Allow mesh data to be reuploaded without having to recreate the mesh.

Splits mjrfMeshData into config+data parts.

PiperOrigin-RevId: 952042545
Change-Id: I19a572a0f591fa0d33bbc2c32b974efc075310f4

doc/APIreference/APItypes.rst

@@ -1452,12 +1452,22 @@ culling. Alternatively, the bounds can be computed at runtime (though there is a
 are provided (or calculated), then frustum culling will not be performed.
 
 
+.. _mjrfMeshConfig:
+
+mjrfMeshConfig
+~~~~~~~~~~~~~~~~~
+
+Parameters for creating a :ref:`mesh<mjrfMesh>`.
+
+.. mujoco-include:: mjrfMeshConfig
+
+
 .. _mjrfMeshData:
 
 mjrfMeshData
 ~~~~~~~~~~~~
 
-Binary data used for creating a :ref:`mesh<mjrfMesh>`.
+Binary data for a :ref:`mesh<mjrfMesh>`.
 
 .. mujoco-include:: mjrfMeshData
 

doc/APIreference/functions.rst

@@ -3249,14 +3249,14 @@ Returns the height of the texture.
 Returns the sampler type (mjrSamplerType) used by the texture.
 [returns: mjrSamplerType]
 
-.. _mjrf_defaultMeshData:
+.. _mjrf_defaultMeshConfig:
 
-`mjrf_defaultMeshData <#mjrf_defaultMeshData>`__
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+`mjrf_defaultMeshConfig <#mjrf_defaultMeshConfig>`__
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. mujoco-include:: mjrf_defaultMeshData
+.. mujoco-include:: mjrf_defaultMeshConfig
 
-Initializes the mjrfMeshData to default values.
+Initializes the mjrfMeshConfig to default values.
 
 .. _mjrf_createMesh:
 
@@ -3265,7 +3265,7 @@ Initializes the mjrfMeshData to default values.
 
 .. mujoco-include:: mjrf_createMesh
 
-Creates a mesh with the given data.
+Creates an empty mesh with the given config.
 
 .. _mjrf_destroyMesh:
 
@@ -3276,6 +3276,24 @@ Creates a mesh with the given data.
 
 Destroys the mesh.
 
+.. _mjrf_defaultMeshData:
+
+`mjrf_defaultMeshData <#mjrf_defaultMeshData>`__
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. mujoco-include:: mjrf_defaultMeshData
+
+Initializes the mjrfMeshData to default values.
+
+.. _mjrf_setMeshData:
+
+`mjrf_setMeshData <#mjrf_setMeshData>`__
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. mujoco-include:: mjrf_setMeshData
+
+Uploads the given mesh data to the mesh.
+
 .. _mjrf_defaultSceneParams:
 
 `mjrf_defaultSceneParams <#mjrf_defaultSceneParams>`__

doc/changelog.rst

@@ -66,6 +66,9 @@ Engine
    - :ref:`mju_round` now breaks ties away from zero rather than towards :math:`+\infty`. This only affects
      negative half-integers, e.g. ``mju_round(-2.5)`` now returns -3 rather than -2.
    - Removed unneeded `mjvScene` argument from :ref:`mjv_moveCamera`.
+   - Split up :ref:`mjrfMeshData` into `mjrfMeshData` and `mjrfMeshConfig` to allow reuploading of mesh data without
+     having to recreate the mesh object. Introduces :ref:`mjrfDefaultMeshConfig` and :ref:`mjrfSetMeshData` functions.
+   - Removed `bytes` field from :ref:`mjrVertexAttribute`.
 
 .. admonition:: Breaking ABI changes
    :class: caution

doc/includes/references.h

@@ -1425,7 +1425,6 @@ typedef struct mjrRendererInfo_ {  // active renderer identity
   const char* backend;             // graphics backend: opengl, vulkan; empty if uninitialized
 } mjrRendererInfo;
 typedef struct mjrVertexAttribute_ {  // vertex attribute format specification
-  const void* bytes;                  // vertex data
   int usage;                          // position, normal, etc [mjrVertexAttributeUsage]
   int type;                           // float3, ubyte4, etc. [mjrVertexAttributeType]
 } mjrVertexAttribute;
