gmtk24/scripts/BuildingBlockCreator.cs

using Godot;

namespace Gmtk24 {
    public partial class BuildingBlockCreator : Node3D {
        [Export]
        public Node3D TrenchbroomMap;
        [Export]
        public PackedScene BuildingBlockPrefab;
        [Export]
        public ShaderMaterial BuildingBlockMaterial;
        [Export]
        public float BuildingBlockScale = 0.05f;

        public override void _Ready() {
            var children = TrenchbroomMap.FindChildren("*_buildingblock");
            foreach (var buildingBlockStaticBody in children) {
                var buildingBlock = BuildingBlockPrefab.Instantiate();

                var smallMesh = (MeshInstance3D)buildingBlockStaticBody.GetChild<MeshInstance3D>(0).Duplicate();
                smallMesh.Scale = Vector3.One * BuildingBlockScale;
                for (int i = 0; i < smallMesh.GetSurfaceOverrideMaterialCount(); i++) {
                    var replacedMaterial = smallMesh.Mesh.SurfaceGetMaterial(i);
                    var transparency = replacedMaterial.Get("transparency");
                    if (((int)transparency) != 0) {
                        // Make a new material, using the partly-transparent albedo as an alpha mask
                        var blockMaterialWithAlphaMask = (ShaderMaterial)BuildingBlockMaterial.Duplicate();
                        blockMaterialWithAlphaMask.SetShaderParameter("texture_albedo_for_alpha", replacedMaterial.Get("albedo_texture"));
                        smallMesh.SetSurfaceOverrideMaterial(i, blockMaterialWithAlphaMask);
                    } else {
                        smallMesh.SetSurfaceOverrideMaterial(i, BuildingBlockMaterial);
                    }
                }
                buildingBlock.AddChild(smallMesh);

                var collisionShapes = buildingBlockStaticBody.FindChildren("*_collision_shape");
                foreach (var shape in collisionShapes) {
                    CollisionShape3D newShape = (CollisionShape3D)shape.Duplicate();
                    var bigPoints = ((ConvexPolygonShape3D)newShape.Shape).Points;
                    var points = new Vector3[bigPoints.Length];
                    for (int i = 0; i < bigPoints.Length; i++) {
                        points[i] = bigPoints[i] * BuildingBlockScale;
                    }
                    ((ConvexPolygonShape3D)newShape.Shape).Points = points;
                    buildingBlock.AddChild(newShape);
                }

                AddChild(buildingBlock);
            }
        }

        public override void _Process(double delta) {
        }
    }
}