Routines
Prev: 9689 Up: Map Next: 9955
969A: Background : Draws a single column, including paths.
Used by the routines at BG_ScrollInDirection and Bg_DrawAll.
Input
HL Ptr to offscreen
IX Ptr to table of path offsets
Output
Bg_DrawColumn 969A LD (Ptr_Offscreen),HL
969D LD DE,$0022 Clear column of offscreen starting at supplied address in HL.
96A0 AND A
96A1 SBC HL,DE
96A3 LD B,$51
96A5 XOR A
Bg_DrawColumn_0 96A6 LD (HL),A
96A7 ADD HL,DE
96A8 DJNZ Bg_DrawColumn_0
96AA LD HL,(Ptr_Offscreen)
The addresses here point to where in the data doors can be inserted.
96AD LD DE,$0044
96B0 AND A
96B1 SBC HL,DE
96B3 LD A,(CurrentRoom_AreaColour)
96B6 LD (HL),A
96B7 LD A,(Camera_Compass) Get offset based on camera compass value.
96BA AND A
96BB RLA
96BC RLA
96BD LD C,A
96BE LD B,$00
96C0 ADD IX,BC
96C2 LD DE,(Coords_EW) Calculate which coordinate we need to work on.
96C6 LD HL,(Coords_NS)
96C9 LD A,(Camera_Compass)
96CC BIT 0,A
96CE JR NZ,Bg_DrawColumn_1
96D0 EX DE,HL
Bg_DrawColumn_1 96D1 PUSH HL Calculate correct position based on camera position offset to the correct end column of the stage.
96D2 LD E,(IX+$00)
96D5 LD D,(IX+$01)
96D8 ADD HL,DE
96D9 LD (_9689_coordsA),HL
96DC POP HL
96DD LD E,(IX+$02)
96E0 LD D,(IX+$03)
96E3 ADD HL,DE
96E4 LD (_968b_coordsB),HL
Search for junctions.
_969a_data 96E7 DEFW $FFFC This bit gets modified by code later on...
_969a_VectorMargin 96E9 DEFW $0004 Size of the margin when checking if the man is on a path's vector.
96EB DEFW $0000
96ED XOR A
96EE LD (_9692),A
96F1 LD A,$CA Set junction to draw bitmap index 'leading in'.
96F3 LD (Bmp_IndexJunction),A
96F6 LD HL,$0004 Set values to search for paths connecting from above current path.
96F9 LD DE,$0002
96FC LD BC,$0010
96FF LD A,$02
Bg_DrawColumn_2 9701 PUSH AF
9702 LD (_969a_data),HL
9705 LD (_969a_VectorMargin),DE
9709 LD ($96EB),BC
970D LD A,(_9692)
9710 LD ($9691),A
9713 XOR A
9714 LD (_9692),A
9717 LD A,(Camera_Compass) Get correct path information based on camera compass.
971A BIT 0,A
971C JR Z,Bg_DrawColumn_3
971E LD IX,(CurrentRoom_Ptr_Path_EW) Information for E/W path.
9722 LD BC,(_9689_coordsA)
9726 LD DE,(Coords_EW)
972A JR Bg_DrawColumn_4
Bg_DrawColumn_3 972C LD IX,(CurrentRoom_Ptr_Path_NS) Information for N/S path.
9730 LD BC,(_9689_coordsA)
9734 LD DE,(Coords_NS)
Bg_DrawColumn_4 9738 INC BC
9739 INC BC
973A LD HL,(_969a_data)
973D CP $01 Check camera compass.
973F JR Z,Bg_DrawColumn_5
9741 CP $02
9743 JR Z,Bg_DrawColumn_5
9745 EX DE,HL Offset position.
9746 AND A
9747 SBC HL,DE
9749 JR Bg_DrawColumn_6
Bg_DrawColumn_5 974B ADD HL,DE
Bg_DrawColumn_6 974C EX DE,HL
Find path crossing position.
Bg_DrawColumn_7 974D PUSH BC
974E PUSH DE
974F LD L,(IX+$00) Get coordinate of path's axis.
9752 LD H,(IX+$01)
9755 AND A See if person is on the same vector within a margin.
9756 SBC HL,BC
9758 LD BC,(_969a_VectorMargin)
975C JR NC,Bg_DrawColumn_8
975E AND A Path is to the left of position, see if within margin.
975F ADC HL,BC
9761 JP M,Bg_DrawColumn_10
9764 JR Bg_DrawColumn_9 Path is within position and its margin.
Path found?
Bg_DrawColumn_8 9766 AND A Path is either same position or further on.
9767 SBC HL,BC Check to see if further on...
9769 JR NC,Bg_DrawColumn_11
Bg_DrawColumn_9 976B LD L,(IX+$02) Get coordinates of right hand end of path and see if camera is within range.
