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https://frontier.innolan.net/github/AmigaExamples.git
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179 lines
3.3 KiB
ArmAsm
179 lines
3.3 KiB
ArmAsm
include "includes.i"
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xdef RenderPathway
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xdef ClearPathway
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RenderPathway:
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move.l pathwayPlayerTileAddress,d5
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andi.w #$fff0,d5 ; point the address to the last tile of the previous column
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move.l d5,a4
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move.w #0,d5
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.loopX:
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move.w #6,d6 ; y index
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move.w #0,d7 ; number of rows without a pathway
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.loopY:
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move.l pathwayMapPtr,a2
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jsr GetMapTile
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cmp.l a4,a2 ; search for the start column
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ble .next
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cmp.l pathwayPlayerTileAddress,a2
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beq .next
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move.l d0,a2
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move.w (a2),d0
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cmp.w #0,d0
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beq .dontBlit
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lea foregroundTilemap,a1
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add.w d0,a1 ; source tile
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move.l foregroundScrollX,d0
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lsr.w #FOREGROUND_SCROLL_SHIFT_CONVERT,d0 ; convert to pixels
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lsr.w #3,d0 ; bytes to scroll
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move.l foregroundOffscreen,a0
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add.l d0,a0
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move.l #-BITPLANE_WIDTH_BYTES*SCREEN_BIT_DEPTH*8,d0
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move.w d5,d4
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mulu.w #2,d4
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add.l d4,d0
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add.l #10,d0
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add.l d0,a0
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move.l #10,d2
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sub.l d6,d2
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jsr BlitTile
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bra .next
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.dontBlit:
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add.w #1,d7
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cmp.w #7,d7
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beq .skip
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.next:
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dbra d6,.loopY
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add.w #1,d5
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cmp.w #(FOREGROUND_PLAYAREA_WIDTH_WORDS/2)-0,d5 ; don't render pathways off the play area
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beq .pathwayNotComplete
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bra .loopX
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.skip:
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sub.w #1,pathwayRenderPending
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rts
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.pathwayNotComplete:
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rts
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ClearPathway:
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sub.w #1,pathwayClearPending
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move.l foregroundPlayerTileAddress,d7
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andi.w #$fff0,d7 ; address of the last tile in the previous column
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move.w #0,d5 ; x index
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.loopX:
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move.w #6,d6 ; y index
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.loopY:
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move.l foregroundMapPtr,a2 ;; todo: this will be too slow, it will render too many tiles
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bsr GetMapTile
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cmp.l d7,a2 ; finished clearing...
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bgt .done
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move.l d0,a2
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move.w (a2),d0
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if 0
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move.l foregroundMapPtr,a3
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move.w (a3),d0
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endif
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cmp.w #0,d0
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beq .dontBlit
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lea foregroundTilemap,a1
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add.w d0,a1 ; source tile
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move.l foregroundScrollX,d0
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lsr.w #FOREGROUND_SCROLL_SHIFT_CONVERT,d0 ; convert to pixels
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lsr.w #3,d0 ; bytes to scroll
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move.l foregroundOffscreen,a0
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add.l d0,a0
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move.l #-BITPLANE_WIDTH_BYTES*SCREEN_BIT_DEPTH*8,d0
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move.w d5,d4
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mulu.w #2,d4
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add.l d4,d0
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add.l #10,d0
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add.l d0,a0
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move.l #10,d2
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sub.l d6,d2
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jsr BlitTile
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bra .next
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.dontBlit:
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.next:
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dbra d6,.loopY
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add.w #1,d5
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bra .loopX
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;; dbra d5,.loopX
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.done
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rts
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RenderMapTile:
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;; d5 - x map index
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;; d6 - y map index
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move.l foregroundMapPtr,a2
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bsr GetMapTile
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move.l d0,a2
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move.w (a2),d0
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cmp.w #0,d0
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beq .dontBlit
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lea foregroundTilemap,a1
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add.w d0,a1 ; source tile
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move.l foregroundScrollX,d0
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lsr.w #FOREGROUND_SCROLL_SHIFT_CONVERT,d0 ; convert to pixels
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lsr.w #3,d0 ; bytes to scroll
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move.l foregroundOffscreen,a0
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add.l d0,a0
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move.l #-BITPLANE_WIDTH_BYTES*SCREEN_BIT_DEPTH*8,d0
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move.w d5,d4
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mulu.w #2,d4
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add.l d4,d0
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add.l #10,d0
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add.l d0,a0
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move.l #10,d2
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sub.l d6,d2
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jsr BlitTile
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.dontBlit:
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rts
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GetMapTile:
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;; d5 - x board index
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;; d6 - y board index
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;; a2 - map
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;;
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;; d0 - pathwayOffset
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;; calculate the a2 offset of the top right tile based on foreground scroll
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move.l foregroundScrollX,d0
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lsr.l #FOREGROUND_SCROLL_TILE_INDEX_CONVERT,d0
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lsr.l #1,d0
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and.b #$f0,d0
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add.l d0,a2
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move.l #(FOREGROUND_PLAYAREA_WIDTH_WORDS/2)-1,d1
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sub.w d5,d1 ; x column
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mulu.w #FOREGROUND_PLAYAREA_HEIGHT_WORDS*2,d1
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sub.l d1,a2 ; player x if y == bottom ?
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sub.l d1,d1
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move.w #FOREGROUND_PLAYAREA_HEIGHT_WORDS-1,d1
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sub.w d6,d1 ; y row
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lsl.w #1,d1
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add.l d1,a2
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;; a2 now points at the tile at the coordinate
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move.l a2,d0
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rts |