pouët.net

it's interesting we can use fpu stack and sse at once, but i guess the cases where we can pack down 8 fpu instructions in one sse instructions are slighly restrictive, as i can imagine.

it's anyway interesting to work arround it a bit. let's go. :-)

Anyway, how exactly do you reduce the ray-sphere to a linear equation? (that is what you meant by "first grade" right?)
I don't see how using the (0,0,1) ray can reduce the quadratic function to a linear one...
Or did I misunderstand something?

at first look.. i got at least the equation: d=sqrt(r^2-x^2-y^2)....

Oh, and as for why x*(1/sqrt(x)) == sqrt(x):

Let y = sqrt(x)
So x = y^2
x*1/sqrt(x) = y^2 * 1/y = y^2/y = y = sqrt(x)