Add cell_size to HeightMapShape3D

[mthaddon]

Closes godotengine/godot-proposals#3870 - adding a cell_size property to HeightMapShape3D.

[mthaddon]

This seems to correctly size the debug outlines, but not the heightmapshape itself. I think it's because I'm doing this:

void HeightMapShape3D::_update_shape() {
    Dictionary d; 
    d["width"] = map_width;
    d["depth"] = map_depth; 
    d["heights"] = map_data;
    d["min_height"] = min_height;
    d["max_height"] = max_height;
    d["tile_size"] = tile_size;
    PhysicsServer3D::get_singleton()->shape_set_data(get_shape(), d);
    Shape3D::_update_shape();
}

I've added "tile_size" in here, but I think I'll need to update something in shape_set_data to actually do something with that.

[mthaddon]

Ok, seems like https://github.com/godotengine/godot/blob/master/modules/godot_physics_3d/godot_shape_3d.cpp#L1675 is significant, will look into that

[mthaddon]

This still isn't working as expected. I'll keep looking at it, but if anyone more familiar with the code can point me in the right direction that'd be great 👍 Alternatively any pointers for how to see the location of the generated collision shape itself (not the debug outlines which already seem to be what we want) would be appreciated.

I thought I could just change the AABB size and the _get_point inline function in modules/godot_physics_3d/godot_shape_3d.{cpp,h}, but this doesn't seem to work.

[AThousandShips]

Please avoid pushing several times in a row, make sure you've finished adding new changes before you push (Will run CI once you're done)

[mthaddon]

I'm trying a different approach, which is to update map_data in place before passing it to the physics shape for rendering. Not working as expected yet, but wanted to push up changes while I keep working on it.