;************************************** ;*** 3D_Core - World Transformation *** ;*** Version 1.04 05/11/96 *** ;*** Copyright (c) J.Gregory 1996 *** ;************************************** ;Parameters a0 - Pointer to RotatetWork ; a1 - Pointer to ActObj array ; a2 - Pointer to DepthList ; a3 - Pointer to SIN/COS tables ; a4 - Pointer to ViewPoint WObject ;*************************************************************** ; Note a possible optimisation may be do drop the storing of ; Vx & Vy back to the ActObj record as probably will not be used ; as generally Rx,Ry will be more usefull !!!!!!!! ;*************************************************************** _ASM_Rotate_World: movem.l d0-d7/a0-a6,-(sp) ; Stack all registers (60 bytes) move.l 64(sp),a0 ; Get RotateWork ptr (+4 for ret addr) move.l 68(sp),a1 ; Get ActObj pointer move.l 72(sp),a2 ; Get Pointer to DepthList move.l 76(sp),a3 ; Get Pointer to SIN/COS tables move.l 80(sp),a4 ; Get Pointer to ViewPoint struct clr.l d1 ; Clear angle move.w RW_Angle(a0),d1 ; Get Angle from RotWork move.l SinTab(a3,d1.l*4),d6 ; Get Sin of Angle move.l CosTab(a3,d1.l*4),d7 ; Get Cos of Angle move.l WO_Wx(a4),a3 ; Get ViewPoints World X co-ord move.l WO_Wy(a4),a6 ; Get Viewpoints World Y co-ord move.l RW_Tan(a0),a4 ; Get Pointer to Tangents Table clr.l d0 ; Clear ActObj array size move.w RW_Count(a0),d0 ; Get ActObj array size subq.l #1,d0 ; Dec ActObj count for use with dbra RW_Loop1: tst.l (a1) ; Is this ActObj active ? beq RW_Next ; if not skip to next RW_Rot: move.l (a1),a5 ; Get Pointer to parent WObject move.l WO_Wx(a5),d1 ; Get Objects World X co-ord move.l WO_Wy(a5),d2 ; Get Objects World Y co-ord sub.l a3,d1 ; Sub VP X from Obj X sub.l a6,d2 ; Sub VP Y from Obj Y move.l d1,AO_Vx(a1) ; Write back view relative X move.l d2,AO_Vy(a1) ; Write back view relative Y move.l d1,d3 ; Get copy of X move.l d2,d4 ; Get copy of Y muls.l d7,d3 ; d3 = X * Cos(angle) muls.l d6,d4 ; d4 = Y * Sin(angle) sub.l d4,d3 ; d3 (New X) = d3 - d4 move.l d1,d4 ; Get Copy of X move.l d2,d5 ; Get Copy of Y muls.l d6,d4 ; d4 = X * Sin(angle) muls.l d7,d5 ; d5 = Y * Cos(angle) add.l d5,d4 ; d4 (New Y) = d4 + d5 asr.l #TRIGSHFT1,d3 ; Remove SIN/COS tab precision shift asr.l #TRIGSHFT2,d3 asr.l #TRIGSHFT1,d4 ; Remove SIN/COS tab precision shift asr.l #TRIGSHFT2,d4 move.l d3,AO_Rx(a1) ; Store New X back to WObject move.l d4,AO_Ry(a1) ; Store New Y back to WObject ble RW_ClrDist ; If Y is <= 0 don't add to DepthList tst.l d3 ; **** Discard peripheral objects **** bpl RW_Cont1 ; If X Dist = Negative then flip sign neg.l d3 RW_Cont1: asr.l #2,d3 ; Divide X Distance by 4 cmp.l d3,d4 ; Compare DY with DX/4 if less then skip ble RW_ClrDist asl.l #2,d3 bsr RW_FindAngle ; Calc viewpoint to object angle move.l d5,(a2)+ ; Write Distance into DepthList move.l a1,(a2)+ ; Write ActObj