Tetris/Julia

Julia

This is a fairly complete, configurable pure Julia implementation of Tetris, played in the standard Julia terminal. No external packages are used.

Detailed notes are in the long comment below the Julia script, to be attached to the code. At least its first few lines are needed, as they are shown as info, upon the request of the user.

Works with: Julia version 1.0
struct B4                         # Tetromino made of 4 Blocks
bg::Int # ANSI code of tetromino color (bground of " ")
d::Array{Int,2} # d[b,1:2] = row,col/2 offset of block b
# constructor: set centered offsets of blocks
B4(bg,A::Array{Int,2}) = new(bg,A.-sum.(extrema(A,dims=1)).>>1)
end
# in loops ITERATE over the blocks in B4
Base.iterate(B::B4,i=1) = i<5 ? (B.d[i,:],i+1) : nothing
# PRINT/CLEAR tetromino on terminal
drw(B,r,c)=(for(i,j)=B print("\e[\$(B.bg)m\e[\$(r+i);\$(c+2j)H ") end)
clr(B,r,c)=(for(i,j)=B print("\e[0m\e[\$(r+i);\$(c+2j)H ") end)
# HIT other B4s or border?
hit(B,r,c)=(for(i,j)=B try BD[r+i,c>>1+j]>0 catch;true end&& return true end;false)

function mov(B,r,c,x,y) # MOVE tetrominos left/right/down, if no hit
hit(B,r+x,c+y) || (clr(B,r,c); drw(B,r+=x,c+=y))
TMv || (global tmr=Timer(tm)); return (r,c)
end

function rot(B,r,c,rt=0) # ROTATE tetrominos left/right, if no hit
TMv || (global tmr=Timer(tm))
A = B4(B.bg, rt>0 ? [B.d[:,2] (3 .-B.d[:,1])] : [(3 .-B.d[:,2]) B.d[:,1]])
for j = c.+(0,+2,-2) # try shifted positions
hit(A,r,j) || (clr(B,r,c); drw(A,r,j); return (A,j))
end; return (B,c) # cannot rotate: all 3 positions hit
end

function mrk(B,r,c) # RECORD place,CLEAR full-lines,DROP-above,score
global lines,score,level; n,l = 0,0
for(i,j)=B BD[r+i,c>>1+j]=B.bg end # record stuck B4
for i in r.+sort(unique(B.d[:,1])) # empty full rows in board; drop all above
if all(BD[i,:].>0) n += 1; l = i # l = lowest line changed
for j=i-1:-1:1 BD[j+1,:]=BD[j,:] end
print("\e[0m\e[\$i;2H\$s20"); sleep(0.3)
end end # update changed display from board data ->
for i=1:l,j=1:10 print("\e[\$(BD[i,j])m\e[\$i;\$(2j)H ") end
score+=(level+1)*(0,100,300,500,800)[n+1]
lines+=n; level=isqrt(lines>>3) # update lines, score, level
end

function cnf(p) # CONFIRMATION dialog. p = 1-line prompt
print("\$p - Enter confirms, other keys ignore")
t = take!(chnl); println("\e[2K"); t==[0xd]
end
# SHOW basic usage- and status info
inf()=print("\e[0m\e[26H\e[2K i: Info, l: Locked drop=\$LDr, t: Timed move=\$TMv")

# SETUP nonblocking, non-echoed keyboard INPUT
ccall(:jl_tty_set_mode,Cint,(Ptr{Cvoid},Cint),stdin.handle,1)==0 ||
throw("Terminal cannot enter raw mode.") # raw terminal mode to catch keystrokes
const chnl = Channel{Array{UInt8,1}}(0) # unbuffered channel for key codes
@async while true put!(chnl,readavailable(stdin)) end # task, catching keystrokes

I = B4(106,[0 0; 0 1; 0 2; 0 3]) # define the 7 tetrominos
T = B4(105,[0 1; 1 0; 1 1; 1 2]); O = B4(103,[0 0; 0 1; 1 0; 1 1])
S = B4(102,[0 1; 0 2; 1 0; 1 1]); Z = B4(101,[0 0; 0 1; 1 1; 1 2])
J = B4(104,[0 0; 1 0; 1 1; 1 2]); L = B4(107,[0 2; 1 0; 1 1; 1 2])
LDr,TMv,Ifo = falses(3)

begin @label RESTART # @label - @goto: require begin..end
global lines,score,level,s20,eq = 0,0,0," "^20,"="^6
BD = fill(0,22,10) # empty BOARD. Screen_Col = 2*Board_Col

print("\e[0m\e[2J\e[?25l\e[1H") # Set default colors/clear screen/hide cursor
print("▐\$(s20)▌\n"^22*"▝\$("▀"^20)▘\n\n\$s20\n\$s20") # screen BORDER, Cols=2:2:20

