| 25 |
|
#define rand3c(x,y,z) frand(89*(x)+97*(y)+101*(z)) |
| 26 |
|
#define rand3d(x,y,z) frand(103*(x)+107*(y)+109*(z)) |
| 27 |
|
|
| 28 |
< |
#define hermite(p0,p1,r0,r1,t) ( p0*((2.0*t-3.0)*t*t+1.0) + \ |
| 29 |
< |
p1*(-2.0*t+3.0)*t*t + \ |
| 30 |
< |
r0*((t-2.0)*t+1.0)*t + \ |
| 31 |
< |
r1*(t-1.0)*t*t ) |
| 28 |
> |
#define hpoly1(t) ((2.0*t-3.0)*t*t+1.0) |
| 29 |
> |
#define hpoly2(t) (-2.0*t+3.0)*t*t |
| 30 |
> |
#define hpoly3(t) ((t-2.0)*t+1.0)*t |
| 31 |
> |
#define hpoly4(t) (t-1.0)*t*t |
| 32 |
|
|
| 33 |
< |
double *noise3(), noise3coef(), argument(), frand(); |
| 33 |
> |
#define hermite(p0,p1,r0,r1,t) ( p0*hpoly1(t) + \ |
| 34 |
> |
p1*hpoly2(t) + \ |
| 35 |
> |
r0*hpoly3(t) + \ |
| 36 |
> |
r1*hpoly4(t) ) |
| 37 |
|
|
| 38 |
+ |
static char noise_name[4][8] = {"noise3a", "noise3b", "noise3c", "noise3"}; |
| 39 |
+ |
static char fnoise_name[] = "fnoise3"; |
| 40 |
+ |
static char hermite_name[] = "hermite"; |
| 41 |
+ |
|
| 42 |
+ |
double *noise3(), fnoise3(), argument(), frand(); |
| 43 |
+ |
|
| 44 |
|
static long xlim[3][2]; |
| 45 |
|
static double xarg[3]; |
| 46 |
|
|
| 47 |
|
#define EPSILON .0001 /* error allowed in fractal */ |
| 48 |
|
|
| 49 |
< |
#define frand3(x,y,z) frand((long)((12.38*(x)-22.30*(y)-42.63*(z))/EPSILON)) |
| 49 |
> |
#define frand3(x,y,z) frand(17*(x)+23*(y)+29*(z)) |
| 50 |
|
|
| 42 |
– |
double fnoise3(); |
| 51 |
|
|
| 52 |
< |
|
| 53 |
< |
double |
| 54 |
< |
l_noise3() /* compute 3-dimensional noise function */ |
| 52 |
> |
static double |
| 53 |
> |
l_noise3(nam) /* compute a noise function */ |
| 54 |
> |
register char *nam; |
| 55 |
|
{ |
| 56 |
< |
return(noise3coef(D)); |
| 56 |
> |
register int i; |
| 57 |
> |
double x[3]; |
| 58 |
> |
/* get point */ |
| 59 |
> |
x[0] = argument(1); |
| 60 |
> |
x[1] = argument(2); |
| 61 |
> |
x[2] = argument(3); |
| 62 |
> |
/* make appropriate call */ |
| 63 |
> |
if (nam == fnoise_name) |
| 64 |
> |
return(fnoise3(x)); |
| 65 |
> |
i = 4; |
| 66 |
> |
while (i--) |
| 67 |
> |
if (nam == noise_name[i]) |
| 68 |
> |
return(noise3(x)[i]); |
| 69 |
> |
eputs(nam); |
| 70 |
> |
eputs(": called l_noise3!\n"); |
| 71 |
> |
quit(1); |
| 72 |
|
} |
| 73 |
|
|
| 74 |
|
|
| 75 |
|
double |
| 76 |
< |
l_noise3a() /* compute x slope of noise function */ |
| 76 |
> |
l_hermite() /* library call for hermite interpolation */ |
| 77 |
|
{ |
| 78 |
< |
return(noise3coef(A)); |
| 78 |
> |
double t; |
| 79 |
> |
|
| 80 |
> |
t = argument(5); |
| 81 |
> |
return( hermite(argument(1), argument(2), |
| 82 |
> |
argument(3), argument(4), t) ); |
| 83 |
|
} |
| 84 |
|
|
| 85 |
|
|
| 86 |
< |
double |
| 60 |
< |
l_noise3b() /* compute y slope of noise function */ |
