Drawing of Shape very slow?

[JAssange]

I'm trying to use Shape to draw random noise in 8x8 blocks but it's running at about 11FPS. This is my code:

Code: [Select]

//PIXEL_SIZE is defined to 8
size_t h = (engine::Window->GetHeight() / PIXEL_SIZE) + 1;
size_t w = (engine::Window->GetWidth() / PIXEL_SIZE) + 1;
Shape s;
for (size_t y = 0; y < h; y++) {
for (size_t x = 0; x < w; x++) {
s = Shape::Rectangle(FloatRect(float(x * PIXEL_SIZE), float(y * PIXEL_SIZE), float(PIXEL_SIZE), float(PIXEL_SIZE) ), Color(utils::Rand(5,10), utils::Rand(10,14), utils::Rand(200,255) ) );
rt.Draw(s);
}
}
rt.Display();
engine::Window->Draw( Sprite( rt.GetImage() ) );

What is a better way to draw noise like this?

In case it helps this is what it renders, albeit slowly:


If there is no way to do this with Shape, can someone give me an example of how to do this with a shader?

[onEnterFrame]

i have never used shape before. i just picked up this library 2 days ago.

but its not the fault of shape or the library.

you are creating at least 600/8 * 400/8 = 3750 new shape objects every frame.

not to mention all the color objects and rect objects that you are copying and moving around.

and if its within an infinite loop in the function itself i dont even know what the memory stack looks like. i dont remember the fine details of allocation in C++ but it cannot be good.

the bottom line is that youre being wasteful and need to think about the best way to utilize your resources.

[Laurent]

Filling a raw array of sf::Uint8 [width * height * 4] and then uploading it to an sf::Image with Image::LoadFromPixels will probably be faster.

[JAssange]

Filling a raw array of sf::Uint8 [width * height * 4] and then uploading it to an sf::Image with Image::LoadFromPixels will probably be faster.

Thanks, that works, it draws at acceptable speed even with PIXEL_SIZE set to 1 now.