add a generic n-body VisB visualisation file

using new svg_objects feature (ProB 1.12.x)

Signed-off-by: Michael Leuschel <leuschel@uni-duesseldorf.de>

Physics/MovingParticles3.mch

@@ -3,6 +3,7 @@ MACHINE MovingParticles3
 INCLUDES MovingParticles PROMOTES Move
 DEFINITIONS
   VISB_JSON_FILE == "three_bodies.json";
+  NOBJS == 3;
   SCALE == 1.25e11; // 100 % in visualisation
   SCALE100 == (SCALE/100.0);
   SPEED_MULTIPLIER == 1000000.0;
@@ -16,7 +17,7 @@ DEFINITIONS
                                            unit_vec(delta_vec(pos(j),pos(i)))))
                                      )  ) ) // acceleration due to gravitation
 PROPERTIES
-   nobjs = 3 & 
+   nobjs = NOBJS & 
    /*@label "mass_values" */ mass = [5.97e24, 1.989e30, 1.989e30]
     /*@desc "The mass of the 3 objects" */
    &

Physics/MovingParticles4.mch

@@ -3,6 +3,7 @@ MACHINE MovingParticles4
 INCLUDES MovingParticles PROMOTES Move
 DEFINITIONS
   VISB_JSON_FILE == "four_bodies.json";
+  NOBJS == 4;
   SCALE == 5.0e10; // 100 % in visualisation
   SCALE100 == (SCALE/100.0);
   SPEED_MULTIPLIER == 1000000.0;
@@ -16,7 +17,7 @@ DEFINITIONS
                                            unit_vec(delta_vec(pos(j),pos(i)))))
                                      )  ) ) // acceleration due to gravitation 
 PROPERTIES
-   nobjs = 4 & 
+   nobjs = NOBJS & 
    mass = [3.0e28, 3.0e28, 3.0e28, 3.0e28]
    &
    initial_pos =   [ make_vec([-3.5e10,0.0e00]),  make_vec([-1.0e10,0.0e00]),

Physics/n_bodies_visb.json

+{
+  "svg": "n_bodies.svg",
+  "comment": "version which uses new svg object creation",
+  "svg_objects":[
+    {
+      "for":{"from":1,"to":"NOBJS"}, 
+      "svg_class":"circle",
+      "id":"body%0",
+      "cx":"45",
+      "cy":"15",
+      "r":"10",
+      "stroke":"black",
+      "stroke-width":"0.5",
+      "fill":"green"
+    },
+    {
+      "for":{"from":1,"to":"NOBJS"}, 
+      "svg_class":"line",
+      "id":"speed%0",
+      "x1":"45",
+      "y1":"15",
+      "x2":"55",
+      "y2":"15",
+      "stroke":"#000",
+      "stroke-width":"0.3",
+      "marker-end":"url(#arrowhead)"
+    },
+    {
+      "for":{"from":1,"to":"NOBJS"}, 
+      "svg_class":"line",
+      "id":"gravitation%0",
+      "x1":"45",
+      "y1":"15",
+      "x2":"55",
+      "y2":"15",
+      "stroke":"green",
+      "stroke-width":"0.3",
+      "marker-end":"url(#endarrow)"
+    }
+  ],
+  "items": [
+    { "id": "body2",
+      "attr": "fill",
+      "optional":"true",
+      "value": "\"blue\""
+    },
+    { "id": "body3",
+      "attr": "fill",
+      "optional":"true",
+      "value": "\"yellow\""
+    },
+    { "id": "body4",
+      "attr": "fill",
+      "optional":"true",
+      "value": "\"orange\""
+    },
+	{
+	  "for": {"from":1, "to":"NOBJS"},
+      "id": "body%0",
+      "attr": "cx",
+      "value" : "pos(%0)(1) / SCALE100"
+    },
+	{
+	  "for": {"from":1, "to":"NOBJS"},
+      "id": "body%0",
+      "attr": "cy",
+      "value" : "pos(%0)(2) / SCALE100"
+    },
+    
+	{
+	  "for": {"from":1, "to":"NOBJS"},
+      "id": "body%0",
+      "attr": "r",
+      "value" : "2.0+5.0*mass(%0)/MAXMASS"
+    },
+    
+	{
+	  "for": {"from":1, "to":"NOBJS"},
+      "id": "speed%0",
+      "attr": "x1",
+      "value" : "pos(%0)(1) / SCALE100"
+    },
+	{
+	  "for": {"from":1, "to":"NOBJS"},
+      "id": "speed%0",
+      "attr": "y1",
+      "value" : "pos(%0)(2) / SCALE100"
+    },
+	{
+	  "for": {"from":1, "to":"NOBJS"},
+      "id": "speed%0",
+      "attr": "x2",
+      "value" : "(pos(%0)(1)+ SPEED_MULTIPLIER*speed(%0)(1)) / SCALE100"
+    },
+	{
+	  "for": {"from":1, "to":"NOBJS"},
+      "id": "speed%0",
+      "attr": "y2",
+      "value" : "(pos(%0)(2)+ SPEED_MULTIPLIER*speed(%0)(2)) / SCALE100"
+    },
+    
+	{
+	  "for": {"from":1, "to":"NOBJS"},
+      "id": "gravitation%0",
+      "attr": "x1",
+      "value" : "pos(%0)(1) / SCALE100"
+    },
+	{
+	  "for": {"from":1, "to":"NOBJS"},
+      "id": "gravitation%0",
+      "attr": "y1",
+      "value" : "pos(%0)(2) / SCALE100"
+    },
+	{
+	  "for": {"from":1, "to":"NOBJS"},
+      "id": "gravitation%0",
+      "attr": "x2",
+      "value" : "(pos(%0)(1)+ GRAV_MULTIPLIER*gravitation(%0)(1)) / SCALE100"
+    },
+	{
+	  "for": {"from":1, "to":"NOBJS"},
+      "id": "gravitation%0",
+      "attr": "y2",
+      "value" : "(pos(%0)(2)+ GRAV_MULTIPLIER*gravitation(%0)(2)) / SCALE100"
+    }
+  ],
+  "events": [
+    {
+	  "for": {"from":1, "to":"NOBJS"},
+      "id": "body%0",
+      "event": "Move",
+      "hovers": [{ "attr":"stroke-width", "enter":"6", "leave":"1"},
+                 { "attr":"opacity", "enter":"0.8", "leave":"1.0"}]
+    }
+  ]
+}