Add offset when placing blocks

scripts/BuildingBlock.cs

@@ -10,11 +10,14 @@ namespace Gmtk24 {
         public ShaderMaterial Material;
         public ShaderMaterial HoverMaterial;
         public float RelativeScale;
+
         public uint PhysicalModeLayer;
+        public uint NonPhysicalModeLayer = 0;
+        public uint PlacedLayer = 0b10000;
 
         public BlockMode Mode = BlockMode.Physical;
 
-        private MeshInstance3D MeshInstance;
+        public MeshInstance3D MeshInstance { private set; get; }
 
         private ShaderMaterial[] NormalMaterialArr;
         private ShaderMaterial[] HoverMaterialArr;
@@ -88,7 +91,7 @@ namespace Gmtk24 {
         private void UpdatePhysics() {
             if (Mode == BlockMode.Physical || Mode == BlockMode.Dragged) {
                 CollisionLayer = PhysicalModeLayer;
-                CollisionMask = PhysicalModeLayer + 0b10000;
+                CollisionMask = PhysicalModeLayer | PlacedLayer;
                 if (Mode == BlockMode.Dragged) {
                     FreezeMode = FreezeModeEnum.Kinematic;
                     Freeze = true;
@@ -97,11 +100,11 @@ namespace Gmtk24 {
                 }
             } else if (Mode == BlockMode.NonPhysical || Mode == BlockMode.Placed) {
                 if (Mode == BlockMode.Placed) {
-                    CollisionLayer = 0b10000;
+                    CollisionLayer = PlacedLayer;
-                    CollisionMask = 0b10000;
+                    CollisionMask = PlacedLayer;
                 } else {
-                    CollisionLayer = 0;
+                    CollisionLayer = NonPhysicalModeLayer;
-                    CollisionMask = 0;
+                    CollisionMask = NonPhysicalModeLayer;
                 }
                 FreezeMode = FreezeModeEnum.Static;
                 Freeze = true;
@@ -127,6 +130,29 @@ namespace Gmtk24 {
             EmitSignal(SignalName.PickUp, this);
         }
 
+        // Only works for Ghost blocks, which are always on Collision Layer 6
+        // (nothing else should ever be on that layer.)
+        public Vector3 OffsetFrom(Vector3 Normal, uint mask = 0b100000) {
+            var origin = ((-Normal) * 10f) + GlobalPosition;
+            var normal = (Normal * 10f) + GlobalPosition;
+
+            var ray = new PhysicsRayQueryParameters3D {
+                From = origin,
+                To = normal,
+                CollideWithBodies = true,
+                CollisionMask = mask,
+                HitBackFaces = false,
+                HitFromInside = false,
+            };
+            var newRes = GetWorld3D().DirectSpaceState.IntersectRay(ray);
+            if (newRes.ContainsKey("position")) {
+                var GlobalPos = (Vector3)newRes["position"];
+                var Offset = GlobalPos - GlobalPosition;
+                return -Offset;
+            }
+            return Vector3.Zero;
+        }
+
         public struct BaseBlock {
             public Mesh Mesh;
             public Array<CollisionShape3D> Colliders;

scripts/Table.cs

@@ -15,6 +15,8 @@ namespace Gmtk24 {
         public Node3D SpawnPoint;
         [Export(PropertyHint.LayersAvoidance)]
         public uint BlockMask;
+        [Export(PropertyHint.LayersAvoidance)]
+        public uint GhostOnlyMask = 0b100000;
         [ExportCategory("BlockMaterials")]
         [Export]
         public ShaderMaterial BlockMaterial;
@@ -71,8 +73,12 @@ namespace Gmtk24 {
             if (GhostBlock != null) {
                 var res = Util.RaycastFromMouse(Orbit.Camera, 0b10100);
                 if (res is RaycastResult results) {
-                    Vector3 Pos = results.Position - GlobalPosition;
+                    Vector3 LocalPos = results.Position - GlobalPosition;
-                    GhostBlock.Position = Pos * Basis;
+                    if (results.Collider is BuildingBlock) {
+                        Vector3 offset = GhostBlock.OffsetFrom(results.Normal, GhostOnlyMask);
+                        LocalPos += offset;
+                    }
+                    GhostBlock.Position = LocalPos * Basis;
                 }
             }
         }
@@ -84,6 +90,7 @@ namespace Gmtk24 {
                 Base = block.Base,
                 Material = BlockGhostMaterial,
                 PhysicalModeLayer = 0,
+                NonPhysicalModeLayer = GhostOnlyMask,
                 RelativeScale = RelativeScale,
                 Position = LocalPos,
                 Mode = BuildingBlock.BlockMode.NonPhysical,

textures/building_block_ghost.tres

@@ -3,7 +3,7 @@
 [ext_resource type="Shader" path="res://textures/building_block.gdshader" id="1_dis1h"]
 
 [resource]
-render_priority = 0
+render_priority = 1
 shader = ExtResource("1_dis1h")
 shader_parameter/albedo = Color(0.276387, 0.574926, 0.813629, 0.54902)
 shader_parameter/roughness = 0.533