fastest way to get pixel from RenderTexture?

[NinjaFighter]

I don't know how to Get a pixel information of a RenderTexture, without copy it on a new Image. There's a way to do this more faster?

[Laurent]

There's no way, the texture lives in the graphics card's memory, you have to copy it in an image in system memory to read a pixel.

Why do you need to read pixels of a render-texture?

[NinjaFighter]

It's just curiosity, because I remember that old versions uses myRenderImage.Image.GetPixel() for that purpose. So, in old versions do you store for (each Image instance) a Texture and another Image for Set/Get pixel purposes?
I don't want to use GetPixel now, but I think could be useful for some graphics editing application.
I repeat, it's only curiosity. This is not crucial for me. 

[eXpl0it3r]

Depending on what you're doing, I guess it's faster to work directly with a sf::Image instead of a sf::RenderTexture and then just call Update(...) on a sf::Texture.
But if you need to do some shape/image rendering, I guess you'll have copy the texture to an image.
If you want to create a graphics editing application I bet there are better libraries for that.

[Laurent]

In SFML 1.6, the Image class was maintaining a copy of the pixel data both in graphics and system memory. When one was outdated, it performed an automatic copy -- so GetPixel could be very slow.

That's why things are now split in two classes

[NinjaFighter]

Ah... this make sense now. Thats 100% clear my doubts. Thanks