A Platformer game written entirely in bash script without calling any external programs

bash_game

#!/bin/bash --noprofile

#extra strict flags
set -euo pipefail

#screen buffer
declare -a level

#globals
declare -i lv_w=0 #width of level
declare -i lv_h=0 #height of level
declare -i status_line=0
nextTile=''

#constants, added after the fact to improve tweaking the numbers
kFPSdelay='0.03'  #DEFAULT: 0.03, 33 FPS - good setting
kBarrierBlock='#' #DEFAULT: '#' - the block you can stand on
kEmptyBlock=' '   #DEFAULT: ' ' - air
kCoinBlock='$'    #DEFAULT: '$' - it's not a platformer unless you can increment a variable
kSpikeBlock='^'   #DEFAULT: '^' - instant death when touching this
kWinBlock='%'     #DEFAULT: '%' - instant win when touching this
kUpVelocity=-25   #DEFAULT: -25 - could be too high
kLeftVelocity=-5  #DEFAULT: -5
kRightVelocity=5  #DEFAULT: 5
kGravityFPSMod=5  #DEFAULT: 5 - provides a delay when falling
kVelocityMod=5    #DEFAULT: 5


#Art is hard
 you_won='###############################################################\n'
you_won+='##  __ __  ______  __  __    __  __  __  ______  ______  __  ##\n'
you_won+='##  || ||  |====|  ||  ||    ||  ||  ||  |====|  |====|  ||  ##\n'
you_won+='##  |===|  ||  ||  ||  ||    ||  ||  ||  ||  ||  ||  ||  ||  ##\n'
you_won+='##     ||  ||  ||  ||  ||    ||  ||  ||  ||  ||  ||  ||      ##\n'
you_won+='##  |===|  |====|  |====|    |===||===|  |====|  ||  ||  []  ##\n'
you_won+='##                                                           ##\n'
you_won+='###############################################################\n'

#less ambitious art this time
game_over='You fell into the pit, landed on a spike, and became less of an adventurer.\n'
game_over+='Game Over'

#move the cursor to a specific row and colunm
function put_cursor() {
	echo -en "\e[${1};${2}f"
}

function init_screen() {
	local height
	#get the size of the terminal
	put_cursor 999 999
	echo -en '\e[6n'
	read -s -r -d'['
	read -s -r -d';' height
	read -s -r -d'R' lv_w
	
	lv_h=$((height-1))
	status_line=height
}

#usage: mvprintw $row $col $string
function mvprintw() {
	local row=$(($1+1)) #rows count at 1 in escape sequences, I guess
	local col=$2
	printf "%s%s%s" $'\x1b[' "${row};${col}f" "$3"
}

#usage: draw_row $row_number
function draw_row() {
	mvprintw "$1" 0 "${level[$1]}"
}

#use really fancy procedural generation
function gen_level() {
	local rowstr=''
	local foo=0
	
	for (( y=0; y<lv_h; ++y ))
	do
		for (( x=0; x<lv_w; ++x ))
		do
			foo=$((RANDOM % 4))
			case "$foo" in
				( 0 ) rowstr+="$kBarrierBlock" ;;
				( 1 ) rowstr+="$kEmptyBlock" ;;
				( 2 ) rowstr+="$kEmptyBlock" ;;
				( 3 ) rowstr+="$kCoinBlock" ;;
			esac
		done
		
		level[$y]="$rowstr"
		rowstr=''
	done
}

#usage: twidle $row $col $replace_char
function twidle() {
	local row="$1"
	local col="$2"
	local chr="$3"
	local lvrest="${level[$row]:$col}"
	local lvfirst=''
	col=$((col-1))
	(( col > 0 )) && lvfirst="${level[$row]:0:$col}"
	level[$row]="${lvfirst}${chr}${lvrest}" 
}

#usage: draw_player $row $col
function draw_player() {
	#Display Attribtes         #Foreground Colours   #Background Colours
	#0	Reset all attributes   #30	Black            #40	Black
	#1	Bright                 #31	Red              #41	Red
	#2	Dim                    #32	Green            #42	Green
	#4	Underscore	           #33	Yellow           #43	Yellow
	#5	Blink                  #34	Blue             #44	Blue
	#7	Reverse                #35	Magenta          #45	Magenta
	#8	Hidden                 #36	Cyan             #46	Cyan
    #                          #37	White            #47	White
	mvprintw "$1" "$2" $'\x1b[32m@\x1b[0m'
}

function draw_level() {
	for (( x=0; x<lv_h; ++x ))
	do draw_row "$x"
	done
}

#usage: checktile $row $col
function checktile() {
	local row=$1
	local col=$(($2-1))
	
