glBindTexture (GL_TEXTURE_2D, bp->texture);
glCopyTexImage2D (GL_TEXTURE_2D, 0, GL_LUMINANCE, 0, 0,
bp->tex_w, bp->tex_h, 0);
glBindTexture (GL_TEXTURE_2D, bp->texture);
glCopyTexImage2D (GL_TEXTURE_2D, 0, GL_LUMINANCE, 0, 0,
bp->tex_w, bp->tex_h, 0);