| 86 |
> |
setnoisefuncs() /* add noise functions to library */ |
| 87 |
|
{ |
| 88 |
< |
return(noise3coef(B)); |
| 63 |
< |
} |
| 88 |
> |
register int i; |
| 89 |
|
|
| 90 |
< |
|
| 91 |
< |
double |
| 92 |
< |
l_noise3c() /* compute z slope of noise function */ |
| 93 |
< |
{ |
| 94 |
< |
return(noise3coef(C)); |
| 90 |
> |
funset(hermite_name, 5, ':', l_hermite); |
| 91 |
> |
funset(fnoise_name, 3, ':', l_noise3); |
| 92 |
> |
i = 4; |
| 93 |
> |
while (i--) |
| 94 |
> |
funset(noise_name[i], 3, ':', l_noise3); |
| 95 |
|
} |
| 96 |
|
|
| 97 |
|
|
| 73 |
– |
double |
| 74 |
– |
l_fnoise3() /* compute fractal noise function */ |
| 75 |
– |
{ |
| 76 |
– |
double x[3]; |
| 77 |
– |
|
| 78 |
– |
x[0] = argument(1); |
| 79 |
– |
x[1] = argument(2); |
| 80 |
– |
x[2] = argument(3); |
| 81 |
– |
|
| 82 |
– |
return(fnoise3(x)); |
| 83 |
– |
} |
| 84 |
– |
|
| 85 |
– |
|
| 86 |
– |
static double |
| 87 |
– |
noise3coef(coef) /* return coefficient of noise function */ |
| 88 |
– |
int coef; |
| 89 |
– |
{ |
| 90 |
– |
double x[3]; |
| 91 |
– |
|
| 92 |
– |
x[0] = argument(1); |
| 93 |
– |
x[1] = argument(2); |
| 94 |
– |
x[2] = argument(3); |
| 95 |
– |
|
| 96 |
– |
return(noise3(x)[coef]); |
| 97 |
– |
} |
| 98 |
– |
|
| 99 |
– |
|
| 98 |
|
double * |
| 99 |
|
noise3(xnew) /* compute the noise function */ |
| 100 |
|
register double xnew[3]; |
| 122 |
|
double f[4]; |
| 123 |
|
register int i, n; |
| 124 |
|
{ |
| 125 |
< |
double f0[4], f1[4]; |
| 125 |
> |
double f0[4], f1[4], hp1, hp2; |
| 126 |
|
|
| 127 |
|
if (n == 0) { |
| 128 |
|
f[A] = rand3a(xlim[0][i&1],xlim[1][i>>1&1],xlim[2][i>>2]); |
| 133 |
|
n--; |
| 134 |
|
interpolate(f0, i, n); |
| 135 |
|
interpolate(f1, i | 1<<n, n); |
| 136 |
< |
f[A] = (1.0-xarg[n])*f0[A] + xarg[n]*f1[A]; |
| 137 |
< |
f[B] = (1.0-xarg[n])*f0[B] + xarg[n]*f1[B]; |
| 138 |
< |
f[C] = (1.0-xarg[n])*f0[C] + xarg[n]*f1[C]; |
| 139 |
< |
f[D] = hermite(f0[D], f1[D], f0[n], f1[n], xarg[n]); |
| 136 |
> |
hp1 = hpoly1(xarg[n]); hp2 = hpoly2(xarg[n]); |
| 137 |
> |
f[A] = f0[A]*hp1 + f1[A]*hp2; |
| 138 |
> |
f[B] = f0[B]*hp1 + f1[B]*hp2; |
| 139 |
> |
f[C] = f0[C]*hp1 + f1[C]*hp2; |
| 140 |
> |
f[D] = f0[D]*hp1 + f1[D]*hp2 + |
| 141 |
> |
f0[n]*hpoly3(xarg[n]) + f1[n]*hpoly4(xarg[n]); |
| 142 |
|
} |
| 143 |
|
} |
| 144 |
|
|
| 153 |
|
|
| 154 |
|
|
| 155 |
|
double |
| 156 |
– |
l_hermite() /* library call for hermite interpolation */ |
| 157 |
– |
{ |
| 158 |
– |
double t; |
| 159 |
– |
|
| 160 |
– |
t = argument(5); |
| 161 |
– |
return( hermite(argument(1), argument(2), |
| 162 |
– |
argument(3), argument(4), t) ); |
| 163 |
– |
} |
| 164 |
– |
|
| 165 |
– |
|
| 166 |
