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Draw a sphere: Difference between revisions
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→{{header|REXX}}: added/changed whitespace and comments, reduced need for some temp variables.
m (J: torgb better fits than tograyscale - the gray of that image is because we're only using one channel of intensity and using it for all three colors - but the conversion routine does support all three...) |
m (→{{header|REXX}}: added/changed whitespace and comments, reduced need for some temp variables.) |
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<br>Same with the '''CEIL'''ing and '''FLOOR''' functions.
<br><br>Programming note: the output will appear slightly different when executed on an EBCDIC machine (due to different dithering characters).
<lang rexx>/*REXX program expresses a lighted sphere with simple
call drawSphere 19, 4, 2/10 /*draw a sphere with a radius of 19. */
call drawSphere 10, 2, 4/10 /*
exit /*stick a fork in it, we're all done. */
/*──────────────────────────────────DRAWSPHERE
drawSphere: procedure; parse arg r, k, ambient
if 1=='f1'x then shading='.:!*oe&#%@'
else shading='·:!°oe@░▒▓'
lightSource = '30 30 -50'
parse value norm(lightSource) with s1 s2 s3
sLen=length(shading)-1;
do i=floor(-r) to ceil(r) ; x= i+.5; xx=x**2; aLine=
do j=floor(-2*r) to ceil(
if xx+yy<=rr then do
parse value norm(x y sqrt(rr-xx-yy)) with v1 v2 v3
dot=s1*v1 + s2*v2 + s3*v3
if dot>0 then dot=0
b=abs(dot)**k + ambient
if b<=0 then brite=
else brite=trunc( max( (1-b) *
aLine=(aLine
end
else aLine=aLine' '
end /*j*/
say strip(aLine,'trailing')
end /*i*/
return
/*─────────────────────────────────────one─liner subroutines──────────────────*/
ceil: procedure; parse arg x; _=trunc(x); return _ + (x>0) *
floor: procedure; parse arg x; _=trunc(x); return _ - (x<0) *
norm: parse arg _1 _2 _3;
/*─────────────────────────────────────SQRT subroutine────────────────────────*/
sqrt: procedure; parse arg x; if x=0 then return 0; d=digits(); p=d+d%4+2; m.=11
do k=j+5 to 0 by -1; if m.k>11 then numeric digits m.k; g=.5*(g+x/g); end
<pre style="height:105ex">
eeeeeeeeee@@@@@@@
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