/** Move the snake forward every update. */
public void advance() {
if (currentState == State.IDLE) {
currentState = State.MOVING;
}
SnakePart head = snakeParts.get(0);
int snakeLength = snakeParts.size() - 1;
for (int i = snakeLength; i > 0; i--) {
SnakePart previousPart = snakeParts.get(i - 1);
SnakePart snakePart = snakeParts.get(i);
// set the part's new position to the previous parts position.
snakePart.setX(previousPart.getX());
snakePart.setY(previousPart.getY());
}
switch (movementDirection) {
case UP:
head.setY(head.getY() - 1);
break;
case DOWN:
head.setY(head.getY() + 1);
break;
case LEFT:
head.setX(head.getX() - 1);
break;
case RIGHT:
head.setX(head.getX() + 1);
break;
}
}
/** Adds a new part to the end of the snake. */
public void addPart() {
numberOfParts++;
SnakePart tailPart = snakeParts.get(snakeParts.size() - 1);
SnakePart newTailPart = new SnakePart(tailPart.getX(), tailPart.getY(), snakeColor);
snakeParts.add(newTailPart);
}
/**
* Checks whether any parts overlap.
*
* @return true if parts overlap, false otherwise.
*/
public boolean checkGameOver() {
int snakeLength = snakeParts.size();
SnakePart head = snakeParts.get(0);
for (int i = 1; i < snakeLength; i++) {
SnakePart snakePart = snakeParts.get(i);
if (head.getX() == snakePart.getX() && head.getY() == snakePart.getY()) {
return true;
}
}
// check boundary conditions
if (head.getX() < 0 || head.getX() >= Utils.WORLD_WIDTH) {
// check x coordinates.
return true;
} else if (head.getY() < 0 || head.getY() >= Utils.WORLD_HEIGHT) {
// check y coordinates.
return true;
}
return false;
}