private static void ExportObj(string path, Mesh mesh)
{
var meshName = Path.GetFileNameWithoutExtension(path).Replace(" ", "");
Vector3 minVertex = Vector3.positiveInfinity;
Vector3 maxVertex = Vector3.negativeInfinity;
//we calculate the min and max vertices so that later on we can centerize the mesh
foreach (var vertex in mesh.vertices)
{
if (vertex.x < minVertex.x)
{
minVertex.x = vertex.x;
}
if (vertex.y < minVertex.y)
{
minVertex.y = vertex.y;
}
if (vertex.z < minVertex.z)
{
minVertex.z = vertex.z;
}
if (vertex.x > maxVertex.x)
{
maxVertex.x = vertex.x;
}
if (vertex.y > maxVertex.y)
{
maxVertex.y = vertex.y;
}
if (vertex.z > maxVertex.z)
{
maxVertex.z = vertex.z;
}
}
string data = "";
data += $"mtllib ./{Path.GetFileNameWithoutExtension(path)}.mtl\n";
data += $"o {meshName}\n";
data += $"\n";
data += $"g {meshName}\n";
data += $"\n";
List <Vector3> distinctVertices = new List <Vector3>();
//a map which links the old vertice's positions to the new ones
Dictionary <int, int> verticesMap = new Dictionary <int, int>();
for (int i = 0; i < mesh.vertexCount; i++)
{
var vertex = mesh.vertices[i];
int distinctIndex = distinctVertices.IndexOf(vertex);
if (distinctIndex == -1)
{
verticesMap[i] = distinctVertices.Count;
distinctVertices.Add(vertex);
data += $"v {vertex.x - (minVertex.x + maxVertex.x) / 2} {vertex.y - (minVertex.y + maxVertex.y) / 2} {vertex.z - (minVertex.z + maxVertex.z) / 2}\n";
}
else
{
verticesMap[i] = distinctIndex;
}
}
data += $"\n";
List <Vector2> distinctUvs = new List <Vector2>();
Dictionary <int, int> uvsMap = new Dictionary <int, int>();
for (int i = 0; i < mesh.uv.Length; i++)
{
var uv = mesh.uv[i];
int distinctIndex = distinctUvs.IndexOf(uv);
if (distinctIndex == -1)
{
uvsMap[i] = distinctUvs.Count;
distinctUvs.Add(uv);
data += $"vt {uv.x} {uv.y}\n";
}
else
{
uvsMap[i] = distinctIndex;
}
}
data += $"\n";
List <Vector3> distinctNormals = new List <Vector3>();
Dictionary <int, int> normalsMap = new Dictionary <int, int>();
for (int i = 0; i < mesh.normals.Length; i++)
{
var normal = mesh.normals[i];
int distinctIndex = distinctNormals.IndexOf(normal);
if (distinctIndex == -1)
{
normalsMap[i] = distinctNormals.Count;
distinctNormals.Add(normal);
data += $"vn {normal.x} {normal.y} {normal.z}\n";
}
else
{
normalsMap[i] = distinctIndex;
}
}
data += $"\n";
data += $"g {meshName}\n";
data += $"usemtl DefaultColorPalette\n";
for (int i = 0; i < mesh.triangles.Length / 3; i++)
{
data += string.Format("f {0}/{3}/{6} {1}/{4}/{7} {2}/{5}/{8}\n",
verticesMap[mesh.triangles[i * 3]] + 1, verticesMap[mesh.triangles[i * 3 + 1]] + 1, verticesMap[mesh.triangles[i * 3 + 2]] + 1,
uvsMap[mesh.triangles[i * 3]] + 1, uvsMap[mesh.triangles[i * 3 + 1]] + 1, uvsMap[mesh.triangles[i * 3 + 2]] + 1,
normalsMap[mesh.triangles[i * 3]] + 1, normalsMap[mesh.triangles[i * 3 + 1]] + 1, normalsMap[mesh.triangles[i * 3 + 2]] + 1);
}
File.WriteAllText(path, data);
File.WriteAllText(Path.GetDirectoryName(path) + "/" + Path.GetFileNameWithoutExtension(path) + ".mtl", GetMaterialData());
File.WriteAllBytes(Path.GetDirectoryName(path) + "/DefaultColorPalette.png", ((Texture2D)ColorPaletteManager.GetPaletteTexture()).EncodeToJPG());
}
