add a "overdamp factor"

svn path=/trunk/externals/pmpd/; revision=17070

4 files changed, 52 insertions, 3 deletions

diff --git a/pmpd3d.c b/pmpd3d.c
index 5c9515b..ace3541 100644
--- a/pmpd3d.c
+++ b/pmpd3d.c
@@ -99,7 +99,8 @@ void pmpd3d_setup(void)
     class_addmethod(pmpd3d_class, (t_method)pmpd3d_posX,            		gensym("setPosX"), A_GIMME, 0);

     class_addmethod(pmpd3d_class, (t_method)pmpd3d_posY,            		gensym("setPosY"), A_GIMME, 0);

     class_addmethod(pmpd3d_class, (t_method)pmpd3d_posZ,          		  	gensym("setPosZ"), A_GIMME, 0);

-      

+    class_addmethod(pmpd3d_class, (t_method)pmpd3d_overdamp,     		  	gensym("setOverdamp"), A_GIMME, 0);

+          

 /*        

  pmpd3d_get

  --

diff --git a/pmpd3d.h b/pmpd3d.h
index 88d21ab..4101f54 100644
--- a/pmpd3d.h
+++ b/pmpd3d.h
@@ -26,6 +26,7 @@ typedef struct _mass {
     t_float forceZ;
     t_float D2;
     t_float D2offset;
+    t_float overdamp;
     int num;
 } foo;
 
@@ -65,4 +66,4 @@ typedef struct _pmpd3d {
     t_float minX, maxX, minY, maxY, minZ, maxZ;
     t_int grab; // si on grab une mass ou pas
     t_int grab_nb; // la masse grabé
-} t_pmpd3d;
\ No newline at end of file
+} t_pmpd3d;
diff --git a/pmpd3d_core.c b/pmpd3d_core.c
index a2a0d16..1ad06fd 100644
--- a/pmpd3d_core.c
+++ b/pmpd3d_core.c
@@ -74,7 +74,7 @@ void *pmpd3d_new()
 void pmpd3d_bang(t_pmpd3d *x)
 {
 	// this part is doing all the PM
-    t_float F, L, Lx,Ly, Lz, Fx, Fy, Fz, tmpX, tmpY, tmpZ, speed;
+    t_float F, L, Lx,Ly, Lz, Fx, Fy, Fz, tmp, tmpX, tmpY, tmpZ, speed;
     t_int i;
     // post("bang");
 	
@@ -82,15 +82,34 @@ void pmpd3d_bang(t_pmpd3d *x)
 		// compute new masses position
         if (x->mass[i].mobile > 0) // only if mobile
         {
+			// amplify force that opose to movement
+			if (x->mass[i].overdamp != 0)
+			{
+				tmp = x->mass[i].speedX * x->mass[i].forceX + x->mass[i].speedY * x->mass[i].forceY + x->mass[i].speedZ * x->mass[i].forceZ;
+				tmp = min(0,tmp); // overdamped only if force opose movment
+				tmp *= -x->mass[i].overdamp;
+				tmp += 1;
+				x->mass[i].forceX *= tmp;
+				x->mass[i].forceY *= tmp;
+				x->mass[i].forceZ *= tmp;
+			}
+			
+			// compute new velocity thanks to forces. (Forces = M * acceleration) 
             x->mass[i].speedX += x->mass[i].forceX * x->mass[i].invM;
             x->mass[i].speedY += x->mass[i].forceY * x->mass[i].invM;
             x->mass[i].speedZ += x->mass[i].forceZ * x->mass[i].invM;
+            
+            // no need to reset force to 0, because we compute a new force latter thanks to velocity damping
             // x->mass[i].forceX = 0;
             // x->mass[i].forceY = 0;        
             // x->mass[i].forceZ = 0;        
+            
+            // compute new speed thanks to new velocity
             x->mass[i].posX += x->mass[i].speedX ;
             x->mass[i].posY += x->mass[i].speedY ;
             x->mass[i].posZ += x->mass[i].speedZ ;
+            
+            // space limitation
             if ( (x->mass[i].posX < x->minX) || (x->mass[i].posX > x->maxX) || (x->mass[i].posY < x->minY) 
                 || (x->mass[i].posY > x->maxY) || (x->mass[i].posZ < x->minZ) || (x->mass[i].posZ > x->maxZ) ) 
             {
@@ -104,9 +123,12 @@ void pmpd3d_bang(t_pmpd3d *x)
                 x->mass[i].posY = tmpY;
                 x->mass[i].posZ = tmpZ;
             }
+            // velocity damping of every masse (set a new force)
             x->mass[i].forceX = -x->mass[i].D2 * x->mass[i].speedX;
             x->mass[i].forceY = -x->mass[i].D2 * x->mass[i].speedY;
             x->mass[i].forceZ = -x->mass[i].D2 * x->mass[i].speedZ;
+            
+            // offset on velocity damping (to impose a specific velocity)
             speed = sqrt(x->mass[i].speedX * x->mass[i].speedX + x->mass[i].speedY * x->mass[i].speedY + x->mass[i].speedZ * x->mass[i].speedZ);
             if (speed != 0) {
                 x->mass[i].forceX += x->mass[i].D2offset * (x->mass[i].speedX/speed);
@@ -186,6 +208,7 @@ void pmpd3d_mass(t_pmpd3d *x, t_symbol *s, int argc, t_atom *argv)
         x->mass[x->nb_mass].num = x->nb_mass;
         x->mass[x->nb_mass].D2 = 0;
         x->mass[x->nb_mass].D2offset = 0;
+		x->mass[x->nb_mass].overdamp = 0;
 		
         x->nb_mass++ ;
         x->nb_mass = min ( nb_max_mass -1, x->nb_mass );
diff --git a/pmpd3d_set.c b/pmpd3d_set.c
index 3577613..1e5dddc 100644
--- a/pmpd3d_set.c
+++ b/pmpd3d_set.c
@@ -677,3 +677,27 @@ void pmpd3d_posZ(t_pmpd3d *x, t_symbol *s, int argc, t_atom *argv)
 	}
 }
 
+
+void pmpd3d_overdamp(t_pmpd3d *x, t_symbol *s, int argc, t_atom *argv)
+{
+// set the overdamped factor to a mass
+	t_int tmp, i;
+
+	if ( (argc == 2) && ( argv[0].a_type == A_FLOAT ) && ( argv[1].a_type == A_FLOAT ) )
+	{
+		tmp = atom_getfloatarg(0, argc, argv);
+		tmp = max(0, min( x->nb_mass-1, tmp));
+		x->mass[tmp].overdamp = atom_getfloatarg(1, argc, argv);
+	}
+	if ( (argc == 2) && ( argv[0].a_type == A_SYMBOL ) && ( argv[1].a_type == A_FLOAT ) )
+	{
+		for (i=0; i< x->nb_mass; i++)
+		{
+			if ( atom_getsymbolarg(0,argc,argv) == x->mass[i].Id)
+			{
+				x->mass[i].overdamp = atom_getfloatarg(1, argc, argv);
+			}
+		}
+	}
+}
+