void calc_midpoints(Atom *atoms, int n_atoms, double *prd, Point *mid_points)
{
int i,j,k,i1,i2,i3,i4,im;
int n_dna=2;
int nbp=n_atoms/(2*n_dna);
double *n1, *n2;
double x[3], x0[3], dn, max;
int nx=0,k_max;
for (i=0;i<n_dna;i++) {
for (j=0;j<nbp;j++) {
i1 = 2*nbp*i+j;
i2 = 2*nbp*i+nbp+j;
im = i*nbp+j;
nx = 0; max = 0.0;
n1 = unit_vector(atoms[i1].x, atoms[i2].x, prd); // n1 = (x2 - x1)/|x2-x1|
x[0] = x[1] = x[2] = 0.0;
for (k=-3;k<=3;++k) {
if (k==0 || j+k<0 || j+k>=nbp) continue;
i3 = 2*nbp*i+j+k;
i4 = 2*nbp*i+nbp+j+k;
n2 = unit_vector(atoms[i3].x, atoms[i4].x, prd); // n2 = (x4 - x3)/|x4-x3|
dn = 1-dot(n1,n2,1.0);
if (dn>max) { max=dn; k_max=k; }
if (dn>0.05) {
find_intersect(i1, i2, i3, i4, atoms, prd, n1, n2, x, nx==0 ? NULL : x0);
if (nx==0) { x0[0] = x[0]; x0[1] = x[1]; x0[2] = x[2]; }
nx++;
}
}
if (nx==0) {
i3 = 2*nbp*i+j+k_max;
i4 = 2*nbp*i+nbp+j+k_max;
n2 = unit_vector(atoms[i3].x, atoms[i4].x, prd); // n2 = (x4 - x3)/|x4-x3|
find_intersect(i1, i2, i3, i4, atoms, prd, n1, n2, x, nx==0 ? NULL : x0);
nx++;
}
mid_points[im].x = x[0]/nx;
mid_points[im].y = x[1]/nx;
mid_points[im].z = x[2]/nx;
}
}
}
void display(void)
{
int i;
glClearColor(1.0f,1.0f,1.0f,1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glPointSize(1.0);
glBegin(GL_POINTS);
init_buffer(); //initialize buffer
rotate_all(); //rotate object
project_data(); //project object
drawPoly_zbuffer(); //draws cube
performUpdate(); //moves balls and handles collisions
//draws the balls
for(i=0;i<no_balls;i++)
{
find_intersect(Balls[i].pos[0],Balls[i].pos[1],Balls[i].pos[2],Balls[i].r);
fill_color(Balls[i].pos[0],Balls[i].pos[1],Balls[i].pos[2],i%6);
}
//draws the z-buffer
disp_zbuf();
glEnd();
glutSwapBuffers();
}
