/// <summary>
/// Parse a material library declaration in a .OBJ file (a line of the kind "mtllib file.mtl").
/// </summary>
private void ParseObjUseMtlDeclaration()
{
// Check that the line contains a material name
if (objParser.IsEndOfLine)
{
throw new InvalidObjMtlFileException(string.Format(
"{0}: Material usage declaration without a corresponding material name.", objParser.GetFilePositionStr()));
}
// Load the associated material library
string materialName = objParser.ReadRestOfLine().Trim();
if (!materials.ContainsKey(materialName))
{
throw new InvalidObjMtlFileException(string.Format(
"{0}: Can't find the material '{1}'.", objParser.GetFilePositionStr(), materialName));
}
currentUsedMaterial = materials[materialName];
// Create a new mesh since the material has changed
currentMesh = null;
}
/// <summary>
/// Parses a object name declaration in a .OBJ file (a line of the kind "o [object name]").
/// </summary>
private void ParseObjObjectDeclaration()
{
// Check that the line contains an object name
if (objParser.IsEndOfLine)
{
throw new InvalidObjMtlFileException(string.Format(
"{0}: Object declaration without a corresponding object name.", objParser.GetFilePositionStr()));
}
// Create the new object instance
string newObjectName = objParser.ReadRestOfLine().Trim();
currentObject = new ObjMtlObject();
currentMesh = null;
// Add the object to the object list
if (model.Objects.ContainsKey(newObjectName))
{
throw new InvalidObjMtlFileException(string.Format(
"{0}: Duplicate object name '{1}'.", objParser.GetFilePositionStr(), newObjectName));
}
model.Objects.Add(newObjectName, currentObject);
}
/// <summary>
/// Load the model from the .OBJ file
/// </summary>
/// <param name="objPath">The path of a file containing the .OBJ file.</param>
/// <returns>A list of warnings while loading the file.</returns>
public List <string> LoadObj(string objPath)
{
if (objPath == null)
{
throw new ArgumentNullException("objPath");
}
// Set up the parser status to load a new .OBJ file
this.warningLog = new List <string>();
this.objPath = objPath;
this.objParser = null;
this.vertexPositions = new List <Vector4>();
this.vertexNormals = new List <Vector3>();
this.vertexTexCoords = new List <Vector3>();
this.currentObject = null;
this.currentMesh = null;
this.currentUsedMaterial = null;
this.mtlPath = null;
this.mtlParser = null;
this.materials = new Dictionary <string, ObjMtlMaterial>();
this.currentLoadMaterial = null;
using (objParser = new ObjMtlParser(objPath))
{
while (objParser.ReadNextLine())
{
// Parse according to the keyword
string keyword = objParser.GetNextWord();
switch (keyword)
{
case "o":
ParseObjObjectDeclaration();
break;
case "mtllib":
ParseObjMtlLibDeclaration();
break;
case "usemtl":
ParseObjUseMtlDeclaration();
break;
case "v":
ParseObjVertexPositionDeclaration();
break;
case "vn":
ParseObjVertexNormalDeclaration();
break;
case "vt":
ParseObjVertexTexCoordDeclaration();
break;
case "f":
ParseObjFaceDeclaration();
break;
case null: // Empty line
break;
default:
warningLog.Add(string.Format(
"{0}: Unrecognized keyword '{1}'.", objParser.GetFilePositionStr(), keyword));
break;
}
}
}
return(warningLog);
}
/// <summary>
/// Parse a face declaration in a .OBJ file (a line of the kind "f 1 2 3").
