-/* === S Y N F I G ========================================================= */
-/*! \file mod_particle/random.cpp
-** \brief blehh
-**
-** $Id$
-**
-** \legal
-** Copyright (c) 2002-2005 Robert B. Quattlebaum Jr., Adrian Bentley
-** Copyright (c) 2007 Chris Moore
-**
-** This package is free software; you can redistribute it and/or
-** modify it under the terms of the GNU General Public License as
-** published by the Free Software Foundation; either version 2 of
-** the License, or (at your option) any later version.
-**
-** This package is distributed in the hope that it will be useful,
-** but WITHOUT ANY WARRANTY; without even the implied warranty of
-** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
-** General Public License for more details.
-** \endlegal
-*/
-/* ========================================================================= */
-
-/* === H E A D E R S ======================================================= */
-
-#ifdef USING_PCH
-# include "pch.h"
-#else
-#ifdef HAVE_CONFIG_H
-# include <config.h>
-#endif
-
-#include "random.h"
-#include <cmath>
-#include <cstdlib>
-
-#endif
-
-/* === M A C R O S ========================================================= */
-
-#define PI (3.1415927)
-
-/* === G L O B A L S ======================================================= */
-
-/* === P R O C E D U R E S ================================================= */
-
-/* === M E T H O D S ======================================================= */
-
-void
-Random::set_seed(int x)
-{
- seed_=x;
- srand(x);
- int i;
- for(i=0;i<POOL_SIZE;i++)
- pool_[i]=rand();
-
- x_mask=rand()+rand()*RAND_MAX;
- y_mask=rand()+rand()*RAND_MAX;
- t_mask=rand()+rand()*RAND_MAX;
-}
-
-// this picks one of the POOL_SIZE (256) preset values out of the pool
-// and scales it to be in the range (-1, 1). is that what it was
-// intended to do? the distribution is pretty terrible, too, with
-// some elements being picked a hundred times more often than others
-float
-Random::operator()(const int salt,const int x,const int y,const int t)const
-{
- const int salt_hash(pool_[salt&(POOL_SIZE-1)]);
-
- int index(((x^x_mask)+(y^y_mask)*234672+(t^t_mask)*8439573)^salt_hash);
-
- index+=index*(index/POOL_SIZE);
-
- return (float(pool_[index&(POOL_SIZE-1)])/float(RAND_MAX))*2.0f-1.0f;
-}
-
-float
-Random::operator()(SmoothType smooth,int subseed,float xf,float yf,float tf)const
-{
- int x((int)floor(xf));
- int y((int)floor(yf));
- int t((int)floor(tf));
-
- switch(smooth)
- {
- case SMOOTH_CUBIC: // cubic
- {
- #define f(j,i,k) ((*this)(subseed,i,j,k))
- //Using catmull rom interpolation because it doesn't blur at all
- // ( http://www.gamedev.net/reference/articles/article1497.asp )
