140 lines
3.0 KiB
Forth
Executable File
140 lines
3.0 KiB
Forth
Executable File
#! /usr/bin/env ueforth
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\ Copyright 2022 Bradley D. Nelson
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\
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\ Licensed under the Apache License, Version 2.0 (the "License");
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\ you may not use this file except in compliance with the License.
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\ You may obtain a copy of the License at
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\
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\ http://www.apache.org/licenses/LICENSE-2.0
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\
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\ Unless required by applicable law or agreed to in writing, software
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\ distributed under the License is distributed on an "AS IS" BASIS,
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\ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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\ See the License for the specific language governing permissions and
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\ limitations under the License.
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DEFINED? windows [IF] windows dpi-aware [THEN]
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also graphics
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also structures
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struct ScanSpan
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ptr field ->next
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ptr field ->edge
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2048 constant max-scanlines
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create scanlines max-scanlines cells allot
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scanlines max-scanlines cells erase
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0 value free-edges
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: new-edge ( n next -- a )
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free-edges if
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free-edges dup ->next @ to free-edges
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else
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ScanSpan allocate throw
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then
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{ np }
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np ->next !
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np ->edge !
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np
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;
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: row-span ( y -- a ) cells scanlines + ;
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: add-edge { x y }
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y 0< y max-scanlines >= or if exit then
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y row-span { yp }
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begin yp @ while
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x yp @ ->edge @ <= if
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x yp @ new-edge yp !
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exit
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then
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yp @ ->next to yp
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repeat
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x yp @ new-edge yp !
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;
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: remove-edge ( y -- x )
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row-span { yp }
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yp @ 0= if 10000 exit then
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yp @ { old }
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yp @ ->edge @
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yp @ ->next @ yp !
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free-edges old ->next !
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old to free-edges
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;
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: draw-row { y }
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begin y row-span @ while
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y remove-edge y remove-edge over - y swap 1 box
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repeat
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;
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: draw-spans max-scanlines 0 do i draw-row loop ;
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: 0.<< ( n -- n ) 16 lshift ;
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: 0.>> ( n -- n ) 16 rshift ;
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: line ( x1 y1 x2 y2 )
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0 0 0 0 { x1 y1 x2 y2 dx dy sy ey }
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y1 y2 > if
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y1 y2 to y1 to y2
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x1 x2 to x1 to x2
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then
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x2 x1 - to dx
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y1 0.>> to sy
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y2 0.>> to ey
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ey sy - to dy
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dy 0 ?do
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x1 dx i dy */ + 0.>> sy i + add-edge
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loop
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;
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: distance2 { x1 y1 x2 y2 } x1 x2 - dup * y1 y2 - dup * + ;
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: raw-bezier 0 0 { x1 y1 x2 y2 x3 y3 d xn yn }
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d 0< if
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x1 y1 x3 y3 line
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else
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x1 x2 2* + x3 + 2/ 2/ to xn
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y1 y2 2* + y3 + 2/ 2/ to yn
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x1 y1 x1 x2 + 2/ y1 y2 + 2/ xn yn d 1- recurse
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xn yn x2 x3 + 2/ y2 y3 + 2/ x3 y3 d 1- recurse
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then
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;
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: bezier 10 raw-bezier ;
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0 value pen-x 0 value pen-y
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: move-to { x y } x 0.<< to pen-x y 0.<< to pen-y ;
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: line-to { x y } pen-x pen-y x 0.<< y 0.<< line x y move-to ;
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: bezier-to { x' y' x y } pen-x pen-y x' 0.<< y' 0.<< x 0.<< y 0.<< bezier x y move-to ;
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-1 -1 window
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$ff0000 constant red
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$ffff00 constant yellow
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$ffffff constant white
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$000000 constant black
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$0000bb constant blue
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: draw
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black to color 0 0 width height box
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yellow to color 0 0 width 2/ height 2/ box
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red to color
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width 3 / 100 move-to
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mouse-x 1 mouse-x mouse-y bezier-to
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mouse-x 2/ 1 line-to
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300 200 200 400 bezier-to
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1 mouse-y 2 3 */ line-to
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width 3 / 100 line-to
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blue to color draw-spans
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flip
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;
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: run
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begin
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poll
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IDLE event = if draw then
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event FINISHED = until
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bye
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;
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run
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