Gradient Rectangle

[teunissenstefan]

I was searching for how to use gradient, then I found this: http://en.sfml-dev.org/forums/index.php?topic=6750.0
I tried the code that laurent provided but it doesn't work. No errors, just a black screen.
Pieces of code in question:

sf::Vertex backgroundgr[] =
        {
                sf::Vertex(sf::Vector2f(0, 0), sf::Color::Blue),
                sf::Vertex(sf::Vector2f(0, 1280), sf::Color::Blue),
                sf::Vertex(sf::Vector2f(720, 0), sf::Color::Cyan),
                sf::Vertex(sf::Vector2f(720, 1280), sf::Color::Cyan)
        };

m_window.draw(backgroundgr, 4, sf::Quads);

Now, I don't know if I'm using it wrong, or if it just doesn't work. 

[Jesper Juhl]

Just asking the obvious questions here:

Do you clear() before you draw()?
Do you display() after you draw()?

[teunissenstefan]

Yep, both. Just thought those were too obvious to show it to you

[G.]

http://en.sfml-dev.org/forums/index.php?topic=16094.msg115303#msg115303 ?

That's not a rectangle.
And is your window 720, 1280?

[teunissenstefan]

Uhm 1280 x 720, but even with 720, 1280 it should at least be drawn for a bit.

[G.]

Yep, but are you going to post an SSCCE or is this thread not worth coming back?

>Good luck then.

[teunissenstefan]

Well I guess it's not worth for you to come back then.

[zsbzsb]

All primitive types must be defined in either clockwise or counter clockwise direction. Your code should be changed to the following.

Note: I changed the vertex order.

sf::Vertex backgroundgr[] =
        {
                sf::Vertex(sf::Vector2f(0, 0), sf::Color::Blue),
                sf::Vertex(sf::Vector2f(0, 1280), sf::Color::Blue),
                sf::Vertex(sf::Vector2f(720, 1280), sf::Color::Cyan)
                sf::Vertex(sf::Vector2f(720, 0), sf::Color::Cyan),
        };

[teunissenstefan]

Kay thanks, but it didn't fix the problem.

[zsbzsb]

Lets keep guessing here..... Or will you follow G.'s advice?

[teunissenstefan]

FINE YA DINGUS, for you, because you're nice. Not for G...

#include <memory>
#include <iostream>

#include "StateMachine.hpp"
#include "Level1State.hpp"
#include "PlayState.hpp"
#include "GameState.hpp"
#include "StateMachine.hpp"
#include "MenuState.hpp"
#include "Application.hpp"

#include <SFML/Graphics/RenderWindow.hpp>
#include <SFML/Window/Event.hpp>

int main() {
    sf::RenderWindow window( sf::VideoMode(1280, 720, 32), "Vieze kut" );
        sf::Vertex backgroundgr[] =
        {
                sf::Vertex(sf::Vector2f(0, 0), sf::Color::Blue),
                sf::Vertex(sf::Vector2f(0, 1280), sf::Color::Blue),
                sf::Vertex(sf::Vector2f(720, 1280), sf::Color::Cyan),
                sf::Vertex(sf::Vector2f(720, 0), sf::Color::Cyan),
        };
       
    while( window.isOpen() ) {
        sf::Event event;
        while( window.pollEvent( event ) ) {
            if( event.type == sf::Event::Closed ) {
                window.close();
            }
        }

                window.clear();
                window.draw(backgroundgr, 4, sf::Quads);
        window.display();
    }

    return EXIT_SUCCESS;
}

[teunissenstefan]

Hmm okay so that alone works, but not if

sf::Vertex backgroundgr[4];

is set in header?

And if I just put

sf::Vertex backgroundgr[4] =
        {
                sf::Vertex(sf::Vector2f(0, 0), sf::Color::Blue),
                sf::Vertex(sf::Vector2f(0, 1280), sf::Color::Blue),
                sf::Vertex(sf::Vector2f(720, 1280), sf::Color::Cyan),
                sf::Vertex(sf::Vector2f(720, 0), sf::Color::Cyan),
        };

in the .cpp it says: backgroundgr : undeclared identifier

[Nexus]

You can't just declare variables anywhere. Either declare the array of vertices as a local variable, or use a function... Then I recommend sf::VertexArray or at least std::array<sf::Vertex, 4> for value semantics. Plain C arrays should be avoided where possible.

By the way, this is not a SFML-related question... It might be worth having a look at a good C++ book