976E LD H,(IX+$03)
9771 AND A
9772 SBC HL,DE
9774 JR NC,Bg_DrawColumn_10
9776 LD L,(IX+$04)
9779 LD H,(IX+$05)
977C SCF
977D SBC HL,DE
977F JR C,Bg_DrawColumn_10
Found path crossing position.
9781 LD L,(IX+$00)
9784 LD H,(IX+$01)
9787 LD (_9694),HL
978A LD A,$01
978C LD (_9692),A
978F LD IX,_9694
9793 LD HL,($96EB)
9796 CALL Bg_DrawItemColumn Draw junction bitmap.
9799 JR Bg_DrawColumn_11
Next Path
Bg_DrawColumn_10 979B LD BC,$000C
979E ADD IX,BC
97A0 POP DE
97A1 POP BC
97A2 JR Bg_DrawColumn_7
Search for junctions below path.
Bg_DrawColumn_11 97A4 POP DE
97A5 POP BC
97A6 LD A,$CC Set junction bitmap index to 'leading out'
97A8 LD (Bmp_IndexJunction),A
97AB LD HL,$FFFC Set values in order to seach paths conneting just below the current path.
97AE LD DE,$0004
97B1 LD BC,$0000
97B4 POP AF
97B5 DEC A
97B6 JP NZ,Bg_DrawColumn_2
97B9 LD A,(Camera_Compass)
97BC BIT 0,A
97BE JR NZ,Bg_DrawColumn_12
97C0 LD DE,(Coords_NS)
97C4 LD IX,(Hero_PathPtr)
97C8 JR Bg_DrawColumn_13
Bg_DrawColumn_12 97CA LD DE,(Coords_EW)
97CE LD IX,(Hero_PathPtr)
Bg_DrawColumn_13 97D2 LD L,(IX+$00)
97D5 LD H,(IX+$01)
97D8 AND A
97D9 SBC HL,DE
97DB JR Z,Bg_DrawColumn_15
97DD JP NC,Bg_DrawColumn_19
Bg_DrawColumn_14 97E0 LD BC,$000C
97E3 ADD IX,BC
97E5 JR Bg_DrawColumn_13
Draw bottom road edge.
Bg_DrawColumn_15 97E7 LD BC,(_9689_coordsA)
97EB INC BC
97EC LD L,(IX+$02)
97EF LD H,(IX+$03)
97F2 AND A
97F3 SBC HL,BC
97F5 JR NC,Bg_DrawColumn_14
97F7 LD A,L ABS(hl)
97F8 CPL
97F9 LD L,A
97FA LD A,H
97FB CPL
97FC LD H,A
97FD INC HL
97FE LD (TempAl),HL
9801 LD L,(IX+$04)
9804 LD H,(IX+$05)
9807 AND A
9808 SBC HL,BC
980A JR C,Bg_DrawColumn_14
980C LD (TempBl),HL
980F LD A,C Using odd/even of the offset, decide which column of the path image is drawn.
9810 RRA
9811 AND $01
9813 LD C,A
9814 LD B,$00
9816 LD A,(_9692)
9819 AND A
981A JR NZ,Bg_DrawColumn_17
981C PUSH BC
981D LD HL,(BmpPtr_RoadEdgeBottom) Get the ptr to the bitmap of the road edge.
9820 ADD HL,BC Offset to correct column to draw.
9821 EX DE,HL
9822 LD HL,(Ptr_Offscreen)
9825 LD BC,$0990
9828 ADD HL,BC
9829 LD BC,$0022
982C LD A,$08
Bg_DrawColumn_16 982E EX AF,AF'
982F LD A,(DE)
9830 XOR (HL)
9831 LD (HL),A
9832 ADD HL,BC
9833 INC DE
9834 INC DE
9835 EX AF,AF'
9836 DEC A
9837 JR NZ,Bg_DrawColumn_16
9839 POP BC
Bg_DrawColumn_17 983A LD A,($9691)
983D AND A
983E JR NZ,Bg_DrawColumn_20
9840 LD HL,(TempBl)
9843 LD DE,$0002
9846 SBC HL,DE
9848 JR C,Bg_DrawColumn_20
984A LD HL,(TempAl)
984D SBC HL,DE
984F JR C,Bg_DrawColumn_20
Draw top road edge.
