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1

Graphics / Render a rectangle with vertices using a texture and a color

« on: August 18, 2014, 03:22:54 am »

Hello,

This is maybe easy to achieve but (as I just started learning Graphics Programming) I couldn't manage to get it working as intended.
So I have a red rectangle rendered via a vertex array :

Now I want to draw on top of it a texture (white question mark with transparent background) using "textCoord" :

so the final result would be like this :

But this is what I get instead:

I assume this because SFML infernally multiplies the texture's pixels by the vertices' colors. If that's true, how can I change the blend mode used to draw the rectangle? And what's the appropriate mode to use in this case?

Thank you in advance.

PS: Here is a minimal code ("questionMark.png" is attached to this post):

int main()
{
    sf::RenderWindow window(sf::VideoMode(400, 240), "My window");

    sf::Texture texture;
    if (!texture.loadFromFile("questionMark.png"))
    {
        // error...
    }

    // create an array of 4 vertices that define a quad primitive
    sf::VertexArray quad(sf::Quads, 4);

    // define the position of the quad's points
    quad[0].position = sf::Vector2f(10, 10);
    quad[1].position = sf::Vector2f(100, 10);
    quad[2].position = sf::Vector2f(100, 100);
    quad[3].position = sf::Vector2f(10, 100);

    // define the color of the quad's points
    quad[0].color = sf::Color::Red;
    quad[1].color = sf::Color::Red;
    quad[2].color = sf::Color::Red;
    quad[3].color = sf::Color::Red;

    // define its texture area
    quad[0].texCoords = sf::Vector2f(0, 0);
    quad[1].texCoords = sf::Vector2f(8, 0);
    quad[2].texCoords = sf::Vector2f(8, 8);
    quad[3].texCoords = sf::Vector2f(0, 8);

    // define the render states
    sf::RenderStates states;
    //states.blendMode = ???;
    states.texture = &texture;


    // run the program as long as the window is open
    while (window.isOpen())
    {
        // check all the window's events that were triggered since the last iteration of the loop
        sf::Event event;
        while (window.pollEvent(event))
        {
            // "close requested" event: we close the window
            if (event.type == sf::Event::Closed)
                window.close();
        }

        // clear the window with black color
        window.clear(sf::Color::Black);

        // draw everything here...
        window.draw(quad, states);

        // end the current frame
        window.display();
    }

    return 0;
}
 

2

General discussions / An interesting reddit post about SFML : "why_do_so_few_games_use_sfml"

« on: August 09, 2014, 04:08:18 am »

http://www.reddit.com/r/gamedev/comments/2cywca/why_do_so_few_games_use_sfml/