Merge pull request #54401 from Chaosus/fix_fog_error

servers/rendering/renderer_rd/renderer_scene_render_rd.cpp

@@ -4167,7 +4167,7 @@ void RendererSceneRenderRD::_update_volumetric_fog(RID p_render_buffers, RID p_e
 			u.uniform_type = RD::UNIFORM_TYPE_TEXTURE;
 			u.binding = 19;
 			RID radiance_texture = storage->texture_rd_get_default(is_using_radiance_cubemap_array() ? RendererStorageRD::DEFAULT_RD_TEXTURE_CUBEMAP_ARRAY_BLACK : RendererStorageRD::DEFAULT_RD_TEXTURE_CUBEMAP_BLACK);
-			RID sky_texture = sky.sky_get_radiance_texture_rd(env->sky);
+			RID sky_texture = env->sky.is_valid() ? sky.sky_get_radiance_texture_rd(env->sky) : RID();
 			u.ids.push_back(sky_texture.is_valid() ? sky_texture : radiance_texture);
 			uniforms.push_back(u);
 		}