void Strand::Render() const {
glDisable(GL_LIGHTING);
// Reusables
V3D<float> diffv;
float x;
// Draw and influence pairs
for (unsigned int n = 1; n < Nodes.size(); ++n) {
diffv = Nodes[n-1]->Pos - Nodes[n]->Pos;
x = diffv.Length() - MiniTargL();
x = fmin(abs(x)/3.f, 1.f);
glColor3f(0.867, 0.867, 0.867);
glBegin(GL_LINES);
glVertex3f(Nodes[n]->Pos.x, Nodes[n]->Pos.y, Nodes[n]->Pos.z);
glVertex3f(Nodes[n-1]->Pos.x, Nodes[n-1]->Pos.y, Nodes[n-1]->Pos.z);
glEnd();
}
glBegin(GL_LINES);
diffv = Nodes[0]->Pos - Head->Pos;
x = diffv.Length() - MiniTargL();
x = fmin(fabs(x)/3.f, 1.f);
glColor3f(0.867, 0.867, 0.867);
glVertex3f(Nodes[0]->Pos.x, Nodes[0]->Pos.y, Nodes[0]->Pos.z);
glVertex3f(Head->Pos.x, Head->Pos.y, Head->Pos.z);
glEnd();
glBegin(GL_LINES);
diffv = (*Nodes.rbegin())->Pos - Head->Pos;
x = diffv.Length() - MiniTargL();
x = fmin(fabs(x)/3.f, 1.f);
glColor3f(0.867, 0.867, 0.867);
glVertex3f((*Nodes.rbegin())->Pos.x, (*Nodes.rbegin())->Pos.y, (*Nodes.rbegin())->Pos.z);
glVertex3f(Tail->Pos.x, Tail->Pos.y, Tail->Pos.z);
glEnd();
glEnable(GL_LIGHTING);
}
// Private helper function
void Strand::InfluencePair(Pushable* A, Pushable* B, bool viscize) {
float k;
V3D<float> diffp = B->Pos - A->Pos;
V3D<float> force;
// F [varies with] k*x
k = .012; // Spring Constant
float x = diffp.Length() - MiniTargL();
force = diffp.Normalized()*x*k;
A->PushGlobal(force);
B->PushGlobal(-force);
// Viscosity
if (viscize) {
k = .015; // Viscosity Constant
V3D<float> diffvel = B->Vel - A->Vel;
force = diffvel*k;
A->PushGlobal(force);
B->PushGlobal(-force);
}
}
