Routines
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AA5B: Build View
Used by the routine at RunGame.
Builds the view buffer at ScreenBuffer from the position of the view in ViewPosition and 5CE4, one strip at a time in twelve passes.
build-view
BuildView AA5B LD HL,$0000 HL is 00.
AA5E LD ($5CF6),HL Store it in TurningRate.
AA61 LD HL,($5CE2) Fetch the first value from ViewPosition.
AA64 LD DE,($5CE4) Fetch the second value from 5CE4.
AA68 PUSH HL Save the first value.
AA69 ADD HL,DE Add the second value.
AA6A LD BC,$0080 BC is 80.
AA6D ADD HL,BC Add it.
AA6E LD ($5CE7),HL Store the result in ViewOriginSum.
AA71 POP HL Retrieve the first value.
AA72 SRL D Halve the second value...
AA74 RR E ...with the carry going into E.
AA76 SRL H Halve the first value...
AA78 RR L ...with the carry going into L.
AA7A AND A Subtract the second halved value from the first.
AA7B SBC HL,DE
AA7D LD ($5CEE),HL Store the result in ViewOriginDifference.
AA80 LD DE,$FFA8 DE is FFA8.
AA83 CALL AdjustViewOrigin_Signed Call AdjustViewOrigin_Signed.
AA86 LD HL,$E5D1 Point HL at the first strip of the view buffer.
AA89 LD ($5CBB),HL Store it in StripAddress.
AA8C LD B,$0C Set the number of passes to 0C.
BuildView_Pass AA8E PUSH BC Save the number of passes.
AA8F LD HL,$E5D1 Point HL at the first strip of the view buffer.
AA92 LD DE,$0017 Set the size of a row to 17.
AA95 LD B,$80 Set the number of rows to 80.
AA97 XOR A Set A to zero.
AA98 LD ($5CF0),A Store it in DrawingFlags.
AA9B LD ($AA5A),A Store it in RenderFlag.
BuildView_Clear AA9E LD (HL),A Clear a byte of the strip.
AA9F INC HL Move onto the next byte.
AAA0 LD (HL),A Clear that byte.
AAA1 ADD HL,DE Move onto the next row.
AAA2 DJNZ BuildView_Clear Jump back until all of the rows have been cleared.
AAA4 LD HL,$C0E1 HL is C0E1.
AAA7 CALL DrawLevelObjects Call DrawLevelObjects.
AAAA POP BC Restore the number of passes.
AAAB DEC B Decrease it by one.
AAAC RET Z Return if all of the passes have been done.
AAAD EXX Switch to the alternate registers.
AAAE CALL RemoveObjectEntities Call RemoveObjectEntities.
AAB1 LD DE,$E5BB Point DE at ScreenBuffer.
AAB4 LD HL,$E5BD Point HL at the second column of the view buffer.
AAB7 LD BC,$0BFE Set the number of bytes to 0BFE.
AABA LDIR Move the contents of the view buffer along by two bytes.
AABC LD E,$08 E is 08.
AABE CALL AdjustViewOrigin Call AdjustViewOrigin.
AAC1 EXX Switch back to the normal registers.
AAC2 JR BuildView_Pass Jump back for the next pass.
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