Edit comment text.

[synfig.git] / synfig-core / trunk / src / modules / mod_noise / random.cpp

diff --git a/synfig-core/trunk/src/modules/mod_noise/random.cpp b/synfig-core/trunk/src/modules/mod_noise/random.cpp
index 6814f08..7bc87e5 100644 (file)
--- a/synfig-core/trunk/src/modules/mod_noise/random.cpp
+++ b/synfig-core/trunk/src/modules/mod_noise/random.cpp
@@ -6,6 +6,7 @@
 **
 **     \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
@@ -30,43 +31,11 @@
 #endif
 
 #include "random.h"
+#include <synfig/quick_rng.h>
 #include <cmath>
 #include <cstdlib>
 #endif
 
-// A fast 32-bit linear congruential random number generator
-class quick_rng
-{
-       unsigned long next;
-public:
-       quick_rng(unsigned long seed):next(seed) { }
-
-       void set_seed(unsigned long x)
-       {
-               next=x;
-       }
-
-       unsigned long i32()
-       {
-               static const unsigned long a(1664525);
-               static const unsigned long c(1013904223);
-
-               return next=next*a+c;
-       }
-
-       unsigned long i16()
-       {
-               return i32()>>16;
-       }
-
-       float f()
-       {
-               static const float m(int(65535));
-
-               return float(i16())/m;
-       }
-};
-
 /* === M A C R O S ========================================================= */
 
 #define PI     (3.1415927)
@@ -102,7 +71,7 @@ Random::operator()(const int salt,const int x,const int y,const int t)const
 }
 
 float
-Random::operator()(int smooth,int subseed,float xf,float yf,float tf)const
+Random::operator()(SmoothType smooth,int subseed,float xf,float yf,float tf)const
 {
        int x((int)floor(xf));
        int y((int)floor(yf));
@@ -110,18 +79,17 @@ Random::operator()(int smooth,int subseed,float xf,float yf,float tf)const
 
        switch(smooth)
        {
-       case 4: // cubic
+       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);
@@ -170,7 +138,7 @@ Random::operator()(int smooth,int subseed,float xf,float yf,float tf)const
                break;
 
 
-       case 5: // Fast Spline (non-animated)
+       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)
@@ -178,8 +146,8 @@ Random::operator()(int smooth,int subseed,float xf,float yf,float tf)const
 #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 symetric
-#define XT(i,j,k)      // placeholder... To make box more symetric
+#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);
 
@@ -193,7 +161,7 @@ Random::operator()(int smooth,int subseed,float xf,float yf,float tf)const
                return ret;
        }
 
-       case 3: // Spline (animated)
+       case SMOOTH_SPLINE:     // Spline (animated)
                {
                        float a(xf-x), b(yf-y), c(tf-t);
 
@@ -243,7 +211,7 @@ Random::operator()(int smooth,int subseed,float xf,float yf,float tf)const
 #undef P
 #undef R
 
-       case 2: // Cosine
+       case SMOOTH_COSINE:
        if((float)t==tf)
        {
                int x((int)floor(xf));
@@ -267,12 +235,12 @@ Random::operator()(int smooth,int subseed,float xf,float yf,float tf)const
                float b=yf-y;
                float c=tf-t;
 
-               a=(1.0f-cos(a*3.1415927))*0.5f;
-               b=(1.0f-cos(b*3.1415927))*0.5f;
+               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*3.1415927))*0.5f;
+               //c=(1.0f-cos(c*PI))*0.5f;
 
                float d=1.0-a;
                float e=1.0-b;
@@ -290,7 +258,7 @@ Random::operator()(int smooth,int subseed,float xf,float yf,float tf)const
                        (*this)(subseed,x,y2,t2)*(d*b*c)+
                        (*this)(subseed,x2,y2,t2)*(a*b*c);
        }
-       case 1: // Linear
+       case SMOOTH_LINEAR:
        if((float)t==tf)
        {
                int x((int)floor(xf));
@@ -330,7 +298,7 @@ Random::operator()(int smooth,int subseed,float xf,float yf,float tf)const
                        (*this)(subseed,x2,y2,t2)*(a*b*c);
        }
        default:
-       case 0:
+       case SMOOTH_DEFAULT:
                return (*this)(subseed,x,y,t);
        }
 }