Question

I believe I have all the components to make a simple green drawing, obviously I’m wrong. Maybe someone can shed some light on what I am missing?

@Override
public synchronized void onDrawFrame(GL10 unused) {
    Bitmap b = Bitmap.createBitmap(512, 512, Bitmap.Config.RGB_565); 
    b.eraseColor(Color.GREEN);
    GLES20.glEnable(GLES20.GL_TEXTURE_2D);
    GLUtils.texImage2D(GLES20.GL_TEXTURE_2D, 0, b, 0);
}

Answer 1

glTexImage2D does not draw anything. It merely copies an image into a texture. You still have to draw some geometry (a quad or so) that’s being textured with said image.

Also glTexImage needs a bound texture object to work with. Which means you first have to use glGenTextures to obtain a new texture ID and then glBindTexture to bind/create it.

I should also point out that if the image remains constant you should not re-upload it upon every frame drawing.

But most importantly if you just want to draw some green quad, why not just draw a green quad? You don’t need a texture for this.