X0 = (I,T,O,S,Z,J,L)[rand(1:7)]
while true # random B4, timed drop, act on keystrokes
global lines,score,level,tm,tmr,LDr,TMv,Ifo
global X0,X,r,c = (I,T,O,S,Z,J,L)[rand(1:7)],X0,2,10
clr(X,24,10); drw(X0,24,10); inf() # show next piece, information
print("\n Level =\t\$level\n Lines filled =\t\$lines\n Score =\t\$score")
tm=(.8-level*.007)^level; tmr=Timer(0.5) # 0.5s initial delay
hit(X,r,c) && (while true cnf("\e[31H Game Over: RESTART")&&@goto RESTART end)
while isready(chnl) take!(chnl) end # flush queued keystrokes, max 1
while true
global X,r,c,tm,tmr
if !isopen(tmr) # time to drop tetromino by a line
hit(X,r+1,c) && (mrk(X,r,c); break)
clr(X,r,c); drw(X,r+=1,c); tmr=Timer(tm)
end
if isready(chnl) # if there is a queued keystroke
global X,r,c,score
ch = take!(chnl) # take keys
if ch==[0x1b,0x5b,0x41] X,c=rot(X,r,c) # UP
elseif ch==[0x1b,0x5b,0x42] r,c=mov(X,r,c,1, 0);score+=1# DOWN
elseif ch==[0x1b,0x5b,0x43] r,c=mov(X,r,c,0, 2) # RIGHT
elseif ch==[0x1b,0x5b,0x44] r,c=mov(X,r,c,0,-2) # LEFT
elseif ch==[0x61] X,c=rot(X,r,c) # a
elseif ch==[0x64] X,c=rot(X,r,c,1) # d
elseif ch==[0x20] r0=r; clr(X,r,c); tmr=Timer(tm*!LDr) # SPACE
while !hit(X,r+=1,c) end; drw(X,r-=1,c); score+=2r-2r0; continue
elseif ch==[0x1b,0x5b,0x31,0x7e] # HOME
cnf("\e[0m\e[31H RESTART") && @goto RESTART
elseif ch==[0x1b,0x5b,0x34,0x7e] # END
cnf("\e[0m\e[31H EXIT") && return
elseif ch==[0x6c] LDr=!LDr; inf() # l: Locked drop
elseif ch==[0x74] TMv=!TMv; inf() # t: Timed move
elseif ch==[0x69] if (Ifo=!Ifo) open(@__FILE__) do f # i: long-Info
else print("\e[0m\e[32H\e[J") # erase txt
end end end
sleep(0.01) # not to take all CPU time
end end end

The following long comment block has to be appended to program code:

#======       Julia-TETRIS by Laszlo Hars, Version 1.2 10/31/2018
(Set Terminal window to 43+ rows, don't scroll)
-- Key assignments --
↑: rotate +90° counterclockwise   i: Info about the program on/off
↓: soft drop (one line)           l: Locked hard drop on/off
←: shift left                     t: restart Timer after move on/off
→: shift right                    SPACE: hard drop until hit
a: rotate +90° counterclockwise   HOME: restart game
d: rotate -90° clockwise          END:  exit
======
The game is played in the Julia standard Unicode character based Terminal
Controlled by ANSI escape sequences (Windows conhost, ConEmu...)
Set font to e.g. Fantasque Sans Mono
Monospace, height:width = 2:1, line drawing chars

Playfield rows*cols: 10x20 active, +2 extra rows on top
Tetrominos appear centered in row 2 (and 1)

Rotate is around the center of the tetromino. It is not unique
thus the rotated tetromino is also shifted left, then right.
The first of the 3 positions, which does not hit anything is taken.

Naive gravity is used
Full rows (lines) get cleared
Rows above it move down, but floating blocks can remain

Information is displayed under the board
PREVIEW next tetromino
Game LEVEL
Number of LINES cleared
SCORE
Keys for short Info, Locked-drop-, and Timed-move status

Game LEVEL: 0,1...= [sqrt(LINES/8)]
Increase after 8,32,72,128,200... lines cleared

SCORE: Cleared_Line values: *(LEVEL+1)
Single = 100
Double = 300
Triple = 500
Tetris = 800

Bonus points: (not increasing with level)
Soft drop = 1 point per line
Hard drop = 2 points per line

Time_delay per drop one line, decreasing with LEVEL
(0.8-LEVEL*0.007)^LEVEL (seconds)

Timing values
Initial delay for new tetromino = 0.5s
Cleared line is shown for 0.3s

Tetrominos are drawn by blocks of 2 space characters with color background
Background color is set by ANSI codes, e.g print("\e[101m  ")
bg-color_code  shape
Black   100
████
Red     101   Z        ████
████
Green   102   S ████
████
Yellow  103   O        ████
██
Blue    104   J ██████
██
Magenta 105   T      ██████

Cyan    106   I ████████
██
White   107   L      ██████

Julia specifics
Terminal is switched to RAW mode to catch keystrokes.
Non-blocking keyboard input is by asynchronous (maybe blocked) 2nd TASK.
Keystrokes are transferred to the main program through a CHANNEL.
STRUCTs (B4) describe Tetrominos, with color code and coordinates of blocks.
At construction the coordinates get centralized.
Assigning Struct to a variable (X) only creates a REFERENCE, not copied.
Memory used by orphan instance is cleared by internal GARBAGE COLLECTION.
Out of range indices are caught with TRY..CATCH, to keep tetrominos in board.
A TIMER controls the dropping delay of tetrominos.
ITERATE is defined for tetrominos, looping over the coordinates of blocks.
In loops when variables get assigned before other use, Julia 1.0 assumes
local variables, therefore many GLOBAL variables are declared and used
For simplicity Int variables are used; in 64-bit OS versions: 8 Bytes.
In most places 1 Byte Int8 (or Int16, Int32) would work. Take care
when changing: Int8(x)+1->Int64, Int8(x)+0x1->UInt8. Use +Int8(1).
Only "lines" and "score" need to be UInt32 or longer.
LABEL - GOTO (for restart) require the main loop enclosed in Begin..End.
Several instructions are written in single lines of at most 84 chars,
to keep the program well under 100 non-comment/non-blank lines!
#.. Comments denote tasks, explain important points.
In strings some UNICODE characters appear. They can be replaced with
\u{hex_digits} to make the program all ASCII (for old editors).
======#