Only want a function to get called once on a keyDown.

[dotty]

Hello, I'm using AniSprite to animate my sprites, this works well and I can play animation with ease.

When I press D on my keyboard I'm adding some velocity to move my sprite, but at the same time I'm calling AniSprite.Play(0,5); to play the animation. The obvious issue here is that Play(0,5) is called every frame, so that the animation never actually starts.

How do people get around this?

[MarekkPie]

No idea about more elegant solutions, but you could do a if statement with a bool once, and the first time it gets called toggle that bool so the keyDown event only calls that particular bit of code once.

[Tex Killer]

If you use input events instead of simple checks it will not happen every frame.

[dotty]

I'm using this

this->LeftButton = sf::Keyboard::IsKeyPressed(sf::Keyboard::A);
if( this->LeftButton ){
      this->MoveLeft();
   }

[dotty]

Can anyone lend a hand on this? I'm struggling to get this working.

[Tex Killer]

http://sfml-dev.org/tutorials/1.6/window-events.php

If you are using SFML 2, use .PollEvent instead of .GetEvent

[model76]

He/she is using SFML 2 and I don't think it is clear that the problem is what everyone assumes.

Dotty, do you want something to happen every time the button is pressed, or do you want something to happen every frame, as long as the button is pressed?

Events are good for the first case. Documentation for SFML 2 is here: http://www.sfml-dev.org/documentation/2.0/classsf_1_1Event.php

Real-time inputs, as you are using now, is for the latter.

Also, what is AniSprite?

[MarekkPie]

I think the issue here is that this "AniSprite" library as it's own little update loop, that iterates through the animation frames once you press play and give it a start frame. However, s/he is calling Play(0,5), the start trigger for the animation, every time that event gets called. So, it would start running its animation, get a call to start over, then run back to the beginning and start again, endlessly.

[dotty]

I want to do something every time the button is pressed.

[model76]

Then you need to use sf::Event.

There is a really good example in the link I provided in the previous post, so that is where I think you should start.

[dotty]

sf::Event does seem the best way to do this. However, it seems that I cannot pass my window instance to my class. Any idea's how to use sf::Event within my class?

[Tex Killer]

You have to either pass the windows as parameter or have it global (if you choose this, you better have a window pointer made global, instead of the windows itself, because global variables cause trouble with SFML).

[dotty]

I've got something like this going on

Code: [Select]



Player {
public:
    sf::Window win;
    void SetWindow(sf::Window window);
}

void Player::SetWindow(sf::Window window){
    this->win = window;
}



But it's telling me it's 'Not copyable'

[Tex Killer]

Use a pointer or a reference.

[model76]

Why don't you do something like this in your main event loop:

Code: [Select]

if ( event.Type == sf::Event::KeyPressed && event.Key.Code == sf::Keyboard::Left )
    aniSprite.MoveLeft();