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Yeaseen/OpenGLClipping.cpp

Created January 17, 2019 14:35
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OpenGLClipping.cpp
homogeneous_point intersect(homogeneous_point p3,homogeneous_point p2, double z){
homogeneous_point ans;
ans.w=1;
ans.z=z;
ans.x=p2.x + ((p3.x-p2.x)/(p3.z-p2.z))*(z-p2.z);
ans.y=p2.y + ((p3.y-p2.y)/(p3.z-p2.z))*(z-p2.z);
//ans.print();
return ans;
}
void stage3()
{
//cout<<"ok"<<endl;
if (near == far) return;
ifstream stage2;
ofstream stage3;
stage2.open ("stage2.txt");
stage3.open ("stage3.txt");
stage3 << std::fixed;
stage3 << std::setprecision(7);
fov_y=fov_y*(pi/180);
fov_x=fov_y * aspectRatio;
double t= near * tan(fov_y/2);
double r=near * tan(fov_x/2);
matrix projectMat(4);
projectMat.values[0][0]=near/r;
projectMat.values[0][1]=0;
projectMat.values[0][2]=0;
projectMat.values[0][3]=0;
projectMat.values[1][0]=0;
projectMat.values[1][1]=near/t;
projectMat.values[1][2]=0;
projectMat.values[1][3]=0;
projectMat.values[2][0]=0;
projectMat.values[2][1]=0;
projectMat.values[2][2]=-((far + near)/(far - near));
projectMat.values[2][3]=-((2 * far * near)/(far - near));
projectMat.values[3][0]=0;
projectMat.values[3][1]=0;
projectMat.values[3][2]=-1;
projectMat.values[3][3]=0;
//projectMat.print();
//cout<<clrs.size()<<endl;
//cout<<finalclrs.size()<<endl;
double NEAR=-near;
double FAR=-far;
homogeneous_point s2p;
int cnt=1;
homogeneous_point Points[3];
int ic=0;
while(stage2>> s2p.x >> s2p.y >> s2p.z){
s2p.w=1;
//s2p.print();
Points[cnt-1]=s2p;
//homogeneous_point projP=projectMat*s2p;
//stage3 << projP.x <<" "<<projP.y <<" "<<projP.z<<endl;
if((cnt%3)==0){
//case 1
if((Points[0].z>=FAR && Points[0].z<= NEAR) && (Points[1].z>=FAR && Points[1].z<= NEAR)
&& (Points[2].z>=FAR && Points[2].z<= NEAR)){
//cout<<"T"<<endl;
for(int i=0;i<3;i++){
homogeneous_point projP=projectMat*Points[i];
stage3 << projP.x <<" "<<projP.y <<" "<<projP.z<<endl;
}
stage3<<endl;
cnt=0;
//clrs[ic].print();
finalclrs.push_back(clrs[ic]);
//finalclrs[ic].print();
ic++;
}
//case 2
else if((Points[0].z>NEAR || Points[0].z<FAR) && (Points[1].z>=FAR && Points[1].z<=NEAR)
&& (Points[2].z>=FAR && Points[2].z<=NEAR)){
//cout<< "nice"<<endl;
double z;
if( (Points[0].z>NEAR) && (Points[1].z==NEAR ) &&(Points[2].z==NEAR)){
cnt=0;
continue;
}
else if((Points[0].z>NEAR) && (Points[1].z<NEAR ) &&(Points[2].z<NEAR)) {
z=NEAR;
}
else if((Points[0].z<FAR) && (Points[1].z==FAR ) &&(Points[2].z==FAR)){
//z=NEAR;
cnt=0;
continue;
}
else if((Points[0].z<FAR) && (Points[1].z>FAR ) &&(Points[2].z>FAR)) {
z=FAR;
}
homogeneous_point p=intersect(Points[0],Points[1],z);
p=projectMat*p;
//p.print();
homogeneous_point q=intersect(Points[0],Points[2],z);
q=projectMat*q;
//q.print();
Points[1]=projectMat*Points[1];
Points[2]=projectMat*Points[2];
stage3 << Points[1].x<<" "<<Points[1].y<<" "<<Points[1].z<<endl;
