MMesh processMesh(Mesh mesh, Scene scene, string sName, Matrix4d trans)
{
// data to fill
List <TexturedVertex> vertices = new List <TexturedVertex>();
List <int> indices = new List <int>();
List <MTexture> textures = new List <MTexture>();
// Walk through each of the mesh's vertices
for (int i = 0; i < mesh.VertexCount; i++)
{
TexturedVertex vertex = new TexturedVertex();
Vector3 vector = new Vector3(); // we declare a placeholder vector since assimp uses its own vector class that doesn't directly convert to glm's vec3 class so we transfer the data to this placeholder glm::vec3 first.
// positions
vector.X = mesh.Vertices[i].X;
vector.Y = mesh.Vertices[i].Y;
vector.Z = mesh.Vertices[i].Z;
vertex._position = vector;
// normals
if (mesh.HasNormals)
{
vector.X = mesh.Normals[i].X;
vector.Y = mesh.Normals[i].Y;
vector.Z = mesh.Normals[i].Z;
vertex._normal = vector;
}
// texture coordinates
if (mesh.HasTextureCoords(0)) // does the mesh contain texture coordinates?
{
Vector2 vec = new Vector2();
// a vertex can contain up to 8 different texture coordinates. We thus make the assumption that we won't
// use models where a vertex can have multiple texture coordinates so we always take the first set (0).
vec.X = mesh.TextureCoordinateChannels[0][i].X;
vec.Y = 1 - mesh.TextureCoordinateChannels[0][i].Y;
vertex._textureCoordinate = vec;
}
else
{
vertex._textureCoordinate = new Vector2(0.0f, 0.0f);
}
if (mesh.HasTangentBasis)
{
// tangent
vector.X = mesh.Tangents[i].X;
vector.Y = mesh.Tangents[i].Y;
vector.Z = mesh.Tangents[i].Z;
/// vertex.Tangent = vector;
// bitangent
vector.X = mesh.BiTangents[i].X;
vector.Y = mesh.BiTangents[i].Y;
vector.Z = mesh.BiTangents[i].Z;
/// vertex.BiTangent = vector;
}
vertices.Add(vertex);
}
// now wak through each of the mesh's faces (a face is a mesh its triangle) and retrieve the corresponding vertex indices.
for (int i = 0; i < mesh.FaceCount; i++)
{
Face face = mesh.Faces[i];
// retrieve all indices of the face and store them in the indices vector
for (int j = 0; j < face.IndexCount; j++)
{
indices.Add(face.Indices[j]);
}
}
// process materials
Material material = scene.Materials[mesh.MaterialIndex];
// we assume a convention for sampler names in the shaders. Each diffuse texture should be named
// as 'texture_diffuseN' where N is a sequential number ranging from 1 to MAX_SAMPLER_NUMBER.
// Same applies to other texture as the following list summarizes:
// diffuse: texture_diffuseN
// specular: texture_specularN
// normal: texture_normalN
// 1. diffuse maps
/*
* List<MTexture> diffuseMaps = loadMaterialTextures(material, TextureType_DIFFUSE, "texture_diffuse");
* textures.insert(textures.end(), diffuseMaps.begin(), diffuseMaps.end());
* // 2. specular maps
* List<Texture> specularMaps = loadMaterialTextures(material, aiTextureType_SPECULAR, "texture_specular");
* textures.insert(textures.end(), specularMaps.begin(), specularMaps.end());
* // 3. normal maps
* List<Texture> normalMaps = loadMaterialTextures(material, aiTextureType_HEIGHT, "texture_normal");
* textures.insert(textures.end(), normalMaps.begin(), normalMaps.end());
* // 4. height maps
* List<Texture> heightMaps = loadMaterialTextures(material, aiTextureType_AMBIENT, "texture_height");
* textures.insert(textures.end(), heightMaps.begin(), heightMaps.end());
*/
// return a mesh object created from the extracted mesh data
MMesh m = new MMesh(sName);
// trans.Transpose();
m.transform.Position = trans.ExtractTranslation();
m.transform.Rotation = trans.ExtractRotation();
m.transform.Scale = trans.ExtractScale();
m.AddMaterial(this.material);
m.SetupMesh(vertices, indices, textures);
return(m);
}
