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Help => Graphics => Topic started by: eXpl0it3r on April 23, 2012, 06:21:42 pm

Title: Clearing only a part of a sf::RenderTexture
Post by: eXpl0it3r on April 23, 2012, 06:21:42 pm

I was working with a sf::RenderTexture but on which I'd draw diffrent stuff. Now at the beginning the rendertexture gets clear with a fully transparent color thus when exctracting the texture later it will only show something at the place I've drawn something.
The problem is now when I want to remove a drawn square I wont' be able to do this, since I can't clear only a specific area and thus have to clear the whole rendertexture and draw everything again.
If I'd use a non transparent background color it would be easy, I'd just draw a shape over the section I want to remove but you obviously can't draw a transparent shape over something, because it will just shine through.

Am I missing a function here or any other possibilty that doesn't involve direct OpenGL calls or clearing the whole rendertexture?

If not, consider this a feature request... :)

Title: Re: Clearing only a part of a sf::RenderTexture
Post by: Dienes on April 23, 2012, 06:48:58 pm

Somewhat related to the thread we had here:
http://en.sfml-dev.org/forums/index.php?topic=7427.0

Since it seems like you want to clear a rectangular shape, use the method shown by Laurent where you draw a shape with sf::Color::Transparent and sf::BlendNone.

Title: Re: Clearing only a part of a sf::RenderTexture
Post by: eXpl0it3r on April 23, 2012, 07:29:33 pm

Oh right! ;D
sf::BlendNone will do the trick.