0),a0 dbra d7,.loop3 bra.b .end .normal move SKY_COUNT(a0),d6 ;get sky height bmi.b .next .drawsky move.b (a1),(a2) ;draw one sky column add.l d5,a2 add.l a3,a1 dbra d6,.drawsky .next addq.l #1,d2 ;next column addq.l #1,d4 lea SKY_SIZE(a0),a0 dbra d7,.loop3 .end movem.l (sp)+,d0-a6 rts ;;/ ;// Calculation_T_A (calculates one voxelspace frame - column width 1) ****************************************************************************** * * Calculation_T_A * * calculates one voxelspace frame with column width = 1 * the results are written into the chunkybuffer * optimized for direct rendering into GfxRAM * approximation routine * ****************************************************************************** Calculation_T_A movem.l d0-a6,-(sp) move.l HeightData,a0 ;a0 -> place for online persp. move StartHeight,d0 sub ActualHeight,d0 ;calc difference to standard muls ViewDistance,d0 ;perspective muls AreaHeight,d0 ;dh * z * AreaHeight moveq #0,d5 move MinRange,d5 moveq #0,d1 move.b PixCount,d1 lsl.l d1,d5 ;pix count * min. range moveq #0,d3 move Pix_Count,d7 subq #1,d7 .calc move.l d3,d4 move MaxRange,d2 sub MinRange,d2 mulu d2,d4 add.l d5,d4 divu Pix_Count,d4 ;calc actual x position move d4,d6 add ViewDistance,d4 ;x + z ext.l d4 move.l d0,d1 divsl.l d4,d1 ;dh * z / (x + z) * AreaHeight divs DispHeight,d1 ;d1 / Dispheight move d1,(a0)+ ;store value addq #1,d3 dbra d7,.calc move.l MapFile+FILE_ADDRESS,a2 ;a2 -> map move.l ChunkyBuffer,a3 ;a3 -> chunky buffer move AreaHeight,d0 subq #1,d0 moveq #0,d1 move BitmapWidth,d1 move.l d1,a6 mulu d1,d0 add.l d0,a3 ;a3 -> last line in chunky buf. move.l a3,ChunkyPtr move.l TempBuffer,a3 move.l ViewCircle,a0 move.l ViewAngle,a5 move Direction,d0 moveq #0,d1 move Ray_Count,d1 move d1,d2 subq #1,d2 mulu Angle,d1 divu #360*2,d1 ;subtract half angle from dir. sub d1,d0 ;d0 = starting ray and d2,d0 ;wrap around ext.l d0 lsl.l #4,d0 ext.l d2 lsl.l #4,d2 moveq #0,d4 move ActualHeight,d4 ;get actual height moveq #0,d3 move.b SkyScroll,d3 divu d3,d4 ;calc sky scroll value sub SkyPos,d4 ;subtract offset neg d4 swap d4 move.l a6,DestOffset move.l SkyData,a1 ;a1 -> sky definition moveq #9,d7 move.l PosXDet,d5 lsl.l d7,d5 move.l PosYDet,d6 lsl.l d7,d6 move ColumnCount,d7 ;number of columns subq #1,d7 .loop movem.l d2/d3/d5/d6/a0/a3,-(sp) add.l (a5)+,d0 ;jump to next ray and.l d2,d0 ;mask out add.l d0,a0 ;a0 -> new view circle add.l (a0)+,d6 add.l (a0)+,d5 move.l (a0)+,d3 move.l (a0)+,d1 movem.l d0/a0/a5,-(sp) move.l d3,a0 move.l Perspective,a5 ;a5 -> perspective move.l HeightData,a6 ;a1 -> online perspective moveq #0,d3 move HRotActual,d3 ;hor. rotation value ext.l d3 asl.l #8,d3 moveq #0,d0 move ColumnCount,d0 lsr #1,d0 divsl.l d0,d3 ;/ half column count move d7,d4 neg d4 add d0,d4 add d4,d4 subq #1,d4 move d4,d2 ext.l d2 muls.l d2,d3 ;* actual x value moveq #17,d2 asr.l d2,d3 move d3,a4 move #0,d4 ;old height swap d7 move PixelCount,d7 ;number of pixels subq #1,d7 .loop2 move.l d6,d2 move.l d5,d0 lsr.l #16-_PICSIZE,d2 swap d0 and.l #(((1<<_PICSIZE)-1)<<_PICSIZE),d2 and.l #(1<<_PICSIZE)-1,d0 or.l d0,d2 moveq #0,d3 move.b 0(a2,d2.l*2),d3 ;read pixel height from map add.l a0,d6 add.l d1,d5 move 0(a5,d3.w*2),d0 ;calc perspective height lea 256(a5),a5 ;new tab for new distance sub a4,d0 ;subtract HRot offset add (a6)+,d0 ;add online perspective value sub d4,d0 ;calc height difference ble.b .loopend add d0,d4 ;calc new height move.b 1(a2,d2.l*2),d3 ;read pixel color from map subq #1,d0 ;now draw the vertical bar .copy move.b d3,(a3) addq.l #4,a3 dbra d0,.copy dbra d7,.loop2 bra.b .colOK .approx subq #1,d7 bmi.b .colOK lea 256(a5),a5 addq.l #2,a6 add.l a0,d6 add.l d1,d5 dbra d7,.loop2 bra.b .colOK .loopend blt.b .approx dbra d7,.loop2 .colOK sub AreaHeight,d4 neg d4 ;area height - actual height move d4,d0 ;d0 = sky height to draw move #-1,SKY_COUNT(a1) subq #1,d0 bmi.b .jump ;no sky to draw -> jump swap d4 move d4,d3 ;get sky offset sub a4,d3 ;subtract hor. rotation value add SkyHeight,d3 sub AreaHeight,d3 ;calc real sky offset muls SkyWidth2,d3 ;mulitply by sky width move.l d3,SKY_SOURCE(a1) ;write sky offset move d0,SKY_COUNT(a1) ;write sky height swap d4 .jump movem.l (sp)+,d0/a0/a5 movem.l (sp)+,d2/d3/d5/d6/a0/a3 addq.l #1,a3 ;next column lea SKY_SIZE(a1),a1 ;next sky definition swap d7 move d7,d4 andi #$3,d4 bne.w .loopend2 movem.l d0/d2/d5-d7,-(sp) move.l ChunkyPtr,a4 addq.l #4,ChunkyPtr subq.l #4,a3 move AreaHeight,d4 subq #2,d4 move -4*SKY_SIZE+SKY_COUNT(a1),d2 move -3*SKY_SIZE+SKY_COUNT(a1),d5 move -2*SKY_SIZE+SKY_COUNT(a1),d1 move -SKY_SIZE+SKY_COUNT(a1),d3 move.l DestOffset,d0 move d3,d6 cmp d6,d1 bge.b .cmp1 move d1,d6 .cmp1 cmp d6,d5 bge.b .cmp2 move d5,d6 .cmp2 cmp d6,d2 bge.b .cmp3 move d2,d6 .cmp3 sub d4,d6 neg d6 tst d6 bmi.b .nodraw .copycol move.l (a3)+,(a4) sub.l d0,a4 dbra d6,.copycol .nodraw movem.l (sp)+,d0/d2/d5-d7 move.l TempBuffer,a3 .loopend2 dbra d7,.loop sub.l a3,a3 move.l DestOffset,d5 move SkyWidth2,a3 move.l SkyBuffer,a1 ;a1 -> sky graphics move Direction,d7 ;get direction mulu SkyWidth2,d7 divu Ray_Count,d7 ;calc sky hor. position cmp SkyWidth,d7 ;check for overflow blt.b .cont sub SkyWidth,d7 .cont add d7,a1 ;a1 -> sky start pos move.l a1,d2 move.l SkyData,a0 ;a0 -> sky definition move.l ChunkyBuffer,a2 ;a2 -> chunky buffer move.l a2,d4 move ColumnCount,d7 subq #1,d7 .loop3 move.l SKY_SOURCE(a0),d0 ;get sky source offset move.l d2,a1 move.l d4,a2 add.l d0,a1 ;a1 -> sky start pos cmp #3,d7 blt.w .normal cmp.l SKY_SOURCE+SKY_SIZE(a0),d0 ;next offset equal? bne.w .normal ;no -> normal draw cmp.l SKY_SOURCE+2*SKY_SIZE(a0),d0 ;next offset equal? bne.w .normal ;no -> normal draw cmp.l SKY_SOURCE+3*SKY_SIZE(a0),d0 ;next offset equal? bne.w .normal ;no -> normal draw subq #3,d7 movem.l d0/d2/d4/d7,-(sp) move SKY_COUNT(a0),d6 move SKY_COUNT+SKY_SIZE(a0),d3 move SKY_COUNT+2*SKY_SIZE(a0),d1 move SKY_COUNT+3*SKY_SIZE(a0),d0 move d6,d2 cmp d2,d3 bge.b .scmp1 move d3,d2 .scmp1 cmp d2,d1 bge.b .scmp2 move d1,d2 .scmp2 cmp d2,d0 bge.b .scmp3 move d0,d2 .scmp3 tst d2 bmi.b .ssingle1 sub d2,d6 sub d2,d3 sub d2,d1 sub d2,d0 subq #1,d6 subq #1,d3 subq #1,d1 subq #1,d0 .drawsky4 move.l (a1),(a2) ;draw 4 columns at once add.l d5,a2 add.l a3,a1 dbra d2,.drawsky4 .ssingle1 tst d6 bmi.b .ssingle2 move.l a1,d4 move.l a2,d7 .ssloop1 move.b (a1),(a2) add.l d5,a2 add.l a3,a1 dbra d6,.ssloop1 move.l d4,a1 move.l d7,a2 .ssingle2 tst d3 bmi.b .ssingle3 move.l a1,d4 move.l a2,d7 .ssloop2 move.b 1(a1),1(a2) add.l d5,a2 add.l a3,a1 dbra d3,.ssloop2 move.l d4,a1 move.l d7,a2 .ssingle3 tst d1 bmi.b .ssingle4 move.l a1,d4 move.l a2,d7 .ssloop3 move.b 2(a1),2(a2) add.l d5,a2 add.l a3,a1 dbra d1,.ssloop3 move.l d4,a1 move.l d7,a2 .ssingle4 tst d0 bmi.b .ssingle5 move.l a1,d4 move.l a2,d7 .ssloop4 move.b 3(a1),3(a2) add.l d5,a2 add.l a3,a1 dbra d0,.ssloop4 move.l d4,a1 move.l d7,a2 .ssingle5 movem.l (sp)+,d0/d2/d4/d7 addq.l #4,d2 ;increase by 4 columns addq.l #4,d4 lea SKY_SIZE*4(a0),a0 dbra d7,.loop3 bra.b .end .normal move SKY_COUNT(a0),d6 ;get sky height bmi.b .next .drawsky move.b (a1),(a2) ;draw one sky column add.l d5,a2 add.l a3,a1 dbra d6,.drawsky .next addq.l #1,d2 ;next column addq.l #1,d4 lea SKY_SIZE(a0),a0 dbra d7,.loop3 .end movem.l (sp)+,d0-a6 rts ;;/ ;// Calculation2_T (calculates one voxelspace frame - column width 2) ****************************************************************************** * * Calculation2_T * * calculates one voxelspace frame with column width = 2 * the results are written into the chunkybuffer * optimized for direct rendering into GfxRAM * ****************************************************************************** Calculation2_T movem.l d0-a6,-(sp) move.l HeightData,a0 ;a0 -> place for online persp. move StartHeight,d0 sub ActualHeight,d0 ;calc difference to standard muls ViewDistance,d0 ;perspective muls AreaHeight,d0 ;dh * z * AreaHeight moveq #0,d5 move MinRange,d5 moveq #0,d1 move.b PixCount,d1 lsl.l d1,d5 ;pix count * min. range moveq #0,d3 move Pix_Count,d7 subq #1,d7 .calc move.l d3,d4 move MaxRange,d2 sub MinRange,d2 mulu d2,d4 add.l d5,d4 divu Pix_Count,d4 ;calc actual x position move d4,d6 add ViewDistance,d4 ;x + z ext.l d4 move.l d0,d1 divsl.l d4,d1 ;dh * z / (x + z) * AreaHeight divs DispHeight,d1 ;d1 / Dispheight move d1,(a0)+ ;store value addq #1,d3 dbra d7,.calc move.l MapFile+FILE_ADDRESS,a2 ;a2 -> map move.l ChunkyBuffer,a3 ;a3 -> chunky buffer move AreaHeight,d0 subq #1,d0 moveq #0,d1 move BitmapWidth,d1 move.l d1,a6 mulu d1,d0 add.l d0,a3 ;a3 -> last line in chunky buf. move.l a3,ChunkyPtr move.l TempBuffer,a3 move.l ViewCircle,a0 move.l ViewAngle,a5 move Direction,d0 moveq #0,d1 move Ray_Count,d1 move d1,d2 subq #1,d2 mulu Angle,d1 divu #360*2,d1 ;subtract half angle from dir. sub d1,d0 ;d0 = starting ray and d2,d0 ;wrap around ext.l d0 lsl.l #4,d0 ext.l d2 lsl.l #4,d2 moveq #0,d4 move ActualHeight,d4 ;get actual height moveq #0,d3 move.b SkyScroll,d3 