// Calculates the vertex normals corresponding to the smoothing group
// settings for each face of a mesh.
//
// \param mesh A pointer to the mesh to calculate the normals for.
// \param normals A pointer to a buffer to store the calculated
// normals. The buffer must have the size:
// 3*3*sizeof(float)*mesh.nfaces.
//
// To allocate the normal buffer do for example the following:
// \code
// Lib3dsVector *normals = malloc(3*3*sizeof(float)*mesh.nfaces);
// \endcode
//
// To access the normal of the i-th vertex of the j-th face do the
// following:
// \code
// normals[3*j+i]
// \endcode
public static void lib3ds_mesh_calculate_vertex_normals(Lib3dsMesh mesh, float[][] normals)
{
if (mesh.nfaces == 0)
{
return;
}
Lib3dsFaces[] fl = new Lib3dsFaces[mesh.nvertices];
Lib3dsFaces[] fa = new Lib3dsFaces[3 * mesh.nfaces];
for (int i = 0; i < fa.Length; i++)
{
fa[i] = new Lib3dsFaces();
}
for (int i = 0; i < mesh.nfaces; i++)
{
for (int j = 0; j < 3; j++)
{
Lib3dsFaces l = fa[3 * i + j];
float[] p = new float[3], q = new float[3], n = new float[3];
float len, weight;
l.index = i;
l.next = fl[mesh.faces[i].index[j]];
fl[mesh.faces[i].index[j]] = l;
lib3ds_vector_sub(p, mesh.vertices[mesh.faces[i].index[j < 2?j + 1:0]], mesh.vertices[mesh.faces[i].index[j]]);
lib3ds_vector_sub(q, mesh.vertices[mesh.faces[i].index[j > 0?j - 1:2]], mesh.vertices[mesh.faces[i].index[j]]);
lib3ds_vector_cross(n, p, q);
len = lib3ds_vector_length(n);
if (len > 0)
{
weight = (float)Math.Atan2(len, lib3ds_vector_dot(p, q));
lib3ds_vector_scalar_mul(l.normal, n, weight / len);
}
else
{
lib3ds_vector_zero(l.normal);
}
}
}
for (int i = 0; i < mesh.nfaces; i++)
{
Lib3dsFace f = mesh.faces[i];
for (int j = 0; j < 3; j++)
{
float[] n = new float[3];
Lib3dsFaces p;
Lib3dsFace pf;
Debug.Assert(mesh.faces[i].index[j] < mesh.nvertices);
if (f.smoothing_group != 0)
{
uint smoothing_group = f.smoothing_group;
lib3ds_vector_zero(n);
for (p = fl[mesh.faces[i].index[j]]; p != null; p = p.next)
{
pf = mesh.faces[p.index];
if ((pf.smoothing_group & f.smoothing_group) != 0)
{
smoothing_group |= pf.smoothing_group;
}
}
for (p = fl[mesh.faces[i].index[j]]; p != null; p = p.next)
{
pf = mesh.faces[p.index];
if ((smoothing_group & pf.smoothing_group) != 0)
{
lib3ds_vector_add(n, n, p.normal);
}
}
}
else
{
lib3ds_vector_copy(n, fa[3 * i + j].normal);
}
lib3ds_vector_normalize(n);
lib3ds_vector_copy(normals[3 * i + j], n);
}
}
}
// Calculates the vertex normals corresponding to the smoothing group
// settings for each face of a mesh.
//
// \param mesh A pointer to the mesh to calculate the normals for.
// \param normals A pointer to a buffer to store the calculated
// normals. The buffer must have the size:
// 3*3*sizeof(float)*mesh.nfaces.
//
// To allocate the normal buffer do for example the following:
// \code
// Lib3dsVector *normals = malloc(3*3*sizeof(float)*mesh.nfaces);
// \endcode
//
// To access the normal of the i-th vertex of the j-th face do the
// following:
// \code
// normals[3*j+i]
// \endcode
public static void lib3ds_mesh_calculate_vertex_normals(Lib3dsMesh mesh, float[][] normals)
{
if(mesh.nfaces==0) return;
Lib3dsFaces[] fl=new Lib3dsFaces[mesh.nvertices];
Lib3dsFaces[] fa=new Lib3dsFaces[3*mesh.nfaces];
for(int i=0; i<fa.Length; i++) fa[i]=new Lib3dsFaces();
for(int i=0; i<mesh.nfaces; i++)
{
for(int j=0; j<3; j++)
{
Lib3dsFaces l=fa[3*i+j];
float[] p=new float[3], q=new float[3], n=new float[3];
float len, weight;
l.index=i;
l.next=fl[mesh.faces[i].index[j]];
fl[mesh.faces[i].index[j]]=l;
lib3ds_vector_sub(p, mesh.vertices[mesh.faces[i].index[j<2?j+1:0]], mesh.vertices[mesh.faces[i].index[j]]);
lib3ds_vector_sub(q, mesh.vertices[mesh.faces[i].index[j>0?j-1:2]], mesh.vertices[mesh.faces[i].index[j]]);
lib3ds_vector_cross(n, p, q);
len=lib3ds_vector_length(n);
if(len>0)
{
weight=(float)Math.Atan2(len, lib3ds_vector_dot(p, q));
lib3ds_vector_scalar_mul(l.normal, n, weight/len);
}
else lib3ds_vector_zero(l.normal);
}
}
for(int i=0; i<mesh.nfaces; i++)
{
Lib3dsFace f=mesh.faces[i];
for(int j=0; j<3; j++)
{
float[] n=new float[3];
Lib3dsFaces p;
Lib3dsFace pf;
Debug.Assert(mesh.faces[i].index[j]<mesh.nvertices);
if(f.smoothing_group!=0)
{
uint smoothing_group=f.smoothing_group;
lib3ds_vector_zero(n);
for(p=fl[mesh.faces[i].index[j]]; p!=null; p=p.next)
{
pf=mesh.faces[p.index];
if((pf.smoothing_group&f.smoothing_group)!=0) smoothing_group|=pf.smoothing_group;
}
for(p=fl[mesh.faces[i].index[j]]; p!=null; p=p.next)
{
pf=mesh.faces[p.index];
if((smoothing_group&pf.smoothing_group)!=0) lib3ds_vector_add(n, n, p.normal);
}
}
else lib3ds_vector_copy(n, fa[3*i+j].normal);
lib3ds_vector_normalize(n);
lib3ds_vector_copy(normals[3*i+j], n);
}
}
}
