// mesh and loader based on work by JTalton; http://www.opentk.com/node/642

public class MeshLoader

{

public bool Load( Mesh mesh, string fileName )

{

try

{

using( StreamReader streamReader = new StreamReader( fileName ) )

{

Load( mesh, streamReader );

streamReader.Close();

return true;

}

}

catch { return false; }

}

char[] splitCharacters = new char[] { ' ' };

List<Vector3> vertices;

List<Vector3> normals;

List<Vector2> texCoords;

List<Mesh.ObjVertex> objVertices;

List<Mesh.ObjTriangle> objTriangles;

List<Mesh.ObjQuad> objQuads;

void Load( Mesh mesh, TextReader textReader )

{

vertices = new List<Vector3>();

normals = new List<Vector3>();

texCoords = new List<Vector2>();

objVertices = new List<Mesh.ObjVertex>();

objTriangles = new List<Mesh.ObjTriangle>();

objQuads = new List<Mesh.ObjQuad>();

string line;

while ((line = textReader.ReadLine()) != null)

{

line = line.Trim( splitCharacters );

line = line.Replace(" ", " ");

string[] parameters = line.Split( splitCharacters );

switch (parameters[0])

{

case "p": // point

break;

case "v": // vertex

float x = float.Parse( parameters[1] );

float y = float.Parse( parameters[2] );

float z = float.Parse( parameters[3] );

vertices.Add( new Vector3( x, y, z ) );

break;

case "vt": // texCoord

float u = float.Parse( parameters[1] );

float v = float.Parse( parameters[2] );

texCoords.Add( new Vector2( u, v ) );

break;

case "vn": // normal

float nx = float.Parse( parameters[1] );

float ny = float.Parse( parameters[2] );

float nz = float.Parse( parameters[3] );

normals.Add( new Vector3( nx, ny, nz ) );

break;

case "f":

switch (parameters.Length)

{

case 4:

Mesh.ObjTriangle objTriangle = new Mesh.ObjTriangle();

objTriangle.Index0 = ParseFaceParameter( parameters[1] );

objTriangle.Index1 = ParseFaceParameter( parameters[2] );

objTriangle.Index2 = ParseFaceParameter( parameters[3] );

objTriangles.Add( objTriangle );

break;

case 5:

Mesh.ObjQuad objQuad = new Mesh.ObjQuad();

objQuad.Index0 = ParseFaceParameter( parameters[1] );

objQuad.Index1 = ParseFaceParameter( parameters[2] );

objQuad.Index2 = ParseFaceParameter( parameters[3] );

objQuad.Index3 = ParseFaceParameter( parameters[4] );

objQuads.Add( objQuad );

break;

}

break;

}

}

mesh.vertices = objVertices.ToArray();

mesh.triangles = objTriangles.ToArray();

mesh.quads = objQuads.ToArray();

vertices = null;

normals = null;

texCoords = null;

objVertices = null;

objTriangles = null;

objQuads = null;

}

char[] faceParamaterSplitter = new char[] { '/' };

int ParseFaceParameter( string faceParameter )

{

Vector3 vertex = new Vector3();

Vector2 texCoord = new Vector2();

Vector3 normal = new Vector3();

string[] parameters = faceParameter.Split( faceParamaterSplitter );

int vertexIndex = int.Parse( parameters[0] );

if (vertexIndex < 0) vertexIndex = vertices.Count + vertexIndex;

else vertexIndex = vertexIndex -1;

vertex = vertices[vertexIndex];

if (parameters.Length > 1) if (parameters[1] != "")

{

int texCoordIndex = int.Parse( parameters[1] );

if (texCoordIndex < 0) texCoordIndex = texCoords.Count + texCoordIndex;

else texCoordIndex = texCoordIndex - 1;

texCoord = texCoords[texCoordIndex];

}

if (parameters.Length > 2)

{

int normalIndex = int.Parse( parameters[2] );

if (normalIndex < 0) normalIndex = normals.Count + normalIndex;

else normalIndex = normalIndex - 1;

normal = normals[normalIndex];

}

return AddObjVertex(ref vertex, ref texCoord, ref normal);

}

int AddObjVertex( ref Vector3 vertex, ref Vector2 texCoord, ref Vector3 normal)

{

Mesh.ObjVertex newObjVertex = new Mesh.ObjVertex();

newObjVertex.Vertex = vertex;

newObjVertex.TexCoord = texCoord;

newObjVertex.Normal = normal;

objVertices.Add( newObjVertex );

return objVertices.Count - 1;

}

}