/// </summary>
private void ParseObjFaceDeclaration()
{
ObjMtlFace face = new ObjMtlFace();
for (string word = objParser.GetNextWord(); word != null; word = objParser.GetNextWord())
{
// There are four accepted formats for the face declarations:
// Position, No Normal, No TexCoord: f POS
// Position, TexCoord, No Normal: f POS/TEXCOORD
// Position, No TexCoord, Normal: f POS//NORMAL
// Position, TexCoord, Normal: f POS/TEXCOORD/NORM
// Also, take note that the vertex indexes start are one-based and not zero-based
// Split into components
string[] vertexIndexStrings = word.Split('/');
if (vertexIndexStrings.Length > 3)
{
throw new InvalidObjMtlFileException(string.Format(
"{0}: Invalid face declaration format (too many components).", objParser.GetFilePositionStr()));
}
// Validate valid format specification
if (vertexIndexStrings[0] == "")
{
throw new InvalidObjMtlFileException(string.Format(
"{0}: Invalid face declaration format (vertex position index can't be empty).", objParser.GetFilePositionStr()));
}
if (vertexIndexStrings.Length == 2 && vertexIndexStrings[1] == "")
{
throw new InvalidObjMtlFileException(string.Format(
"{0}: Invalid face declaration format (texture coordinate index can't be empty unless followed by vertex normal index).", objParser.GetFilePositionStr()));
}
if (vertexIndexStrings.Length == 3 && vertexIndexStrings[2] == "")
{
throw new InvalidObjMtlFileException(string.Format(
"{0}: Invalid face declaration format (texture normal index can't be empty).", objParser.GetFilePositionStr()));
}
// Parse vertex position index (always the first component, always present)
int vertexPositionIdx;
if (!int.TryParse(vertexIndexStrings[0], NumberStyles.Integer, CultureInfo.InvariantCulture, out vertexPositionIdx))
{
throw new InvalidObjMtlFileException(string.Format(
"{0}: Invalid face declaration format (vertex position index not an integer).", objParser.GetFilePositionStr()));
}
if (vertexPositionIdx - 1 < 0 || vertexPositionIdx - 1 >= vertexPositions.Count)
{
throw new InvalidObjMtlFileException(string.Format(
"{0}: Invalid face declaration format (vertex position index out of bounds).", objParser.GetFilePositionStr()));
}
// Parse vertex texture coordinate (always the third component, may not be present)
int vertexTexCoordIdx = -1;
if (vertexIndexStrings.Length >= 2 && vertexIndexStrings[1] != "")
{
if (!int.TryParse(vertexIndexStrings[1], NumberStyles.Integer, CultureInfo.InvariantCulture, out vertexTexCoordIdx))
{
throw new InvalidObjMtlFileException(string.Format(
"{0}: Invalid face declaration format (vertex texture coordinate index not an integer).", objParser.GetFilePositionStr()));
}
if (vertexTexCoordIdx - 1 < 0 || vertexTexCoordIdx - 1 >= vertexTexCoords.Count)
{
throw new InvalidObjMtlFileException(string.Format(
"{0}: Invalid face declaration format (vertex texture coordinate index out of bounds).", objParser.GetFilePositionStr()));
}
}
// Parse vertex normal index (always the second component, may not be present)
int vertexNormalIdx = -1;
if (vertexIndexStrings.Length == 3)
{
if (!int.TryParse(vertexIndexStrings[2], NumberStyles.Integer, CultureInfo.InvariantCulture, out vertexNormalIdx))
{
throw new InvalidObjMtlFileException(string.Format(
"{0}: Invalid face declaration format (vertex normal index not an integer).", objParser.GetFilePositionStr()));
}
if (vertexNormalIdx - 1 < 0 || vertexNormalIdx - 1 >= vertexNormals.Count)
{
throw new InvalidObjMtlFileException(string.Format(
"{0}: Invalid face declaration format (vertex normal index out of bounds).", objParser.GetFilePositionStr()));
}
}
ObjMtlVertex vtx = new ObjMtlVertex(
vertexPositions[vertexPositionIdx - 1],
(vertexNormalIdx != -1) ? (Vector3?)vertexNormals[vertexNormalIdx - 1] : null,
(vertexTexCoordIdx != -1) ? (Vector3?)vertexTexCoords[vertexTexCoordIdx - 1] : null);
// Check that all the faces have the same elements
if (face.Count != 0)
{
if (face[0].Normal.HasValue != vtx.Normal.HasValue ||
face[0].TexCoord.HasValue != vtx.TexCoord.HasValue)
{
throw new InvalidObjMtlFileException(string.Format(
"{0}: Invalid face declaration format (not all elements have the same components).", objParser.GetFilePositionStr()));
}
}
// Add the vertex to the face
face.Add(vtx);
}
// Validate the number of vertices in the face
if (face.Count < 3)
{
throw new InvalidObjMtlFileException(string.Format(
"{0}: A face must have at least 3 vertices.", objParser.GetFilePositionStr()));
}
// If no object is currently initialized (this happens if the face is outside any object),
// we add the face to an object named as the empty string.
if (currentObject == null)
{
if (!model.Objects.ContainsKey(""))
{
model.Objects.Add("", new ObjMtlObject());
}
currentObject = model.Objects[""];
}
// If no mesh is currently initialized (this happens if the face is the first one
// within the current material), start a new material
if (currentMesh == null)
{
// If no material is used (this happens if the face is before any usemtl declaration),
// create a new empty material for the face
if (currentUsedMaterial == null)
{
currentUsedMaterial = new ObjMtlMaterial();
}
currentMesh = new ObjMtlMesh(currentUsedMaterial);
currentObject.Meshes.Add(currentMesh);
}
// Add the face to the mesh
currentMesh.Faces.Add(face);
}