synfig-core/tags/stable/src/modules/mod_particle/random.cpp

   1 /* === S Y N F I G ========================================================= */
   2 /*!     \file mod_particle/random.cpp
   3 **      \brief blehh
   4 **
   5 **      $Id$
   6 **
   7 **      \legal
   8 **      Copyright (c) 2002-2005 Robert B. Quattlebaum Jr., Adrian Bentley
   9 **      Copyright (c) 2007 Chris Moore
  10 **
  11 **      This package is free software; you can redistribute it and/or
  12 **      modify it under the terms of the GNU General Public License as
  13 **      published by the Free Software Foundation; either version 2 of
  14 **      the License, or (at your option) any later version.
  15 **
  16 **      This package is distributed in the hope that it will be useful,
  17 **      but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 **      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  19 **      General Public License for more details.
  20 **      \endlegal
  21 */
  22 /* ========================================================================= */
  23
  24 /* === H E A D E R S ======================================================= */
  25
  26 #ifdef USING_PCH
  27 #       include "pch.h"
  28 #else
  29 #ifdef HAVE_CONFIG_H
  30 #       include <config.h>
  31 #endif
  32
  33 #include "random.h"
  34 #include <cmath>
  35 #include <cstdlib>
  36
  37 #endif
  38
  39 /* === M A C R O S ========================================================= */
  40
  41 #define PI      (3.1415927)
  42
  43 /* === G L O B A L S ======================================================= */
  44
  45 /* === P R O C E D U R E S ================================================= */
  46
  47 /* === M E T H O D S ======================================================= */
  48
  49 void
  50 Random::set_seed(int x)
  51 {
  52         seed_=x;
  53         srand(x);
  54         int i;
  55         for(i=0;i<POOL_SIZE;i++)
  56                 pool_[i]=rand();
  57
  58         x_mask=rand()+rand()*RAND_MAX;
  59         y_mask=rand()+rand()*RAND_MAX;
  60         t_mask=rand()+rand()*RAND_MAX;
  61 }
  62
  63 // this picks one of the POOL_SIZE (256) preset values out of the pool
  64 // and scales it to be in the range (-1, 1).  is that what it was
  65 // intended to do?  the distribution is pretty terrible, too, with
  66 // some elements being picked a hundred times more often than others
  67 float
  68 Random::operator()(const int salt,const int x,const int y,const int t)const
  69 {
  70         const int salt_hash(pool_[salt&(POOL_SIZE-1)]);
  71
  72         int index(((x^x_mask)+(y^y_mask)*234672+(t^t_mask)*8439573)^salt_hash);
  73
  74         index+=index*(index/POOL_SIZE);
  75
  76         return (float(pool_[index&(POOL_SIZE-1)])/float(RAND_MAX))*2.0f-1.0f;
  77 }
  78
  79 float
  80 Random::operator()(SmoothType smooth,int subseed,float xf,float yf,float tf)const
  81 {
  82         int x((int)floor(xf));
  83         int y((int)floor(yf));
  84         int t((int)floor(tf));
  85
  86         switch(smooth)
  87         {
  88         case SMOOTH_CUBIC:      // cubic
  89                 {
  90                         #define f(j,i,k)        ((*this)(subseed,i,j,k))
  91                         //Using catmull rom interpolation because it doesn't blur at all
  92                         // ( http://www.gamedev.net/reference/articles/article1497.asp )
  93                         //bezier curve with intermediate ctrl pts: 0.5/3(p(i+1) - p(i-1)) and similar
  94                         float xfa [4], tfa[4];
  95
  96                         //precalculate indices (all clamped) and offset
  97                         const int xa[] = {x-1,x,x+1,x+2};
  98
  99                         const int ya[] = {y-1,y,y+1,y+2};
 100
 101                         const int ta[] = {t-1,t,t+1,t+2};
 102
 103                         const float dx(xf-x);
 104                         const float dy(yf-y);
 105                         const float dt(tf-t);
 106
 107                         //figure polynomials for each point
 108                         const float txf[] =
 109                         {
 110                                 0.5*dx*(dx*(dx*(-1) + 2) - 1),  //-t + 2t^2 -t^3
 111                                 0.5*(dx*(dx*(3*dx - 5)) + 2),   //2 - 5t^2 + 3t^3
 112                                 0.5*dx*(dx*(-3*dx + 4) + 1),    //t + 4t^2 - 3t^3
