Session 12:
Memory Game Prototype, part 1
the concept
html
the scaffold
<!DOCTYPE html>
<html lang="en" dir="ltr">
<head>
memorize!
</head>
<body>
memorize!
</body>
</html>
the content
Health:
Count:
css
not a lot
body div.container {
width: 800px;
margin: auto;
}
#cards {
width: 100%;
padding: 1em 0;
}
#cards .row {
display: flex;
justify-content: space-around;
}
#cards .card {
width: 100px;
height: 100px;
margin: 1em;
border: 1px solid black;
border-radius: 5%;
}
#cards .card .content {
padding-top: 20px;
text-align: center;
font-size: 3em;
display: none;
}
javascript
game config & randInt
const memoryItemPool = [
'🌕', '🚀', '🐝', '🍀', '⌛', '📞', '👀', '📪', '📫', '🚃',
'🚢', '🚇', '⛄', '🍦', '🏂', '🥶', '🐧', '💜', '🔥', '🌶',
'🍵', '🫖', '⭐', '💋', '🌏', '💪'
]
let currentGameItems = []
const gameState = {
status: 'uninitialised',
processing: false,
difficulty: 'count only',
favourite: false,
stats: {
health: 0,
count: 0,
},
grid: [],
}
// little helper function to get a random integer
function randInt(max) {
return Math.floor(Math.random() * max);
}
initialisation
function init () {
// create new random array of current game items
let memoryPool = [...memoryItemPool]
currentGameItems = []
while (currentGameItems.length < 12) {
let i = randInt(memoryPool.length)
let [item] = memoryPool.splice(i, 1) // using a destructuring assignment
// to get the single item out of the array returned by splice
currentGameItems.push(item)
}
// create a grid with pairs of game items
let currentItemPool = [...currentGameItems]
currentItemPool.push(...currentGameItems)
gameState.grid = []
for (let row=0; row < 4; row++) {
gameState.grid.push([])
for (let col=0; col < 6; col++) {
let i = randInt(currentItemPool.length)
let [item] = currentItemPool.splice(i, 1)
gameState.grid[row].push({
item: item,
hidden: true,
solved: false,
})
}
}
// now create the memory cards from this grid
createCards(gameState.grid)
gameState.status = 'initialised'
}
creating cards
function createCards(grid) {
$cards = $( '#cards' )
$cards.children().remove()
for (let row=0; row<4; row++) {
let $row = $( '' )
$cards.append($row)
for (let col=0; col<6; col++) {
$card = $( `${grid[row][col].item}` )
$card.attr('row', row)
$card.attr('col', col)
$card.on('click', clickMemoryCard)
$row.append($card)
}
}
}
handle card clicks
function clickMemoryCard(event) {
// if the current game is completed or the grid is just being processed,
// ignore all clicks on cards
if (gameState.status === 'done' || gameState.processing) {
return
}
// if the card is not yet visible the event.target will be the card itself,
// but if it is already visible the target will point to the content
let $card = $( event.target )
if ($card.hasClass('content')) {
$card = $card.parent()
}
// fetch row and col attributes and show the card if it is still hidden
let row = $card.attr('row')
let col = $card.attr('col')
if ( gameState.grid[row][col].hidden ) {
gameState.grid[row][col].hidden = false
// reveal the card slowly and afterwards process the grid
$card.children().show( 'slow', processGrid )
}
}
processing the grid
function processGrid () {
gameState.processing = true
let openUnsolved = getOpenUnsolvedCards()
if (openUnsolved.length < 2) {
gameState.processing = false
return
}
if (openUnsolved[0].card.item === openUnsolved[1].card.item) {
openUnsolved[0].card.solved = true
openUnsolved[1].card.solved = true
gameState.processing = false
return
}
// wait for a short amount of time and then hide unsolved cards
setTimeout(() => {
let row, col
let $card
let $cards = $( '#cards' )
row = openUnsolved[0].row
col = openUnsolved[0].col
gameState.grid[row][col].hidden = true
$card = $cards.children().eq(row).children().eq(col)
$card.children().hide('slow')
row = openUnsolved[1].row
col = openUnsolved[1].col
gameState.grid[row][col].hidden = true
$card = $cards.children().eq(row).children().eq(col)
// after the second card is hidden set the processing stat to false
$card.children().hide('slow', () => {gameState.processing = false})
}, 500)
}
a little helper & document ready function
function getOpenUnsolvedCards () {
let ret = []
for (let row=0; row < 4; row++) {
for (let col=0; col < 6; col++) {
if (!gameState.grid[row][col].hidden && !gameState.grid[row][col].solved) {
ret.push({
row: row,
col: col,
card: gameState.grid[row][col]
})
}
}
}
return ret
}
$( document ).ready(function () {
init()
})
additional debugging help
// a little helper function throughout development, to be able to log the
// grid nicely to the console; should/could be removed after development;
// but on the other hand, a person who opens the source code of your game
// and uses the console while gaming, might find out a way to "cheat" anyways,
// so you could also just leave it in. as mentioned in the intro session,
// cheating often is also just a different way to learn something ;)
function debugGrid () {
for (let row=0; row < 4; row++) {
let r = ''
for(let col=0; col < 6; col++) {
r += gameState.grid[row][col].item + ' '
}
console.log(r)
}
}
Remember: Use the console, young Codawan!
(you can now use debugGrid() in the console any time you need to know where the pairs are hidden)
Current state: a first prototype
Still missing functionality:
- Implementation of buttons
- Storage of current state and favourite
- Difficulty, health and stats
to be continued next session