288 lines
6.3 KiB
C++
288 lines
6.3 KiB
C++
/* OpenSceneGraph example, osgshaders.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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/************************************************************************
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* *
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* Copyright (C) 2002 3Dlabs Inc. Ltd. *
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* *
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************************************************************************/
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#include <math.h>
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#include <stdlib.h>
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/* Coherent noise function over 1, 2 or 3 dimensions */
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/* (copyright Ken Perlin) */
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#define MAXB 0x100
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#define N 0x1000
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#define NP 12 /* 2^N */
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#define NM 0xfff
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#define s_curve(t) ( t * t * (3. - 2. * t) )
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#define lerp(t, a, b) ( a + t * (b - a) )
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#define setup(i,b0,b1,r0,r1)\
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t = vec[i] + N;\
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b0 = ((int)t) & BM;\
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b1 = (b0+1) & BM;\
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r0 = t - (int)t;\
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r1 = r0 - 1.;
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#define at2(rx,ry) ( rx * q[0] + ry * q[1] )
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#define at3(rx,ry,rz) ( rx * q[0] + ry * q[1] + rz * q[2] )
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static void initNoise(void);
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static int p[MAXB + MAXB + 2];
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static double g3[MAXB + MAXB + 2][3];
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static double g2[MAXB + MAXB + 2][2];
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static double g1[MAXB + MAXB + 2];
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int start;
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int B;
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int BM;
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void SetNoiseFrequency(int frequency)
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{
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start = 1;
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B = frequency;
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BM = B-1;
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}
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double noise1(double arg)
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{
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int bx0, bx1;
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double rx0, rx1, sx, t, u, v, vec[1];
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vec[0] = arg;
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if (start) {
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start = 0;
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initNoise();
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}
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setup(0,bx0,bx1,rx0,rx1);
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sx = s_curve(rx0);
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u = rx0 * g1[ p[ bx0 ] ];
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v = rx1 * g1[ p[ bx1 ] ];
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return(lerp(sx, u, v));
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}
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double noise2(double vec[2])
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{
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int bx0, bx1, by0, by1, b00, b10, b01, b11;
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double rx0, rx1, ry0, ry1, *q, sx, sy, a, b, t, u, v;
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int i, j;
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if (start) {
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start = 0;
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initNoise();
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}
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setup(0, bx0,bx1, rx0,rx1);
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setup(1, by0,by1, ry0,ry1);
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i = p[ bx0 ];
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j = p[ bx1 ];
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b00 = p[ i + by0 ];
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b10 = p[ j + by0 ];
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b01 = p[ i + by1 ];
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b11 = p[ j + by1 ];
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sx = s_curve(rx0);
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sy = s_curve(ry0);
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q = g2[ b00 ] ; u = at2(rx0,ry0);
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q = g2[ b10 ] ; v = at2(rx1,ry0);
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a = lerp(sx, u, v);
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q = g2[ b01 ] ; u = at2(rx0,ry1);
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q = g2[ b11 ] ; v = at2(rx1,ry1);
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b = lerp(sx, u, v);
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return lerp(sy, a, b);
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}
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double noise3(double vec[3])
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{
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int bx0, bx1, by0, by1, bz0, bz1, b00, b10, b01, b11;
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double rx0, rx1, ry0, ry1, rz0, rz1, *q, sy, sz, a, b, c, d, t, u, v;
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int i, j;
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if (start) {
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start = 0;
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initNoise();
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}
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setup(0, bx0,bx1, rx0,rx1);
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setup(1, by0,by1, ry0,ry1);
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setup(2, bz0,bz1, rz0,rz1);
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i = p[ bx0 ];
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j = p[ bx1 ];
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b00 = p[ i + by0 ];
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b10 = p[ j + by0 ];
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b01 = p[ i + by1 ];
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b11 = p[ j + by1 ];
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t = s_curve(rx0);
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sy = s_curve(ry0);
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sz = s_curve(rz0);
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q = g3[ b00 + bz0 ] ; u = at3(rx0,ry0,rz0);
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q = g3[ b10 + bz0 ] ; v = at3(rx1,ry0,rz0);
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a = lerp(t, u, v);
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q = g3[ b01 + bz0 ] ; u = at3(rx0,ry1,rz0);
