92 lines
2.6 KiB
ArmAsm
92 lines
2.6 KiB
ArmAsm
; Functions to handle rendering sprites into 8x8 tile buffers for dirty tile rendering. Because we
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; are rendering directly to the graphics screen instead of the code field, we can map the direct
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; page into Bank 01 and use that to avoid writing the merge sprite and tile data to an intermediate
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; buffer.
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;DirtyTileSpriteProcs dw _TBDirtySpriteTile_00,_TBDirtySpriteTile_0H,_TBDirtySpriteTile_V0,_TBDirtySpriteTile_VH
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; Optimization Note: The single-sprite blitter seems like it could be made faster by taking advantage of
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; the fact that only a single set of sprite data needs to be read, but the extra overhead
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; of using the direct page and setting up and restoring registers wipes out the 2 cycle
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; per word advantage.
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;
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; A = screen address
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; X = address of sprite data
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; Y = address of tile data
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; B = tile data bank
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_OneDirtySprite_00
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_OneDirtySprite_0H
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phd
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sei
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clc
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tcd
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_R0W1
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_ODS_Line 0,0,$0
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_ODS_Line 1,1,$A0
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tdc
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adc #320
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tcd
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_ODS_Line 2,2,$0
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_ODS_Line 3,3,$A0
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tdc
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adc #320
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tcd
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_ODS_Line 4,4,$0
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_ODS_Line 5,5,$A0
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tdc
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adc #320
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tcd
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_ODS_Line 6,6,$0
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_ODS_Line 7,7,$A0
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_R0W0
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cli
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pld
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rts
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_OneDirtySprite_V0
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_OneDirtySprite_VH
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phd
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sei
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clc
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tcd
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_R0W1
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_ODS_Line 0,7,$0
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_ODS_Line 1,6,$A0
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tdc
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adc #320
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tcd
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_ODS_Line 2,5,$0
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_ODS_Line 3,4,$A0
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tdc
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adc #320
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tcd
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_ODS_Line 4,3,$0
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_ODS_Line 5,2,$A0
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tdc
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adc #320
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tcd
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_ODS_Line 6,1,$0
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_ODS_Line 7,0,$A0
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_R0W0
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cli
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pld
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rts
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; Build up from here
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_FourDirtySprites
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lda TileStore+TS_VBUFF_ADDR_0,y
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sta spriteIdx
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lda TileStore+TS_VBUFF_ADDR_1,y
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sta spriteIdx+4
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lda TileStore+TS_VBUFF_ADDR_2,y
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sta spriteIdx+8
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lda TileStore+TS_VBUFF_ADDR_3,y
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sta spriteIdx+12 |