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Help => General => Topic started by: meto28 on March 09, 2011, 04:40:23 pm

Title: Keep sprite in movement
Post by: meto28 on March 09, 2011, 04:40:23 pm

Hi,

I'm doing a Snake game and I would like to know if there is a "clean" way to make it continue moving after pressing a key and not only at the press of the key

Title: Keep sprite in movement
Post by: Lupinius on March 09, 2011, 04:41:44 pm

You could store the direction of the last key pressed and move your sprite in the according direction every frame.

Title: Keep sprite in movement
Post by: meto28 on March 09, 2011, 05:09:59 pm

You mean like this:

Code: [Select]


if (direction = "L")
{
Sprite.Move(-x, y);
}
if (direction = "U")
{
Sprite.Move(x, -y);
}

etc...

With Events instead of Input
Is that really a right way to do it ??

Title: Keep sprite in movement
Post by: Lupinius on March 09, 2011, 06:41:45 pm

There is no "wrong" way. As long as you know what you're doing your code will probably be good (or at least understandable).

Title: Keep sprite in movement
Post by: devlin on March 09, 2011, 07:00:26 pm

Code: [Select]

namespace SnakeDirection
{
  enum Value
  {
    UP, DOWN, LEFT, RIGHT
  };
}

// and then in your app class:
SnakeDirection::Value m_direction;


Then when you get a button press:

Code: [Select]

switch (key)
{
case sf::Key::Up:
   m_direction = SnakeDirection::UP;
   break;

case sf::Key::Left:
   m_direction = SnakeDirection::LEFT;
   break;

//etc
}

And in your update function:

Code: [Select]

switch (m_direction)
{
case SnakeDirection::LEFT:
   //moveLeft
break;

case SnakeDirection::RIGHT:
   //moveRight
break;

//etc
}

Title: Keep sprite in movement
Post by: bastien on March 10, 2011, 12:38:49 am

You can use the Input class to know whether a key is currently pressed. Obtain the Input instance with RenderWindow.GetInput().

Title: Keep sprite in movement
Post by: devlin on March 10, 2011, 08:36:51 am

Quote from: "bastien"

You can use the Input class to know whether a key is currently pressed. Obtain the Input instance with RenderWindow.GetInput().

That's not what the OP wanted though:

"after pressing a key and not only at the press of the key"

:)

Title: Keep sprite in movement
Post by: meto28 on March 10, 2011, 04:00:02 pm

Thanks for your answers, now I have another issues.
I want my snake to always move on a distance of 1 tile
So I tried instead of Move the SetPosition but it still moving the same way (not "jumping" from a square to another)

The other one is that the snake only moves up or left if I use GetFrameTime:

Code: [Select]

     if (direction == "D")
        {
          Sprite.SetPosition(X, Y);
          Y += TileSize * ElapsedTime; //Doesn't work
        }
      if (direction == "U")
        {
          Sprite.SetPosition(X, Y);
          Y -= TileSize * ElapsedTime; //Works
        }
      if (direction == "L")
        {
          Sprite.SetPosition(X, Y);
          X -= TileSize * ElapsedTime; //Works
        }
      if (direction == "R")
        {
          Sprite.SetPosition(X, Y);
          X += TileSize; //Works
        }