134 lines
3.3 KiB
Fennel
134 lines
3.3 KiB
Fennel
(local {: lo : hi} (require :lib.util))
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(local {: vm : mapw : maph : org} (require :neuttower.defs))
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; Graphics routines
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(vm:def :mixed [:sta :0xc053])
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(vm:def :textmode [:sta :0xc051])
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(vm:def :page1 [:sta :0xc054])
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(vm:def :page2 [:sta :0xc055])
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; starting address:
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; 0x2000 + (x*2) + (y%4 * 0x100) + ((y/4) * 0x28)
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; x between 0-19
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; y between 0-12
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; yx - 16-bit value, low byte x, high byte y
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(vm.code:append :screeny-lookup [:bytes "\0\040\080"])
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(vm:def :yx>screen ; yx -- p
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[:lda vm.TOPH :x] ; a=y
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[:lsr :a] [:lsr :a] ; a=y/4
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[:tay] ; y=y/4
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[:lda 0x03]
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[:and vm.TOPH :x] ; a=y%4
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[:ora 0x20] ; a=0x20 + y%4
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[:sta vm.TOPH :x] ; high byte is set (and y is wiped)
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[:lda vm.TOP :x] ; a=x
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[:asl :a] ; a = x*2
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[:clc]
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[:adc :screeny-lookup :y] ; a=x*2 + (y/4)*0x28
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[:sta vm.TOP :x] ; low byte is set
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)
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; note: the graphical tile data must not cross a page boundary
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; (this happens automatically because each tile is 32 bytes and we
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; start them on a page; this lets lookup-tile be fast)
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(fn draw-block []
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[:block
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[:clc]
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[:ldy 8]
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:loop
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[:lda [vm.TOP :x]]
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[:sta [vm.ST1 :x]]
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[:inc vm.TOP :x]
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[:lda vm.ST1H :x]
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[:adc 4]
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[:sta vm.ST1H :x]
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[:dey]
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[:bne :loop]])
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(fn draw-vertical-block []
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[:block
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(draw-block)
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[:lda vm.ST1H :x]
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[:sbc 31] ; with carry clear this is 32
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[:sta vm.ST1H :x]
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[:lda vm.ST1 :x]
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[:ora 0x80]
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[:sta vm.ST1 :x]
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(draw-block)])
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(vm:def :drawtile ; p gfx --
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(draw-vertical-block)
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[:lda vm.ST1H :x]
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[:sbc 31]
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[:sta vm.ST1H :x]
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[:lda vm.ST1 :x]
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[:sbc 0x7f]
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[:sta vm.ST1 :x]
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(draw-vertical-block)
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(vm:drop) (vm:drop))
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(vm:def :clearline ; pscreen --
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[:lda vm.TOP :x] [:sta vm.W]
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[:lda vm.TOPH :x] [:sta vm.WH]
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(vm:drop)
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[:block
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:row
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[:ldy 0x27] [:lda 0]
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:start
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[:sta [vm.W] :y]
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[:dey]
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[:bpl :start]
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[:lda vm.WH]
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[:cmp 0x3c]
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[:bcs :done]
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; cmp has cleared carry for us here
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[:lda 4] [:adc vm.WH] [:sta vm.WH]
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[:bcc :row]
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:done])
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(vm:word :drawfooter
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0x39d0 :clearline
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0x2250 :clearline 0x22d0 :clearline 0x2350 :clearline 0x23d0 :clearline)
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(vm:word :drawmaprow ; pscreen pmap -- pmap
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mapw (vm:for
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:2dup :bget :lookup-tile :drawtile
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:inc :swap :inc :inc :swap) :swap :drop)
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(vm:word :drawmap
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:map 0x0c00 (vm:until 0x100 :-
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:dup :yx>screen ; pmap yx pscreen
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:<rot :drawmaprow :swap ; pmap yx
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:dup :not) :drop :drop)
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(vm:word :clearfooter
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:map 0x0300 (vm:until 0x100 :-
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:dup 0x0900 :+ :yx>screen
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:<rot :drawmaprow :swap
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:dup :not) :drop :drop :player-redraw)
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(vm.code:append :tilepage [:db #(hi ($1:lookup-addr :jaye-tileset))])
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(vm:def :lookup-tile ; itile -- ptile
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; each tile is 32 bytes; 2^5
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; we save some cycles by storing the indices as lllhhhhh, so we don't need to shift them'
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[:lda vm.TOP :x] [:tay]
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[:and 0x1f]
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[:clc] [:adc :tilepage]
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[:sta vm.TOPH :x]
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[:tya] [:and 0xe0]
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[:sta vm.TOP :x])
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(vm:def :set-human-tileset
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[:lda #(hi ($1:lookup-addr :jaye-tileset))]
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[:sta :tilepage])
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(vm:def :set-prog-tileset
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[:lda #(hi ($1:lookup-addr :neut-tileset))]
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[:sta :tilepage])
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(vm:word :draw-portrait ; pgfx
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0x2252 :over :drawtile
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0x2352 :over 32 :+ :drawtile
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0x2254 :over 64 :+ :drawtile
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0x2354 :swap 96 :+ :drawtile)
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