Why is trying to draw multiple global shaders so slow for me?

[zombiekiller222]

This is my code.

                RenderTexture front = new RenderTexture(Width, Height);
                        RenderTexture back = new RenderTexture(Width, Height);
                        Texture texture = new Texture(Width, Height);
                        texture.Update (window);
                        back.Draw (new Sprite(texture));
                        foreach (Effect effect in ShaderManager.ScreenShaders)
                        {
                                front.Clear ();
                                front.Draw (new Sprite(back.Texture), effect.Shader);
                                front.Display ();
                               
                                RenderTexture temp = front;
                        front = back;
                        back = temp;
                        }
                        back.Display ();
                        window.Draw (new Sprite(back.Texture));

Without it my fps is 120+ and with it it's 5. Why does this happen?

Also, would testing if a sprite's bounding box collides with the screen a quick way to test whether or not to draw it?

[Laurent]

Without it my fps is 120+ and with it it's 5. Why does this happen?

Probably because you create new RenderTexture and Texture objects every time

Also, would testing if a sprite's bounding box collides with the screen a quick way to test whether or not to draw it?

Yes.