 113                                 0.5*dx*dx*(dx-1)                                //-t^2 + t^3
 114                         };
 115
 116                         const float tyf[] =
 117                         {
 118                                 0.5*dy*(dy*(dy*(-1) + 2) - 1),  //-t + 2t^2 -t^3
 119                                 0.5*(dy*(dy*(3*dy - 5)) + 2),   //2 - 5t^2 + 3t^3
 120                                 0.5*dy*(dy*(-3*dy + 4) + 1),    //t + 4t^2 - 3t^3
 121                                 0.5*dy*dy*(dy-1)                                //-t^2 + t^3
 122                         };
 123
 124                         const float ttf[] =
 125                         {
 126                                 0.5*dt*(dt*(dt*(-1) + 2) - 1),  //-t + 2t^2 -t^3
 127                                 0.5*(dt*(dt*(3*dt - 5)) + 2),   //2 - 5t^2 + 3t^3
 128                                 0.5*dt*(dt*(-3*dt + 4) + 1),    //t + 4t^2 - 3t^3
 129                                 0.5*dt*dt*(dt-1)                                //-t^2 + t^3
 130                         };
 131
 132                         //evaluate polynomial for each row
 133                         for(int i = 0; i < 4; ++i)
 134                         {
 135                                 for(int j = 0; j < 4; ++j)
 136                                 {
 137                                         tfa[j] = f(ya[i],xa[j],ta[0])*ttf[0] + f(ya[i],xa[j],ta[1])*ttf[1] + f(ya[i],xa[j],ta[2])*ttf[2] + f(ya[i],xa[j],ta[3])*ttf[3];
 138                                 }
 139                                 xfa[i] = tfa[0]*txf[0] + tfa[1]*txf[1] + tfa[2]*txf[2] + tfa[3]*txf[3];
 140                         }
 141
 142                         //return the cumulative column evaluation
 143                         return xfa[0]*tyf[0] + xfa[1]*tyf[1] + xfa[2]*tyf[2] + xfa[3]*tyf[3];
 144 #undef f
 145                 }
 146                 break;
 147
 148
 149         case SMOOTH_FAST_SPLINE:        // Fast Spline (non-animated)
 150                 {
 151 #define P(x)    (((x)>0)?((x)*(x)*(x)):0.0f)
 152 #define R(x)    ( P(x+2) - 4.0f*P(x+1) + 6.0f*P(x) - 4.0f*P(x-1) )*(1.0f/6.0f)
 153 #define F(i,j)  ((*this)(subseed,i+x,j+y)*(R((i)-a)*R(b-(j))))
 154 #define FT(i,j,k)       ((*this)(subseed,i+x,j+y,k+t)*(R((i)-a)*R(b-(j))*R((k)-c)))
 155 #define Z(i,j) ret+=F(i,j)
 156 #define ZT(i,j,k) ret+=FT(i,j,k)
 157 #define X(i,j)  // placeholder... To make box more symmetric
 158 #define XT(i,j,k)       // placeholder... To make box more symmetric
 159
 160                 float a(xf-x), b(yf-y);
 161
 162                 // Interpolate
 163                 float ret(F(0,0));
 164                 Z(-1,-1); Z(-1, 0); Z(-1, 1); Z(-1, 2);
 165                 Z( 0,-1); X( 0, 0); Z( 0, 1); Z( 0, 2);
 166                 Z( 1,-1); Z( 1, 0); Z( 1, 1); Z( 1, 2);
 167                 Z( 2,-1); Z( 2, 0); Z( 2, 1); Z( 2, 2);
 168
 169                 return ret;
 170         }
 171
 172         case SMOOTH_SPLINE:     // Spline (animated)
 173                 {
 174                         float a(xf-x), b(yf-y), c(tf-t);
 175
 176                         // Interpolate
 177                         float ret(FT(0,0,0));
 178                         ZT(-1,-1,-1); ZT(-1, 0,-1); ZT(-1, 1,-1); ZT(-1, 2,-1);
 179                         ZT( 0,-1,-1); ZT( 0, 0,-1); ZT( 0, 1,-1); ZT( 0, 2,-1);
 180                         ZT( 1,-1,-1); ZT( 1, 0,-1); ZT( 1, 1,-1); ZT( 1, 2,-1);
 181                         ZT( 2,-1,-1); ZT( 2, 0,-1); ZT( 2, 1,-1); ZT( 2, 2,-1);
 182
 183                         ZT(-1,-1, 0); ZT(-1, 0, 0); ZT(-1, 1, 0); ZT(-1, 2, 0);
 184                         ZT( 0,-1, 0); XT( 0, 0, 0); ZT( 0, 1, 0); ZT( 0, 2, 0);
 185                         ZT( 1,-1, 0); ZT( 1, 0, 0); ZT( 1, 1, 0); ZT( 1, 2, 0);
 186                         ZT( 2,-1, 0); ZT( 2, 0, 0); ZT( 2, 1, 0); ZT( 2, 2, 0);
 187
 188                         ZT(-1,-1, 1); ZT(-1, 0, 1); ZT(-1, 1, 1); ZT(-1, 2, 1);
 189                         ZT( 0,-1, 1); ZT( 0, 0, 1); ZT( 0, 1, 1); ZT( 0, 2, 1);
 190                         ZT( 1,-1, 1); ZT( 1, 0, 1); ZT( 1, 1, 1); ZT( 1, 2, 1);
 191                         ZT( 2,-1, 1); ZT( 2, 0, 1); ZT( 2, 1, 1); ZT( 2, 2, 1);
 192
 193                         ZT(-1,-1, 2); ZT(-1, 0, 2); ZT(-1, 1, 2); ZT(-1, 2, 2);
 194                         ZT( 0,-1, 2); ZT( 0, 0, 2); ZT( 0, 1, 2); ZT( 0, 2, 2);
