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Help => General => Topic started by: cdesseno on March 07, 2010, 09:12:21 pm

Title: Global vars
Post by: cdesseno on March 07, 2010, 09:12:21 pm

This question is more a general question than a SFML one. How I may declare the "sf::RenderWindow App" so I can use it in every class? Or is better passing it by a parameter?

Thanks.

Title: Global vars
Post by: RetroX on March 07, 2010, 10:10:30 pm

It's perfectly fine to define a RenderWindow outside of the main() function.  You just can't actually do anything with it until it's within the functions.

Title: Global vars
Post by: Tank on March 08, 2010, 12:19:53 am

It's always better to encapsulate the render window. Normally only some classes of your application need it. In those cases it's better to give a reference to it. For example, you may use methods like:

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void Render( sf::RenderTarget& target );

Title: Global vars
Post by: Walker on March 08, 2010, 03:59:33 am

I'm not sure if I'm doing it "correctly", but I usually try not to need to do this.

I try to make my classes (except for window/drawing classes) never have to access the window themselves.

For example, if you have a class that has a sprite you need to draw, you can write a getSprite() function, that returns the sprite. Then do

Code: [Select]

RenderWindow.Draw (object.getSprite());

Someone else can hopefully explain whether or not this is a good idea...  :lol:

Title: Global vars
Post by: Laurent on March 08, 2010, 08:28:07 am

Quote

Someone else can hopefully explain whether or not this is a good idea...

A class should offer services, not data. So actually, this would be a better idea:

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object.Draw(RenderWindow);
This way nobody has to know that object is drawn with a sprite, all we know about this object is that it is able to draw itself into a render target.

A class that provides services and hides its internal data is generally more flexible and maintainable.

Title: Global vars
Post by: Walker on March 08, 2010, 08:37:45 am

Yes, that makes much more sense.

Quote

A class should offer services, not data.

I probably would have told someone that even though I'm not really doing it myself, lol.

Thanks for the tips