source: trunk/src/formats/md5_loader.cc @ 190

// Copyright (C) 2012-2013 ChaosForge / Kornel Kisielewicz
// http://chaosforge.org/
//
// This file is part of NV Libraries.
// For conditions of distribution and use, see copyright notice in nv.hh

#include "nv/formats/md5_loader.hh"

#include <glm/gtc/constants.hpp>
#include <glm/gtx/string_cast.hpp>
#include "nv/logging.hh"
#include "nv/io/std_stream.hh"
#include <cstring>

using namespace nv;

static void next_line( std::istream& stream )
{
        stream.ignore( std::numeric_limits<std::streamsize>::max(), '\n' );
}

static inline void discard( std::istream& stream, const std::string& token )
{
        std::string discarded;
        stream >> discarded;
        assert( discarded == token );
}


static void remove_quotes( std::string& str )
{
        size_t n;
        while ( ( n = str.find('\"') ) != std::string::npos ) str.erase(n,1);
}

void unit_quat_w( glm::quat& quat )
{
        float t = 1.0f - ( quat.x * quat.x ) - ( quat.y * quat.y ) - ( quat.z * quat.z );
        quat.w = ( t < 0.0f ? 0.0f : -sqrtf(t) );
}

bool md5_loader::load( stream& source )
{
        std_stream sstream( &source );
        std::string command;

        sstream >> command;
        while ( !sstream.eof() )
        {
                if ( command == "MD5Version" )
                {
                        sstream >> m_md5_version;
                        assert( m_md5_version == 10 );
                }
                else if ( command == "commandline" )
                {
                        next_line( sstream ); 
                }
                else if ( command == "numJoints" )
                {
                        sstream >> m_num_joints;
                        m_joints.reserve( m_num_joints );
                }
                else if ( command == "numMeshes" )
                {
                        sstream >> m_num_meshes;
                        m_meshes.reserve( m_num_meshes );
                }
                else if ( command == "joints" )
                {
                        discard( sstream, "{" );
                        md5_joint joint;
                        for ( int i = 0; i < m_num_joints; ++i )
                        {
                                sstream >> joint.name >> joint.parent_id;
                                discard( sstream, "(" );
                                sstream >> joint.pos.x >> joint.pos.y >> joint.pos.z;
                                discard( sstream, ")" );
                                discard( sstream, "(" );
                                sstream >> joint.orient.x >> joint.orient.y >> joint.orient.z;
                                remove_quotes( joint.name );
                                unit_quat_w( joint.orient );
                                m_joints.push_back( joint );
                                next_line( sstream );
                        }
                        discard( sstream, "}" );
                }
                else if ( command == "mesh" )
                {
                        // TODO : efficiency dammit
                        md5_mesh mesh;
                        int num_verts, num_tris, num_weights;

                        discard( sstream, "{" );
                        sstream >> command;
                        while ( command != "}" ) 
                        {
                                if ( command == "shader" )
                                {
                                        sstream >> mesh.shader;
                                        remove_quotes( mesh.shader );
                                        // texturePath.replace_extension( ".tga" );
                                        next_line( sstream );
                                }
                                else if ( command == "numverts")
                                {
                                        sstream >> num_verts; 
                                        next_line( sstream );
                                        for ( int i = 0; i < num_verts; ++i )
                                        {
                                                md5_vertex vert;
                                                std::string ignore;
                                                discard( sstream, "vert" );
                                                sstream >> ignore;
                                                discard( sstream, "(" );
                                                sstream >> vert.texcoord.x >> vert.texcoord.y;
                                                discard( sstream, ")" );
                                                sstream >> vert.start_weight >> vert.weight_count;
                                                next_line( sstream );

                                                mesh.verts.push_back(vert);
                                                mesh.texcoord_buffer.push_back( vert.texcoord );
                                        }  
                                }
                                else if ( command == "numtris" )
                                {
                                        sstream >> num_tris;
                                        next_line( sstream );
                                        for ( int i = 0; i < num_tris; ++i )
                                        {
                                                md5_triangle tri;
                                                std::string ignore;
                                                discard( sstream, "tri" );
                                                sstream >> ignore >> tri.indices[0] >> tri.indices[1] >> tri.indices[2];
                                                next_line( sstream );

                                                mesh.tris.push_back( tri );
                                                mesh.index_buffer.push_back( (uint32)tri.indices[0] );
                                                mesh.index_buffer.push_back( (uint32)tri.indices[1] );
                                                mesh.index_buffer.push_back( (uint32)tri.indices[2] );
                                        }              
                                }
                                else if ( command == "numweights" )
                                {
                                        sstream >> num_weights;
                                        next_line( sstream );
                                        for ( int i = 0; i < num_weights; ++i )
                                        {
                                                md5_weight weight;
                                                std::string ignore;
                                                discard( sstream, "weight" );
                                                sstream >> ignore >> weight.joint_id >> weight.bias;
                                                discard( sstream, "(" );
                                                sstream >> weight.pos.x >> weight.pos.y >> weight.pos.z;
                                                discard( sstream, ")" );
                                                next_line( sstream );
                                                mesh.weights.push_back(weight);
                                        }
                                }
                                else
                                {
                                        next_line( sstream );
                                }

