thief-mission-viewer/project/code/TMV/Model.cs

using System.Collections.Generic;
using System.IO;
using Godot;
using Godot.Collections;
using KeepersCompound.LGS;
using KeepersCompound.TMV.UI;

namespace KeepersCompound.TMV;

public partial class Model : Node3D
{
    public override void _Ready()
    {
        var modelSelector = GetNode<Control>("%ModelSelector") as ModelSelector;
        modelSelector.LoadModel += BuildModel;
    }

    private void BuildModel(string rootPath, string modelPath)
    {
        foreach (var node in GetChildren())
        {
            node.QueueFree();
        }

        var modelFile = new ModelFile(modelPath);
        if (modelFile == null)
        {
            GD.Print("UH OH");
        }

        // TODO: Remove this disgusting hack
        var baseDir = ProjectSettings.GlobalizePath($"user://objects/tmp");
        var options = new EnumerationOptions
        {
            MatchCasing = MatchCasing.CaseInsensitive,
            RecurseSubdirectories = true,
        };
        foreach (var material in modelFile.Materials)
        {
            var paths = Directory.GetFiles(baseDir, material.Name, options);
            if (paths.IsEmpty()) continue;

            var texture = TextureLoader.LoadTexture(paths[0]);
            var saveName = material.Name.GetBaseName() + ".png";
            texture.GetImage().SavePng(ProjectSettings.GlobalizePath($"user://debug/{saveName}"));
        }

        var vertices = new List<Vector3>();
        var indices = new List<int>();

        foreach (var v in modelFile.Vertices)
        {
            vertices.Add(v.ToGodotVec3());
        }

        foreach (var poly in modelFile.Polygons)
        {
            for (var i = 1; i < poly.VertexCount - 1; i++)
            {
                indices.Add(poly.VertexIndices[0]);
                indices.Add(poly.VertexIndices[i]);
                indices.Add(poly.VertexIndices[i + 1]);
            }
        }

        var array = new Array();
        array.Resize((int)Mesh.ArrayType.Max);
        array[(int)Mesh.ArrayType.Vertex] = vertices.ToArray();
        array[(int)Mesh.ArrayType.Index] = indices.ToArray();

        var mesh = new ArrayMesh();
        mesh.AddSurfaceFromArrays(Mesh.PrimitiveType.Triangles, array);

        var meshInstance = new MeshInstance3D { Mesh = mesh };
        AddChild(meshInstance);
    }
}