1 /* === S Y N F I G ========================================================= */
2 /*! \file mod_particle/random.cpp
8 ** Copyright (c) 2002-2005 Robert B. Quattlebaum Jr., Adrian Bentley
10 ** This package is free software; you can redistribute it and/or
11 ** modify it under the terms of the GNU General Public License as
12 ** published by the Free Software Foundation; either version 2 of
13 ** the License, or (at your option) any later version.
15 ** This package is distributed in the hope that it will be useful,
16 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
17 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 ** General Public License for more details.
21 /* ========================================================================= */
23 /* === H E A D E R S ======================================================= */
38 /* === M A C R O S ========================================================= */
40 /* === G L O B A L S ======================================================= */
42 /* === P R O C E D U R E S ================================================= */
44 /* === M E T H O D S ======================================================= */
47 Random::set_seed(int x)
52 for(i=0;i<POOL_SIZE;i++)
55 x_mask=rand()+rand()*RAND_MAX;
56 y_mask=rand()+rand()*RAND_MAX;
57 t_mask=rand()+rand()*RAND_MAX;
60 // this picks one of the POOL_SIZE (256) preset values out of the pool
61 // and scales it to be in the range (-1, 1). is that what it was
62 // intended to do? the distribution is pretty terrible, too, with
63 // some elements being picked a hundred times more often than others
65 Random::operator()(const int salt,const int x,const int y,const int t)const
67 const int salt_hash(pool_[salt&(POOL_SIZE-1)]);
69 int index(((x^x_mask)+(y^y_mask)*234672+(t^t_mask)*8439573)^salt_hash);
71 index+=index*(index/POOL_SIZE);
73 return (float(pool_[index&(POOL_SIZE-1)])/float(RAND_MAX))*2.0f-1.0f;
77 Random::operator()(SmoothType smooth,int subseed,float xf,float yf,float tf)const
79 int x((int)floor(xf));
80 int y((int)floor(yf));
81 int t((int)floor(tf));
85 case SMOOTH_CUBIC: // cubic
87 #define f(j,i,k) ((*this)(subseed,i,j,k))
88 //Using catmull rom interpolation because it doesn't blur at all
89 // ( http://www.gamedev.net/reference/articles/article1497.asp )
90 //bezier curve with intermediate ctrl pts: 0.5/3(p(i+1) - p(i-1)) and similar
91 float xfa [4], tfa[4];
93 //precalculate indices (all clamped) and offset
94 const int xa[] = {x-1,x,x+1,x+2};
96 const int ya[] = {y-1,y,y+1,y+2};
98 const int ta[] = {t-1,t,t+1,t+2};
100 const float dx(xf-x);
101 const float dy(yf-y);
102 const float dt(tf-t);
104 //figure polynomials for each point
107 0.5*dx*(dx*(dx*(-1) + 2) - 1), //-t + 2t^2 -t^3
108 0.5*(dx*(dx*(3*dx - 5)) + 2), //2 - 5t^2 + 3t^3
109 0.5*dx*(dx*(-3*dx + 4) + 1), //t + 4t^2 - 3t^3
110 0.5*dx*dx*(dx-1) //-t^2 + t^3
115 0.5*dy*(dy*(dy*(-1) + 2) - 1), //-t + 2t^2 -t^3
116 0.5*(dy*(dy*(3*dy - 5)) + 2), //2 - 5t^2 + 3t^3
117 0.5*dy*(dy*(-3*dy + 4) + 1), //t + 4t^2 - 3t^3
118 0.5*dy*dy*(dy-1) //-t^2 + t^3
123 0.5*dt*(dt*(dt*(-1) + 2) - 1), //-t + 2t^2 -t^3
124 0.5*(dt*(dt*(3*dt - 5)) + 2), //2 - 5t^2 + 3t^3
125 0.5*dt*(dt*(-3*dt + 4) + 1), //t + 4t^2 - 3t^3
126 0.5*dt*dt*(dt-1) //-t^2 + t^3
129 //evaluate polynomial for each row
130 for(int i = 0; i < 4; ++i)
132 for(int j = 0; j < 4; ++j)
134 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];