pointer into DepthList bra RW_Next RW_ClrDist: move.l #0,AO_Dist(a1) ; Clear ActObj distance if not vissible RW_Next: adda.w #AO_SizeOf,a1 ; Move pointer to next actobj dbra d0,RW_Loop1 ; Dec ActObj Count, loop if more move.l #0,(a2) ; Write terminating DepthEntry move.l #0,(a2) ; Write terminating DepthEntry move.l 72(sp),a6 ; Get Pointer to DepthList sub.l a6,a2 ; Sub list start from list end move.l a2,d0 ; Move to a data register asr.l #3,d0 ; 8 bytes per entry so divide by 8 move.w d0,RW_Count(a0) ; Write to rotate work (d0 = AQSSort param) move.l a6,a0 ; Get DepthList start (a0 = AQSSort param) jsr AQSSort2 ; Call Reg.Param. Entry to QuickSort RW_Ret: movem.l (sp)+,d0-d7/a0-a6 ; Restore registers rts ;*************************************************** ;*** Find Angle x2,y2 falls in relative to x1,y1 *** ;*** Low res version (nearest 10 degrees) *** ;*************************************************** ;Params - d3,d4 - x1,y1 ; - x2,y2 - Allways 0,0 (VP) ; - a4 - Pointer to Tangent Table ;Trashes - d1,d2,d3,d4,d5,a5 ;Return - Sets AO_Octant of ActObj to Angle x2,y2 falls ; in relative to x1,y1 to nearest 10 degrees ; d5 - Set to angle to place in depth list ;NOTE - Only used within rotate world !!!!! RW_FindAngle: move.l d6,a5 ; Save d6 move.l d3,d1 ; Get copy of X1 bpl RWFA_SkipNeg1 ; DX = Abs(DX) neg.l d1 RWFA_SkipNeg1: move.l d1,d5 ; Get copy of DX asl.l #TRIGSHFT1,d5 ; TDX = TDX * 2048 asl.l #TRIGSHFT2,d5 move.l d4,d2 ; Get copy of Y1 divu.l d2,d5 ; RATIO = TDX / DY move.l #6,d2 ; Set Counter for 7 Iterations move.l #128,d1 ; Current angle (AVPT) move.l #128,d6 ; Set Initial Power RWFA_Loop1: asr.l #1,d6 ; Lower current Power by 1 power of 2 cmp.l (a4,d1.l*4),d5 ; Compare ratio with tangent beq RWFA_OctAdj ; If found exact match end loop bgt RWFA_SkipHigher ; If Ration>Tangent Skip Higher RWFA_SkipLower: sub.l d6,d1 ; Skip downwards dbra d2,RWFA_Loop1 ; Loop if more iterations required bra RWFA_OctAdj RWFA_SkipHigher: add.l d6,d1 ; Skip upwards dbra d2,RWFA_Loop1 ; Loop if more iterations required RWFA_OctAdj: move.l d4,d5 ; Get Copy of DY bpl RWFA_SkipNeg3 ; If not negative skip sign flip neg.l d5 ; Flip sign of DY RWFA_SkipNeg3: move.l AO_Dist(a1),d6 ; Get Active WObjects Distance ble RWFA_CalcDist ; If Distance <=0 Calculate Distance move.l RW_VPFlags(a0),d2 ; Get VP WObject Flags btst.l #WOBMOVED,d2 ; Test Moved flag bit bne RWFA_CalcDist ; If VP Moved Calculate Distance move.l d6,d5 ; If not recalced use old distance bra RWFA_SkipDist ; If neither moved then skip Distance Calc RWFA_CalcDist: moveq.l #0,d2 move.w HPCOS(a4,d1.l*2),d2 ; Get HP Cosine of Angle asl.l #TRIGSHFT1,d5 ; Multiply distance by 2048 asl.l #TRIGSHFT2,d5 divu.l d2,d5 ; (Dist*2048)/(Cos*2048) move.l d5,AO_Dist(a1) ; Store real distance to ActObj RWFA_SkipDist: tst.l d3 ; Adjust actual angle