Add boolean parameter 'Positive Only' to stop negative affect from large distances.

[synfig.git] / synfig-core / trunk / src / modules / example / metaballs.cpp

diff --git a/synfig-core/trunk/src/modules/example/metaballs.cpp b/synfig-core/trunk/src/modules/example/metaballs.cpp
index c689449..874d7f9 100644 (file)
--- a/synfig-core/trunk/src/modules/example/metaballs.cpp
+++ b/synfig-core/trunk/src/modules/example/metaballs.cpp
@@ -66,7 +66,10 @@ SYNFIG_LAYER_SET_CVS_ID(Metaballs,"$Id$");
 
 Metaballs::Metaballs():
        Layer_Composite(1.0,Color::BLEND_STRAIGHT),
-       gradient(Color::black(), Color::white())
+       gradient(Color::black(), Color::white()),
+       threshold(0),
+       threshold2(1),
+       positive(false)
 {
        centers.push_back(Point( 0, -1.5));     radii.push_back(2.5);   weights.push_back(1);
        centers.push_back(Point(-2,  1));       radii.push_back(2.5);   weights.push_back(1);
@@ -96,6 +99,8 @@ Metaballs::set_param(const String & param, const ValueBase &value)
 
        IMPORT(gradient);
        IMPORT(threshold);
+       IMPORT(threshold2);
+       IMPORT(positive);
 
        return Layer_Composite::set_param(param,value);
 }
@@ -109,6 +114,8 @@ Metaballs::get_param(const String &param)const
        EXPORT(weights);
        EXPORT(centers);
        EXPORT(threshold);
+       EXPORT(threshold2);
+       EXPORT(positive);
 
        EXPORT_NAME();
        EXPORT_VERSION();
@@ -138,7 +145,15 @@ Metaballs::get_param_vocab()const
        );
 
        ret.push_back(ParamDesc("threshold")
-               .set_local_name(_("Threshold"))
+               .set_local_name(_("Gradient Left"))
+       );
+
+       ret.push_back(ParamDesc("threshold2")
+               .set_local_name(_("Gradient Right"))
+       );
+
+       ret.push_back(ParamDesc("positive")
+               .set_local_name(_("Positive Only"))
        );
 
        return ret;
@@ -150,6 +165,7 @@ static inline Real densityfunc(const synfig::Point &p, const synfig::Point &c, R
        const Real dy = p[1] - c[1];
 
        const Real n = (1 - (dx*dx + dy*dy)/(R*R));
+       if (positive && n < 0) return 0;
        return (n*n*n);
 
        /*
@@ -171,7 +187,7 @@ Metaballs::totaldensity(const Point &pos) const
        for(unsigned int i=0;i<centers.size();i++)
                density += weights[i] * densityfunc(pos,centers[i], radii[i]);
 
-       return density;
+       return (density - threshold) / (threshold2 - threshold);
 }
 
 Color