- //bezier curve with intermediate ctrl pts: 0.5/3(p(i+1) - p(i-1)) and similar
- float xfa [4], tfa[4];
-
- //precalculate indices (all clamped) and offset
- const int xa[] = {x-1,x,x+1,x+2};
-
- const int ya[] = {y-1,y,y+1,y+2};
-
- const int ta[] = {t-1,t,t+1,t+2};
-
- const float dx(xf-x);
- const float dy(yf-y);
- const float dt(tf-t);
-
- //figure polynomials for each point
- const float txf[] =
- {
- 0.5*dx*(dx*(dx*(-1) + 2) - 1), //-t + 2t^2 -t^3
- 0.5*(dx*(dx*(3*dx - 5)) + 2), //2 - 5t^2 + 3t^3
- 0.5*dx*(dx*(-3*dx + 4) + 1), //t + 4t^2 - 3t^3
- 0.5*dx*dx*(dx-1) //-t^2 + t^3
- };
-
- const float tyf[] =
- {
- 0.5*dy*(dy*(dy*(-1) + 2) - 1), //-t + 2t^2 -t^3
- 0.5*(dy*(dy*(3*dy - 5)) + 2), //2 - 5t^2 + 3t^3
- 0.5*dy*(dy*(-3*dy + 4) + 1), //t + 4t^2 - 3t^3
- 0.5*dy*dy*(dy-1) //-t^2 + t^3
- };
-
- const float ttf[] =
- {
- 0.5*dt*(dt*(dt*(-1) + 2) - 1), //-t + 2t^2 -t^3
- 0.5*(dt*(dt*(3*dt - 5)) + 2), //2 - 5t^2 + 3t^3
- 0.5*dt*(dt*(-3*dt + 4) + 1), //t + 4t^2 - 3t^3
- 0.5*dt*dt*(dt-1) //-t^2 + t^3
- };
-
- //evaluate polynomial for each row
- for(int i = 0; i < 4; ++i)
- {
- for(int j = 0; j < 4; ++j)
- {
- 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];
- }
- xfa[i] = tfa[0]*txf[0] + tfa[1]*txf[1] + tfa[2]*txf[2] + tfa[3]*txf[3];
- }
-
- //return the cumulative column evaluation
- return xfa[0]*tyf[0] + xfa[1]*tyf[1] + xfa[2]*tyf[2] + xfa[3]*tyf[3];
-#undef f
- }
- break;
-
-
- case SMOOTH_FAST_SPLINE: // Fast Spline (non-animated)
- {
-#define P(x) (((x)>0)?((x)*(x)*(x)):0.0f)
-#define R(x) ( P(x+2) - 4.0f*P(x+1) + 6.0f*P(x) - 4.0f*P(x-1) )*(1.0f/6.0f)
-#define F(i,j) ((*this)(subseed,i+x,j+y)*(R((i)-a)*R(b-(j))))
-#define FT(i,j,k) ((*this)(subseed,i+x,j+y,k+t)*(R((i)-a)*R(b-(j))*R((k)-c)))
-#define Z(i,j) ret+=F(i,j)
-#define ZT(i,j,k) ret+=FT(i,j,k)
-#define X(i,j) // placeholder... To make box more symmetric
-#define XT(i,j,k) // placeholder... To make box more symmetric
-
- float a(xf-x), b(yf-y);
-
- // Interpolate
- float ret(F(0,0));
- Z(-1,-1); Z(-1, 0); Z(-1, 1); Z(-1, 2);
- Z( 0,-1); X( 0, 0); Z( 0, 1); Z( 0, 2);
- Z( 1,-1); Z( 1, 0); Z( 1, 1); Z( 1, 2);
- Z( 2,-1); Z( 2, 0); Z( 2, 1); Z( 2, 2);
-
- return ret;
- }
-
- case SMOOTH_SPLINE: // Spline (animated)
- {
- float a(xf-x), b(yf-y), c(tf-t);
-
- // Interpolate
- float ret(FT(0,0,0));
- ZT(-1,-1,-1); ZT(-1, 0,-1); ZT(-1, 1,-1); ZT(-1, 2,-1);
- ZT( 0,-1,-1); ZT( 0, 0,-1); ZT( 0, 1,-1); ZT( 0, 2,-1);
- ZT( 1,-1,-1); ZT( 1, 0,-1); ZT( 1, 1,-1); ZT( 1, 2,-1);
- ZT( 2,-1,-1); ZT( 2, 0,-1); ZT( 2, 1,-1); ZT( 2, 2,-1);
-
- ZT(-1,-1, 0); ZT(-1, 0, 0); ZT(-1, 1, 0); ZT(-1, 2, 0);
- ZT( 0,-1, 0); XT( 0, 0, 0); ZT( 0, 1, 0); ZT( 0, 2, 0);
- ZT( 1,-1, 0); ZT( 1, 0, 0); ZT( 1, 1, 0); ZT( 1, 2, 0);
