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Diffstat (limited to 'indra/llmath/llperlin.cpp')
| -rw-r--r-- | indra/llmath/llperlin.cpp | 276 |
1 files changed, 276 insertions, 0 deletions
diff --git a/indra/llmath/llperlin.cpp b/indra/llmath/llperlin.cpp new file mode 100644 index 0000000000..770d80a845 --- /dev/null +++ b/indra/llmath/llperlin.cpp @@ -0,0 +1,276 @@ +/** + * @file llperlin.cpp + * + * Copyright (c) 2001-$CurrentYear$, Linden Research, Inc. + * $License$ + */ + +#include "linden_common.h" +#include "llmath.h" + +#include "llperlin.h" + +#define B 0x100 +#define BM 0xff +#define N 0x1000 +#define NF32 (4096.f) +#define NP 12 /* 2^N */ +#define NM 0xfff + +static S32 p[B + B + 2]; +static F32 g3[B + B + 2][3]; +static F32 g2[B + B + 2][2]; +static F32 g1[B + B + 2]; + +bool LLPerlinNoise::sInitialized = 0; + +static void normalize2(F32 v[2]) +{ + F32 s = 1.f/(F32)sqrt(v[0] * v[0] + v[1] * v[1]); + v[0] = v[0] * s; + v[1] = v[1] * s; +} + +static void normalize3(F32 v[3]) +{ + F32 s = 1.f/(F32)sqrt(v[0] * v[0] + v[1] * v[1] + v[2] * v[2]); + v[0] = v[0] * s; + v[1] = v[1] * s; + v[2] = v[2] * s; +} + +static void fast_setup(F32 vec, U8 &b0, U8 &b1, F32 &r0, F32 &r1) +{ + S32 t_S32; + + r1 = vec + NF32; + t_S32 = lltrunc(r1); + b0 = (U8)t_S32; + b1 = b0 + 1; + r0 = r1 - t_S32; + r1 = r0 - 1.f; +} + + +void LLPerlinNoise::init(void) +{ + int i, j, k; + + for (i = 0 ; i < B ; i++) + { + p[i] = i; + + g1[i] = (F32)((rand() % (B + B)) - B) / B; + + for (j = 0 ; j < 2 ; j++) + g2[i][j] = (F32)((rand() % (B + B)) - B) / B; + normalize2(g2[i]); + + for (j = 0 ; j < 3 ; j++) + g3[i][j] = (F32)((rand() % (B + B)) - B) / B; + normalize3(g3[i]); + } + + while (--i) + { + k = p[i]; + p[i] = p[j = rand() % B]; + p[j] = k; + } + + for (i = 0 ; i < B + 2 ; i++) + { + p[B + i] = p[i]; + g1[B + i] = g1[i]; + for (j = 0 ; j < 2 ; j++) + g2[B + i][j] = g2[i][j]; + for (j = 0 ; j < 3 ; j++) + g3[B + i][j] = g3[i][j]; + } + + sInitialized = true; +} + + +//============================================================================ +// Noise functions + +#define s_curve(t) ( t * t * (3.f - 2.f * t) ) + +#define lerp_m(t, a, b) ( a + t * (b - a) ) + +F32 LLPerlinNoise::noise1(F32 x) +{ + int bx0, bx1; + F32 rx0, rx1, sx, t, u, v; + + if (!sInitialized) + init(); + + t = x + N; + bx0 = (lltrunc(t)) & BM; + bx1 = (bx0+1) & BM; + rx0 = t - lltrunc(t); + rx1 = rx0 - 1.f; + + sx = s_curve(rx0); + + u = rx0 * g1[ p[ bx0 ] ]; + v = rx1 * g1[ p[ bx1 ] ]; + + return lerp_m(sx, u, v); +} + +static F32 fast_at2(F32 rx, F32 ry, F32 *q) +{ + return rx * q[0] + ry * q[1]; +} + +F32 LLPerlinNoise::noise2(F32 x, F32 y) +{ + U8 bx0, bx1, by0, by1; + U32 b00, b10, b01, b11; + F32 rx0, rx1, ry0, ry1, *q, sx, sy, a, b, u, v; + S32 i, j; + + if (!sInitialized) + init(); + + fast_setup(x, bx0, bx1, rx0, rx1); + fast_setup(y, by0, by1, ry0, ry1); + + i = *(p + bx0); + j = *(p + bx1); + + b00 = *(p + i + by0); + b10 = *(p + j + by0); + b01 = *(p + i + by1); + b11 = *(p + j + by1); + + sx = s_curve(rx0); + sy = s_curve(ry0); + + + q = *(g2 + b00); + u = fast_at2(rx0, ry0, q); + q = *(g2 + b10); + v = fast_at2(rx1, ry0, q); + a = lerp_m(sx, u, v); + + q = *(g2 + b01); + u = fast_at2(rx0,ry1,q); + q = *(g2 + b11); + v = fast_at2(rx1,ry1,q); + b = lerp_m(sx, u, v); + + return lerp_m(sy, a, b); +} + +static F32 fast_at3(F32 rx, F32 ry, F32 rz, F32 *q) +{ + return rx * q[0] + ry * q[1] + rz * q[2]; +} + +F32 LLPerlinNoise::noise3(F32 x, F32 y, F32 z) +{ + U8 bx0, bx1, by0, by1, bz0, bz1; + S32 b00, b10, b01, b11; + F32 rx0, rx1, ry0, ry1, rz0, rz1, *q, sy, sz, a, b, c, d, t, u, v; + S32 i, j; + + if (!sInitialized) + init(); + + fast_setup(x, bx0,bx1, rx0,rx1); + fast_setup(y, by0,by1, ry0,ry1); + fast_setup(z, bz0,bz1, rz0,rz1); + + i = p[ bx0 ]; + j = p[ bx1 ]; + + b00 = p[ i + by0 ]; + b10 = p[ j + by0 ]; + b01 = p[ i + by1 ]; + b11 = p[ j + by1 ]; + + t = s_curve(rx0); + sy = s_curve(ry0); + sz = s_curve(rz0); + + q = g3[ b00 + bz0 ]; + u = fast_at3(rx0,ry0,rz0,q); + q = g3[ b10 + bz0 ]; + v = fast_at3(rx1,ry0,rz0,q); + a = lerp_m(t, u, v); + + q = g3[ b01 + bz0 ]; + u = fast_at3(rx0,ry1,rz0,q); + q = g3[ b11 + bz0 ]; + v = fast_at3(rx1,ry1,rz0,q); + b = lerp_m(t, u, v); + + c = lerp_m(sy, a, b); + + q = g3[ b00 + bz1 ]; + u = fast_at3(rx0,ry0,rz1,q); + q = g3[ b10 + bz1 ]; + v = fast_at3(rx1,ry0,rz1,q); + a = lerp_m(t, u, v); + + q = g3[ b01 + bz1 ]; + u = fast_at3(rx0,ry1,rz1,q); + q = g3[ b11 + bz1 ]; + v = fast_at3(rx1,ry1,rz1,q); + b = lerp_m(t, u, v); + + d = lerp_m(sy, a, b); + + return lerp_m(sz, c, d); +} + +F32 LLPerlinNoise::turbulence2(F32 x, F32 y, F32 freq) +{ + F32 t, lx, ly; + + for (t = 0.f ; freq >= 1.f ; freq *= 0.5f) + { + lx = freq * x; + ly = freq * y; + t += noise2(lx, ly)/freq; + } + return t; +} + +F32 LLPerlinNoise::turbulence3(F32 x, F32 y, F32 z, F32 freq) +{ + F32 t, lx, ly, lz; + + for (t = 0.f ; freq >= 1.f ; freq *= 0.5f) + { + lx = freq * x; + ly = freq * y; + lz = freq * z; + t += noise3(lx,ly,lz)/freq; +// t += fabs(noise3(lx,ly,lz)) / freq; // Like snow - bubbly at low frequencies +// t += sqrt(fabs(noise3(lx,ly,lz))) / freq; // Better at low freq +// t += (noise3(lx,ly,lz)*noise3(lx,ly,lz)) / freq; + } + return t; +} + +F32 LLPerlinNoise::clouds3(F32 x, F32 y, F32 z, F32 freq) +{ + F32 t, lx, ly, lz; + + for (t = 0.f ; freq >= 1.f ; freq *= 0.5f) + { + lx = freq * x; + ly = freq * y; + lz = freq * z; +// t += noise3(lx,ly,lz)/freq; +// t += fabs(noise3(lx,ly,lz)) / freq; // Like snow - bubbly at low frequencies +// t += sqrt(fabs(noise3(lx,ly,lz))) / freq; // Better at low freq + t += (noise3(lx,ly,lz)*noise3(lx,ly,lz)) / freq; + } + return t; +} |