Material Based Footsteps
++ To do this we need to raycast in order to check what texture a face is so we can play an appropriate + sound effect such as snow sounds for snowy textures and stone sounds for stone textures. +
++ Firstly, you will need a Raycast3D. Secondly, you will need a FuncGodotFGDSolidClass. In the Mesh metadata + you will need to tick "Add Textures Metadata" found under Mesh Metadata. The collision mask for the Racyast3D must match a collision + layer of the FuncGodotFGDSolidClass, otherwise it will not report a collision. +
+
+ Ticking "Add Textures Metadata" adds two metadata properties to generated nodes of that Solid Class. It adds "textures" which is
+ a PackedInt32Array, where the index in the array is the face index, and the value at any point is an
+ integer. This integer is then used by the "texture_names", the 2nd metadata property which is added.
+ Indexing that array with that integer gets us the texture name string. So how do I get the face index?
+ Raycast3D has a handy method called get_collision_face_index() which we use.
+
NOTE: If you are using Jolt Physics as your Physics Engine, you must tick Enable Ray Cast + Face Index in your project settings! This can be found in Project Settings > Physics > Jolt Physics 3D > + Queries > Enable Ray Cast Face Index. Enabling this has a non-trivial memory cost.+
Putting this all together, as a script on our Raycast3D, the following function returns the Texture Name when + we call it.
+func do_check() -> String:
+ var col := get_collider()
+ if !col:
+ return "" # No collision, no texture
+ if !col.has_meta("func_godot_mesh_data"):
+ return "" # Metadata not added
+ var metadata: Dictionary = col.get_meta("func_godot_mesh_data")
+ if !("textures" in metadata):
+ return "" # Textures Metadata not added
+ if !("texture_names" in metadata):
+ return "" # Textures Metadata not added
+ var textures: PackedInt32Array = metadata["textures"]
+ var texture_names: Array = metadata["texture_names"]
+ var texture: String = texture_names.get(
+ textures.get(
+ get_collision_face_index()
+ )
+ )
+ return texture;
+ When we call do_check();, we now get the texture String for the face the Raycast3D collided
+ with, if it collided with anything at all. The rest of the implementation of material based footsteps is
+ left as an exercise to the reader as it is project specific, but you will likely want some way to convert
+ from a texture name to a Stream and to then play that Stream with an AudioStreamPlayer.
+
+ As a note you can also use this same approach for running code on specific textures. For example damage on + lava textures, slowness on cobweb textures, though these may be better accomplished with a + FuncGodotFGDSolidClass that creates an Area3D instead. You can also use this to get material-specific decal + textures. +
+