gmtk24/scripts/BuildingBlockCreator.cs

using System.Collections.Generic;
using Godot;
using Godot.Collections;

namespace Gmtk24 {
    public partial class BuildingBlockCreator : Node3D {
        [Export]
        public Node3D TrenchbroomMap;
        [Export]
        public PackedScene BuildingBlockPrefab;
        [Export]
        public ShaderMaterial BuildingBlockMaterial;

        public override void _Ready() {
            var scale = 0.05f;
            var children = TrenchbroomMap.FindChildren("*_buildingblock");
            foreach (var buildingBlockStaticBody in children) {
                var buildingBlock = BuildingBlockPrefab.Instantiate();

                var smallMesh = new MeshInstance3D {
                    Mesh = buildingBlockStaticBody.GetChild<MeshInstance3D>(0).Mesh,
                    Scale = Vector3.One * scale,
                };
                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 = new ShaderMaterial {
                            Shader = BuildingBlockMaterial.Shader,
                        };
                        foreach (var uniform in BuildingBlockMaterial.Shader.GetShaderUniformList()) {
                            var uniformName = (StringName)((Dictionary)uniform).GetValueOrDefault("name");
                            blockMaterialWithAlphaMask.SetShaderParameter(uniformName, BuildingBlockMaterial.GetShaderParameter(uniformName));
                        }
                        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) {
                    var bigPoints = ((ConvexPolygonShape3D)((CollisionShape3D)shape).Shape).Points;
                    var points = new Vector3[bigPoints.Length];
                    for (int i = 0; i < bigPoints.Length; i++) {
                        points[i] = bigPoints[i] * scale;
                    }
                    buildingBlock.AddChild(new CollisionShape3D {
                        Shape = new ConvexPolygonShape3D {
                            Points = points,
                        },
                    });
                }

                AddChild(buildingBlock);
            }
        }

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