On 07 Mar 2008 06:06:21 +0100, Soeren Sandmann <<a href="mailto:sandmann@daimi.au.dk">sandmann@daimi.au.dk</a>> wrote: <div class="gmail_quote"><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"> Comments appreciated, both on the math and the attached patch. </blockquote> I can't really comment on the math but +       v.vector[0] -= (pixman_fixed_e * v.vector[2]) >> 16; +       v.vector[1] -= (pixman_fixed_e * v.vector[2]) >> 16; +       unit.vector[0] -= (pixman_fixed_e * unit.vector[2]) >> 16; +       unit.vector[0] -= (pixman_fixed_e * unit.vector[2]) >> 16; Shouldn't the last line be "unit.vector[1]"? Also, I'd put the common subexpression in a local variable but maybe that's just me. </div> Rob -- "He was pierced for our transgressions, he was crushed for our iniquities; the punishment that brought us peace was upon him, and by his wounds we are healed. We all, like sheep, have gone astray, each of us has turned to his own way; and the LORD has laid on him the iniquity of us all." [Isaiah 53:5-6]