NeXT Education Software Sampler 1992 Fall/NeXT Education Software Sampler 1992 Fall.iso/SoundAndMusic/cmix/lib/bbuzz.c

C/C++ Source or Header | 1989-02-25 | 489 b | 28 lines

float *
bbuzz(amp,si,hn,f,phs,a,alen)
float amp,si,hn,*f,*phs,*a;
long alen;
{
    register i,j,k;
    float q,d,h2n,h2np1;
    float *fp= a;
    h2n = hn+hn;
    h2np1 = h2n+1.;
    for(i=0; i<alen; i++) {
        j = *phs;
        k = (j+1) % 1024;
        q = (int)((*phs - (float)j) * h2np1)/h2np1;
        d = *(f+j);
        d += (*(f+k)-d)*q;
        if(!d) *fp++  = amp;
        else {
            k = (long)(h2np1 * *phs) % 1024;
            *fp++  = amp * (*(f+k)/d - 1.)/h2n;
        }
        *phs += si;
        while(*phs >= 1024.)
            *phs -= 1024.;
    }
    return(a);
}