Two spheres collision - c++

Question

I have to make a program which is doing the collision between two spheres. I made this but when the spheres collide everything is blocked. I can't move the sphere anymore. I made only the sphere1 to move and the other to be static. The code is written in VB/ C++.
#include "GLOS.H"
#include <math.h>
#include <GL/gl.h>
#include <GL/glu.h>
#include <glaux.h>
GLfloat max1=0,max2=0,v,v1;
FLOAT d,distanta=0;
int i,j;
void myinit(void);
void CALLBACK display(void);
void CALLBACK myReshape(GLsizei w, GLsizei h);
void CALLBACK MutaStanga(void);
void CALLBACK MutaDreapta(void);
int k=0,k1=0;
int dist_ramasa;
static float dx1=200,dy1=300,dz1=0;
int deplasare=100;
float rez;
static int flag=1;
float pxc,pyc,pzc,sum,suma_raze;
void myinit (void) { //iluminating
glClearColor(1.0, 1.0, 1.0, 1.0);
GLfloat mat_ambient[] = { 0.3, 0.3, 0.3, 1.0 };
GLfloat mat_diffuse[] = { 0.8, 0.8, 0.8, 1.0 };
GLfloat mat_specular[] = { 1.0, 1.0, 1.0, 1.0 };
GLfloat mat_shininess[] = { 100.0 };
GLfloat light_ambient[] = { 0.4, 0.4, 0.4, 1.0 };
GLfloat light_diffuse[] = { 1.0, 1.0, 1.0, 1.0 };
GLfloat light_specular[] = { 1.0, 1.0, 1.0, 1.0 };
GLfloat light_position[] = { 1.0, 1.0, 0.0, 0.0 };
GLfloat lmodel_ambient[] = { 0.5, 0.5, 0.5, 1.0 };
glMaterialfv(GL_FRONT, GL_AMBIENT, mat_ambient);
glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse);
glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular);
glMaterialfv(GL_FRONT, GL_SHININESS, mat_shininess);
glLightfv(GL_LIGHT0, GL_AMBIENT, light_ambient);
glLightfv(GL_LIGHT0, GL_DIFFUSE, light_diffuse);
glLightfv(GL_LIGHT0, GL_SPECULAR, light_specular);
glLightfv(GL_LIGHT0, GL_POSITION, light_position);
glLightModelfv(GL_LIGHT_MODEL_AMBIENT, lmodel_ambient);
glEnable(GL_LIGHTING); // activare iluminare
glEnable(GL_LIGHT0); // activare sursa 0
glColorMaterial(GL_FRONT,GL_DIFFUSE);
glEnable(GL_COLOR_MATERIAL);
glDepthFunc(GL_LESS);
glEnable(GL_DEPTH_TEST);
}
struct sfera //the spheres
{
GLfloat raza, xcentru, ycentru, zcentru; //the radius and the centers
GLfloat xd1,xd2,yd1,yd2,zd1,zd2;
}sf[2];
void initRaza(){ //radius init
sf[0].raza=100;
sf[1].raza=100;
}
int conditie(void){ //this is where I verify if collide
initRaza();
double xac1,yac1,zac1,xac2,yac2,zac2;//the new centers after the movement
xac1=sf[0].xcentru+dx1;
yac1=sf[0].ycentru+dy1;
zac1=sf[0].zcentru+dz1;
//static sphere
xac2=sf[1].xcentru+700;
yac2=sf[1].ycentru+300;
zac2=sf[1].zcentru;
pxc = pow((xac1-xac2),2);
pyc = pow((yac1-yac2),2);
pzc = pow((zac1-zac2),2);
sum=(pxc + pyc + pzc);
distanta=sqrt(sum); //the distance between the centers
//the sum of the radiuses
suma_raze=sf[0].raza+sf[1].raza;
dist_ramasa=distanta-sf[0].raza-sf[1].raza;
// we compare the distance and the sum of radiuses
//if the distance is lower than the sum -> collide
if(distanta>suma_raze)
return 1;
else
return 0;
}
void CALLBACK MutaStanga(void) //movement left
{
if(conditie()==1){
if(dist_ramasa<deplasare)
dx1=dx1-dist_ramasa;
else
dx1=dx1-deplasare;
}
}
void CALLBACK MutaDreapta(void) //movement right
{
if(conditie()==1){
if(dist_ramasa<deplasare)
dx1=dx1+dist_ramasa;
else
dx1=dx1+deplasare;
}
}
void CALLBACK MutaSus(void) //movement up
{
if(conditie()==1){
if(dist_ramasa<deplasare)
dy1=dy1+dist_ramasa;
else
dy1=dy1+deplasare;
}
}
void CALLBACK MutaJos(void) //movement down
{
if(conditie()==1){
if(dist_ramasa<deplasare)
dy1=dy1-dist_ramasa;
else
dy1=dy1-deplasare;
}
}
void drawBall1() //the first sphere
{
glPushMatrix();
glColor3f(0,1,0);
glTranslatef(dx1, dy1, 0.0);
glRotatef(30,1,0,0);
auxSolidSphere(sf[0].raza);
glPopMatrix();
}
void drawBall2() //the second sphere
{
glPushMatrix();
glColor3f(1,0,0);
glTranslatef(700,300,0);
glRotatef(30,1,0,0);
auxWireSphere(sf[1].raza);
glPopMatrix();
}
void CALLBACK display (void)
{
initRaza();
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity ();
drawBall1();
drawBall2();
auxSwapBuffers();
}
void CALLBACK myReshape(GLsizei w, GLsizei h)
{
if (!h) return;
glViewport(0, 0, w, h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
if (w <= h)
glOrtho (0, 800.0, 0*(GLfloat)h/(GLfloat)w,
-860.0*(GLfloat)h/(GLfloat)w, -200.0, 200.0);
else
glOrtho (0*(GLfloat)w/(GLfloat)h,
900.0*(GLfloat)w/(GLfloat)h, 0, 900.0, -500.0, 500.0);
glMatrixMode(GL_MODELVIEW);
}
int main(int argc, char** argv)
{
auxInitDisplayMode (AUX_SINGLE | AUX_RGB | AUX_DEPTH16);
auxInitPosition (0, 0, 900, 700);
auxInitWindow ("Bounding sphere collision");
myinit ();
auxKeyFunc (AUX_LEFT, MutaStanga);
auxKeyFunc (AUX_RIGHT, MutaDreapta);
auxKeyFunc (AUX_UP, MutaSus);
auxKeyFunc(AUX_DOWN,MutaJos);
auxReshapeFunc (myReshape);
auxMainLoop(display);
return(0);
}
I don't know what is not working. When they collide I want to reject each other . I hope you can help me.

Answer 1

Once the spheres collide, your function conditie will return 1. All your keypress functions check this before modifying the sphere's position, thus, once they collide, you can no longer move the sphere.