farzana

void stage3()
{
    if (near == far) return;
    ifstream stage2;
    ofstream stage3;
    stage2.open ("stage2.txt");
    stage3.open ("stage3.txt");
    stage3 << std::fixed;
    stage3 << std::setprecision(7);

    // process input from stage2 and write to stage3
    fov_x = fov_y * aspectRatio;
    double r, t;
    t = near*tan(pi*fov_y/(2*180));
    r = near*tan(pi*fov_x/(2*180));

    matrix proj = matrix::make_identity(4);
    proj.values[0][0] = near/r;
    proj.values[1][1] = near/t;
    proj.values[2][2] = -(far+near)/(far-near);
    proj.values[2][3] = -(2*far*near)/(far-near);
    proj.values[3][3] = 0;
    proj.values[3][2] = -1;

    int tc = 0;

    while(tc < triangleCount)
    {
        tc++;
        homogeneous_point input[3];
        homogeneous_point output[3];
        homogeneous_point outfinal[3];

        for(int i=0; i<3; i++)
        {
            double x,y,z;
            stage2 >> x >> y >> z;
            homogeneous_point h(x,y,z);
            input[i]=h;
        }


        int oput = 0;
        for(int i=0; i<3; i++)
        {
            homogeneous_point s = input[i];
            homogeneous_point p = input[(i+1)%3];

            if(s.z < -near && p.z < -near)
            {
                output[oput] = p;
                oput++;
            }

            // s inside and p outside
            else if(s.z < -near && p.z >= -near)
            {
                homogeneous_point temp(s.x, s.y, -near);
                output[oput] = temp;
                oput++;
            }

            // s outside and p inside
            else if(s.z >= -near && p.z < -near)
            {
                homogeneous_point temp(p.x, p.y, -near);
                output[oput] = temp;
                oput++;
                output[oput] = p;
                oput++;
            }

            // both outside
            else
            {

            }
        }

        //clipping by far plane

        oput = 0;
        for(int i=0; i<3; i++)
        {
            homogeneous_point s = output[i];
            homogeneous_point p = output[(i+1)%3];

            // both inside the clip region

            if(s.z >= -far && p.z >= -far)
            {
                outfinal[oput] = p;
                oput++;
            }

            // s inside and p outside
            else if(s.z >= -far && p.z < -far)
            {
                homogeneous_point temp(s.x, s.y, -far);
                outfinal[oput] = temp;
                oput++;
            }

            // s outside and p inside
            else if(s.z < -far && p.z >= -far)
            {
                homogeneous_point temp(p.x, p.y, -far);
                outfinal[oput] = temp;
                oput++;
                outfinal[oput] = p;
                oput++;
            }

            // both outside
            else
            {

            }
        }
        // final output write to stage3 file

        for(int i=1; i<4; i++)
        {
            homogeneous_point now = proj*outfinal[i%3];
            stage3 << now.x <<" "<<now.y<< " "<<now.z<<" "<<endl;
        }
        stage3<<endl;
    }

    stage3.close();
    stage2.close();
}