fix: shadow casting cases

src/terrain_3d_mesh_asset.cpp

@@ -399,6 +399,10 @@ GeometryInstance3D::ShadowCastingSetting Terrain3DMeshAsset::get_lod_cast_shadow
 	if (_cast_shadows == GeometryInstance3D::SHADOW_CASTING_SETTING_OFF) {
 		return GeometryInstance3D::SHADOW_CASTING_SETTING_OFF;
 	}
+	// We never cast shadows
+	if (_cast_shadows == GeometryInstance3D::SHADOW_CASTING_SETTING_SHADOWS_ONLY) {
+		return GeometryInstance3D::SHADOW_CASTING_SETTING_SHADOWS_ONLY;
+	}
 	// This lod id is for the shadow impostor and is set to cast shadows only
 	if (p_lod_id == SHADOW_LOD_ID) {
 		return GeometryInstance3D::SHADOW_CASTING_SETTING_SHADOWS_ONLY;
@@ -407,17 +411,16 @@ GeometryInstance3D::ShadowCastingSetting Terrain3DMeshAsset::get_lod_cast_shadow
 	if (p_lod_id < _first_shadow_lod) {
 		return GeometryInstance3D::SHADOW_CASTING_SETTING_OFF;
 	}
-	// This lod is too far to get a shadow
+	// This lod is too far to cast a shadow
 	if (p_lod_id > _last_shadow_lod) {
 		return GeometryInstance3D::SHADOW_CASTING_SETTING_OFF;
 	}
 	return _cast_shadows;
 }
 
 Ref<Mesh> Terrain3DMeshAsset::get_lod_mesh(const int p_lod_id) {
-	// Requesting the shadow impostor
 	if (p_lod_id == SHADOW_LOD_ID) {
-		// we don't use a shadow lod because we're in case where each lod uses its own shadow
+		// Each lod uses its own shadow
 		if (_first_shadow_lod == 0) {
 			return Ref<Mesh>();
 		}
@@ -429,10 +432,17 @@ Ref<Mesh> Terrain3DMeshAsset::get_lod_mesh(const int p_lod_id) {
 		return get_mesh(_first_shadow_lod);
 	}
 
+	// This lod is too far to get a mesh
 	if (p_lod_id > _last_lod) {
 		return Ref<Mesh>();
 	}
 
+	// In the case where we're rendering shadows only,
+	// This lod is also too far to get a mesh
+	if (_cast_shadows == GeometryInstance3D::SHADOW_CASTING_SETTING_SHADOWS_ONLY && p_lod_id >= _last_shadow_lod) {
+		return Ref<Mesh>();
+	}
+
 	return get_mesh(p_lod_id);
 }