Build Me a Pyramid

Question

You need to build a pyramid from cubes. Cubes can be viewed from 2 angles:

  _____        _____
 /\    \      /    /\
/  \____\    /____/  \
\  /    /    \    \  /
 \/____/      \____\/

This is an example for 2-size cubes from the 2 possible angles. The height of the cubes is $size slashes (or back-slashes), and the width of the cube is 2 * $size underscores. The top level width should contain an extra underscore character.

Input will be provided as a string containing a number (size of cubes), slash or backslash (to indicate direction/angle), and another number (height of the pyramid).

Examples:

Input:

1/1

Output:

 ___
/\__\
\/__/

Input:

1\1

Output:

 ___
/__/\
\__\/

Input:

2/1

Output:

  _____
 /\    \
/  \____\
\  /    /
 \/____/

Input:

1/2

Output:

     ___ 
 ___/\__\
/\__\/__/
\/__/\__\
    \/__/

Input:

2\2

Output:

  _____          
 /    /\         
/____/  \_____   
\    \  /    /\ 
 \____\/____/  \ 
 /    /\    \  /
/____/  \____\/ 
\    \  /        
 \____\/        

Input:

1/3

Output:

         ___  
     ___/\__\
 ___/\__\/__/
/\__\/__/\__\
\/__/\__\/__/
    \/__/\__\
        \/__/

• Trailing/leading whitespaces are OK.
• Standard loopholes are disallowed.
• You can assume input will always be valid.
• You may assume the input won't cause too big output, i.e: no line wrapping when the output is printed to the terminal.
• Size of cube & height of pyramid is positive (i.e. ≥ 1)
• This is code-golf, so shortest code in bytes wins.

Current Winner is:

Glen O with 270 bytes in julia

challenge stays open. if you beat the current best, I'll update the accepted answer.

Answer 1

Perl, 343 bytes

$_=<>;$_=~/(\d+)(\S)(\d+)/;$v=$2eq'/';$w=$1*3+1;for$y(0..$1*2*$3){$k=$w*$3+$1-1;for$z(0..$k){$x=$v?$k-$z:$z;$q=($y+$1-1)/$1|0;$r=$x/$w|0;$d=$q+$r&1;$f=($y-1)%$1;$f=$1-$f-1if$d;$g=($x-$f)%$w;$u=$r;$q=2*$3-$q+1,$u++if$q>$3;print(($q>=$r&&$q&&$g==0)||($q>$r&&$g==$w-$1)?$d^$v?'/':'\\':$q>=$u&&$y%$1==0&&$g>0&&$g<($w-$1+($q==$r))?"_":$")}print$/}

Multiline with comments:

$_=<>;$_=~/(\d+)(\S)(\d+)/;$v=$2eq'/'; # read input
$w=$1*3+1; # compute width of each cube in chars
for$y(0..$1*2*$3){$k=$w*$3+$1-1;for$z(0..$k){ # iterate over rows, columns
    $x=$v?$k-$z:$z;   # flip x co-ordinate based on 2nd param
    $q=($y+$1-1)/$1|0;$r=$x/$w|0;   # parallelogram row and column index
    $d=$q+$r&1;  # flag parallelogram as left or right leaning
    $f=($y-1)%$1;$f=$1-$f-1if$d;  # compute a zig-zag offset
    $g=($x-$f)%$w;  # compute column position, offset by zig-zag
    $u=$r;$q=2*$3-$q+1,$u++if$q>$3; # vertical threshold for printing chars   
    print(($q>=$r&&$q&&$g==0)||($q>$r&&$g==$w-$1)?$d^$v?'/':'\\': # output slash
    $q>=$u&&$y%$1==0&&$g>0&&$g<($w-$1+($q==$r))?"_":$") # underscore or space
}print$/}   # print out newline at end of row

Example output:

2/3
                _____  
               /\    \ 
         _____/  \____\
        /\    \  /    /
  _____/  \____\/____/ 
 /\    \  /    /\    \ 
/  \____\/____/  \____\
\  /    /\    \  /    /
 \/____/  \____\/____/ 
       \  /    /\    \ 
        \/____/  \____\
              \  /    /
               \/____/ 

I also tried implementing it as a C function using the same algorithm, hoping to save bytes from the luxury of single-character variable names, but it ended up 15 bytes larger, at 358 bytes (needs to be compiled with -std=c89 under gcc to leave off the void in the function header):

j(char*s){int c,p,v,x,y,k,z,u,g,w,r,d,q,f;char e;sscanf(s,"%d%c%d",&c,&e,&p);v=e=='/';w=c*3+1;for(y=0;y<=c*2*p;y++){k=w*p+c-1;for(z=0;z<=k;z++){x=v?k-z:z;q=(y+c-1)/c;r=x/w;d=q+r&1;f=(y+c-1)%c;if(d)f=c-f-1;g=(x-f)%w;u=r;if(q>p){q=2*p-q+1;u++;}printf("%c",(q>=r&&q&&g==0)||(q>r&&g==w-c)?d^v?'/':'\\':q>=u&&y%c==0&&g>0&&g<(w-c+(q==r))?'_':' ');}printf("\n");}}

Answer 2

Julia - 503 455 369 346 313 270 bytes

f=A->(t=47∉A;h='/'+45t;(m,n)=int(split(A,h));W=2m*n+1;X=(l=3m+1)n+m+1;s=fill(' ',X,W);s[end,:]=10;for i=1:n,j=i:n,M=1:m s[M+i*l+[[L=[J=(2j-i)m,J,J-m]+M W-L]X.-[l,m,0] [0 m].+[1,m,m].+[J,J+m,J-m]X-l]]=[1,1,1]*[h 139-h 95 s[i*l,i*m-m+1]=95]end;print((t?s:flipud(s))...))

