How do I move snake as intended in a snakeGame? [closed] - c++

Question

Closed. This question needs to be more focused. It is not currently accepting answers.
Want to improve this question? Update the question so it focuses on one problem only by editing this post.
Closed 2 years ago.
Improve this question
I actually posted one similar question but without any non working code. Now i've got some. So i want to make snake move in one direction(ex: UP) until i press the other button(DOWN, LEFT, RIGHT) where i would change direction to that.
However, i've got this piece of code where i commented out one of the problems, but now it only works partially in this manner:
If i press UP i can only press DOWN once more and than it keeps moving forever, if i press LEFT or RIGHT i can only press UP or DOWN and then alternate so DOWN or UP and it keeps moving in that direction forever
Here is the code:
void Game::ProcessEvents(){
sf::Event event;
while (myWindow.pollEvent(event)){
switch(event.type){
case sf::Event::KeyPressed : handlePlayerInput(event.key.code, true); break;
//case sf::Event::KeyReleased : handlePlayerInput(event.key.code, false); break;
case sf::Event::Closed : myWindow.close(); break;
}
}
}
void Game::handlePlayerInput(sf::Keyboard::Key key, bool isPressed){
if (key == sf::Keyboard::W || key == sf::Keyboard::Up) movingUp = isPressed;
else if (key == sf::Keyboard::S || key == sf::Keyboard::Down) movingDown = isPressed;
else if (key == sf::Keyboard::A || key == sf::Keyboard::Left) movingLeft = isPressed;
else if (key == sf::Keyboard::D || key == sf::Keyboard::Right) movingRight = isPressed;
}
void Game::update(){
sf::Vector2f movement(0.0f, 0.0f);
if (movingUp) { movingLeft = false; movingRight = false; movingDown = false; movement.y -= 0.1f;}
if (movingDown) { movingUp = false; movingLeft = false; movingRight = false; movement.y += 0.1f; }
if (movingLeft) { movingRight = false; movingUp = false; movingDown = false; movement.x -= 0.1f; }
if (movingRight) { movingLeft = false; movingDown = false; movingUp = false; movement.x += 0.1f; }
isColliding(movement);
}

Answer 1

Oof I'm not the biggest fan of how you're reading inputs and then transforming that to your movement object. For example, if movingUp is true, when will it ever be set to false? The answer is NEVER! There is no way for that to happen!
Instead, I'd make an enum with a single variable for the current direction of movement:
enum Dir { RIGHT, LEFT, UP, DOWN };
Dir curr_dir = RIGHT; // Start the game moving right
Now your handlePlayerInput logic can look like:
if (key == sf::Keyboard::W || key == sf::Keyboard::Up) curr_dir = UP;
else if (key == sf::Keyboard::S || key == sf::Keyboard::Down) curr_dir = DOWN;
else if (key == sf::Keyboard::A || key == sf::Keyboard::Left) curr_dir = LEFT;
else if (key == sf::Keyboard::D || key == sf::Keyboard::Right) curr_dir = RIGHT;
And the update logic can now be:
switch(curr_dir) {
case UP:
movement.y -= 0.1f;
break;
case DOWN:
movement.y += 0.1f;
break;
case RIGHT:
movement.x -= 0.1f;
break;
case LEFT:
movement.x += 0.1f;
break;
}

Answer 2

This is how I would do it:
Instead of having multiple bools have a single variable that denotes the direction. It can be an enum.
enum class Dir { up, down, left, right };
void Game::handlePlayerInput(sf::Keyboard::Key key, bool isPressed){
if (key == sf::Keyboard::W || key == sf::Keyboard::Up) direction = Dir::up;
else if (key == sf::Keyboard::S || key == sf::Keyboard::Down) direction = Dir::down;
else if (key == sf::Keyboard::A || key == sf::Keyboard::Left) direction = Dir::left;
else if (key == sf::Keyboard::D || key == sf::Keyboard::Right) direction = Dir::right;
Then use that variable to compute the movement
void Game::update(){
sf::Vector2f movement(0.0f, 0.0f);
if (direction == Dir::up) movement.y -= 0.1f;
else if (direction == Dir::down) movement += 0.1f;
else if (direction == Dir::left) movement.x -= 0.1f;
else if (direction == Dir::right) movement += 0.1f;
isColliding(movement);