stage3 << Points[2].x<<" "<<Points[2].y<<" "<<Points[2].z<<endl;
stage3 << p.x <<" "<<p.y <<" "<<p.z<<endl;
stage3 <<endl;
finalclrs.push_back(clrs[ic]);
stage3 << p.x <<" "<<p.y <<" "<<p.z<<endl;
stage3 << q.x <<" "<<q.y <<" "<<q.z<<endl;
stage3 << Points[2].x<<" "<<Points[2].y<<" "<<Points[2].z<<endl;
stage3 << endl;
finalclrs.push_back(clrs[ic]);
cnt=0;
ic++;
}
else if((Points[1].z>NEAR || Points[1].z<FAR) && (Points[0].z>=FAR && Points[0].z<=NEAR)
&& (Points[2].z>=FAR && Points[2].z<=NEAR)){
//cout<< "nice"<<endl;
double z;
if( (Points[1].z>NEAR) && (Points[0].z==NEAR ) &&(Points[2].z==NEAR)){
cnt=0;
continue;
}
else if((Points[1].z>NEAR) && (Points[0].z<NEAR ) &&(Points[2].z<NEAR)) {
z=NEAR;
}
else if((Points[1].z<FAR) && (Points[0].z==FAR ) &&(Points[2].z==FAR)){
//z=NEAR;
cnt=0;
continue;
}
else if((Points[1].z<FAR) && (Points[0].z>FAR ) &&(Points[2].z>FAR)) {
z=FAR;
}
homogeneous_point p=intersect(Points[1],Points[0],z);
p=projectMat*p;
//p.print();
homogeneous_point q=intersect(Points[1],Points[2],z);
q=projectMat*q;
//q.print();
Points[0]=projectMat*Points[0];
Points[2]=projectMat*Points[2];
stage3 << Points[0].x<<" "<<Points[0].y<<" "<<Points[0].z<<endl;
stage3 << Points[2].x<<" "<<Points[2].y<<" "<<Points[2].z<<endl;
stage3 << p.x <<" "<<p.y <<" "<<p.z<<endl;
stage3 <<endl;
finalclrs.push_back(clrs[ic]);
stage3 << p.x <<" "<<p.y <<" "<<p.z<<endl;
stage3 << q.x <<" "<<q.y <<" "<<q.z<<endl;
stage3 << Points[2].x<<" "<<Points[2].y<<" "<<Points[2].z<<endl;
stage3 << endl;
finalclrs.push_back(clrs[ic]);
cnt=0;
ic++;
}
else if((Points[2].z>NEAR || Points[2].z<FAR) && (Points[0].z>=FAR && Points[0].z<=NEAR)
&& (Points[1].z>=FAR && Points[1].z<=NEAR)){
//cout<< "nice"<<endl;
double z;
if( (Points[2].z>NEAR) && (Points[0].z==NEAR ) &&(Points[1].z==NEAR)){
cnt=0;
continue;
}
else if((Points[2].z>NEAR) && (Points[0].z<NEAR ) &&(Points[1].z<NEAR)) {
z=NEAR;
}
else if((Points[2].z<FAR) && (Points[0].z==FAR ) &&(Points[1].z==FAR)){
//z=NEAR;
cnt=0;
continue;
}
else if((Points[2].z<FAR) && (Points[0].z>FAR ) &&(Points[1].z>FAR)) {
z=FAR;
}
homogeneous_point p=intersect(Points[2],Points[0],z);
p=projectMat*p;
//p.print();
homogeneous_point q=intersect(Points[2],Points[1],z);
q=projectMat*q;
//q.print();
Points[0]=projectMat*Points[0];
Points[1]=projectMat*Points[1];
stage3 << Points[0].x<<" "<<Points[0].y<<" "<<Points[0].z<<endl;
stage3 << Points[1].x<<" "<<Points[1].y<<" "<<Points[1].z<<endl;
stage3 << p.x <<" "<<p.y <<" "<<p.z<<endl;
stage3 <<endl;
finalclrs.push_back(clrs[ic]);
stage3 << p.x <<" "<<p.y <<" "<<p.z<<endl;
stage3 << q.x <<" "<<q.y <<" "<<q.z<<endl;
stage3 << Points[1].x<<" "<<Points[1].y<<" "<<Points[1].z<<endl;
stage3 << endl;
finalclrs.push_back(clrs[ic]);
cnt=0;
ic++;
}
//case 3
else if((Points[0].z<=FAR && Points[1].z<=FAR && Points[2].z<=FAR)
||(Points[0].z >=NEAR && Points[1].z>=NEAR && Points[2].z>=NEAR)){
