OpenGL ES 2.0 texture clamping

Question

i'm trying to get my texture to be tiled when texture-coordinates go beyond 1.

I have tried this:

glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT),

How ever, when settings these two lines, all I see is black color, no texture at all!

This works, but doesn't give the repeating effect, which i need:

glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

Help! I've used already couple of hours to investigate with no results!

Answer 1

Setting GL_TEXTURE_WRAP_S and GL_TEXTURE_WRAP_T to GL_REPEAT requires your texture dimensions to be powers of two.

Answer 2

You can convert texture coordinate values greater than one to values in the range 0...1 by discarding the fractional part. Here's some code you can put in your fragment shader, assuming that the texture coordinates are in texture_coord:

        texture_coord.x = mod(texture_coord.x,1.0);
        texture_coord.y = mod(texture_coord.y,1.0);
        gl_FragColor = texture2D(s_texture,texture_coord);

I have tested this in OpenGL ES 2.0 and it works as expected, allowing you to use textures of any size, not just powers of two.