 195                         ZT( 1,-1, 2); ZT( 1, 0, 2); ZT( 1, 1, 2); ZT( 1, 2, 2);
 196                         ZT( 2,-1, 2); ZT( 2, 0, 2); ZT( 2, 1, 2); ZT( 2, 2, 2);
 197
 198                         return ret;
 199
 200 /*
 201
 202                         float dx=xf-x;
 203                         float dy=yf-y;
 204                         float dt=tf-t;
 205
 206                         float ret=0;
 207                         int i,j,h;
 208                         for(h=-1;h<=2;h++)
 209                                 for(i=-1;i<=2;i++)
 210                                         for(j=-1;j<=2;j++)
 211                                                 ret+=(*this)(subseed,i+x,j+y,h+t)*(R(i-dx)*R(j-dy)*R(h-dt));
 212                         return ret;
 213 */
 214                 }
 215                 break;
 216 #undef X
 217 #undef Z
 218 #undef F
 219 #undef P
 220 #undef R
 221
 222         case SMOOTH_COSINE:
 223         if((float)t==tf)
 224         {
 225                 int x((int)floor(xf));
 226                 int y((int)floor(yf));
 227                 float a=xf-x;
 228                 float b=yf-y;
 229                 a=(1.0f-cos(a*PI))*0.5f;
 230                 b=(1.0f-cos(b*PI))*0.5f;
 231                 float c=1.0-a;
 232                 float d=1.0-b;
 233                 int x2=x+1,y2=y+1;
 234                 return
 235                         (*this)(subseed,x,y,t)*(c*d)+
 236                         (*this)(subseed,x2,y,t)*(a*d)+
 237                         (*this)(subseed,x,y2,t)*(c*b)+
 238                         (*this)(subseed,x2,y2,t)*(a*b);
 239         }
 240         else
 241         {
 242                 float a=xf-x;
 243                 float b=yf-y;
 244                 float c=tf-t;
 245
 246                 a=(1.0f-cos(a*PI))*0.5f;
 247                 b=(1.0f-cos(b*PI))*0.5f;
 248
 249                 // We don't perform this on the time axis, otherwise we won't
 250                 // get smooth motion
 251                 //c=(1.0f-cos(c*PI))*0.5f;
 252
 253                 float d=1.0-a;
 254                 float e=1.0-b;
 255                 float f=1.0-c;
 256
 257                 int x2=x+1,y2=y+1,t2=t+1;
 258
 259                 return
 260                         (*this)(subseed,x,y,t)*(d*e*f)+
 261                         (*this)(subseed,x2,y,t)*(a*e*f)+
 262                         (*this)(subseed,x,y2,t)*(d*b*f)+
 263                         (*this)(subseed,x2,y2,t)*(a*b*f)+
 264                         (*this)(subseed,x,y,t2)*(d*e*c)+
 265                         (*this)(subseed,x2,y,t2)*(a*e*c)+
 266                         (*this)(subseed,x,y2,t2)*(d*b*c)+
 267                         (*this)(subseed,x2,y2,t2)*(a*b*c);
 268         }
 269         case SMOOTH_LINEAR:
 270         if((float)t==tf)
 271         {
 272                 int x((int)floor(xf));
 273                 int y((int)floor(yf));
 274                 float a=xf-x;
 275                 float b=yf-y;
 276                 float c=1.0-a;
 277                 float d=1.0-b;
 278                 int x2=x+1,y2=y+1;
 279                 return
 280                         (*this)(subseed,x,y,t)*(c*d)+
 281                         (*this)(subseed,x2,y,t)*(a*d)+
 282                         (*this)(subseed,x,y2,t)*(c*b)+
 283                         (*this)(subseed,x2,y2,t)*(a*b);
 284         }
 285         else
 286         {
 287
 288                 float a=xf-x;
 289                 float b=yf-y;
 290                 float c=tf-t;
 291
 292                 float d=1.0-a;
 293                 float e=1.0-b;
 294                 float f=1.0-c;
 295
 296                 int x2=x+1,y2=y+1,t2=t+1;
 297
 298                 return
 299                         (*this)(subseed,x,y,t)*(d*e*f)+
 300                         (*this)(subseed,x2,y,t)*(a*e*f)+
 301                         (*this)(subseed,x,y2,t)*(d*b*f)+
 302                         (*this)(subseed,x2,y2,t)*(a*b*f)+
 303                         (*this)(subseed,x,y,t2)*(d*e*c)+
 304                         (*this)(subseed,x2,y,t2)*(a*e*c)+
 305                         (*this)(subseed,x,y2,t2)*(d*b*c)+
 306                         (*this)(subseed,x2,y2,t2)*(a*b*c);
 307         }
 308         default:
 309         case SMOOTH_DEFAULT:
 310                 return (*this)(subseed,x,y,t);
 311         }
 312 }