TempleOSCDV4.11.ISO

Apps/Span/SpanDerive.HC

@@ -0,0 +1,47 @@
+U0 MyDerivative(CMathODE *ode,F64,COrder2D3 *,COrder2D3 *)
+{
+//The forces due to springs and drag are
+  //automatically handled by the
+  //ode code.  We can add new forces
+  //here.
+  CTask *task=ode->win_task;
+  F64 d,dd;
+  CD3 p,p2;
+  MyMass *tempm1,*tempm2;
+
+  //Collisions
+  tempm1=ode->next_mass;
+  while (tempm1!=&ode->next_mass) {
+    tempm2=tempm1->next;
+    while (tempm2!=&ode->next_mass) {
+      D3Sub(&p,&tempm2->state->x,&tempm1->state->x);
+      dd=D3NormSqr(&p);
+      if (dd<=Sqr(tempm1->radius+tempm2->radius)) {
+	d=Sqrt(dd)+0.0001;
+	dd=10.0*Sqr(Sqr(Sqr(tempm1->radius+tempm2->radius)-dd));
+	D3MulEqu(&p,dd/d);
+	D3AddEqu(&tempm2->DstateDt->DxDt,&p);
+	D3SubEqu(&tempm1->DstateDt->DxDt,&p);
+      }
+      tempm2=tempm2->next;
+    }
+    tempm1=tempm1->next;
+  }
+
+  tempm1=ode->next_mass;
+  while (tempm1!=&ode->next_mass) {
+    if (!(tempm1->flags&MSF_FIXED))
+      tempm1->DstateDt->DyDt+=10.0*tempm1->mass; //Gravity
+    tempm1=tempm1->next;
+  }
+
+  if (cursor_mass) {
+    p2.x=ip.pos.x-task->pix_left-task->scroll_x;
+    p2.y=ip.pos.y-task->pix_top-task->scroll_y;
+    p2.z=0;
+    D3Sub(&p,&p2,&cursor_mass->state->x);
+    d=10.0*D3NormSqr(&p);
+    D3MulEqu(&p,d);
+    D3AddEqu(&cursor_mass->DstateDt->DxDt,&p);
+  }
+}