- ZT( 2,-1, 0); ZT( 2, 0, 0); ZT( 2, 1, 0); ZT( 2, 2, 0);
-
- ZT(-1,-1, 1); ZT(-1, 0, 1); ZT(-1, 1, 1); ZT(-1, 2, 1);
- ZT( 0,-1, 1); ZT( 0, 0, 1); ZT( 0, 1, 1); ZT( 0, 2, 1);
- ZT( 1,-1, 1); ZT( 1, 0, 1); ZT( 1, 1, 1); ZT( 1, 2, 1);
- ZT( 2,-1, 1); ZT( 2, 0, 1); ZT( 2, 1, 1); ZT( 2, 2, 1);
-
- ZT(-1,-1, 2); ZT(-1, 0, 2); ZT(-1, 1, 2); ZT(-1, 2, 2);
- ZT( 0,-1, 2); ZT( 0, 0, 2); ZT( 0, 1, 2); ZT( 0, 2, 2);
- ZT( 1,-1, 2); ZT( 1, 0, 2); ZT( 1, 1, 2); ZT( 1, 2, 2);
- ZT( 2,-1, 2); ZT( 2, 0, 2); ZT( 2, 1, 2); ZT( 2, 2, 2);
-
- return ret;
-
-/*
-
- float dx=xf-x;
- float dy=yf-y;
- float dt=tf-t;
-
- float ret=0;
- int i,j,h;
- for(h=-1;h<=2;h++)
- for(i=-1;i<=2;i++)
- for(j=-1;j<=2;j++)
- ret+=(*this)(subseed,i+x,j+y,h+t)*(R(i-dx)*R(j-dy)*R(h-dt));
- return ret;
-*/
- }
- break;
-#undef X
-#undef Z
-#undef F
-#undef P
-#undef R
-
- case SMOOTH_COSINE:
- if((float)t==tf)
- {
- int x((int)floor(xf));
- int y((int)floor(yf));
- float a=xf-x;
- float b=yf-y;
- a=(1.0f-cos(a*PI))*0.5f;
- b=(1.0f-cos(b*PI))*0.5f;
- float c=1.0-a;
- float d=1.0-b;
- int x2=x+1,y2=y+1;
- return
- (*this)(subseed,x,y,t)*(c*d)+
- (*this)(subseed,x2,y,t)*(a*d)+
- (*this)(subseed,x,y2,t)*(c*b)+
- (*this)(subseed,x2,y2,t)*(a*b);
- }
- else
- {
- float a=xf-x;
- float b=yf-y;
- float c=tf-t;
-
- a=(1.0f-cos(a*PI))*0.5f;
- b=(1.0f-cos(b*PI))*0.5f;
-
- // We don't perform this on the time axis, otherwise we won't
- // get smooth motion
- //c=(1.0f-cos(c*PI))*0.5f;
-
- float d=1.0-a;
- float e=1.0-b;
- float f=1.0-c;
-
- int x2=x+1,y2=y+1,t2=t+1;
-
- return
- (*this)(subseed,x,y,t)*(d*e*f)+
- (*this)(subseed,x2,y,t)*(a*e*f)+
- (*this)(subseed,x,y2,t)*(d*b*f)+
- (*this)(subseed,x2,y2,t)*(a*b*f)+
- (*this)(subseed,x,y,t2)*(d*e*c)+
- (*this)(subseed,x2,y,t2)*(a*e*c)+
- (*this)(subseed,x,y2,t2)*(d*b*c)+
- (*this)(subseed,x2,y2,t2)*(a*b*c);
- }
- case SMOOTH_LINEAR:
- if((float)t==tf)
- {
- int x((int)floor(xf));
- int y((int)floor(yf));
- float a=xf-x;
- float b=yf-y;
- float c=1.0-a;
- float d=1.0-b;
- int x2=x+1,y2=y+1;
- return
- (*this)(subseed,x,y,t)*(c*d)+
- (*this)(subseed,x2,y,t)*(a*d)+
- (*this)(subseed,x,y2,t)*(c*b)+
- (*this)(subseed,x2,y2,t)*(a*b);
- }
- else
- {
-
- float a=xf-x;
- float b=yf-y;
- float c=tf-t;
-
- float d=1.0-a;
- float e=1.0-b;
- float f=1.0-c;
-
- int x2=x+1,y2=y+1,t2=t+1;
-
- return
- (*this)(subseed,x,y,t)*(d*e*f)+
- (*this)(subseed,x2,y,t)*(a*e*f)+
- (*this)(subseed,x,y2,t)*(d*b*f)+
- (*this)(subseed,x2,y2,t)*(a*b*f)+
- (*this)(subseed,x,y,t2)*(d*e*c)+
- (*this)(subseed,x2,y,t2)*(a*e*c)+
- (*this)(subseed,x,y2,t2)*(d*b*c)+
- (*this)(subseed,x2,y2,t2)*(a*b*c);
- }
- default:
- case SMOOTH_DEFAULT:
- return (*this)(subseed,x,y,t);
- }
-}