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q = g3[ b11 + bz0 ] ; v = at3(rx1,ry1,rz0);
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b = lerp(t, u, v);
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c = lerp(sy, a, b);
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q = g3[ b00 + bz1 ] ; u = at3(rx0,ry0,rz1);
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q = g3[ b10 + bz1 ] ; v = at3(rx1,ry0,rz1);
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a = lerp(t, u, v);
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q = g3[ b01 + bz1 ] ; u = at3(rx0,ry1,rz1);
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q = g3[ b11 + bz1 ] ; v = at3(rx1,ry1,rz1);
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b = lerp(t, u, v);
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d = lerp(sy, a, b);
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//fprintf(stderr, "%f\n", lerp(sz, c, d));
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return lerp(sz, c, d);
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}
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void normalize2(double v[2])
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{
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double s;
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s = sqrt(v[0] * v[0] + v[1] * v[1]);
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v[0] = v[0] / s;
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v[1] = v[1] / s;
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}
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void normalize3(double v[3])
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{
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double s;
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s = sqrt(v[0] * v[0] + v[1] * v[1] + v[2] * v[2]);
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v[0] = v[0] / s;
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v[1] = v[1] / s;
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v[2] = v[2] / s;
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}
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void initNoise(void)
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{
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int i, j, k;
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srand(30757);
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for (i = 0 ; i < B ; i++) {
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p[i] = i;
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g1[i] = (double)((rand() % (B + B)) - B) / B;
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for (j = 0 ; j < 2 ; j++)
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g2[i][j] = (double)((rand() % (B + B)) - B) / B;
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normalize2(g2[i]);
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for (j = 0 ; j < 3 ; j++)
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g3[i][j] = (double)((rand() % (B + B)) - B) / B;
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normalize3(g3[i]);
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}
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while (--i) {
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k = p[i];
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p[i] = p[j = rand() % B];
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p[j] = k;
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}
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for (i = 0 ; i < B + 2 ; i++) {
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p[B + i] = p[i];
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g1[B + i] = g1[i];
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for (j = 0 ; j < 2 ; j++)
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g2[B + i][j] = g2[i][j];
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for (j = 0 ; j < 3 ; j++)
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g3[B + i][j] = g3[i][j];
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}
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}
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/* --- My harmonic summing functions - PDB --------------------------*/
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/*
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In what follows "alpha" is the weight when the sum is formed.
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Typically it is 2, As this approaches 1 the function is noisier.
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"beta" is the harmonic scaling/spacing, typically 2.
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*/
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double PerlinNoise1D(double x,double alpha,double beta,int n)
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{
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int i;
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double val,sum = 0;
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double p,scale = 1;
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p = x;
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for (i=0;i<n;i++) {
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val = noise1(p);
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sum += val / scale;
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scale *= alpha;
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p *= beta;
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}
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return(sum);
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}
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double PerlinNoise2D(double x,double y,double alpha,double beta,int n)
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{
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int i;
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double val,sum = 0;
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double p[2],scale = 1;
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p[0] = x;
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p[1] = y;
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for (i=0;i<n;i++) {
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val = noise2(p);
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sum += val / scale;
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scale *= alpha;
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p[0] *= beta;
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p[1] *= beta;
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}
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return(sum);
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}
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double PerlinNoise3D(double x,double y,double z,double alpha,double beta,int n)
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{
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int i;
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double val,sum = 0;
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double p[3],scale = 1;
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p[0] = x;
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p[1] = y;
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p[2] = z;
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for (i=0;i<n;i++) {
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val = noise3(p);
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sum += val / scale;
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scale *= alpha;
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p[0] *= beta;
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p[1] *= beta;
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p[2] *= beta;
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}
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return(sum);
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}
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