	if (( row < 0 )) || (( col < 0 ))
	then 
		nextTile="$kBarrierBlock"
		return
	elif (( row == lv_h ))
	then
		nextTile="$kSpikeBlock"
		return
	elif (( col == lv_w ))
	then
		nextTile="$kWinBlock"
		return
	else
		nextTile="${level[$row]:$col:1}"
		return
	fi
	
	return
}

function main() {
	local px=1 #player X coordinate
	local py=0 #player Y coordinate
	local pxv=0 #player X velocity
	local pyv=0 #player Y velocity
	local pog=0 #player is on ground
	local npx=0 #new player X, needs to be checked
	local npy=0 #new player Y, needs to be checked
	local score=0 #player score
	local fps_mod=0 #to delay animations
	
	#disable line wrap, clear screen, disable text cursor
	echo -en '\e[7l\e[2J\e[?25l'
	
	init_screen
	
	gen_level
	
	#make spawnpoint safe
	twidle 0 0 ' '
	twidle 0 1 ' '
	twidle 0 2 ' '
	twidle 0 3 ' '
	twidle 0 4 ' '
	twidle 1 0 ' '
	twidle 1 1 ' '
	twidle 1 2 ' '
	twidle 1 3 ' '
	twidle 1 4 ' '
	
	draw_level
	
	#main loop
	while true
	do
		#read input
		if read -r -s -N1 -t "$kFPSdelay" #framerate control
		then case "$REPLY" in
			( $'\x1b' )
				if read -r -s -N1 -t '0.1'
				then case "$REPLY" in
					( '[' )
						if read -r -s -N1 -t '0.1'
						then case "$REPLY" in
							( 'A' )	(( pog == 1 )) && pyv=$kUpVelocity ;; #up
							( 'B' ) ;; #down, no use yet
							( 'C' ) pxv=$kRightVelocity ;; #right
							( 'D' ) pxv=$kLeftVelocity ;; #left
							esac
						fi
						;;
					esac
				fi
				;;
			esac
		fi
		
		##advance animation	
		checktile $((py+1)) $px
		[[ "$nextTile" == "$kBarrierBlock" ]] && pog=1 || pog=0
		
		(( pog == 0 )) && (( (++fps_mod) == kGravityFPSMod )) && pyv=$((pyv+1)) && fps_mod=0
		
		if (( pxv > 0 ))
		then 
			pxv=$((pxv-1))
			if (( (pxv % kVelocityMod) == 0 ))
			then npx=$((px+1))
			fi
		fi
			
		if (( pxv < 0 ))
		then
			pxv=$((pxv+1))
			if (( (pxv % kVelocityMod) == 0 ))
			then npx=$((px-1))
			fi
		fi

		if (( pyv > 0 ))
		then 
			pyv=$((pyv-1))
			if (( (pyv % kVelocityMod) == 0 ))
			then npy=$((py+1))
			fi
		fi
		
		if (( pyv < 0 ))
		then
			pyv=$((pyv+1))
			if (( (pyv % kVelocityMod) == 0 ))
			then npy=$((py-1))
			fi
		fi
		
		#tile based collision detection
		checktile $npy $npx
		case "$nextTile" in
			( "$kBarrierBlock" )
				npx=$px
				npy=$py
				;;
			( "$kCoinBlock" )
				twidle $npy $npx ' '
				score=$((score+1))
				;;
			( "$kSpikeBlock" ) #lose
				mvprintw 0 0 $'\x1b[2J'
				echo -e "$game_over"
				echo "Final Score: $score"
				break
				;;
			( "$kWinBlock" ) #win
				mvprintw 0 0 $'\x1b[2J'
				echo -e "$you_won"
				echo "Final Score: $score"
				break
				;;
		esac
		
		#render player
		if (( npx != px )) || (( npy != py ))
		then
			mvprintw $py $px ' '
			draw_player $npy $npx
			px=$npx
			py=$npy
		fi
		
		#status line
		mvprintw "$status_line" 0 $'\x1b[2K'
		mvprintw "$status_line" 0 "px: $px  py: $py  pog: $pog  score: $score  pxv: $pxv  pyv: $pyv"
	done
}

main "$@"

How would you run this game ?

How would you run this game ?

This game is written in bash. Most linux distributions including those available on windows subsystem for linux utilize bash as the default command shell. To play the game, save the raw script to a .sh file, then mark it as executable, then you may invoke the script from the bash shell. for more information about how to run bash scripts from the command line of a linux system this stackoverflow post explains things in great detail: https://stackoverflow.com/a/55331703

Test it on https://www.onlinegdb.com/online_bash_shell#, putting on a different file.
Pretty cool.

Shameless plug: https://github.com/gmt4/BashGame/