                                sstream >> command;
                        }

                        prepare_mesh( mesh );
                        prepare_normals( mesh );

                        m_meshes.push_back(mesh);
                }
                sstream >> command;
        }

        assert( m_joints.size() == m_num_joints );
        assert( m_meshes.size() == m_num_meshes );
        return true;
}

bool md5_loader::prepare_mesh( md5_mesh& mesh )
{
        mesh.position_buffer.clear();
        mesh.texcoord_buffer.clear();

        for ( uint32 i = 0; i < mesh.verts.size(); ++i )
        {
                md5_vertex& vert = mesh.verts[i];

                vert.position = glm::vec3(0);
                vert.normal   = glm::vec3(0);
                vert.tangent  = glm::vec3(0);

                for ( int j = 0; j < vert.weight_count; ++j )
                {
                        md5_weight& weight = mesh.weights[vert.start_weight + j];
                        md5_joint&  joint  = m_joints[weight.joint_id];

                        glm::vec3 rot_pos = joint.orient * weight.pos;

                        vert.position += ( joint.pos + rot_pos ) * weight.bias;
                }

                mesh.position_buffer.push_back(vert.position);
                mesh.texcoord_buffer.push_back(vert.texcoord);
        }

        return true;
}

bool md5_loader::prepare_normals( md5_mesh& mesh )
{
        mesh.normal_buffer.clear();

        for ( unsigned int i = 0; i < mesh.tris.size(); ++i )
        {
                const md5_triangle& tri = mesh.tris[i];
                glm::vec3 v1 = mesh.verts[ tri.indices[0] ].position;
                glm::vec3 v2 = mesh.verts[ tri.indices[1] ].position;
                glm::vec3 v3 = mesh.verts[ tri.indices[2] ].position;
                glm::vec3 xyz1 = v3 - v1;
                glm::vec3 xyz2 = v2 - v1;

                glm::vec3 normal = glm::cross( xyz1, xyz2 );

                mesh.verts[ tri.indices[0] ].normal += normal;
                mesh.verts[ tri.indices[1] ].normal += normal;
                mesh.verts[ tri.indices[2] ].normal += normal;

                const vec2& w1 = mesh.verts[ tri.indices[0] ].texcoord;
                const vec2& w2 = mesh.verts[ tri.indices[1] ].texcoord;
                const vec2& w3 = mesh.verts[ tri.indices[2] ].texcoord;

                vec2 st1 = w3 - w1;
                vec2 st2 = w2 - w1;

                float coef = 1.0f / (st1.x * st2.y - st2.x * st1.y);

                vec3 tangent = (( xyz1 * st2.y ) - ( xyz2 * st1.y )) * coef;

                mesh.verts[ tri.indices[0] ].tangent += tangent;
                mesh.verts[ tri.indices[1] ].tangent += tangent;
                mesh.verts[ tri.indices[2] ].tangent += tangent;
        }

        for ( unsigned int i = 0; i < mesh.verts.size(); ++i )
        {
                md5_vertex& vert = mesh.verts[i];

                glm::vec3 normal  = glm::normalize( vert.normal );
                glm::vec3 tangent = glm::normalize( vert.tangent );
                mesh.normal_buffer.push_back( normal );
                mesh.tangent_buffer.push_back( tangent );

                vert.normal  = glm::vec3(0);
                vert.tangent = glm::vec3(0);

                for ( int j = 0; j < vert.weight_count; ++j )
                {
                        const md5_weight& weight = mesh.weights[vert.start_weight + j];
                        const md5_joint&  joint  = m_joints[weight.joint_id];
                        vert.normal  += ( normal  * joint.orient ) * weight.bias;
                        vert.tangent += ( tangent * joint.orient ) * weight.bias;
                }
        }

        return true;
}

mesh* md5_loader::release_mesh()
{
        mesh* m = new mesh();
        auto position = m->add_attribute< vec3 >( "nv_position" );
        auto normal   = m->add_attribute< vec3 >( "nv_normal" );
        auto texcoord = m->add_attribute< vec2 >( "nv_texcoord" );
        auto tangent  = m->add_attribute< vec2 >( "nv_tangent" );
        auto indices  = m->add_indices< uint32 >();

        position->get().assign( m_meshes[0].position_buffer.begin(), m_meshes[0].position_buffer.end() );
        normal  ->get().assign( m_meshes[0].normal_buffer.begin(),   m_meshes[0].normal_buffer.end() );
        texcoord->get().assign( m_meshes[0].texcoord_buffer.begin(), m_meshes[0].texcoord_buffer.end() );
        tangent ->get().assign( m_meshes[0].tangent_buffer.begin(),  m_meshes[0].tangent_buffer.end() );
        indices ->get().assign( m_meshes[0].index_buffer.begin(),    m_meshes[0].index_buffer.end() );

        m_size = m_meshes[0].index_buffer.size();
        return m;
}