Name: Anonymous 2010-07-03 9:31
How is it done?
Normally, rotating a vector A(x1, y1) through t radians in order to get vector B(x2, y2) is done with
But trigonometry is expensive, especially without an FPU, so there must be another way.
I was thinking of something similar to Bresenham's circle algorithm, or perhaps reflecting the vector about the origin or something.
So, uh, how would you do it?
Normally, rotating a vector A(x1, y1) through t radians in order to get vector B(x2, y2) is done with
x2 = x1*cos(t) - y1*sin(t),y2 = x1*sin(t) + y1*cos(t).But trigonometry is expensive, especially without an FPU, so there must be another way.
I was thinking of something similar to Bresenham's circle algorithm, or perhaps reflecting the vector about the origin or something.
So, uh, how would you do it?