divu d3,d4 ;calc sky scroll value sub SkyPos,d4 ;subtract offset neg d4 swap d4 move.l a6,DestOffset move.l SkyData,a1 ;a1 -> sky definition moveq #9,d7 move.l PosXDet,d5 lsl.l d7,d5 move.l PosYDet,d6 lsl.l d7,d6 move ColumnCount,d7 ;number of columns subq #1,d7 .loop movem.l d2/d3/d5/d6/a0/a3,-(sp) add.l (a5)+,d0 ;jump to next ray and.l d2,d0 ;mask out add.l d0,a0 ;a0 -> new view circle add.l (a0)+,d6 add.l (a0)+,d5 move.l (a0)+,d3 move.l (a0)+,d1 movem.l d0/a0/a5,-(sp) move.l d3,a0 move.l Perspective,a5 ;a5 -> perspective move.l HeightData,a6 ;a1 -> online perspective moveq #0,d3 move HRotActual,d3 ;hor. rotation value ext.l d3 asl.l #8,d3 moveq #0,d0 move ColumnCount,d0 lsr #1,d0 divsl.l d0,d3 ;/ half column count move d7,d4 neg d4 add d0,d4 add d4,d4 subq #1,d4 move d4,d2 ext.l d2 muls.l d2,d3 ;* actual x value moveq #17,d2 asr.l d2,d3 move d3,a4 move #0,d4 ;old height swap d7 move PixelCount,d7 ;number of pixels subq #1,d7 .loop2 move.l d6,d2 move.l d5,d0 lsr.l #16-_PICSIZE,d2 swap d0 and.l #(((1<<_PICSIZE)-1)<<_PICSIZE),d2 and.l #(1<<_PICSIZE)-1,d0 or.l d0,d2 moveq #0,d3 move.b 0(a2,d2.l*2),d3 ;read pixel height from map add.l a0,d6 add.l d1,d5 move 0(a5,d3.w*2),d0 ;calc perspective height lea 256(a5),a5 ;new tab for new distance sub a4,d0 ;subtract HRot offset add (a6)+,d0 ;add online perspective value sub d4,d0 ;calc height difference ble.b .loopend add d0,d4 ;calc new height move.b 1(a2,d2.l*2),d3 ;read pixel color from map subq #1,d0 ;now draw the vertical bar move.b d3,d2 lsl #8,d3 move.b d2,d3 .copy move d3,(a3) addq.l #4,a3 dbra d0,.copy .loopend dbra d7,.loop2 .colOK sub AreaHeight,d4 neg d4 ;area height - actual height move d4,d0 ;d0 = sky height to draw move #-1,SKY_COUNT(a1) subq #1,d0 bmi.b .jump ;no sky to draw -> jump swap d4 move d4,d3 ;get sky offset sub a4,d3 ;subtract hor. rotation value add SkyHeight,d3 sub AreaHeight,d3 ;calc real sky offset muls SkyWidth2,d3 ;mulitply by sky width move.l d3,SKY_SOURCE(a1) ;write sky offset move d0,SKY_COUNT(a1) ;write sky height swap d4 .jump movem.l (sp)+,d0/a0/a5 movem.l (sp)+,d2/d3/d5/d6/a0/a3 addq.l #2,a3 ;next column lea SKY_SIZE(a1),a1 ;next sky definition swap d7 btst #0,d7 bne.w .loopend2 move.l d0,-(sp) move.l ChunkyPtr,a4 addq.l #4,ChunkyPtr subq.l #4,a3 move AreaHeight,d4 subq #2,d4 move -2*SKY_SIZE+SKY_COUNT(a1),d1 move -SKY_SIZE+SKY_COUNT(a1),d3 move.l DestOffset,d0 cmp d3,d1 ble.b .noexg1 exg d1,d3 .noexg1 sub d4,d1 neg d1 tst d1 bmi.b .nodraw .copycol move.l (a3)+,(a4) sub.l d0,a4 dbra d1,.copycol .nodraw move.l TempBuffer,a3 move.l (sp)+,d0 .loopend2 dbra d7,.loop sub.l a3,a3 move.l DestOffset,d5 move SkyWidth2,a3 move.l SkyBuffer,a1 ;a1 -> sky graphics move Direction,d7 ;get direction mulu SkyWidth2,d7 divu Ray_Count,d7 ;calc sky hor. position cmp SkyWidth,d7 ;check for overflow blt.b .cont sub SkyWidth,d7 .cont add d7,a1 ;a1 -> sky start pos move.l a1,d2 move.l SkyData,a0 ;a0 -> sky definition move.l ChunkyBuffer,a2 ;a2 -> chunky buffer move.l a2,d4 move ColumnCount,d7 subq #1,d7 .loop3 move.l SKY_SOURCE(a0),d0 ;get sky source offset move.l d2,a1 move.l d4,a2 add.l d0,a1 ;a1 -> sky start pos tst d7 ;if last turn beq.b .normal ;then normal draw cmp.l SKY_SOURCE+SKY_SIZE(a0),d0 ;next offset equal? bne.b .normal ;no -> normal draw move SKY_COUNT(a0),d6 ;sky height > 0 ? bmi.b .next ;no -> no draw move SKY_COUNT+SKY_SIZE(a0),d3 ;next sky height > 0? bmi.b .next ;no -> no draw subq #1,d7 ;draw optimized moveq #2,d0 cmp d3,d6 ;compare sky heights ble.b .noexg ;of both columns exg d3,d6 ;change if necessary moveq #0,d0 .noexg move d6,d1 .drawsky2 move.l (a1),(a2) ;draw 2 columns at once add.l d5,a2 add.l a3,a1 dbra d6,.drawsky2 sub d1,d3 ;subtract heights subq #1,d3 bmi.b .next2 ;equal -> done add.l d0,a1 add.l d0,a2 .drawsky3 move (a1),(a2) ;now draw the longer one add.l d5,a2 add.l a3,a1 dbra d3,.drawsky3 .next2 addq.l #4,d2 ;increase by 2 columns addq.l #4,d4 lea SKY_SIZE*2(a0),a0 dbra d7,.loop3 bra.b .end .normal move SKY_COUNT(a0),d6 ;get sky height bmi.b .next .drawsky move (a1),(a2) ;draw one sky column add.l d5,a2 add.l a3,a1 dbra d6,.drawsky .next addq.l #2,d2 ;next column addq.l #2,d4 lea SKY_SIZE(a0),a0 dbra d7,.loop3 .end movem.l (sp)+,d0-a6 rts ;;/ ;// Calculation2_T_A (calculates one voxelspace frame - column width 2) ****************************************************************************** * * Calculation2_T_A * * calculates one voxelspace frame with column width = 2 * the results are written into the chunkybuffer * optimized for direct rendering into GfxRAM * approximation routine * ****************************************************************************** Calculation2_T_A movem.l d0-a6,-(sp) move.l HeightData,a0 ;a0 -> place for online persp. move StartHeight,d0 sub ActualHeight,d0 ;calc difference to standard muls ViewDistance,d0 ;perspective muls AreaHeight,d0 ;dh * z * AreaHeight moveq #0,d5 move MinRange,d5 moveq #0,d1 move.b PixCount,d1 lsl.l d1,d5 ;pix count * min. range moveq #0,d3 move Pix_Count,d7 subq #1,d7 .calc move.l d3,d4 move MaxRange,d2 sub MinRange,d2 mulu d2,d4 add.l d5,d4 divu Pix_Count,d4 ;calc actual x position move d4,d6 add ViewDistance,d4 ;x + z ext.l d4 move.l d0,d1 divsl.l d4,d1 ;dh * z / (x + z) * AreaHeight divs DispHeight,d1 ;d1 / Dispheight move d1,(a0)+ ;store value addq #1,d3 dbra d7,.calc move.l MapFile+FILE_ADDRESS,a2 ;a2 -> map move.l ChunkyBuffer,a3 ;a3 -> chunky buffer move AreaHeight,d0 subq #1,d0 moveq #0,d1 move BitmapWidth,d1 move.l d1,a6 mulu d1,d0 add.l d0,a3 ;a3 -> last line in chunky buf. move.l a3,ChunkyPtr move.l TempBuffer,a3 move.l ViewCircle,a0 move.l ViewAngle,a5 move Direction,d0 moveq #0,d1 move Ray_Count,d1 move d1,d2 subq #1,d2 mulu Angle,d1 divu #360*2,d1 ;subtract half angle from dir. sub d1,d0 ;d0 = starting ray and d2,d0 ;wrap around ext.l d0 lsl.l #4,d0 ext.l d2 lsl.l #4,d2 moveq #0,d4 move ActualHeight,d4 ;get actual height moveq #0,d3 move.b SkyScroll,d3 divu d3,d4 ;calc sky scroll value sub SkyPos,d4 ;subtract offset neg d4 swap d4 move.l a6,DestOffset move.l SkyData,a1 ;a1 -> sky definition moveq #9,d7 move.l PosXDet,d5 lsl.l d7,d5 move.l PosYDet,d6 lsl.l d7,d6 move ColumnCount,d7 ;number of columns subq #1,d7 .loop movem.l d2/d3/d5/d6/a0/a3,-(sp) add.l (a5)+,d0 ;jump to next ray and.l d2,d0 ;mask out add.l d0,a0 ;a0 -> new view circle add.l (a0)+,d6 add.l (a0)+,d5 move.l (a0)+,d3 move.l (a0)+,d1 movem.l d0/a0/a5,-(sp) move.l d3,a0 move.l Perspective,a5 ;a5 -> perspective move.l HeightData,a6 ;a1 -> online perspective moveq #0,d3 move HRotActual,d3 ;hor. rotation value ext.l d3 asl.l #8,d3 moveq #0,d0 move ColumnCount,d0 lsr #1,d0 divsl.l d0,d3 ;/ half column count move d7,d4 neg d4 add d0,d4 add d4,d4 subq #1,d4 move d4,d2 ext.l d2 muls.l d2,d3 ;* actual x value moveq #17,d2 asr.l d2,d3 move d3,a4 move #0,d4 ;old height swap d7 move PixelCount,d7 ;number of pixels subq #1,d7 .loop2 move.l d6,d2 move.l d5,d0 lsr.l #16-_PICSIZE,d2 swap d0 and.l #(((1<<_PICSIZE)-1)<<_PICSIZE),d2 and.l #(1<<_PICSIZE)-1,d0 or.l d0,d2 moveq #0,d3 move.b 0(a2,d2.l*2),d3 ;read pixel height from map add.l a0,d6 add.l d1,d5 move 0(a5,d3.w*2),d0 ;calc perspective height lea 256(a5),a5 ;new tab for new distance sub a4,d0 ;subtract HRot offset add (a6)+,d0 ;add online perspective value sub d4,d0 ;calc height difference ble.b .loopend add d0,d4 ;calc new height move.b 1(a2,d2.l*2),d3 ;read pixel color from map subq #1,d0 ;now draw the vertical bar move.b d3,d2 lsl #8,d3 move.b d2,d3 .copy move d3,(a3) addq.l #4,a3 dbra d0,.copy dbra d7,.loop2 bra.b .colOK .approx subq #1,d7 bmi.b .colOK lea 256(a5),a5 addq.l #2,a6 add.l a0,d6 add.l d1,d5 dbra d7,.loop2 bra.b .colOK .loopend blt.b .approx dbra d7,.loop2 .colOK sub AreaHeight,d4 neg d4 ;area height - actual height move d4,d0 ;d0 = sky height to draw move #-1,SKY_COUNT(a1) subq #1,d0 bmi.b .jump ;no sky to draw -> jump swap d4 move d4,d3 ;get sky offset sub a4,d3 ;subtract hor. rotation value add SkyHeight,d3 sub AreaHeight,d3 ;calc real sky offset muls SkyWidth2,d3 ;mulitply by sky width move.l d3,SKY_SOURCE(a1) ;write sky offset move d0,SKY_COUNT(a1) ;write sky height swap d4 .jump movem.l (sp)+,d0/a0/a5 movem.l (sp)+,d2/d3/d5/d6/a0/a3 addq.l #2,a3 ;next column lea SKY_SIZE(a1),a1 ;next sky definition swap d7 btst #0,d7 bne.w .loopend2 move.l d0,-(sp) move.l ChunkyPtr,a4 addq.l #4,ChunkyPtr subq.l #4,a3 move AreaHeight,d4 subq #2,d4 move -2*SKY_SIZE+SKY_COUNT(a1),d1 move -SKY_SIZE+SKY_COUNT(a1),d3 move.l DestOffset,d0 cmp d3,d1 ble.b .noexg1 exg d1,d3 .noexg1 sub d4,d1 neg d1 tst d1 bmi.b .nodraw .copycol move.l (a3)+,(a4) sub.l d0,a4 dbra d1,.copycol .nodraw move.l TempBuffer,a3 move.l (sp)+,d0 .loopend2 dbra d7,.loop sub.l a3,a3 move.l DestOffset,d5 move SkyWidth2,a3 move.l SkyBuffer,a1 ;a1 -> sky graphics move Direction,d7 ;get direction mulu SkyWidth2,d7 divu Ray_Count,d7 ;calc sky hor. position cmp SkyWidth,d7 ;check for overflow blt.b .cont sub SkyWidth,d7 .cont add d7,a1 ;a1 -> sky start pos move.l a1,d2 move.l SkyData,a0 ;a0 -> sky definition move.l ChunkyBuffer,a2 ;a2 -> chunky buffer move.l a2,d4 move ColumnCount,d7 subq #1,d7 .loop3 move.l SKY_SOURCE(a0),d0 ;get sky source offset move.l d2,a1 move.l d4,a2 add.l d0,a1 ;a1 -> sky start pos tst d7 ;if last turn beq.b .normal ;then normal draw cmp.l SKY_SOURCE+SKY_SIZE(a0),d0 ;next offset equal? bne.b .normal ;no -> normal draw move SKY_COUNT(a0),d6 ;sky height > 0 ? bmi.b .next ;no -> no draw move SKY_COUNT+SKY_SIZE(a0),d3 ;next sky height > 0? bmi.b .next ;no -> no draw subq #1,d7 ;draw optimized moveq #2,d0 cmp d3,d6 ;compare sky heights ble.b .noexg ;of both columns exg d3,d6 ;change if necessary moveq #0,d0 .noexg move d6,d1 .drawsky2 move.l (a1),(a2) ;draw 2 columns at once add.l d5,a2 add.l a3,a1 dbra d6,.drawsky2 sub d1,d3 ;subtract heights subq #1,d3 bmi.b .next2 ;equal -> done add.l d0,a1 add.l d0,a2 .drawsky3 move (a1),(a2) ;now draw the longer one add.l d5,a2 add.l a3,a1 dbra d3,.drawsky3 .next2 addq.l #4,d2 ;increase by 2 columns addq.l #4,d4 lea SKY_SIZE*2(a0),a0 dbra d7,.loop3 bra.b .end .normal move SKY_COUNT(a0),d6 ;get sky height bmi.b .next .drawsky move (a1),(a2) ;draw one sky column add.l d5,a2 add.l a3,a1 dbra d6,.drawsky .next addq.l #2,d2 ;next column addq.l #2,d4 lea SKY_SIZE(a0),a0 dbra d7,.loop3 .end movem.l (sp)+,d0-a6 rts ;;/ ;// Calculation4 (calculates one voxelspace frame - column width 4) ****************************************************************************** * * Calculation4 * * calculates one voxelspace frame with column width = 4 * the results are written into the chunkybuffer * ****************************************************************************** Calculation4 movem.l d0-a6,-(sp) move.l HeightData,a0 ;a0 -> place for online persp. move StartHeight,d0 sub ActualHeight,d0 ;calc difference to standard muls ViewDistance,d0 ;perspective muls AreaHeight,d0 ;dh * z * AreaHeight moveq #0,d5 move MinRange,d5 moveq #0,d1 move.b PixCount,d1 lsl.l d1,d5 ;pix count * min. range moveq #0,d3 move Pix_Count,d7 subq #1,d7 .calc move.l d3,d4 move MaxRange,d2 sub MinRange,d2 mulu d2,d4 add.l d5,d4 divu Pix_Count,d4 ;calc actual x position move d4,d6 add ViewDistance,d4 ;x + z ext.l d4 move.l d0,d1 divsl.l d4,d1 ;dh * z / (x + z) * AreaHeight divs DispHeight,d1 ;d1 / Dispheight move d1,(a0)+ ;store value addq #1,d3 dbra d7,.calc move.l MapFile+FILE_ADDRESS,a2 ;a2 -> map move.l ChunkyBuffer,a3 ;a3 -> chunky buffer move AreaHeight,d0 subq #1,d0 moveq #0,d1 move BitmapWidth,d1 move.l d1,a6 mulu d1,d0 add.l d0,a3 ;a3 -> last line in chunky buf. move.l ViewCircle,a0 move.l ViewAngle,a5 move Direction,d0 moveq #0,d1 move Ray_Count,d1 move d1,d2 subq #1,d2 mulu Angle,d1 divu #360*2,d1 ;subtract half angle from dir. sub d1,d0 ;d0 = starting ray and d2,d0 ;wrap around ext.l d0 lsl.l #4,d0 ext.l d2 lsl.l #4,d2 moveq #0,d4 move ActualHeight,d4 ;get actual height moveq #0,d3 move.b SkyScroll,d3 divu d3,d4 ;calc sky scroll value sub SkyPos,d4 ;subtract offset neg d4 swap d4 move.l a6,DestOffset move.l SkyData,a1 ;a1 -> sky definition moveq #9,d7 move.l PosXDet,d5 lsl.l d7,d5 move.l PosYDet,d6 lsl.l d7,d6 move ColumnCount,d7 ;number of columns subq #1,d7 .loop movem.l d2/d3/d5/d6/a0/a3,-(sp) add.l (a5)+,d0 ;jump to next ray and.l d2,d0 ;mask out add.l d0,a0 ;a0 -> new view circle add.l (a0)+,d6 add.l (a0)+,d5 move.l (a0)+,d3 move.l (a0)+,d1 movem.l d0/a0/a5,-(sp) move.l d3,a0 move.l Perspective,a5 ;a5 -> perspective move.l HeightData,a6 ;a1 -> online perspective moveq #0,d3 move HRotActual,d3 ;hor. rotation value ext.l d3 asl.l #8,d3 moveq #0,d0 move ColumnCount,d0 lsr #1,d0 divsl.l d0,d3 ;/ half column count move d7,d4 neg d4 add d0,d4 add d4,d4 subq #1,d4 move d4,d2 ext.l d2 muls.l d2,d3 ;* actual x value moveq #17,d2 asr.l d2,d3 move d3,a4 move #0,d4 ;old height swap d7 move PixelCount,d7 ;number of pixels subq #1,d7 .loop2 move.l d6,d2 move.l d5,d0 lsr.l #16-_PICSIZE,d2 swap d0 and.l #(((1<<_PICSIZE)-1)<<_PICSIZE),d2 and.l #(1<<_PICSIZE)-1,d0 or.l d0,d2 moveq #0,d3 move.b 0(a2,d2.l*2),d3 ;read pixel height from map add.l a0,d6 add.l d1,d5 move 0(a5,d3.w*2),d0 ;calc perspective height lea 256(a5),a5 ;new tab for new distance sub a4,d0 ;subtract HRot offset add (a6)+,d0 ;add online perspective value sub d4,d0 ;calc height difference ble.b .loopend add d0,d4 ;calc new height move.b 1(a2,d2.l*2),d3 ;read pixel color from map