136 xfa[i] = tfa[0]*txf[0] + tfa[1]*txf[1] + tfa[2]*txf[2] + tfa[3]*txf[3];
139 //return the cumulative column evaluation
140 return xfa[0]*tyf[0] + xfa[1]*tyf[1] + xfa[2]*tyf[2] + xfa[3]*tyf[3];
146 case SMOOTH_FAST_SPLINE: // Fast Spline (non-animated)
148 #define P(x) (((x)>0)?((x)*(x)*(x)):0.0f)
149 #define R(x) ( P(x+2) - 4.0f*P(x+1) + 6.0f*P(x) - 4.0f*P(x-1) )*(1.0f/6.0f)
150 #define F(i,j) ((*this)(subseed,i+x,j+y)*(R((i)-a)*R(b-(j))))
151 #define FT(i,j,k) ((*this)(subseed,i+x,j+y,k+t)*(R((i)-a)*R(b-(j))*R((k)-c)))
152 #define Z(i,j) ret+=F(i,j)
153 #define ZT(i,j,k) ret+=FT(i,j,k)
154 #define X(i,j) // placeholder... To make box more symmetric
155 #define XT(i,j,k) // placeholder... To make box more symmetric
157 float a(xf-x), b(yf-y);
161 Z(-1,-1); Z(-1, 0); Z(-1, 1); Z(-1, 2);
162 Z( 0,-1); X( 0, 0); Z( 0, 1); Z( 0, 2);
163 Z( 1,-1); Z( 1, 0); Z( 1, 1); Z( 1, 2);
164 Z( 2,-1); Z( 2, 0); Z( 2, 1); Z( 2, 2);
169 case SMOOTH_SPLINE: // Spline (animated)
171 float a(xf-x), b(yf-y), c(tf-t);
174 float ret(FT(0,0,0));
175 ZT(-1,-1,-1); ZT(-1, 0,-1); ZT(-1, 1,-1); ZT(-1, 2,-1);
176 ZT( 0,-1,-1); ZT( 0, 0,-1); ZT( 0, 1,-1); ZT( 0, 2,-1);
177 ZT( 1,-1,-1); ZT( 1, 0,-1); ZT( 1, 1,-1); ZT( 1, 2,-1);
178 ZT( 2,-1,-1); ZT( 2, 0,-1); ZT( 2, 1,-1); ZT( 2, 2,-1);
180 ZT(-1,-1, 0); ZT(-1, 0, 0); ZT(-1, 1, 0); ZT(-1, 2, 0);
181 ZT( 0,-1, 0); XT( 0, 0, 0); ZT( 0, 1, 0); ZT( 0, 2, 0);
182 ZT( 1,-1, 0); ZT( 1, 0, 0); ZT( 1, 1, 0); ZT( 1, 2, 0);
183 ZT( 2,-1, 0); ZT( 2, 0, 0); ZT( 2, 1, 0); ZT( 2, 2, 0);
185 ZT(-1,-1, 1); ZT(-1, 0, 1); ZT(-1, 1, 1); ZT(-1, 2, 1);
186 ZT( 0,-1, 1); ZT( 0, 0, 1); ZT( 0, 1, 1); ZT( 0, 2, 1);
187 ZT( 1,-1, 1); ZT( 1, 0, 1); ZT( 1, 1, 1); ZT( 1, 2, 1);
188 ZT( 2,-1, 1); ZT( 2, 0, 1); ZT( 2, 1, 1); ZT( 2, 2, 1);
190 ZT(-1,-1, 2); ZT(-1, 0, 2); ZT(-1, 1, 2); ZT(-1, 2, 2);
191 ZT( 0,-1, 2); ZT( 0, 0, 2); ZT( 0, 1, 2); ZT( 0, 2, 2);
192 ZT( 1,-1, 2); ZT( 1, 0, 2); ZT( 1, 1, 2); ZT( 1, 2, 2);
193 ZT( 2,-1, 2); ZT( 2, 0, 2); ZT( 2, 1, 2); ZT( 2, 2, 2);
208 ret+=(*this)(subseed,i+x,j+y,h+t)*(R(i-dx)*R(j-dy)*R(h-dt));
222 int x((int)floor(xf));
223 int y((int)floor(yf));
226 a=(1.0f-cos(a*3.1415927))*0.5f;
227 b=(1.0f-cos(b*3.1415927))*0.5f;
232 (*this)(subseed,x,y,t)*(c*d)+
233 (*this)(subseed,x2,y,t)*(a*d)+
234 (*this)(subseed,x,y2,t)*(c*b)+
235 (*this)(subseed,x2,y2,t)*(a*b);
243 a=(1.0f-cos(a*3.1415927))*0.5f;
244 b=(1.0f-cos(b*3.1415927))*0.5f;
246 // We don't perform this on the time axis, otherwise we won't
248 //c=(1.0f-cos(c*3.1415927))*0.5f;
254 int x2=x+1,y2=y+1,t2=t+1;
257 (*this)(subseed,x,y,t)*(d*e*f)+
258 (*this)(subseed,x2,y,t)*(a*e*f)+
259 (*this)(subseed,x,y2,t)*(d*b*f)+
260 (*this)(subseed,x2,y2,t)*(a*b*f)+
261 (*this)(subseed,x,y,t2)*(d*e*c)+
262 (*this)(subseed,x2,y,t2)*(a*e*c)+
263 (*this)(subseed,x,y2,t2)*(d*b*c)+
264 (*this)(subseed,x2,y2,t2)*(a*b*c);
269 int x((int)floor(xf));
270 int y((int)floor(yf));
277 (*this)(subseed,x,y,t)*(c*d)+
278 (*this)(subseed,x2,y,t)*(a*d)+
279 (*this)(subseed,x,y2,t)*(c*b)+
280 (*this)(subseed,x2,y2,t)*(a*b);
293 int x2=x+1,y2=y+1,t2=t+1;
296 (*this)(subseed,x,y,t)*(d*e*f)+
297 (*this)(subseed,x2,y,t)*(a*e*f)+
298 (*this)(subseed,x,y2,t)*(d*b*f)+
299 (*this)(subseed,x2,y2,t)*(a*b*f)+
300 (*this)(subseed,x,y,t2)*(d*e*c)+
301 (*this)(subseed,x2,y,t2)*(a*e*c)+
302 (*this)(subseed,x,y2,t2)*(d*b*c)+
303 (*this)(subseed,x2,y2,t2)*(a*b*c);
307 return (*this)(subseed,x,y,t);