Tilemap collision sfml c++ platformer

Question

I have a problem with my 2d platformer. As i have just started out with c++ i'm having trouble with tile collision. I'm able to prevent the player from entering the tile and also being able to move away from it but somehow he cant move along the tile.

This is the function for checking if the new position is inside a solid tile:

void Maps::drawColMap(Player& _player){

for (int i = 0; i < _player.tiles.size(); i++)
{
    if (colMap[_player.tiles[i].y][_player.tiles[i].x] == 1) //solid tile = 1
    {
        _player.willCollide = true;
        break;
    }
    else {
        _player.willCollide = false;
    }
}

}

And here is the code for moving the player:

void Player::update() {

sf::Vector2f newPosition;  
sf::Vector2f oldPosition;

oldPosition.x = playerImage.getPosition().x; // store the current position
oldPosition.y = playerImage.getPosition().y;

newPosition.x = playerImage.getPosition().x; // store the new position
newPosition.y = playerImage.getPosition().y;

if (sf::Keyboard::isKeyPressed(sf::Keyboard::Left))
{
    source.y = Left; //sprite stuff
    moving = true;
    newPosition.x -= 2;
}
if (sf::Keyboard::isKeyPressed(sf::Keyboard::Right))
{

    source.y = Right;
    moving = true;
    newPosition.x += 2;
}


if (sf::Keyboard::isKeyPressed(sf::Keyboard::Up))
{

    source.y = Up;
    moving = true;
    newPosition.y -= 2;

}
if (sf::Keyboard::isKeyPressed(sf::Keyboard::Down))
{

    source.y = Down;
    moving = true;
    newPosition.y += 2;
}

if (!(sf::Keyboard::isKeyPressed(sf::Keyboard::Left) || sf::Keyboard::isKeyPressed(sf::Keyboard::Right) || sf::Keyboard::isKeyPressed(sf::Keyboard::Up) || sf::Keyboard::isKeyPressed(sf::Keyboard::Down)))
{
    moving = false;
}

//create corners to check collision

bottom = newPosition.y + 32; //tile size is 32 px
left = newPosition.x;
right = newPosition.x + 32;
top = newPosition.y;

sf::Vector2i topLeft(sf::Vector2i((int)left / 32, (int)top / 32)); // get the corners of the new position
sf::Vector2i topRight(sf::Vector2i((int)right / 32, (int)top / 32));
sf::Vector2i bottomLeft(sf::Vector2i((int)left / 32, (int)bottom / 32));
sf::Vector2i bottomRight(sf::Vector2i((int)right / 32, (int)bottom / 32));

tiles.clear();

tiles.push_back(topLeft);
if (std::find(tiles.begin(), tiles.end(), topRight) == tiles.end()) tiles.push_back(topRight);  //check the corners
if (std::find(tiles.begin(), tiles.end(), bottomLeft) == tiles.end()) tiles.push_back(bottomLeft);
if (std::find(tiles.begin(), tiles.end(), bottomRight) == tiles.end()) tiles.push_back(bottomRight);

//if no collision set the position to the new position
if (!willCollide)                
    playerImage.setPosition(newPosition);
else
    playerImage.setPosition(oldPosition);  //if collision then set the position to the previous position

}

Any help is appreciated!

//edit 1

I tried logging the collision and it says that the player is still in the collision area even if i dont press anything. But how do i prevent the player from entering? I cant find the problem.

//edit 2

I think i found another problem. The collision check should probably be run just before moving the player and after moving the new position.

DCurro DCurro · Accepted Answer · 2014-06-06T17:47:07

After the player collides, and you change the positions, move it over by 1 pixel in the away from the collision area (the appropriate direction). It's possible that your corner is still within the collision bounds if it wasn't moved out of of the collision area properly.

Tilemap collision sfml c++ platformer

1 Answers