9851 LD HL,(BmpPtr_RoadEdgeTop)
9854 ADD HL,BC
9855 EX DE,HL
9856 LD HL,(Ptr_Offscreen)
9859 LD BC,$0770
985C ADD HL,BC
985D LD BC,$0022
9860 LD A,$08
Bg_DrawColumn_18 9862 EX AF,AF'
9863 LD A,(DE)
9864 XOR (HL)
9865 LD (HL),A
9866 ADD HL,BC
9867 INC DE
9868 INC DE
9869 EX AF,AF'
986A DEC A
986B JR NZ,Bg_DrawColumn_18
986D JR Bg_DrawColumn_20
Bg_DrawColumn_19 986F LD A,(_9692)
9872 AND A
9873 JR NZ,Bg_DrawColumn_23
9875 LD A,($9691)
9878 AND A
9879 JR NZ,Bg_DrawColumn_23
987B JR Bg_DrawColumn_24
Draw the road leading in and out of screen.
Bg_DrawColumn_20 987D LD HL,(TempBl)
9880 LD DE,$0004
9883 AND A
9884 SBC HL,DE
9886 JR C,Bg_DrawColumn_21
9888 LD DE,(TempAl)
988C LD HL,$0004
988F SBC HL,DE
9891 JR C,Bg_DrawColumn_24
Bg_DrawColumn_21 9893 LD DE,(_9689_coordsA)
9897 LD BC,(Coords_NS)
989B LD A,(Camera_Compass)
989E BIT 0,A
98A0 JR Z,Bg_DrawColumn_22
98A2 LD DE,(_9689_coordsA)
98A6 LD BC,(Coords_EW)
Bg_DrawColumn_22 98AA INC DE
98AB ADD HL,DE
98AC LD (_9694),HL
Bg_DrawColumn_23 98AF LD IX,_9694
98B3 LD (IX+$02),$CB Bitmap index for road leading in.
98B7 LD HL,$0008
98BA CALL Bg_DrawItemColumn
Bg_DrawColumn_24 98BD LD IX,(PathFound_BackgroundPtr)
Bg_DrawColumn_25 98C1 LD A,(IX+$00)
98C4 OR (IX+$01)
98C7 JR Z,Bg_DrawColumn_26
98C9 LD A,(IX+$02)
98CC CALL Bg_DrawItemColumn_4
98CF JR NC,Bg_DrawColumn_27
98D1 LD E,(IX+$03)
98D4 LD D,$00
98D6 ADD IX,DE
98D8 JR Bg_DrawColumn_25
Bg_DrawColumn_26 98DA LD IX,PathFound_StartMargin
98DE LD A,(IX+$02)
98E1 CALL Bg_DrawItemColumn_4
98E4 JR NC,Bg_DrawColumn_27
98E6 LD IX,PathFound_EndMargin
98EA LD A,(IX+$02)
98ED CALL Bg_DrawItemColumn_4
98F0 JR NC,Bg_DrawColumn_27
98F2 JR Bg_DrawColumn_28
Bg_DrawColumn_27 98F4 CALL Bg_CalcAndDraw
Draw object.
Bg_DrawColumn_28 98F7 LD HL,(Ptr_Offscreen) Check column buffer to see if the column can hold an object (1-15)
98FA LD DE,$0022
98FD AND A
98FE SBC HL,DE
9900 LD A,(HL)
9901 AND $0F
9903 RET Z
9904 LD E,A
9905 LD D,$00
9907 LD HL,(Room_CurrentInfoDataPtr) Get the next object stored in room (0 - None)
990A ADD HL,DE
990B LD A,(HL)
990C AND A
990D RET Z
990E CALL Obj_GetBmpIndex Get the object's bitmap value and store it.
9911 LD A,(HL)
9912 LD (Draw_RoomObjectBmpIndex),A
9915 LD L,A Get the bitmap's information.
9916 CALL Bitmap_CopyFrame
9919 LD A,(HL) Bitmap's width.
Calculate which column to draw and if it is on screen.
991A AND $7F
991C LD C,A
991D NEG
991F ADD A,$05
9921 SRL A
9923 NEG
9925 LD HL,($92E3) Which table column has been drawn.
9928 ADD A,L Is any column of the object on that column?
9929 CP C
992A RET NC
992B LD (Bg_ColumnsLeft),A
992E LD A,(Bitmap_InfoCache_Height) Work out Y position of object based on height.
9931 AND $7F
9933 LD B,A
9934 LD HL,$0550
9937 LD DE,$0110
Bg_DrawColumn_29 993A AND A
993B SBC HL,DE
993D DJNZ Bg_DrawColumn_29
993F LD DE,(Ptr_Offscreen) Blit correct column of object.
9943 ADD HL,DE
9944 LD (Temp_BlitTo),HL
9947 LD DE,(Bg_ColumnsLeft)
994B LD D,$00
994D LD HL,(Draw_RoomObjectBmpIndex)
9950 LD H,D
9951 JP Bitmap_DrawColumn
9954 RET
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