gBackgroundPos += 0.0003f;  // gBackgroundPos climbs indefinitely...
GLfloat bgCoords[] = {  gBackgroundPos, 1.0,
            gBackgroundPos + 0.5f,  1.0,
            gBackgroundPos, 0.0,
            gBackgroundPos + 0.5f,  0.0  };

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