r600_mip_minify
w = r600_mip_minify(width, i);
h = r600_mip_minify(height, i);
d = r600_mip_minify(depth, i);
w0 = r600_mip_minify(w0, 0);
h0 = r600_mip_minify(h0, 0);
d0 = r600_mip_minify(d0, 0);
width = r600_mip_minify(w0, i);
height = r600_mip_minify(h0, i);
depth = r600_mip_minify(d0, i);
unsigned r600_mip_minify(unsigned size, unsigned level);