cmp AreaHeight,d4 bge.b .cut subq #1,d0 ;now draw the vertical bar move.b d3,d2 lsl #8,d3 move.b d2,d3 lsl.l #8,d3 move.b d2,d3 lsl.l #8,d3 move.b d2,d3 move.l DestOffset,d2 .copy move.l d3,(a3) sub.l d2,a3 ;subtract one line dbra d0,.copy .loopend dbra d7,.loop2 bra.b .colOK .cut sub AreaHeight,d4 sub d4,d0 ;correct bar height to draw beq.b .zero subq #1,d0 move.b d3,d2 lsl #8,d3 move.b d2,d3 lsl.l #8,d3 move.b d2,d3 lsl.l #8,d3 move.b d2,d3 move.l DestOffset,d2 .copy2 move.l d3,(a3) sub.l d2,a3 dbra d0,.copy2 .zero move #-1,SKY_COUNT(a1) ;no sky bra.b .jump ;column done .colOK sub AreaHeight,d4 neg d4 ;area height - actual height move d4,d0 ;d0 = sky height to draw move #-1,SKY_COUNT(a1) subq #1,d0 bmi.b .jump ;no sky to draw -> jump swap d4 move d4,d3 ;get sky offset sub a4,d3 ;subtract hor. rotation value add SkyHeight,d3 sub AreaHeight,d3 ;calc real sky offset muls SkyWidth2,d3 ;mulitply by sky width move.l d3,SKY_SOURCE(a1) ;write sky offset move d0,SKY_COUNT(a1) ;write sky height swap d4 .jump movem.l (sp)+,d0/a0/a5 movem.l (sp)+,d2/d3/d5/d6/a0/a3 addq.l #4,a3 ;next column lea SKY_SIZE(a1),a1 ;next sky definition swap d7 dbra d7,.loop sub.l a3,a3 move.l DestOffset,d5 move SkyWidth2,a3 move.l SkyBuffer,a1 ;a1 -> sky graphics move Direction,d7 ;get direction mulu SkyWidth2,d7 divu Ray_Count,d7 ;calc sky hor. position cmp SkyWidth,d7 ;check for overflow blt.b .cont sub SkyWidth,d7 .cont add d7,a1 ;a1 -> sky start pos move.l a1,d2 move.l SkyData,a0 ;a0 -> sky definition move.l ChunkyBuffer,a2 ;a2 -> chunky buffer move.l a2,d4 move ColumnCount,d7 subq #1,d7 .loop3 move.l SKY_SOURCE(a0),d0 ;get sky source offset move.l d2,a1 move.l d4,a2 add.l d0,a1 ;a1 -> sky start pos tst d7 ;if last turn beq.b .normal ;then normal draw cmp.l SKY_SOURCE+SKY_SIZE(a0),d0 ;next offset equal? bne.b .normal ;no -> normal draw move SKY_COUNT(a0),d6 ;sky height > 0 ? bmi.b .next ;no -> no draw move SKY_COUNT+SKY_SIZE(a0),d3 ;next sky height > 0? bmi.b .next ;no -> no draw subq #1,d7 ;draw optimized moveq #4,d0 cmp d3,d6 ;compare sky heights ble.b .noexg ;of both columns exg d3,d6 ;change if necessary moveq #0,d0 .noexg move d6,d1 .drawsky2 move.l (a1),(a2) ;draw 2 columns at once move.l 4(a1),4(a2) ;draw 2 columns at once add.l d5,a2 add.l a3,a1 dbra d6,.drawsky2 sub d1,d3 ;subtract heights subq #1,d3 bmi.b .next2 ;equal -> done add.l d0,a1 add.l d0,a2 .drawsky3 move.l (a1),(a2) ;now draw the longer one add.l d5,a2 add.l a3,a1 dbra d3,.drawsky3 .next2 addq.l #8,d2 ;increase by 2 columns addq.l #8,d4 lea SKY_SIZE*2(a0),a0 dbra d7,.loop3 bra.b .end .normal move SKY_COUNT(a0),d6 ;get sky height bmi.b .next .drawsky move.l (a1),(a2) ;draw one sky column add.l d5,a2 add.l a3,a1 dbra d6,.drawsky .next addq.l #4,d2 ;next column addq.l #4,d4 lea SKY_SIZE(a0),a0 dbra d7,.loop3 .end movem.l (sp)+,d0-a6 rts ;;/ ;// Calculation4_A (calculates one voxelspace frame - column width 4) ****************************************************************************** * * Calculation4_A * * calculates one voxelspace frame with column width = 4 * the results are written into the chunkybuffer * approximation routine * ****************************************************************************** Calculation4_A movem.l d0-a6,-(sp) move.l HeightData,a0 ;a0 -> place for online persp. move StartHeight,d0 sub ActualHeight,d0 ;calc difference to standard muls ViewDistance,d0 ;perspective muls AreaHeight,d0 ;dh * z * AreaHeight moveq #0,d5 move MinRange,d5 moveq #0,d1 move.b PixCount,d1 lsl.l d1,d5 ;pix count * min. range moveq #0,d3 move Pix_Count,d7 subq #1,d7 .calc move.l d3,d4 move MaxRange,d2 sub MinRange,d2 mulu d2,d4 add.l d5,d4 divu Pix_Count,d4 ;calc actual x position move d4,d6 add ViewDistance,d4 ;x + z ext.l d4 move.l d0,d1 divsl.l d4,d1 ;dh * z / (x + z) * AreaHeight divs DispHeight,d1 ;d1 / Dispheight move d1,(a0)+ ;store value addq #1,d3 dbra d7,.calc move.l MapFile+FILE_ADDRESS,a2 ;a2 -> map move.l ChunkyBuffer,a3 ;a3 -> chunky buffer move AreaHeight,d0 subq #1,d0 moveq #0,d1 move BitmapWidth,d1 move.l d1,a6 mulu d1,d0 add.l d0,a3 ;a3 -> last line in chunky buf. move.l ViewCircle,a0 move.l ViewAngle,a5 move Direction,d0 moveq #0,d1 move Ray_Count,d1 move d1,d2 subq #1,d2 mulu Angle,d1 divu #360*2,d1 ;subtract half angle from dir. sub d1,d0 ;d0 = starting ray and d2,d0 ;wrap around ext.l d0 lsl.l #4,d0 ext.l d2 lsl.l #4,d2 moveq #0,d4 move ActualHeight,d4 ;get actual height moveq #0,d3 move.b