RosettaCodeData/Task/Draw-a-sphere/Batch-File/draw-a-sphere.bat

106 lines
3.9 KiB
Batchfile

:: Draw a Sphere Task from Rosetta Code
:: Batch File Implementation
@echo off
rem -------------- define arithmetic "functions"
rem more info: https://www.dostips.com/forum/viewtopic.php?f=3&t=6744
rem integer sqrt arithmetic function by Aacini and penpen
rem source: https://www.dostips.com/forum/viewtopic.php?f=3&t=5819&start=30#p44016
set "sqrt(N)=( M=(N),j=M/(11*1024)+40, j=(M/j+j)>>1, j=(M/j+j)>>1, j=(M/j+j)>>1, j=(M/j+j)>>1, j=(M/j+j)>>1, j+=(M-j*j)>>31 )"
rem -------------- define batch file macros with parameters appended
rem more info: https://www.dostips.com/forum/viewtopic.php?f=3&t=2518
setlocal disabledelayedexpansion % == required for macro ==%
(set \n=^^^
%== this creates escaped line feed for macro ==%
)
rem normalize macro
rem argument: v
set normalize=for %%# in (1 2) do if %%#==2 ( %\n%
for /f "tokens=1" %%a in ("!args!") do set "v=%%a" %\n%
set /a "length_sqrd=!v![0]*!v![0]+!v![1]*!v![1]+!v![2]*!v![2]" %\n%
set /a "length=%sqrt(N):N=!length_sqrd!%" %== sqrt(N) applied ==% %\n%
set /a "!v![0]*=100", "!v![1]*=100", "!v![2]*=100" %== normalized elements mult. by 100 ==% %\n%
set /a "!v![0]/=length", "!v![1]/=length", "!v![2]/=length" %\n%
) else set args=
rem dot macro
rem arguments: s t outputvar
set dot=for %%# in (1 2) do if %%#==2 ( %\n%
for /f "tokens=1,2,3" %%a in ("!args!") do ( %\n%
set "s=%%a" %\n%
set "t=%%b" %\n%
set "outputvar=%%c" %\n%
) %\n%
set /a "d=!s![0]*!t![0]+!s![1]*!t![1]+!s![2]*!t![2]" %\n%
if !d! lss 0 (set /a "!outputvar!=-d") else (set "!outputvar!=0") %\n%
) else set args=
rem -------------- define pseudo-arrays
set "shades[0]=."
set "shades[1]=:"
set "shades[2]=!"
set "shades[3]=*"
set "shades[4]=o"
set "shades[5]=e"
set "shades[6]=&"
set "shades[7]=#"
set "shades[8]=%%"
set "shades[9]=@"
set "num_shades=9" %== start at 0 ==%
set "light[0]=30" & set "light[1]=30" & set "light[2]=-50"
rem -------------- main thing: execute drawSphere
setlocal enabledelayedexpansion
%normalize% light %== normalize macro applied ==%
rem note: due to scale up 100x of variables for calculations,
rem k=4 is the maximum value for k that does not cause overflow.
call :drawSphere 20 4 1
exit /b 0
rem -------------- the function to draw the sphere
rem arguments: R k ambient
:drawSphere
rem initialize variables from arguments
set /a "R=%1", "negR=-R", "twiceR=R*2", "twiceNegR=negR*2"
set /a "sqrdR=R*R*10000" %== R^2 is mult. by 100^2 ==%
set "k=%2"
set "ambient=%3"
rem start draw line-by-line
for /l %%i in (%negR%, 1, %R%) do (
set /a "x=100*%%i+50" %== x is mult. by 100 ==%
set "line="
for /l %%j in (%twiceNegR%, 1, %twiceR%) do (
set /a "y=50*%%j+50" %== y is mult. by 100 ==%
set /a "pythag = x*x + y*y"
if !pythag! lss !sqrdR! (
set /a "vec[0]=x"
set /a "vec[1]=y"
set /a "vec[2]=sqrdR-pythag"
set /a "vec[2]=%sqrt(N):N=!vec[2]!%" %== sqrt(N) applied ==%
%normalize% vec %== normalize macro applied ==%
%dot% light vec dot_out %== dot macro applied ==%
rem since both light and vec are normalized to 100,
rem then dot_out is scaled up by 100*100 now.
set /a "dot_out/=100" %== scale-down to 100*[actual] to prevent overflow before exponentiation ==%
set "scaleup=1" %== after exponentiation, b would be scaleup*[actual] ==%
set "b=1"
for /l %%? in (1,1,%k%) do set /a "b*=dot_out","scaleup*=100" %== exponentiation ==%
set /a "b+=ambient*scaleup/10" %== add ambient/10 to b ==%
set /a "b/=scaleup/100" %== scale-down to 100*[actual] ==%
set /a "intensity=(100-b)*num_shades"
set /a "intensity/=100" %== final scale-down ==%
if !intensity! lss 0 set "intensity=0"
if !intensity! gtr %num_shades% set "intensity=%num_shades%"
for %%c in (!intensity!) do set "line=!line!!shades[%%c]!"
) else (
set "line=!line! "
)
)
echo(!line!
)
goto :EOF