– |
double |
| 156 |
|
fnoise3(p) /* compute fractal noise function */ |
| 157 |
< |
register double p[3]; |
| 157 |
> |
double p[3]; |
| 158 |
|
{ |
| 159 |
|
double floor(); |
| 160 |
< |
double v[3], beg[3], fval[8], s, fc; |
| 161 |
< |
int closing, branch; |
| 160 |
> |
long t[3], v[3], beg[3]; |
| 161 |
> |
double fval[8], fc; |
| 162 |
> |
int branch; |
| 163 |
> |
register long s; |
| 164 |
|
register int i, j; |
| 165 |
|
/* get starting cube */ |
| 166 |
< |
for (i = 0; i < 3; i++) |
| 167 |
< |
beg[i] = floor(p[i]); |
| 166 |
> |
s = (long)(1.0/EPSILON); |
| 167 |
> |
for (i = 0; i < 3; i++) { |
| 168 |
> |
t[i] = s*p[i]; |
| 169 |
> |
beg[i] = s*floor(p[i]); |
| 170 |
> |
} |
| 171 |
|
for (j = 0; j < 8; j++) { |
| 172 |
|
for (i = 0; i < 3; i++) { |
| 173 |
|
v[i] = beg[i]; |
| 174 |
|
if (j & 1<<i) |
| 175 |
< |
v[i] += 1.0; |
| 175 |
> |
v[i] += s; |
| 176 |
|
} |
| 177 |
|
fval[j] = frand3(v[0],v[1],v[2]); |
| 178 |
|
} |
| 185 |
– |
s = 1.0; |
| 179 |
|
/* compute fractal */ |
| 180 |
|
for ( ; ; ) { |
| 181 |
< |
s *= 0.5; |
| 181 |
> |
fc = 0.0; |
| 182 |
> |
for (j = 0; j < 8; j++) |
| 183 |
> |
fc += fval[j]; |
| 184 |
> |
fc *= 0.125; |
| 185 |
> |
if ((s >>= 1) == 0) |
| 186 |
> |
return(fc); /* close enough */ |
| 187 |
|
branch = 0; |
| 190 |
– |
closing = 0; |
| 188 |
|
for (i = 0; i < 3; i++) { /* do center */ |
| 189 |
|
v[i] = beg[i] + s; |
| 190 |
< |
if (p[i] > v[i]) { |
| 190 |
> |
if (t[i] > v[i]) { |
| 191 |
|
branch |= 1<<i; |
| 192 |
< |
if (p[i] - v[i] > EPSILON) |
| 196 |
< |
closing++; |
| 197 |
< |
} else if (v[i] - p[i] > EPSILON) |
| 198 |
< |
closing++; |
| 192 |
> |
} |
| 193 |
|
} |
| 194 |
< |
fc = 0.0; |
| 201 |
< |
for (j = 0; j < 8; j++) |
| 202 |
< |
fc += fval[j]; |
| 203 |
< |
fc = 0.125*fc + s*frand3(v[0],v[1],v[2]); |
| 204 |
< |
if (closing == 0) |
| 205 |
< |
return(fc); /* close enough */ |
| 194 |
> |
fc += s*EPSILON*frand3(v[0],v[1],v[2]); |
| 195 |
|
fval[~branch & 7] = fc; |
| 196 |
|
for (i = 0; i < 3; i++) { /* do faces */ |
| 197 |
|
if (branch & 1<<i) |
| 202 |
|
for (j = 0; j < 8; j++) |
| 203 |
|
if (~(j^branch) & 1<<i) |
| 204 |
|
fc += fval[j]; |
| 205 |
< |
fc = 0.25*fc + s*frand3(v[0],v[1],v[2]); |
| 205 |
> |
fc = 0.25*fc + s*EPSILON*frand3(v[0],v[1],v[2]); |
| 206 |
|
fval[~(branch^1<<i) & 7] = fc; |
| 207 |
|
v[i] = beg[i] + s; |
| 208 |
|
} |
| 219 |
|
v[j] -= s; |
| 220 |
|
fc = fval[branch & ~(1<<i)]; |
| 221 |
|
fc += fval[branch | 1<<i]; |
| 222 |
< |
fc = 0.5*fc + s*frand3(v[0],v[1],v[2]); |
| 222 |
> |
fc = 0.5*fc + s*EPSILON*frand3(v[0],v[1],v[2]); |
| 223 |
|
fval[branch^1<<i] = fc; |
| 224 |
|
j = (i+1)%3; |
| 225 |
|
v[j] = beg[j] + s; |
