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| 1 | +// Set up variables for the four-de-lance game. |
| 2 | +let loose = false; |
| 3 | +let snake = []; |
| 4 | +let foodcoordinates = {}; |
| 5 | +let snakeMoveTimeout; |
| 6 | +let snakeDirection; |
| 7 | + |
| 8 | +const SNAKE_UP = 'up'; |
| 9 | +const SNAKE_DOWN = 'down'; |
| 10 | +const SNAKE_LEFT = 'left'; |
| 11 | +const SNAKE_RIGHT = 'right'; |
| 12 | + |
| 13 | +function placeFood() { |
| 14 | + if (snake.length === 16) { |
| 15 | + // There is nowhere to place the food, so "win". |
| 16 | + loose = true; |
| 17 | + score += 1; |
| 18 | + return; |
| 19 | + } |
| 20 | + foodcoordinates = {}; |
| 21 | + placeFoodLoop: while (typeof foodcoordinates.column === 'undefined') { |
| 22 | + const random = randomElement(); |
| 23 | + for (let s = 0; s < snake.length; s += 1) { |
| 24 | + if (snake[s].column === random.column && snake[s].row === random.row) { |
| 25 | + continue placeFoodLoop; |
| 26 | + } |
| 27 | + } |
| 28 | + foodcoordinates = { column: random.column, row: random.row }; |
| 29 | + } |
| 30 | +} |
| 31 | + |
| 32 | +function moveSnake() { |
| 33 | + snakeMoveTimeout = setTimeout(moveSnake, Math.max(2000 - (score * 100), 250)); |
| 34 | + |
| 35 | + const head = structuredClone(snake[0]); |
| 36 | + |
| 37 | + switch (snakeDirection) { |
| 38 | + case SNAKE_LEFT: |
| 39 | + if (snake[0].column >= 1) { |
| 40 | + head.column -= 1; |
| 41 | + } |
| 42 | + else { |
| 43 | + loose = true; |
| 44 | + } |
| 45 | + break; |
| 46 | + case SNAKE_UP: |
| 47 | + if (snake[0].row >= 1) { |
| 48 | + head.row -= 1; |
| 49 | + } else { |
| 50 | + loose = true; |
| 51 | + } |
| 52 | + break; |
| 53 | + case SNAKE_RIGHT: |
| 54 | + if (snake[0].column < 3) { |
| 55 | + head.column += 1; |
| 56 | + } else { |
| 57 | + loose = true; |
| 58 | + } |
| 59 | + break; |
| 60 | + case SNAKE_DOWN: |
| 61 | + if (snake[0].row < 3) { |
| 62 | + head.row += 1; |
| 63 | + } else { |
| 64 | + loose = true; |
| 65 | + } |
| 66 | + break; |
| 67 | + default: |
| 68 | + // Player hasn't moved yet. |
| 69 | + return; |
| 70 | + } |
| 71 | + |
| 72 | + for (let s = 1; s < snake.length; s += 1) { |
| 73 | + if (snake[s].column === head.column && snake[s].row === head.row) { |
| 74 | + loose = true; |
| 75 | + return; |
| 76 | + } |
| 77 | + } |
| 78 | + |
| 79 | + snake.unshift(head); |
| 80 | + |
| 81 | + if (snake[0].column === foodcoordinates.column && snake[0].row === foodcoordinates.row) { |
| 82 | + score += 1; |
| 83 | + placeFood(); |
| 84 | + return; |
| 85 | + } |
| 86 | + |
| 87 | + snake.pop(); |
| 88 | +} |
| 89 | + |
| 90 | +function placeSnake() { |
| 91 | + while (snake.length === 0) { |
| 92 | + const random = randomElement(); |
| 93 | + if (random.column === foodcoordinates.column && random.row === foodcoordinates.row) { |
| 94 | + continue; |
| 95 | + } |
| 96 | + |
| 97 | + snake.push({ column: random.column, row: random.row }); |
| 98 | + } |
| 99 | + if (typeof snakeMoveTimeout !== 'number') { |
| 100 | + snakeMoveTimeout = setTimeout(moveSnake, 100); |
| 101 | + } |
| 102 | +} |
| 103 | + |
| 104 | +function userActionKeyPress(direction) { |
| 105 | + switch (direction) { |
| 106 | + case KEYPRESS_LEFT: |
| 107 | + snakeDirection = SNAKE_LEFT; |
| 108 | + break; |
| 109 | + case KEYPRESS_UP: |
| 110 | + snakeDirection = SNAKE_UP; |
| 111 | + break; |
| 112 | + case KEYPRESS_RIGHT: |
| 113 | + snakeDirection = SNAKE_RIGHT; |
| 114 | + break; |
| 115 | + case KEYPRESS_DOWN: |
| 116 | + snakeDirection = SNAKE_DOWN; |
| 117 | + break; |
| 118 | + default: |
| 119 | + // Do nothing. |
| 120 | + break; |
| 121 | + } |
| 122 | +} |
| 123 | + |
| 124 | +function init() { |
| 125 | + placeSnake(); |
| 126 | + placeFood(); |
| 127 | +} |
| 128 | + |
| 129 | +function update() { |
| 130 | + if (loose === true) { |
| 131 | + // We have a winner! |
| 132 | + // flush the screen. |
| 133 | + cls(); |
| 134 | + // Display the score. |
| 135 | + displayScore(score); |
| 136 | + // Reset some variables. |
| 137 | + score = 0; |
| 138 | + snake = []; |
| 139 | + snakeDirection = undefined; |
| 140 | + |
| 141 | + // Reset the game grid. |
| 142 | + placeSnake(); |
| 143 | + placeFood(); |
| 144 | + |
| 145 | + // Turn off the win state. |
| 146 | + loose = false; |
| 147 | + } |
| 148 | +} |
| 149 | + |
| 150 | +function draw() { |
| 151 | + cls(); |
| 152 | + for (let i = 0; i < gridMaxX; i += 1) { |
| 153 | + for (let j = 0; j < gridMaxY; j += 1) { |
| 154 | + const element = grid[i][j]; |
| 155 | + for (let g = 0; g < snake.length; g += 1) { |
| 156 | + if (snake[g].column === element.column && snake[g].row === element.row) { |
| 157 | + fillBox(element, 'red'); |
| 158 | + } |
| 159 | + } |
| 160 | + if (element.column === foodcoordinates.column && element.row === foodcoordinates.row) { |
| 161 | + fillBox(element, 'green'); |
| 162 | + } |
| 163 | + } |
| 164 | + } |
| 165 | +} |
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