Black box
Implement a version of the Black Box game beginners configuration: 4 Atoms in an 8 x 8 grid.
Black box is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.
Determine where the hidden atoms are in the box, by observing how the light beams fired into the box react when leaving it.
Possible results:
'H': the beam hit an atom and stopped
'R': Either the beam was reflected back the way it came or there was a ball just to one side of its entry point
'Numbers': indicate that the beam entered one of those squares and emerged from the other
Extra credit (Different game types):
-More or less atoms (maybe random)
-Different grid sizes
JavaScript
Play it here. <lang javascript> var sel, again, check, score, done, atoms, guesses, beamCnt, brdSize;
function updateScore( s ) {
score += s || 0; para.innerHTML = "Score: " + score;
} function checkIt() {
check.className = "hide";
again.className = "again";
done = true;
var b, id;
for( var j = 0; j < brdSize; j++ ) {
for( var i = 0; i < brdSize; i++ ) {
if( board[i][j].H ) {
b = document.getElementById( "atom" + ( i + j * brdSize ) );
b.innerHTML = "⚈";
if( board[i][j].T ) {
b.style.color = "#0a2";
} else {
b.style.color = "#f00";
updateScore( 5 );
}
}
}
}
} function isValid( n ) {
return n > -1 && n < brdSize;
} function stepBeam( sx, sy, dx, dy ) {
var s = brdSize - 2
if( dx ) {
if( board[sx][sy].H ) return {r:"H", x:sx, y:sy};
if( ( sx == 1 || sx == s ) && ( ( sy > 0 && board[sx][sy - 1].H ) ||
( sy < s && board[sx][sy + 1].H ) ) ) return {r:"R", x:sx, y:sy};
if( isValid( sx + dx ) ) {
if( isValid( sy - 1 ) && board[sx + dx][sy - 1].H ) {
dx = 0; dy = 1;
}
if( isValid( sy + 1 ) && board[sx + dx][sy + 1].H ) {
dx = 0; dy = -1;
}
sx += dx;
return stepBeam( sx, sy, dx, dy );
} else {
return {r:"O", x:sx, y:sy};
}
} else {
if( board[sx][sy].H ) return {r:"H", x:sx, y:sy};
if( ( sy == 1 || sy == s ) && ( ( sx > 0 && board[sx - 1][sy].H ) ||
( sx < s && board[sx + 1][sy].H ) ) ) return {r:"R", x:sx, y:sy};
if( isValid( sy + dy ) ) {
if( isValid( sx - 1 ) && board[sx - 1][sy + dy].H ) {
dy = 0; dx = 1;
}
if( isValid( sx + 1 ) && board[sx + 1][sy + dy].H ) {
dy = 0; dx = -1;
}
sy += dy;
return stepBeam( sx, sy, dx, dy );
} else {
return {r:"O", x:sx, y:sy};
}
}
} function fireBeam( btn ) {
var sx = btn.i, sy = btn.j, dx = 0, dy = 0;
if( sx == 0 || sx == brdSize - 1 ) dx = sx == 0 ? 1 : - 1;
else if( sy == 0 || sy == brdSize - 1 ) dy = sy == 0 ? 1 : - 1;
var s = stepBeam( sx + dx, sy + dy, dx, dy );
switch( s.r ) {
case "H":
btn.innerHTML = "H";
updateScore( 1 );
break;
case "R":
btn.innerHTML = "R";
updateScore( 1 );
break;
case "O":
if( s.x == sx && s.y == sy ) {
btn.innerHTML = "R";
updateScore( 1 );
}
else {
var b = document.getElementById( "fire" + ( s.x + s.y * brdSize ) );
btn.innerHTML = "" + beamCnt;
b.innerHTML = "" + beamCnt;
beamCnt++;
updateScore( 2 );
}
}
} function setAtom( btn ) {
if( done ) return;
var b = document.getElementById( "atom" + ( btn.i + btn.j * brdSize ) );
if( board[btn.i][btn.j].T == 0 && guesses < atoms ) {
board[btn.i][btn.j].T = 1;
guesses++;
b.innerHTML = "⚈";
} else if( board[btn.i][btn.j].T == 1 && guesses > 0 ) {
board[btn.i][btn.j].T = 0;
guesses--;
b.innerHTML = " ";
}
if( guesses == atoms ) check.className = "check";
else check.className = "hide";
} function startGame() {
score = 0; updateScore(); check.className = again.className = "hide"; var e = document.getElementById( "mid" ); if( e.firstChild ) e.removeChild( e.firstChild ); brdSize = sel.value; done = false;
if( brdSize < 5 ) return;
var brd = document.createElement( "div" );
brd.id = "board";
brd.style.height = brd.style.width = 5.2 * brdSize + "vh"
e.appendChild( brd );
var b, c, d;
for( var j = 0; j < brdSize; j++ ) {
for( var i = 0; i < brdSize; i++ ) {
b = document.createElement( "button" );
b.i = i; b.j = j;
if( j == 0 && i == 0 || j == 0 && i == brdSize - 1 ||
j == brdSize - 1 && i == 0 || j == brdSize - 1 && i == brdSize - 1 ) {
b.className = "corner";
} else {
if( j == 0 || j == brdSize - 1 || i == 0 || i == brdSize - 1 ) {
b.className = "fire";
b.id = "fire" + ( i + j * brdSize );
} else {
b.className = "atom";
b.id = "atom" + ( i + j * brdSize );
}
b.addEventListener( "click",
function( e ) {
if( e.target.className == "fire" && e.target.innerHTML == " " ) fireBeam( e.target );
else if( e.target.className == "atom" ) setAtom( e.target );
}, false );
}
b.appendChild( document.createTextNode( " " ) );
brd.appendChild( b );
}
}
board = new Array( brdSize );
for( var j = 0; j < brdSize; j++ ) {
board[j] = new Array( brdSize );
for( i = 0; i < brdSize; i++ ) {
board[j][i] = {H: 0, T: 0};
}
}
guesses = 0; beamCnt = 1; atoms = brdSize == 7 ? 3 : brdSize == 10 ? 4 : 4 + Math.floor( Math.random() * 5 );
var s = brdSize - 2, i, j;
for( var k = 0; k < atoms; k++ ) {
while( true ) {
i = 1 + Math.floor( Math.random() * s );
j = 1 + Math.floor( Math.random() * s );
if( board[i][j].H == 0 ) break;
}
board[i][j].H = 1;
}
} function init() {
sel = document.createElement( "select"); sel.options.add( new Option( "5 x 5 [3 atoms]", 7 ) ); sel.options.add( new Option( "8 x 8 [4 atoms]", 10 ) ); sel.options.add( new Option( "10 x 10 [4 - 8 atoms]", 12 ) ); sel.addEventListener( "change", startGame, false ); document.getElementById( "top" ).appendChild( sel ); check = document.createElement( "button" ); check.appendChild( document.createTextNode( "Check it!" ) ); check.className = "hide"; check.addEventListener( "click", checkIt, false ); again = document.createElement( "button" ); again.appendChild( document.createTextNode( "Again" ) ); again.className = "hide"; again.addEventListener( "click", startGame, false ); para = document.createElement( "p" ); para.className = "txt"; var d = document.getElementById( "bot" ); d.appendChild( para ); d.appendChild( check ); d.appendChild( again ); startGame();
} </lang>