Only render Parts of a sf::sprite | Light sources?

[Allptraum]

Hey. I want to implement light sources in my game. I want to lay a complete blank sprite (exactly the window size)
over the game.
Is it possible to create masks for the light (like a white circle wich fades out) as a texture and to say, that the black sprite wont render over the lightmasks? (i dont mean with the intersect function. the pixels of the black sprite wich doesnt cover the mask should render).

I'm open for other ideas to implement light sources.

[DarkRoku12]

If you want to render a part of a texture dynamically you need to use shaders.

Check the sf::Shader class and the sf::Shader tutorial.

You also will need a shader tutorial.

Or try to implement LTBL/LTBL2.

[Hapax]

You may also find using sf::BlendMode useful. It can be used to blend/overlay during drawing or used to cut/crop using a render texture.

If you draw a black rectangle containing a white circle using BlendMultiply, it will leave the circle part as it was and change the rest to black.

Maybe using a the Radial Gradient Shader will help if you're looking for smoother light/spotlight masks.