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Help => Graphics => Topic started by: Rubenknex on June 08, 2011, 07:16:08 pm

Title: Settings texture wrapping to repeat using sf::Renderer
Post by: Rubenknex on June 08, 2011, 07:16:08 pm

I was just trying out some ways to generate a racing track from a few points, generating the vertices worked out right but I'm having some problems with the texture coordinates. I currently have a distance variable which keeps track of the current track distance and a textureSize variable which determines how much pixels of the track the texture should cover.

The code which calculates the uv coordinates:

Code: [Select]


float textureSize = 64.0f //The texture is 64x64 so this should display it at the real scale.

// The two sides of the point in the track.
leftVertex.texCoords = sf::Vector2f(0.0f, distance / textureSize);
rightVertex.texCoords = sf::Vector2f(1.0f, distance / textureSize);


I render the vertices like this:

Code: [Select]


renderer.SaveGLStates();
   
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_WRAP);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_WRAP);
   
renderer.SetTexture(&m_Texture);
renderer.Begin(sf::Renderer::TriangleStrip);
    for (int i = 0; i < m_sideVertices.size(); i++)
    {
        renderer.AddVertex(m_sideVertices[i].position.x,
                           m_sideVertices[i].position.y,
                           m_sideVertices[i].texCoords.x,
                           m_sideVertices[i].texCoords.y,
                           sf::Color::White);
    }
renderer.End();

renderer.RestoreGLStates();


But it looks like this (red lines show where the vertices are):
(http://dl.dropbox.com/u/20834329/Screenshot.png)

As you can see the beginning of the track (the left side) is textured correctly because the v coordinates are within the 0-1 range, after that the texture gets stretched out.

So is setting the texture wrapping mode to GL_REPEAT not working or am I using the wrong texture coordinates?

Title: Settings texture wrapping to repeat using sf::Renderer
Post by: Laurent on June 08, 2011, 08:08:36 pm

GL_TEXTURE_WRAP is a per-texture mode, not a global one. Therefore you must set it while the texture is active (and you can do it once at init).

You don't even need to save the GL states.

Code: [Select]

sf::Image m_Texture;
m_Texture.LoadFromFile(...);

m_Texture.Bind();
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);

Title: Settings texture wrapping to repeat using sf::Renderer
Post by: Rubenknex on June 08, 2011, 08:16:21 pm

Ah, I didn't know that, but it works perfectly now  :) .