On 21 July 2010 16:06, Owen Rudge owen@owenrudge.net wrote:
+/* Returns TRUE if num is a power of 2, FALSE otherwise */ +BOOL is_pow2(UINT num) +{
- return !(num & (num - 1));
+}
Minor, but this returns TRUE if num is power of two, *or zero*. That's fine for how it's used, but please mention it.
+/* Returns the smallest power of 2 which is greater than or equal to num */ +UINT make_pow2(UINT num) +{
- UINT result = 1;
- while (result < num)
result <<= 1;- return result;
+}
There's a danger of this looping forever if you pass it something > 0x80000000. I'm not sure if we care though, maybe that simply falls under the heading of "so don't do that".
if (!width && !height)max_mipmaps = 9;
This looks like the number of mipmaps in a 256x256 texture, i.e. log2i(256) + 1. That doesn't match the values of w and h in that case though, so I think a comment for clarification wouldn't hurt there.
while (mip_width > 1 || mip_height > 1){mip_width >>= 1;mip_height >>= 1;max_mipmaps++;}
This one is also minor, but if you don't need mip_width / mip_height for anything else, you can just take max(w, h) before the loop. It's probably not worth the trouble for a single instance of this calculation, but note that wined3d has a wined3d_log2i() function in dlls/wined3d/utils.c.
-
Henri Verbeet