returned bpl RWFA_XP_YP ; based on Quadrant DX & DY fell in RWFA_XN_YP: move.w #1023,d2 ; Angle = 1023 - Angle sub.w d1,d2 move.w d2,AO_Angle(a1) move.l a5,d6 ; Restore d6 rts RWFA_XP_YP: move.w d1,AO_Angle(a1) ; Angle = Angle move.l a5,d6 ; Restore d6 rts ;*************************************************** ;*** Find Angle x2,y2 falls in relative to x1,y1 *** ;*************************************************** ;Heading 0 is parallel with the increasing X access and ;the headings proceed in an anti-clockwise direction ;Params - d0,d1 - x1,y1 ; - d2,d3 - x2,y2 ; - a0 - ptr to Tangents table (must have 90 WORDs !!) ;Return - d0.l - Angle (0-1023) (Not stacked as modified on return) _ASM_FindAngle: movem.l d1-d5/a0,-(sp) ; Stack all used registers (24 bytes) move.l 28(sp),d0 ; Get x1 (+4 for ret addr) move.l 32(sp),d1 ; Get y1 move.l 36(sp),d2 ; Get x2 move.l 40(sp),d3 ; Get y2 move.l 44(sp),a0 ; Get ptr to tangents table sub.l d0,d2 ; d2 = DX beq AFA_DX_Zero ; If DX=0 goto to DX=0 handler sub.l d1,d3 ; d3 = DY beq AFA_DY_Zero ; If DY=0 goto to DY=0 handler move.l d2,d0 ; d0 = Abs(DX) (ADX) bpl AFA_SkipNeg1 neg.l d0 AFA_SkipNeg1: move.l d3,d1 ; d1 = Abs(DY) (ADY) bpl AFA_SkipNeg2 neg.l d1 AFA_SkipNeg2: move.l d0,d4 ; d4 RATIO = (ADX * 2048) / ADY asl.l #TRIGSHFT1,d4 asl.l #TRIGSHFT2,d4 divu.l d1,d4 move.l #6,d0 ; Set Counter for 7 Iterations move.l #128,d1 ; Current angle (AVPT) move.l #128,d5 ; Set Initial Power AFA_Loop1: asr.l #1,d5 ; Lower current Power by 1 power of 2 cmp.l (a0,d1.l*4),d4 ; Compare ratio with tangent beq AFA_CalcFinal ; If found exact match end loop bgt AFA_SkipHigher ; If Ration>Tangent Skip Higher AFA_SkipLower: sub.l d5,d1 ; Skip downwards dbra d0,AFA_Loop1 ; Loop if more iterations required bra AFA_CalcFinal AFA_SkipHigher: add.l d5,d1 ; Skip upwards dbra d0,AFA_Loop1 ; Loop if more iterations required AFA_CalcFinal: ; Calc final angle based on quadrant (d1=angle) tst.l d2 ; Test sign of DX bmi AFA_XN ; If negative jump AFA_XP: tst.l d3 ; Test sign of DY bmi AFA_XP_YN ; If negative jump AFA_XP_YP: move.l d1,d0 bra AFA_Ret ; If X+ Y+ then Angle = Angle AFA_XN: tst.l d3 bmi AFA_XN_YN AFA_XN_YP: move.l #1023,d0 ; Angle = 1023 - Angle sub.l d1,d0 bra AFA_Ret AFA_XN_YN: add.l #512,d1 ; Angle = 512 + Angle move.l d1,d0 bra AFA_Ret AFA_XP_YN: move.l #511,d0 ; Angle = 511 - Angle sub.l d1,d0 AFA_Ret: movem.l (sp)+,d1-d5/a0 ; Retrieve all used registers rts ;*** Antipode handlers *** AFA_DX_Zero: sub.l d1,d3 ; d3 = DY bpl AFA_DXZ_DYP ; Jump if DY is + AFA_DXZ_DYN: move.l #511,d0 ; DY is - so Angle = 511 bra AFA_Ret AFA_DXZ_DYP: moveq.l #0,d0 ; DY is + so Angle = 0 bra AFA_Ret AFA_DY_Zero: tst.l d2 ; Test DX bpl AFA_DYZ_DXP ; Jump if DX is + AFA_DYZ_DXN: move.l #767,d0 ; DX is - so Angle = 767 bra AFA_Ret AFA_DYZ_DXP: move.l #255,d0 ; DX is + so Angle = 255 bra AFA_Ret