uxn/projects/tests/draw.usm

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( tests/draw )
%RTN { JMP2r }
%RTN? { JMP2r? }
;cursor { x 2 y 2 }
;a { x 2 y 2 }
;b { x 2 y 2 }
;s { x 2 y 2 }
|0100 @RESET
#0020 #0020 #0070 #0080 ,draw-line JSR2
#0020 #0080 #0070 #0030 ,draw-line JSR2
#00a0 #0020 #0050 #00b0 ,draw-line JSR2
#00b0 #0090 #0030 #0010 ,draw-line JSR2
BRK
@draw-line ( x1 y1 x2 y2 )
=b.y =b.x ( target, b )
=a.y =a.x ( target, a )
~a.x =Screen.x ~a.y =Screen.y #02 =Screen.color
~b.x =Screen.x ~b.y =Screen.y #02 =Screen.color
( dx = abs[bx - ax] )
~b.x ~a.x SUB2 ABS2 =d.x
( dy = -abs[by - ay] )
~b.y ~a.y SUB2 ABS2 #0000 SWP2 SUB2 =d.y
( sx = ax < bx ? 1 : -1; )
#ffff #00 ~a.x ~b.x LTH2 #0002 MUL2 ADD2 =s.x
( sy = ay < by ? 1 : -1; )
#ffff #00 ~a.y ~b.y LTH2 #0002 MUL2 ADD2 =s.y
( err = dx + dy )
~d.x ~d.y ADD2 =err
( loop )
$loop
( putchr[ax, ay, color]; )
~a.x =Screen.x ~a.y =Screen.y #01 =Screen.color
( if[ax == bx && ay == by] break; )
,$end ~a.x ~b.x EQU2 ~a.y ~b.y EQU2 #0101 EQU2 JMP2?
( fallback, remove )
,$end ~i #90 GTH JMP2? ~i #01 ADD =i
( err2 = 2 * err; )
~err #0002 MUL2 =err2
~err2 =Console.short
( if[err2 >= dy] )
,$skipy ~err2 ~d.y LTH2 JMP2?
( err += dy; )
~err ~d.y ADD2 =err
( ax += sx; )
~a.x ~s.x ADD2 =a.x
$skipy
( if[err2 <= dx] )
,$skipx ~err2 ~d.x GTH2 JMP2?
( err += dx; )
~err ~d.x ADD2 =err
( ay += sy; )
~a.y ~s.y ADD2 =a.y
$skipx
,$loop JMP2
$end
RTN
|c000 @FRAME
|d000 @ERROR
|FF00 ;Console { pad 8 char 1 byte 1 short 2 }
|FFF0 .RESET .FRAME .ERROR ( vectors )
|FFF8 [ 13fd 1ef3 1bf2 ] ( palette )