These functions are using a naive approach: casting double/float to int
and returning the result + 1. That increment by one must only happen for
positive input values though.
As suggested by Joshua, this commit adds the 2-clause BSD license as a
comment block to the top of every source file.
For the first pass, I've just added myself for simplicity. I encourage
everyone to add themselves as copyright holders of any file they've
added or modified in some significant way. If I've added myself in
error somewhere, feel free to replace it with the appropriate copyright
holder instead.
Going forward, all new source files should include a license header.
The old implementation of sin() had a very unacceptable amount of
error that was causing a lot of texture perspective issues in Quake.
This has been remedied through the use of the hardware `fsin`
x87 instruction. As has been noted in #246, this instruction is both
very slow, and can become wildly inaccurate for more precise values,
however the current implementation made an incorrect assumption about
applications "will end up writing their own implemtnation anyways",
which is not the case for Quake in Software mode, which relies heavily
on a correct `sin()` and `cos()` function for `R_ScanEdges()`.
Realistically, we should be using something like the CORDIC algorithm
(https://en.wikipedia.org/wiki/CORDIC) or `Taylor Expansion`, however
for now these provides a somewhat accurate result that allows Quake to
run without any texture or geometry issues.
