Using the Alpha Value embedded in an image file

[pogrady]

Hello,
How do I render an image that has RGBA values?  I would like to utilize the transparency i created in my paint program, but i am unsure how to use OpenGL. I know that there is a blend mode, and that utilization of OpenGL is simple in SFML since OpenGL is the backend, but i'm not sure which blend mode, or which function i should use.

I added this code after the ceation of my window:

sf::RenderWindow window(sf::VideoMode(800, 600, 32), "SFML works!");

        glEnable(GL_BLEND);
        glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_DST_COLOR);
        window.pushGLStates();
 

If somebody has a link to a tutorial that would be awesome as I don't even know what this is called. 

[eXpl0it3r]

Why not just use SFML instead of OpenGL?

sf::Texture tex;
tex.loadFromFile("image.png");
sf::Sprite sprite(tex);
// ...
window.draw(sprite);
// ...

The PNG format supports transparency and so thus SFML.

[pogrady]

Thanks. I was looking through the documentation about SOIL, but it didn't mention that PNG supports RGBA, only TGA, so i was trying to use TGA.

Just a question, but do i need to enable blending, or can i remove that?

[eXpl0it3r]

SFML is built on top of RGBA you don't need to do anything, just load the PNG.

[pogrady]

Thanks for your help.