Question

I am using the Android mobile platform, with OpenGL ES 2.0.

When I make a texture like so, the textures in my scene draw correctly

 //Generate there texture pointer
 GLES20.glGenTextures(1, textureHandle, 0);

    // parameters - we have to make sure we clamp the textures to the edges!!!
            GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureHandle[0]);
    GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_S,GLES20.GL_CLAMP_TO_EDGE);
    GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_T,GLES20.GL_CLAMP_TO_EDGE);
    GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MAG_FILTER,GLES20.GL_LINEAR);
    GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MIN_FILTER,GLES20.GL_LINEAR);

However, I want to be able to scroll a texture, and I believe setting the wrap mode to GLES20.GL_REPEAT would make the needed calculation more possible. However, when using code such as below.

            //Generate there texture pointer
            GLES20.glGenTextures(1, textureHandle, 0);

    // parameters - we have to make sure we clamp the textures to the edges!!!
    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureHandle[0]);
    GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_S,GLES20.GL_REPEAT);
    GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_T,GLES20.GL_REPEAT);
    GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MAG_FILTER,GLES20.GL_LINEAR);
    GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MIN_FILTER,GLES20.GL_LINEAR);

Every texture is black. The only difference I have made here is the setting of the GLES20.GL_REPEAT parameter name in the call to GLES20.glTexParameteri. This seems really odd. Does anyone have some ideas to share?

I appreciate any help.
Thanks.

Answer 1

Are the texture sizes powers of two (POT)? If not, there are some limitations on the wrap modes for NPOT textures; only GL_CLAMP_TO_EDGE is supported in that case, which is what you’re seeing.