void parse_vn_statement()
{
Vector3d n;
m_lexer.eat_blanks();
n.x = m_lexer.accept_double();
m_lexer.eat_blanks();
n.y = m_lexer.accept_double();
m_lexer.eat_blanks();
n.z = m_lexer.accept_double();
m_normals.push_back(n);
}
void parse_vt_statement()
{
Vector2d v;
m_lexer.eat_blanks();
v.x = m_lexer.accept_double();
m_lexer.eat_blanks();
v.y = m_lexer.accept_double();
m_lexer.eat_blanks();
if (!m_lexer.is_eol())
m_lexer.accept_double();
m_tex_coords.push_back(v);
}
void parse_v_statement()
{
Vector3d v;
m_lexer.eat_blanks();
v.x = m_lexer.accept_double();
m_lexer.eat_blanks();
v.y = m_lexer.accept_double();
m_lexer.eat_blanks();
v.z = m_lexer.accept_double();
m_lexer.eat_blanks();
if (!m_lexer.is_eol())
m_lexer.accept_double();
m_vertices.push_back(v);
}
string parse_compound_identifier()
{
string identifier;
m_lexer.eat_blanks();
while (!m_lexer.is_eol())
{
const char* token;
size_t token_length;
m_lexer.accept_string(&token, &token_length);
m_lexer.eat_blanks();
if (!identifier.empty())
identifier += ' ';
identifier.append(token, token_length);
}
return identifier;
}
string parse_mesh_name()
{
string mesh_name;
while (!m_lexer.is_eol())
{
const char* token;
size_t token_length;
m_lexer.accept_string(&token, &token_length);
m_lexer.eat_blanks();
if (!mesh_name.empty())
mesh_name += ' ';
mesh_name.append(token, token_length);
}
return mesh_name;
}
void parse_o_g_statement()
{
m_lexer.eat_blanks();
// Retrieve the name of the upcoming mesh.
const string upcoming_mesh_name = parse_mesh_name();
// Start a new mesh only if the name of the object or group actually changes.
if (upcoming_mesh_name != m_mesh_name)
{
// End the current mesh.
if (m_inside_mesh_def)
{
m_builder.end_mesh();
m_inside_mesh_def = false;
}
clear_keep_memory(m_vertex_index_mapping);
clear_keep_memory(m_tex_coord_index_mapping);
clear_keep_memory(m_normal_index_mapping);
m_mesh_name = upcoming_mesh_name;
}
}
void parse_f_statement()
{
clear_keep_memory(m_face_vertex_indices);
clear_keep_memory(m_face_tex_coord_indices);
clear_keep_memory(m_face_normal_indices);
while (true)
{
m_lexer.eat_blanks();
if (m_lexer.is_eol())
break;
//
// Recognized (epsilon)
// Accept n
//
{
const long n = m_lexer.accept_long();
const size_t v = fix_index(n, m_vertices.size());
m_face_vertex_indices.push_back(v);
}
//
// Recognized n
// Accept (epsilon), /
//
{
const unsigned char c = m_lexer.get_char();
if (m_lexer.is_space(c))
continue;
else if (c == '/')
m_lexer.next_char();
else parse_error();
}
//
// Recognized n/
// Accept /, n
//
{
const unsigned char c = m_lexer.get_char();
if (c == '/')
{
m_lexer.next_char();
goto skip;
}
else
{
const long n = m_lexer.accept_long();
const size_t vt = fix_index(n, m_tex_coords.size());
m_face_tex_coord_indices.push_back(vt);
}
}
//
// Recognized n/n
// Accept (epsilon), /
//
{
const unsigned char c = m_lexer.get_char();
if (m_lexer.is_space(c))
continue;
else if (c == '/')
m_lexer.next_char();
else parse_error();
}
skip:
//
// Recognized n//, n/n/
// Accept (epsilon), n
//
{
const unsigned char c = m_lexer.get_char();
if (m_lexer.is_space(c))
continue;
else
{
const long n = m_lexer.accept_long();
const size_t vn = fix_index(n, m_normals.size());
m_face_normal_indices.push_back(vn);
}
}
}
// Check whether the face is well-formed.
const size_t vc = m_face_vertex_indices.size();
const size_t tc = m_face_tex_coord_indices.size();
const size_t nc = m_face_normal_indices.size();
const bool well_formed =
vc >= 3
&& (tc == 0 || tc == vc)
&& (nc == 0 || nc == vc);
if (well_formed)
{
// The face is well-formed, insert it into the mesh.
insert_face_into_mesh();
}
else
{
// The face is ill-formed, ignore it or abort parsing.
if (m_options & StopOnInvalidFaceDef)
throw ExceptionInvalidFaceDef(m_lexer.get_line_number());
}
}
void parse_file()
{
while (true)
{
m_lexer.eat_blanks();
// Handle end of file.
if (m_lexer.is_eof())
break;
// Handle empty lines.
if (m_lexer.is_eol())
{
m_lexer.accept_newline();
continue;
}
const char* keyword;
size_t keyword_length;
m_lexer.accept_string(&keyword, &keyword_length);
if (keyword_length == 1)
{
switch (keyword[0])
{
case 'f':
parse_f_statement();
break;
case 'g':
case 'o':
parse_o_g_statement();
break;
case 'v':
parse_v_statement();
break;
default:
// Ignore unknown or unhandled statements.
m_lexer.eat_line();
continue;
}
}
else if (keyword_length == 2)
{
switch (keyword[0] * 256 + keyword[1])
{
case 'v' * 256 + 'n':
parse_vn_statement();
break;
case 'v' * 256 + 't':
parse_vt_statement();
break;
default:
// Ignore unknown or unhandled statements.
m_lexer.eat_line();
continue;
}
}
else if (strncmp(keyword, "usemtl", keyword_length) == 0)
{
parse_usemtl_statement();
}
else
{
// Ignore unknown or unhandled statements.
m_lexer.eat_line();
continue;
}
m_lexer.eat_blanks();
m_lexer.accept_newline();
}
// End the definition of the last object.
if (m_inside_mesh_def)
m_builder.end_mesh();
}