SkyScroll,d3 divu d3,d4 ;calc sky scroll value sub SkyPos,d4 ;subtract offset neg d4 swap d4 move.l a6,DestOffset move.l SkyData,a1 ;a1 -> sky definition moveq #9,d7 move.l PosXDet,d5 lsl.l d7,d5 move.l PosYDet,d6 lsl.l d7,d6 move ColumnCount,d7 ;number of columns subq #1,d7 .loop movem.l d2/d3/d5/d6/a0/a3,-(sp) add.l (a5)+,d0 ;jump to next ray and.l d2,d0 ;mask out add.l d0,a0 ;a0 -> new view circle add.l (a0)+,d6 add.l (a0)+,d5 move.l (a0)+,d3 move.l (a0)+,d1 movem.l d0/a0/a5,-(sp) move.l d3,a0 move.l Perspective,a5 ;a5 -> perspective move.l HeightData,a6 ;a1 -> online perspective moveq #0,d3 move HRotActual,d3 ;hor. rotation value ext.l d3 asl.l #8,d3 moveq #0,d0 move ColumnCount,d0 lsr #1,d0 divsl.l d0,d3 ;/ half column count move d7,d4 neg d4 add d0,d4 add d4,d4 subq #1,d4 move d4,d2 ext.l d2 muls.l d2,d3 ;* actual x value moveq #17,d2 asr.l d2,d3 move d3,a4 move #0,d4 ;old height swap d7 move PixelCount,d7 ;number of pixels subq #1,d7 .loop2 move.l d6,d2 move.l d5,d0 lsr.l #16-_PICSIZE,d2 swap d0 and.l #(((1<<_PICSIZE)-1)<<_PICSIZE),d2 and.l #(1<<_PICSIZE)-1,d0 or.l d0,d2 moveq #0,d3 move.b 0(a2,d2.l*2),d3 ;read pixel height from map add.l a0,d6 add.l d1,d5 move 0(a5,d3.w*2),d0 ;calc perspective height lea 256(a5),a5 ;new tab for new distance sub a4,d0 ;subtract HRot offset add (a6)+,d0 ;add online perspective value sub d4,d0 ;calc height difference ble.b .loopend add d0,d4 ;calc new height move.b 1(a2,d2.l*2),d3 ;read pixel color from map cmp AreaHeight,d4 bge.b .cut subq #1,d0 ;now draw the vertical bar move.b d3,d2 lsl #8,d3 move.b d2,d3 lsl.l #8,d3 move.b d2,d3 lsl.l #8,d3 move.b d2,d3 move.l DestOffset,d2 .copy move.l d3,(a3) sub.l d2,a3 ;subtract one line dbra d0,.copy dbra d7,.loop2 bra.b .colOK .approx subq #1,d7 bmi.b .colOK lea 256(a5),a5 addq.l #2,a6 add.l a0,d6 add.l d1,d5 dbra d7,.loop2 bra.b .colOK .loopend blt.b .approx dbra d7,.loop2 bra.b .colOK .cut sub AreaHeight,d4 sub d4,d0 ;correct bar height to draw beq.b .zero subq #1,d0 move.b d3,d2 lsl #8,d3 move.b d2,d3 lsl.l #8,d3 move.b d2,d3 lsl.l #8,d3 move.b d2,d3 move.l DestOffset,d2 .copy2 move.l d3,(a3) sub.l d2,a3 dbra d0,.copy2 .zero move #-1,SKY_COUNT(a1) ;no sky bra.b .jump ;column done .colOK sub AreaHeight,d4 neg d4 ;area height - actual height move d4,d0 ;d0 = sky height to draw move #-1,SKY_COUNT(a1) subq #1,d0 bmi.b .jump ;no sky to draw -> jump swap d4 move d4,d3 ;get sky offset sub a4,d3 ;subtract hor. rotation value add SkyHeight,d3 sub AreaHeight,d3 ;calc real sky offset muls SkyWidth2,d3 ;mulitply by sky width move.l d3,SKY_SOURCE(a1) ;write sky offset move d0,SKY_COUNT(a1) ;write sky height swap d4 .jump movem.l (sp)+,d0/a0/a5 movem.l (sp)+,d2/d3/d5/d6/a0/a3 addq.l #4,a3 ;next column lea SKY_SIZE(a1),a1 ;next sky definition swap d7 dbra d7,.loop sub.l a3,a3 move.l DestOffset,d5 move SkyWidth2,a3 move.l SkyBuffer,a1 ;a1 -> sky graphics move Direction,d7 ;get direction mulu SkyWidth2,d7 divu Ray_Count,d7 ;calc sky hor. position cmp SkyWidth,d7 ;check for overflow blt.b .cont sub SkyWidth,d7 .cont add d7,a1 ;a1 -> sky start pos move.l a1,d2 move.l SkyData,a0 ;a0 -> sky definition move.l ChunkyBuffer,a2 ;a2 -> chunky buffer move.l a2,d4 move ColumnCount,d7 subq #1,d7 .loop3 move.l SKY_SOURCE(a0),d0 ;get sky source offset move.l d2,a1 move.l d4,a2 add.l d0,a1 ;a1 -> sky start pos tst d7 ;if last turn beq.b .normal ;then normal draw cmp.l SKY_SOURCE+SKY_SIZE(a0),d0 ;next offset equal? bne.b .normal ;no -> normal draw move SKY_COUNT(a0),d6 ;sky height > 0 ? bmi.b .next ;no -> no draw move SKY_COUNT+SKY_SIZE(a0),d3 ;next sky height > 0? bmi.b .next ;no -> no draw subq #1,d7 ;draw optimized moveq #4,d0 cmp d3,d6 ;compare sky heights ble.b .noexg ;of both columns exg d3,d6 ;change if necessary moveq #0,d0 .noexg move d6,d1 .drawsky2 move.l (a1),(a2) ;draw 2 columns at once move.l 4(a1),4(a2) ;draw 2 columns at once add.l d5,a2 add.l a3,a1 dbra d6,.drawsky2 sub d1,d3 ;subtract heights subq #1,d3 bmi.b .next2 ;equal -> done add.l d0,a1 add.l d0,a2 .drawsky3 move.l (a1),(a2) ;now draw the longer one add.l d5,a2 add.l a3,a1 dbra d3,.drawsky3 .next2 addq.l #8,d2 ;increase by 2 columns addq.l #8,d4 lea SKY_SIZE*2(a0),a0 dbra d7,.loop3 bra.b .end .normal move SKY_COUNT(a0),d6 ;get sky height bmi.b .next .drawsky move.l (a1),(a2) ;draw one sky column add.l d5,a2 add.l a3,a1 dbra d6,.drawsky .next addq.l #4,d2 ;next column addq.l #4,d4 lea SKY_SIZE(a0),a0 dbra d7,.loop3 .end movem.l (sp)+,d0-a6 rts ;;/ ;// ChunkyToPlanar (converts chunky data to bitplane data) merge macro move.l \2,\4 move.l #\5,\3 and.l \3,\2 and.l \1,\3 eor.l \3,\1 eor.l \2,\4 ifeq \6-1 add.l \3,\3 else lsl.l #\6,\3 endc lsr.l #\6,\4 or.l \3,\2 or.l \4,\1 endm ****************************************************************************** * * ChunkyToPlanar * * converts chunky data into bitplane data (using Bitmap Structure) * works ONLY with a depth of 8! * the 8 bitplanes MUST have been allocated in ONE piece!! * * original algorithm by James McCoull (I found the source somewhere * on the AMINET CD's) * ****************************************************************************** ChunkyToPlanar movem.l d0-a6,-(sp) sub.w #40,sp ; space for temporary variables move.l #256*40,d2 move.l ChunkyBuffer,a0 move.l HiddenBitmap,a1 move.l bm_Planes(a1),a1 ; a0 = chunky buffer ; a1 = output area ; d2 = plsiz ext.l d2 movea.l d2,a3 ; a3 = plsiz move.l a0,a4 move AreaHeight,d2 mulu #320,d2 add.l d2,a4 ; a4 -> end of chunky data first_case move.l (0,a0),d1 move.l (4,a0),d3 move.l (8,a0),d0 move.l (12,a0),d2 move.l (2,a0),d4 move.l (10,a0),d5 move.l (6,a0),d6 move.l (14,a0),d7 move.w (16,a0),d1 move.w (24,a0),d0 move.w (20,a0),d3 move.w (28,a0),d2 move.w (18,a0),d4 move.w (26,a0),d5 move.w (22,a0),d6 move.w (30,a0),d7 adda.w #32,a0 move.l d6,a5 move.l d7,a6 merge d1,d0,d6,d7,$00ff00ff,8 merge d3,d2,d6,d7,$00ff00ff,8 merge d1,d3,d6,d7,$0f0f0f0f,4 merge d0,d2,d6,d7,$0f0f0f0f,4 exg d1,a5 exg d0,a6 merge d4,d5,d6,d7,$00ff00ff,8 merge d1,d0,d6,d7,$00ff00ff,8 merge d4,d1,d6,d7,$0f0f0f0f,4 merge d5,d0,d6,d7,$0f0f0f0f,4 merge d3,d1,d6,d7,$33333333,2 merge d2,d0,d6,d7,$33333333,2 merge d3,d2,d6,d7,$55555555,1 merge d1,d0,d6,d7,$55555555,1 move.l d0,(0*4,sp) ;plane0 move.l d1,(1*4,sp) ;plane1 move.l d2,(2*4,sp) ;plane2 move.l d3,(3*4,sp) ;plane3 move.l a5,d3 move.l a6,d2 merge d3,d4,d6,d7,$33333333,2 merge d2,d5,d6,d7,$33333333,2 merge d3,d2,d6,d7,$55555555,1 merge d4,d5,d6,d7,$55555555,1 move.l d5,(4*4,sp) ;plane4 move.l d4,(5*4,sp) ;plane5 move.l d2,(6*4,sp) ;plane6 move.l d3,(7*4,sp) ;plane7 move.l a1,(32,sp) ; save output address addq.l #4,a1 ; skip 32 pixels on output cmpa.l a0,a4 beq.w final_case main_case move.l a1,(36,sp) ; save current output address move.l (32,sp),a1 ; a1 = previous output address move.l (0,a0),d1 move.l (4,a0),d3 move.l (8,a0),d0 move.l (12,a0),d2 move.l (2,a0),d4 move.l (10,a0),d5 move.l (6,a0),d6 move.l (14,a0),d7 move.w (16,a0),d1 move.w (24,a0),d0 move.w (20,a0),d3 move.w (28,a0),d2 move.w (18,a0),d4 move.w (26,a0),d5 move.w (22,a0),d6 move.w (30,a0),d7 adda.w #32,a0 move.l d6,a5 move.l d7,a6 move.l (0*4,sp),(a1) ;plane0 adda.l a3,a1 ;a1+=plsiz merge d1,d0,d6,d7,$00ff00ff,8 merge d3,d2,d6,d7,$00ff00ff,8 move.l (1*4,sp),(a1) ;plane1 adda.l a3,a1 ;a1+=plsiz merge d1,d3,d6,d7,$0f0f0f0f,4 merge d0,d2,d6,d7,$0f0f0f0f,4 exg d1,a5 exg d0,a6 move.l (2*4,sp),(a1) ;plane2 adda.l a3,a1 ;a1+=plsiz merge d4,d5,d6,d7,$00ff00ff,8 merge d1,d0,d6,d7,$00ff00ff,8 move.l (3*4,sp),(a1) ;plane3 adda.l a3,a1 ;a1+=plsiz merge d4,d1,d6,d7,$0f0f0f0f,4 merge d5,d0,d6,d7,$0f0f0f0f,4 move.l (4*4,sp),(a1) ;plane4 adda.l a3,a1 ;a1+=plsiz merge d3,d1,d6,d7,$33333333,2 merge d2,d0,d6,d7,$33333333,2 move.l (5*4,sp),(a1) ;plane5 adda.l a3,a1 ;a1+=plsiz merge d3,d2,d6,d7,$55555555,1 merge d1,d0,d6,d7,$55555555,1 move.l d0,(0*4,sp) ;plane0 (movem.l is slower!) move.l d1,(1*4,sp) ;plane1 move.l d2,(2*4,sp) ;plane2 move.l d3,(3*4,sp) ;plane3 move.l a5,d3 move.l a6,d2 move.l (6*4,sp),(a1) ;plane6 adda.l a3,a1 ;a1+=plsiz merge d3,d4,d6,d7,$33333333,2 merge d2,d5,d6,d7,$33333333,2 move.l (7*4,sp),(a1) ;plane7 adda.l a3,a1 ;a1+=plsiz merge d3,d2,d6,d7,$55555555,1 merge d4,d5,d6,d7,$55555555,1 move.l d5,(4*4,sp) ;plane4 move.l d4,(5*4,sp) ;plane5 move.l d2,(6*4,sp) ;plane6 move.l d3,(7*4,sp) ;plane7 movea.l (36,sp),a1 ; restore current output address move.l a1,(32,sp) ; save output address addq.l #4,a1 cmpa.l a0,a4 bne.w main_case final_case move.l (32,sp),a1 ; a1 = previous output address move.l (0*4,sp),(a1) ;plane0 adda.l a3,a1 ;a1+=plsiz move.l (1*4,sp),(a1) ;plane1 adda.l a3,a1 ;a1+=plsiz move.l (2*4,sp),(a1) ;plane2 adda.l a3,a1 ;a1+=plsiz move.l (3*4,sp),(a1) ;plane3 adda.l a3,a1 ;a1+=plsiz move.l (4*4,sp),(a1) ;plane4 adda.l a3,a1 ;a1+=plsiz move.l (5*4,sp),(a1) ;plane5 adda.l a3,a1 ;a1+=plsiz move.l (6*4,sp),(a1) ;plane6 adda.l a3,a1 ;a1+=plsiz move.l (7*4,sp),(a1) ;plane7 exit add.w #40,sp movem.l (sp)+,d0-a6 rts ;;/