cnt=0;
continue;
}
//case 4
else if((Points[0].z>FAR && Points[0].z<NEAR)&&((Points[1].z>NEAR && Points[2].z>NEAR)
|| (Points[1].z<FAR && Points[2].z<FAR) )){
double z;
if(Points[1].z>NEAR && Points[2].z>NEAR){
z=NEAR;
}
else if(Points[1].z<FAR && Points[2].z<FAR){
z=FAR;
}
homogeneous_point p=intersect(Points[1],Points[0],z);
homogeneous_point q=intersect(Points[2],Points[0],z);
p=projectMat*p;
q=projectMat*q;
Points[0]=projectMat*Points[0];
stage3 << Points[0].x<<" "<<Points[0].y<<" "<<Points[0].z<<endl;
stage3 << p.x <<" "<<p.y <<" "<<p.z<<endl;
stage3 << q.x <<" "<<q.y <<" "<<q.z<<endl;
stage3 << endl;
finalclrs.push_back(clrs[ic]);
cnt=0;
ic++;
}
else if((Points[1].z>FAR && Points[1].z<NEAR)&&((Points[0].z>NEAR && Points[2].z>NEAR)
|| (Points[0].z<FAR && Points[2].z<FAR) )){
double z;
if(Points[0].z>NEAR && Points[2].z>NEAR){
z=NEAR;
}
else if(Points[0].z<FAR && Points[2].z<FAR){
z=FAR;
}
homogeneous_point p=intersect(Points[0],Points[1],z);
homogeneous_point q=intersect(Points[2],Points[1],z);
p=projectMat*p;
q=projectMat*q;
Points[1]=projectMat*Points[1];
stage3 << Points[1].x<<" "<<Points[1].y<<" "<<Points[1].z<<endl;
stage3 << p.x <<" "<<p.y <<" "<<p.z<<endl;
stage3 << q.x <<" "<<q.y <<" "<<q.z<<endl;
stage3 << endl;
finalclrs.push_back(clrs[ic]);
cnt=0;
ic++;
}
else if((Points[2].z>FAR && Points[2].z<NEAR)&&((Points[0].z>NEAR && Points[1].z>NEAR)
|| (Points[0].z<FAR && Points[1].z<FAR) )){
double z;
if(Points[0].z>NEAR && Points[1].z>NEAR){
z=NEAR;
}
else if(Points[0].z<FAR && Points[1].z<FAR){
z=FAR;
}
homogeneous_point p=intersect(Points[0],Points[2],z);
homogeneous_point q=intersect(Points[1],Points[2],z);
p=projectMat*p;
q=projectMat*q;
Points[2]=projectMat*Points[2];
stage3 << Points[2].x<<" "<<Points[2].y<<" "<<Points[2].z<<endl;
stage3 << p.x <<" "<<p.y <<" "<<p.z<<endl;
stage3 << q.x <<" "<<q.y <<" "<<q.z<<endl;
stage3 << endl;
finalclrs.push_back(clrs[ic]);
cnt=0;
ic++;
}
//case 5 due
else if((Points[0].z>FAR && Points[0].z<NEAR) && ((Points[1].z<FAR && Points[2].z>NEAR)
|| (Points[1].z>NEAR && Points[2].z <FAR) )){
//cout<< "Find"<<endl;
double z2,z3;
homogeneous_point x1=Points[0];
x1.w=1;
homogeneous_point x2,x3;
x2.w=1;
x3.w=1;
z2=FAR;
z3=NEAR;
if(Points[1].z<FAR){
x2=Points[1];
x3=Points[2];
// cout<<"1 is in FAR"<<endl;
}
else{
x2=Points[2];
x3=Points[1];
//cout<<"2 is in FAR"<<endl;
}
homogeneous_point p=intersect(x2,x1,z2);
homogeneous_point q=intersect(x2,x3,z2);
homogeneous_point r=intersect(x3,x1,z3);
homogeneous_point s=intersect(x2,x3,z3);
x1=projectMat*x1;
p=projectMat*p;
q=projectMat*q;
r=projectMat*r;
s=projectMat*s;
stage3 << x1.x <<" "<<x1.y <<" "<<x1.z<<endl;
stage3 << p.x <<" "<<p.y <<" "<<p.z<<endl;
stage3 << r.x <<" "<<r.y <<" "<<r.z<<endl;
stage3<<endl;
finalclrs.push_back(clrs[ic]);
stage3 << p.x <<" "<<p.y <<" "<<p.z<<endl;