Ungolfed:

function f(A)
  t=47∉A      # Determine if '/' is in A ('/' = char(47))
  h='/'+45t   # Set h to the appropriate slash ('\\' = char(92), 92=47+45)
  (m,n)=int(split(A,h)) # Get the two integers from A
  W=2m*n+1    # Get number of rows of output (vertical height of pyramid)
  X=(l=3m+1)n+m+1 # Get columns of output + 1 (for newlines)
  s=fill(' ',X,W) # Create 'canvas' of size X x W
  s[end,:]=10 # Put newlines at end of each output row
  for i=1:n, j=i:n, M=1:m
    # This is where the fun happens.
    # K and L represent the shifting points for '/' and '\\' in the
    # horizontal and vertical directions.
    # They are used to make the code neater (and shorter).
    K=M+i*l-[l,m,0]
    L=[J,J,J-m]+M
    # The next two assign the slashes to appropriate places
    s[K+L*X]=h
    s[K+(W-L)X]=139-h
    # This one puts the first 2m underscores in each of the underscore sets
    s[M+i*l-l+[0 m].+[1,m,m].+[J,J+m,J-m]X]=95
    # This places the final underscores on the top edges (repeatedly)
    s[i*l,i*m-m+1]=95
  end
  # The above produces the array orientation for backslash, but uses
  # the "wrong" slashes along the diagonals if there's a forward slash.
  # This line flips the matrix in that case, before printing it.
  print((t?s:flipud(s))...))
end

Usage:

f("3/2")

or

f("2\\3")

Answer 3

Ruby, 332

The only golfing done so far is elimination of comments and indents. I will golf later.

gets.match(/\D/)
d=$&<=>"@"
n=$`.to_i
m=2*n
p=$'.to_i
a=(0..h=4*n*p).map{' '*h*2}
(p*p).times{|j|
x=h-j/p*(3*n+1)*d
y=h/2+(j/p-j%p*2)*n
if j%p<=j/p
(-n).upto(n){|i|
a[y+i][i>0?x+m+1-i :x-m-i]=?/
a[y+i][i>0?x-m-1+i :x+m+i]='\\'
a[y+n][x+i]=a[y-n][x+i]=a[y][x-d*(n+i-1)]=?_
a[y+i+(i>>9&1)][x+d*i.abs]='\_/'[(0<=>i*d)+1]
}
end
}
puts a

I set up an array of spaces and poke the individual characters into it. There is quite a lot of overdrawing both of one cube on top of another (work from bottom to top) and within the cube itself, to avoid extra code. I make the pyramid by drawing a rhombus (similar to https://codegolf.stackexchange.com/a/54297/15599) and surpressing the top half.

The hard part was drawing the scalable cube. I started off with a perimeter hexagon with 2n+1 _characters on the horizontal sides. I also had had 2n+1 / and \ ,so I had one too many, but by plotting the _ last I overwrite them.

The internal lines are the only ones that are changed depending on the direction the cube is facing. I plot all the / and \ with a single assignment. abs helps reverse the direction, and i>>9&1 adds an extra 1 to the negative values of i, which lowers the top part down. for i=0 one of the required _ is overplotted, so the selector string '\_/' contains all three symbols, selected according to the sign of i.

The whitespace around the output is ample but not excessive: 4*p*n high and 8*p*n wide (the latter is to enable the apex cube to always be in the centre of the output.) I understand "trailing / leading whitespaces" to include whole lines, but can revise if necessary.

Ungolfed code

gets.match(/\D/)                                   #find the symbol that is not a digit. it can be extracted from $&
d=$&<=>"@"                                         #direction, -1 or 1 depends if ascii code for symbol is before or after "@"
n=$`.to_i                                          #side length extracted from match variable $`
m=2*n
p=$'.to_i                                          #pyramid height extracted from match variable $'
a=(0..h=4*n*p).map{' '*h*2}                        #setup an array of h strings of h*2 spaces

(p*p).times{|j|                                    #iterate p**2 times
  x=h-j/p*(3*n+1)*d                                #calculate x and y coordinates for each cube, in a rhombus
  y=h/2+(j/p-j%p*2)*n                              #x extends outwards (and downwards) from the centre, y extends upwards 

  if j%p<=j/p                                      #only print the bottom half of the rhombus, where cube y <= cube x  
    (-n).upto(n){|i|                               #loop 2n+1 times, centred on the centre of the cube 
      a[y+i][i>0?x+m+1-i :x-m-i]=?/                #put the / on the perimeter of the hexagon into the array          
      a[y+i][i>0?x-m-1+i :x+m+i]='\\'              #and the \ also.
      a[y+n][x+i]=a[y-n][x+i]=a[y][x-d*(n+i-1)]=?_ #plot all three lines of _ overwriting the / and \ on the top line    
      a[y+i+(i>>9&1)][x+d*i.abs]='\_/'[(0<=>i*d)+1]#plot the internal / and \ overwriting unwanted _
    }
  end
}
puts a