SFML startup image

[AdrianM]

I noticed than when i create a windows before drawing anything with opengl in it i see some weird images there (memory garbage). I wonder how can this be avoided?

[K-Bal]

Maybe what you search is sf::Renderwindow::Clear() ?

[Hiura]

You have to use Clear before closing your window. Then, your next opened window won't have some waste from old instance.

[Daazku]

You have to use Clear before closing your window. Then, your next opened window won't have some waste from old instance.

you have to use clean before "draw" and "display" anyway...

while
{
Clear
Draw
Draw
Display
}

[Hiura]

or :
draw
display
clear

Rendering is the same. :wink:

[Nexus]

or :
draw
display
clear

But I think the other order is more intuitive, since the first frame you have to clear too - just as you don't need to clear the last frame. It's a detail, I know.

[Hiura]

right

[AdrianM]

Thanks!

[Groogy]

Well if you know that each "frame" will draw over the entire window then you don't need to waste good ol' cpu power on clearing since the drawing will clear the window. Like for instance if you are drawing an 3D world with a skybox.

[Daazku]

or :
draw
display
clear

But I think the other order is more intuitive, since the first frame you have to clear too - just as you don't need to clear the last frame. It's a detail, I know.

Hum it's more than that. The first frame you have can be some shit from memory so you need to clean before display anything (i think).

[Groogy]

or :
draw
display
clear

But I think the other order is more intuitive, since the first frame you have to clear too - just as you don't need to clear the last frame. It's a detail, I know.

Hum it's more than that. The first frame you have can be some shit from memory so you need to clean before display anything (i think).

Back to my point. If you know you will draw over the entire display/window then you don't need to worry about clearing. ^^

[Hiura]

I thought about the problem again, and the good solution (on my opinion) is :

Code: [Select]

int main... {
  /// ...
  sf::RenderWindow w(...);
  w.Clear(); // Prevent waste in memory from other app.
  /// ...
  /// Main loop event ...
  {
    // ...
    // Quit event ...
    {
      w.Clear(); // Our application does not leave waste.
      w.Close();
    }
  /// ...
/// ...

[Groogy]

I thought about the problem again, and the good solution (on my opinion) is :

Code: [Select]

int main... {
  /// ...
  sf::RenderWindow w(...);
  w.Clear(); // Prevent waste in memory from other app.
  /// ...
  /// Main loop event ...
  {
    // ...
    // Quit event ...
    {
      w.Clear(); // Our application does not leave waste.
      w.Close();
    }
  /// ...
/// ...

Erhm. Just cause you "Clear" doesn't mean that it will not leave waste when it exits. The "Clear" actually just paints black over it all. So actually it's just black waste instead.

The Clear function is actually a paint action that will paint the entire display into one consistent colour where the default is black.

[Hiura]

I don't think that this "black" is some waste. It's the default color of the screen so...

Waste is for me some non solid pattern.

But we can discuss about that during hours and hours.  :wink:

[Laurent]

There is no waste, it's just a matter of properly clearing the screen before any display, so that we know that what is actually displayed is not garbage from the video memory.

So any game loop calling Clear before Draw and Display is ok. You can even remove the call to Clear if the whole window area is covered with sprites.