stage3 << q.x <<" "<<q.y <<" "<<q.z<<endl;
stage3 << r.x <<" "<<r.y <<" "<<r.z<<endl;
stage3 <<endl;
finalclrs.push_back(clrs[ic]);
stage3 << q.x <<" "<<q.y <<" "<<q.z<<endl;
stage3 << r.x <<" "<<r.y <<" "<<r.z<<endl;
stage3 << s.x <<" "<<s.y <<" "<<s.z<<endl;
stage3 <<endl;
finalclrs.push_back(clrs[ic]);
cnt=0;
ic++;
}
else if((Points[1].z>FAR && Points[1].z<NEAR) && ((Points[0].z<FAR && Points[2].z>NEAR)
|| (Points[0].z>NEAR && Points[2].z <FAR) )){
//cout<< "Find"<<endl;
double z2,z3;
homogeneous_point x1=Points[1];
x1.w=1;
homogeneous_point x2,x3;
x2.w=1;
x3.w=1;
z2=FAR;
z3=NEAR;
if(Points[0].z<FAR){
x2=Points[0];
x3=Points[2];
// cout<<"0 is in FAR"<<endl;
}
else{
x2=Points[2];
x3=Points[0];
// cout<<"2bc is in FAR"<<endl;
}
homogeneous_point p=intersect(x2,x1,z2);
homogeneous_point q=intersect(x2,x3,z2);
homogeneous_point r=intersect(x3,x1,z3);
homogeneous_point s=intersect(x2,x3,z3);
x1=projectMat*x1;
p=projectMat*p;
q=projectMat*q;
r=projectMat*r;
s=projectMat*s;
stage3 << x1.x <<" "<<x1.y <<" "<<x1.z<<endl;
stage3 << p.x <<" "<<p.y <<" "<<p.z<<endl;
stage3 << r.x <<" "<<r.y <<" "<<r.z<<endl;
stage3<<endl;
finalclrs.push_back(clrs[ic]);
stage3 << p.x <<" "<<p.y <<" "<<p.z<<endl;
stage3 << q.x <<" "<<q.y <<" "<<q.z<<endl;
stage3 << r.x <<" "<<r.y <<" "<<r.z<<endl;
stage3 <<endl;
finalclrs.push_back(clrs[ic]);
stage3 << q.x <<" "<<q.y <<" "<<q.z<<endl;
stage3 << r.x <<" "<<r.y <<" "<<r.z<<endl;
stage3 << s.x <<" "<<s.y <<" "<<s.z<<endl;
stage3 <<endl;
finalclrs.push_back(clrs[ic]);
cnt=0;
ic++;
}
else if((Points[2].z>FAR && Points[2].z<NEAR) && ((Points[1].z<FAR && Points[0].z>NEAR)
|| (Points[1].z>NEAR && Points[0].z <FAR) )){
//cout<< "Find"<<endl;
double z2,z3;
homogeneous_point x1=Points[2];
x1.w=1;
homogeneous_point x2,x3;
x2.w=1;
x3.w=1;
z2=FAR;
z3=NEAR;
if(Points[0].z<FAR){
x2=Points[0];
x3=Points[1];
// cout<<"1 is in FAR"<<endl;
}
else{
x2=Points[1];
x3=Points[0];
// cout<<"2 is in FAR"<<endl;
}
homogeneous_point p=intersect(x2,x1,z2);
homogeneous_point q=intersect(x2,x3,z2);
homogeneous_point r=intersect(x3,x1,z3);
homogeneous_point s=intersect(x2,x3,z3);
x1=projectMat*x1;
p=projectMat*p;
q=projectMat*q;
r=projectMat*r;
s=projectMat*s;
stage3 << x1.x <<" "<<x1.y <<" "<<x1.z<<endl;
stage3 << p.x <<" "<<p.y <<" "<<p.z<<endl;
stage3 << r.x <<" "<<r.y <<" "<<r.z<<endl;
stage3<<endl;
finalclrs.push_back(clrs[ic]);
stage3 << p.x <<" "<<p.y <<" "<<p.z<<endl;
stage3 << q.x <<" "<<q.y <<" "<<q.z<<endl;
stage3 << r.x <<" "<<r.y <<" "<<r.z<<endl;
stage3 <<endl;
finalclrs.push_back(clrs[ic]);
stage3 << q.x <<" "<<q.y <<" "<<q.z<<endl;
stage3 << r.x <<" "<<r.y <<" "<<r.z<<endl;
stage3 << s.x <<" "<<s.y <<" "<<s.z<<endl;
stage3 <<endl;
finalclrs.push_back(clrs[ic]);
cnt=0;
ic++;
}
}
cnt++;
}
// process input from stage2 and write to stage3
stage3.close();
stage2.close();
}
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