sf::Texture and OpenGL

[Richy19]

Do you know how you would use a sf::Texture with openGL?
The only way I can think of is converting it to a sf::Image and then

Code: [Select]

// Give the image to OpenGL
    glTexImage2D(GL_TEXTURE_2D, 0,GL_RGBA, TextureResourceManager::textureResourceManager.getFile("./Data/Pedro.png").GetWidth(), TextureResourceManager::textureResourceManager.getFile("./Data/Pedro.png").GetHeight(), 0, GL_RGBA, GL_UNSIGNED_BYTE,TextureResourceManager::textureResourceManager.getFile("./Data/Pedro.png").CopyToImage().GetPixelsPtr() );
 

[Laurent]

Isn't it what we talked about in the previous page? :roll:

[Richy19]

Yea but you mentioned that it wasnt good to call sf::Texture.getImage() each frame as it takes quite a bit of resources to swap from GPU to CPU, so I was wondering how you use the sf::Texture straight away

[Laurent]

But why do you start with a texture? If all you want is to use the pixel data of an image file, load it directly as a sf::Image. And why does it have to happen each frame? The source is an image file, it doesn't change every frame, does it?

[Richy19]

no, but if I used renderTextures then they would

[Laurent]

If you used sf::RenderTexture it would be another problem, with another solution.

[DFPercush]

Hate to resurrect a dead thread, but I don't think anyone ever explicitly said this: The OpenGL coordinate system, if no transformations are applied besides the identity matrix, puts the origin at the bottom left of the screen, when dealing with vertices, and at the bottom left of an image when dealing with textures. The positive Y axis points up in the plane of the screen/image, and the Z axis points out of the screen toward the viewer, meaning openGL is a right handed coordinate system. Of course, one can reverse any of these with a transformation matrix which simply negates the desired axis.