void cryptoRandom (int iCount, CIPInteger *retx)
// cryptoRandom
//
// Generate iCount BYTEs of randomness
{
// Edge cases
if (iCount == 0)
*retx = CIPInteger();
// Generate bytes
CBuffer Chaos(iCount);
int iLeft = iCount;
while (iLeft)
{
// rand_s is Window's cryptographic random number generator.
// NOTE: rand_s IS thread-safe, since it just calls an internal OS
// function.
unsigned int dwRnd;
rand_s(&dwRnd);
int iWrite = Min(iLeft, (int)sizeof(DWORD));
Chaos.Write(&dwRnd, iWrite);
iLeft -= iWrite;
}
// Initialize. Note that CIPInteger expects the byte stream to be in big-
// endian order, but since random is random it doesn't matter that we're
// backwards.
retx->InitFromBytes(Chaos);
}
/*
* Apply a "mount" texture.
*/
void
MountApply(
Mount *mount,
Geom * /*prim*/,
Ray * /*ray*/,
Vector *pos,
Vector *norm,
Vector * /*gnorm*/,
Surface *surf)
{
int index;
Float t;
t = Chaos(pos, 7);
index = (int)(pos->z + mount->turb*t - mount->slope*(1.-norm->z))*256;
if (index < 0)
index = 0;
if (index > 255)
index = 255;
ColorMultiply(surf->amb, mount->cmap[index], &surf->amb);
ColorMultiply(surf->diff, mount->cmap[index], &surf->diff);
ColorMultiply(surf->spec, mount->cmap[index], &surf->spec);
}
