void GameScreen::createBall()
{
ball = new Label(this, "ball");
ball->setPixmap(*ballIcon);
int width = (this->width() - (this->width() - ui->rightLine->pos().x()));
ball->setGeometry((width / 2) - (BALLWIDTH / 2), paddle->pos().y() - PADDLEHEIGHT, BALLWIDTH, BALLHEIGHT);
ball->setEnabled(false);
ball->show();
Timer *timer = new Timer(ball, "ball");
ball->object = timer;
timer->object = ball;
timer->setInterval(ballSpeed);
connect(timer, SIGNAL(lifeLost()), this, SLOT(decrementLives()));
connect(timer, SIGNAL(gameWon()), this, SLOT(gameIsWon()));
emit(eventTriggered("Ball created"));
}
static pos createFood(int width, int height, posList snake) {
// The high level view of how this code works: (1) Creates a list of
// open positions (i.e positions not occuipied by the snake) and (2)
// grabs a random element from that list. But it does this without
// creating a list of open positions.
int maxRand = width*height - snake.len;
if (maxRand <= 0) {
return (pos){ .x = -1, .y = -1 };
}
int randIndex = rand() % maxRand;
int curRandIndex = 0;
for (int y = 0; y < height; y++) {
for (int x = 0; x < width; x++) {
pos p = { .x = x, .y = y };
if (posList_contains(snake, p)) {
continue;
}
if (curRandIndex == randIndex) {
return p;
}
curRandIndex++;
}
}
// This should never be reached but I added it to get rid of the
// compiler warning.
return (pos){ .x = -1, .y = -1 };
}
static const dir NO_DIRECTION = { .x = 0, .y = 0 };
static dir actionToDirection(playeraction a) {
if (a == UP) {
return (dir){ .x = 0, .y = -1 };
}
if (a == DOWN) {
return (dir){ .x = 0, .y = 1 };
}
if (a == LEFT) {
return (dir){ .x = -1, .y = 0 };
}
if (a == RIGHT) {
return (dir){ .x = 1, .y = 0 };
}
return NO_DIRECTION;
}
static void initState(int width, int height, posList *snake, pos *food, playeractionQueue *queue, dir *curDirection, bool *paused, int *score) {
srand(time(NULL));
snake->len = 4;
snake->list[0] = (pos){ .x = 0, .y = 1 };
snake->list[1] = (pos){ .x = 0, .y = 0 };
snake->list[2] = (pos){ .x = 1, .y = 0 };
snake->list[3] = (pos){ .x = 1, .y = 1 };
*food = createFood(width, height, *snake);
while (playeractionQueue_dequeue(queue) != NO_ACTION);
*curDirection = actionToDirection(DOWN);
*paused = false;
*score = 0;
}
static bool gameIsWon(int width, int height, posList snake) {
return width*height == snake.len;
}
static bool gameIsLost(int width, int height, posList snake) {
{
posList headless = snake;
headless.len--;
if (posList_contains(headless, snake.list[snake.len-1])) {
return true;
}
}
{
pos head = snake.list[snake.len-1];
if (head.x < 0 || width <= head.x) {
return true;
}
if (head.y < 0 || height <= head.y) {
return true;
}
}
return false;
}
static void updateGameState(playeraction action, int width, int height, bool *paused, posList *snake, pos *food, dir *d, int *score) {
if (action == PAUSE) {
*paused = !(*paused);
return;
}
if (*paused) {
return;
}
dir newDir = actionToDirection(action);
if (!dir_equal(newDir, NO_DIRECTION)) {
*d = newDir;
}
pos newHead = { .x = snake->list[snake->len-1].x + d->x, .y = snake->list[snake->len-1].y + d->y };
if (pos_equal(newHead, *food)) {
*snake = posList_append(*snake, newHead);
*food = createFood(width, height, *snake);
(*score)++;
} else {
for (int i = 0; i < snake->len-1; i++) {
snake->list[i] = snake->list[i+1];
}
snake->list[snake->len-1].x += d->x;
snake->list[snake->len-1].y += d->y;
}
}
char *playeraction_toString(playeraction p) {
switch (p) {
case NO_ACTION:
return "no action";
case UP:
return "move the snake up";
case DOWN:
return "move the snake down";
case LEFT:
return "move the snake left";
case RIGHT:
return "move the snake right";
case PAUSE:
return "pause the game";
case QUIT:
return "quit the game";
case NEW_GAME:
return "start a new game";
default:
return "BUG!!! Unknown player action, please add another case to the switch statement";
}
}
void playeractionQueue_enqueue(playeractionQueue *q, playeraction c) {
if (q->isFull) {
return;
}
pthread_mutex_lock(q->mu);
q->arr[q->tail] = c;
q->tail = (q->tail+1) % PLAYERACTIONQUEUE_SIZE;
if (q->tail == q->head) {
q->isFull = 1;
}
pthread_mutex_unlock(q->mu);
}
size_t snakeSpaceRequired(int width, int height) {
posList snake;
return width * height * sizeof(*snake.list);
}
void snake(int width, int height, struct timespec frameRate, void *snakeMem, playeractionQueue *actionsQueue, void (*render)(int width, int height, posList snake, pos food, bool paused, int score, bool gameIsWon, bool gameIsLost)) {
posList snake;
pos food;
dir curDirection;
bool paused;
int score;
snake.list = snakeMem;
initState(width, height, &snake, &food, actionsQueue, &curDirection, &paused, &score);
while (true) {
bool won = gameIsWon(width, height, snake);
bool lost = gameIsLost(width, height, snake);
render(width, height, snake, food, paused, score, won, lost);
nanosleep(&frameRate, NULL);
playeraction action = playeractionQueue_dequeue(actionsQueue);
while (!dir_orthogonal(curDirection, actionToDirection(action))) {
action = playeractionQueue_dequeue(actionsQueue);
}
if (action == QUIT) {
break;
}
if (action == NEW_GAME) {
initState(width, height, &snake, &food, actionsQueue, &curDirection, &paused, &score);
continue;
}
if (won || lost) {
continue;
}
updateGameState(action, width, height, &paused, &snake, &food, &curDirection, &score);
}
}