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Draw a sphere: Difference between revisions
m
→{{header|REXX}}: elided one comment, added/changed whitespace and comments, optimized sqrt function.
SqrtNegInf (talk | contribs) m (→Pure Perl 6: fix file open error handling) |
m (→{{header|REXX}}: elided one comment, added/changed whitespace and comments, optimized sqrt function.) |
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Line 4,175:
exit /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
ceil: procedure; parse arg x; _= trunc(x);
floor: procedure; parse arg x; _= trunc(x);
norm: parse arg $a $b $c; _= sqrt($a**2 + $b**2 + $c**2);
/*──────────────────────────────────────────────────────────────────────────────────────*/
drawSphere: procedure; parse arg r, k, ambient /*get the arguments from CL*/
Line 4,184:
lightSource= '30 30 -50' /*position of light source.*/
parse value norm(lightSource) with s1 s2 s3 /*normalize light source. */
shadeLen= length(shading) - 1;
do i=floor( -r) to ceil( r); x= i + .5; xx= x**2;
do j=floor(-r2) to ceil(r2); y= j * .5 + .5; yy= y**2
if xx+yy<=rr then do /*is point within sphere ? */
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= -dot**k + ambient
if b<=0 then brite= shadeLen
else brite= max( (1-b) * shadeLen, 0) % 1
$= ($)substr(shading, brite + 1, 1)
end /* [↑] build display line.*/
else $= $' '
end /*j*/ /*[↓] strip trailing blanks*/
say strip($, 'T') /*show a line of the sphere*/
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return
/*──────────────────────────────────────────────────────────────────────────────────────*/
sqrt: procedure;
numeric
{{out|output|text= when using the default input and executed on an '''ASCII''' machine:}}
<pre>
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