Soft Body Rendering

From Physics Simulation Wiki

Give a btSoftBody, here is some code snippet to retrieve the vertex/node, and edge/link information:

/* Dummy 'graphic driver'   */ 
struct   {
      void DrawPoint(const btVector3&) {}
      void DrawLine(const btVector3&,const btVector3&) {}
      void DrawTriangle(const btVector3&,const btVector3&,const btVector3&) {}
      }         *mygfx=0;
/* Get a ref to the array of softbodies   */ 
btSoftBodyArray&         softbodies(world->getSoftBodyArray());
/* For each soft bodies               */ 
for(int i=0;i<softbodies.size();++i)
   {
   btSoftBody*            softbody(softbodies[i]);
   /* Each soft body contain an array of vertices (nodes/particles_mass)   */ 
   btSoftBody::tNodeArray&   nodes(softbody->m_nodes);
   /* And edges (links/distances constraints)                        */ 
   btSoftBody::tLinkArray&   links(softbody->m_links);
   /* And finally, faces (triangles)                                 */ 
   btSoftBody::tFaceArray&   faces(softbody->m_faces);
   /* Then, you can draw vertices...      */ 
   /* Node::m_x => position            */ 
   /* Node::m_n => normal (if meaningful)   */ 
   for(int j=0;j<nodes.size();++j)
      {
      mygfx->DrawPoint(nodes[j].m_x);
      }
   /* Or edges (for ropes)               */ 
   /* Link::m_n[2] => pointers to nodes   */ 
   for(int j=0;j<links.size();++j)
      {
      btSoftBody::Node*   node_0=links[j].m_n[0];
      btSoftBody::Node*   node_1=links[j].m_n[1];
      mygfx->DrawLine(node_0->m_x,node_1->m_x);
      /* Or if you need indices...      */ 
      const int         indices[]={   int(node_0-&nodes[0]),
                              int(node_1-&nodes[0])};
      }
   /* And even faces                  */ 
   /* Face::m_n[3] -> pointers to nodes   */ 
   for(int j=0;j<faces.size();++j)
      {
      btSoftBody::Node*   node_0=faces[j].m_n[0];
      btSoftBody::Node*   node_1=faces[j].m_n[1];
      btSoftBody::Node*   node_2=faces[j].m_n[2];
      mygfx->DrawTriangle(node_0->m_x,node_1->m_x,node_2->m_x);
      /* Or if you need indices...      */ 
      const int         indices[]={   int(node_0-&nodes[0]),
                              int(node_1-&nodes[0]),
                              int(node_2-&nodes[0])};
      }
   }