Implement RenderableManager.

Similar to LightManager, the RenderableManager manages
renderables based on an mjModel and its mjData.

PiperOrigin-RevId: 941510745
Change-Id: I97b44cc857f136aa7c90ceb85a42e299fc759b73

src/render/filament/support/mesh_util.h

@@ -0,0 +1,45 @@
+// Copyright 2026 DeepMind Technologies Limited
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef MUJOCO_SRC_RENDER_FILAMENT_SUPPORT_MESH_UTIL_H_
+#define MUJOCO_SRC_RENDER_FILAMENT_SUPPORT_MESH_UTIL_H_
+
+#include <vector>
+#include <math/vec4.h>
+#include <mujoco/mujoco.h>
+#include <mujoco/mjrfilament.h>
+#include "render/filament/mjrfilament_cpp.h"
+
+namespace mujoco {
+
+// Creates a mjrfMesh for the given flex object.
+UniquePtr<mjrfMesh> CreateFlexMesh(mjrfContext* ctx, const mjModel* model,
+                                   const mjData* data, int flex_id,
+                                   int flex_layer, bool smooth_skinning,
+                                   bool generate_edges, bool generate_vertices);
+
+// Creates a mjrfMesh for the given skin object.
+UniquePtr<mjrfMesh> CreateSkinMesh(mjrfContext* ctx, const mjModel* model,
+                                   const mjData* data, int skin_id);
+
+// Populates the set of points that define the given tendon. Points are
+// added in pairs, representing the start and end of a segment of the tendon.
+// The w-component of the point stores the width/radius of the tendon.
+void GatherSpatialTendonPoints(const mjModel* model, const mjData* data,
+                               int tendon_id,
+                               std::vector<filament::math::float4>& points);
+
+}  // namespace mujoco
+
+#endif  // MUJOCO_SRC_RENDER_FILAMENT_SUPPORT_MESH_UTIL_H_