static Real formfactor(int i, int j, int n, Poly **p, Real *a)
{
Vector3 vi, vj, vji, d;
Real r2, ci, cj;
vi = poly_centr(p[i]);
vj = poly_centr(p[j]);
vji = v3_sub(vi, vj);
if ((r2 = v3_sqrnorm(vji)) < REL_EPS)
return 0;
d = v3_scale(1.0/sqrt(r2), vji);
if ((cj = v3_dot(poly_normal(p[j]), d)) < REL_EPS)
return 0;
if ((ci = -v3_dot(poly_normal(p[i]), d)) < REL_EPS)
return 0;
if (vis_flag && visible(n, p, vj, vji) < REL_EPS)
return 0;
return a[i] * ((cj * ci) / (PI * r2 + a[i]));
}
void SCANLINE::Compute_Poly_Normal()
{
vector< vector<float> > temp_vertex_normal(world_vertex.size(),vector<float>(3));
vector <float> temp_I_light(3);//light intensity
I_light = temp_I_light;
I_light[0] = 1.0;//R
I_light[1] = 0.64;//G
I_light[2] = 0;//B
vector <float> poly_vector_1(3);
vector <float> poly_vector_2(3);
vector <float> poly_normal(3);
vector <float> temp_H(3);
//calculus H
vector_summation(temp_H, vec_light,vec_view);
for (int j=0; j<3 ;j++ )
H_specular.push_back(temp_H[j]/vector_length(temp_H));
///---Intensity ambient----Ka*I
for (int j=0; j<3 ;j++ )
Intensity_ambient.push_back(K_ambient*I_light[j]);
for(int i=0; i<(int)Poly.size(); i++)
{//compute polygon normal
vector_subtraction(poly_vector_1,
world_vertex[Poly[i][2]-1],
world_vertex[Poly[i][1]-1]);
vector_subtraction(poly_vector_2,
world_vertex[Poly[i][2]-1],
world_vertex[Poly[i][3]-1]);
//compute 2 vector on one polygon
cross_product3D(poly_normal, poly_vector_1, poly_vector_2);
//calculus cross product
for(int j=1; j<(int)Poly[i][0]+1 ;j++)
{//add normal of neibor polygon to vertex
for (int p=0; p<3 ;p++ )
temp_vertex_normal[Poly[i][j]-1][p] += poly_normal[p];
}
}
for(int i=0; i<(int)temp_vertex_normal.size() ;i++ )
{
float temp_length = vector_length(temp_vertex_normal[i]);
for (int j=0; j<3 ;j++ )
{ //normalize the normal on vertex
temp_vertex_normal[i][j] = temp_vertex_normal[i][j] / temp_length;
}
}
vertex_normal = temp_vertex_normal;
//vertex normals as average of surrounding neibor polygon's normal
}
void SCANLINE::Compute_Poly_Normal()
{//compute polygon normal, vertices normal and illumination model
vector< vector<float> >vertex_normal(world_vertex.size(),vector<float>(3));
vector< vector<float> >temp_Light_Intensity//vertex intensity
(world_vertex.size(),vector<float>(3));
vector <float> I_light(3);//light intensity
I_light[0] = 0.8;//R
I_light[1] = 0.0;//G
I_light[2] = 0.0;//B
vector <float> Intensity_diffuse(3);
vector <float> Intensity_specular(3);
vector <float> Intensity_ambient(3);
vector <float> poly_vector_1(3);
vector <float> poly_vector_2(3);
vector <float> poly_normal(3);
vector <float> H(3);
vector <float> temp_H(3);
//calculus H
vector_summation(temp_H, vec_light,vec_view);
for (int j=0; j<3 ;j++ )
H[j] = temp_H[j]/vector_length(temp_H);
///---Intensity ambient----Ka*I
for (int j=0; j<3 ;j++ )
Intensity_ambient[j] = K_ambient*I_light[j];
for(int i=0; i<(int)Poly.size(); i++)
{//compute polygon normal
vector_subtraction(poly_vector_1,
world_vertex[Poly[i][2]-1],
world_vertex[Poly[i][1]-1]);
vector_subtraction(poly_vector_2,
world_vertex[Poly[i][2]-1],
world_vertex[Poly[i][3]-1]);
//compute 2 vector on one polygon
cross_product3D(poly_normal, poly_vector_1, poly_vector_2);
//calculus cross product
// float temp_length = vector_length(poly_normal);
// for (int j=0; j<3 ;j++ )//(normalized)
// poly_normal[j] = poly_normal[j]/ temp_length;
for(int j=1; j<(int)Poly[i][0]+1 ;j++)
{//add normal of neibor polygon to vertex
for (int p=0; p<3 ;p++ )
vertex_normal[Poly[i][j]-1][p] += poly_normal[p];
}
}
for(int i=0; i<(int)vertex_normal.size() ;i++ )
{
float temp_length = vector_length(vertex_normal[i]);
for (int j=0; j<3 ;j++ )
{ //normalize the normal
vertex_normal[i][j] = vertex_normal[i][j] / temp_length;
///----------Intensity diffuse----Kd*I*(NL)
Intensity_diffuse[j] =
K_diffuse*I_light[j]*dot_product3D(vertex_normal[i],vec_light);
///----------Intensity specular----Ks*I*(NH)^n
Intensity_specular[j] =
K_specular*I_light[j]*pow(dot_product3D(vertex_normal[i],H),8);
//---------------sum of all intensity
temp_Light_Intensity[i][j]= Intensity_diffuse[j] +
Intensity_specular[j] + Intensity_ambient[j];
}
}
Light_Intensity = temp_Light_Intensity;
//Light_Intensity match to vertex index
}