@@ -1580,15 +1579,20 @@ typedef struct mjrfTextureData_ {
   mjrfCallback release;            // callback when data has finished uploading
   void* user_data;                 // user data for release callback
 } mjrfTextureData;
-typedef struct mjrfMeshData_ {
-  mjtSize num_vertices;         // number of vertices; all vertex attributes share this size
-  int num_attributes;           // number of attributes defined
+typedef struct mjrfMeshConfig_ {
+  mjtSize max_vertices;         // maximum number of vertices
+  mjtSize max_indices;          // maximum number of indices
+  int num_attributes;           // number of defined attributes
   mjrVertexAttribute attributes[mjMAX_VERTEX_ATTRIBUTES];  // per-vertex attribute information
   mjtBool interleaved;          // true if vertex attributes are interleaved
-  mjtSize num_indices;          // number of indices
-  const void* indices;          // indices data array
   int index_type;               // index data format (e.g. UINT16 or UINT32) [mjrIndexType]
   int primitive_type;           // index interpretation (e.g. TRIANGLES, etc.) [mjrMeshPrimitiveType]
+} mjrfMeshConfig;
+typedef struct mjrfMeshData_ {
+  mjtSize num_vertices;         // number of vertices
+  const void* vertices[mjMAX_VERTEX_ATTRIBUTES];  // per-vertex attribute data arrays
+  mjtSize num_indices;          // number of indices
+  const void* indices;          // indices data array
   mjtBool compute_bounds;       // if true, compute bounds from vertex positions
   float bounds_min[3];          // min/max bounds; assume unset if bounds_min == bounds_max
   float bounds_max[3];
@@ -3422,9 +3426,11 @@ void mjrf_setTextureData(mjrfTexture* texture, const mjrfTextureData* data);
 int mjrf_getTextureWidth(const mjrfTexture* texture);
 int mjrf_getTextureHeight(const mjrfTexture* texture);
 int mjrf_getTextureSamplerType(const mjrfTexture* texture);
-void mjrf_defaultMeshData(mjrfMeshData* data);
-mjrfMesh* mjrf_createMesh(mjrfContext* ctx, const mjrfMeshData* data);
+void mjrf_defaultMeshConfig(mjrfMeshConfig* config);
+mjrfMesh* mjrf_createMesh(mjrfContext* ctx, const mjrfMeshConfig* config);
 void mjrf_destroyMesh(mjrfMesh* mesh);
+void mjrf_defaultMeshData(mjrfMeshData* data);
+void mjrf_setMeshData(mjrfMesh* mesh, const mjrfMeshData* data);
 void mjrf_defaultSceneParams(mjrfSceneParams* params);
 mjrfScene* mjrf_createScene(mjrfContext* ctx, const mjrfSceneParams* params);
 void mjrf_destroyScene(mjrfScene* scene);

include/mujoco/mjrender.h

@@ -124,7 +124,6 @@ typedef struct mjrRendererInfo_ {  // active renderer identity
 
 
 typedef struct mjrVertexAttribute_ {  // vertex attribute format specification
-  const void* bytes;                  // vertex data
   int usage;                          // position, normal, etc [mjrVertexAttributeUsage]
   int type;                           // float3, ubyte4, etc. [mjrVertexAttributeType]
 } mjrVertexAttribute;

include/mujoco/mjrfilament.h

@@ -182,16 +182,32 @@ int mjrf_getTextureSamplerType(const mjrfTexture* texture);
 // Maximum number of vertex attributes in a mesh.
 enum { mjMAX_VERTEX_ATTRIBUTES = 16 };
 
-// Binary data used for creating a mesh (mjrfMesh).
-typedef struct mjrfMeshData_ {
-  mjtSize num_vertices;         // number of vertices; all vertex attributes share this size
-  int num_attributes;           // number of attributes defined
+// Parameters describing a mesh (mjrfMesh).
+typedef struct mjrfMeshConfig_ {
+  mjtSize max_vertices;         // maximum number of vertices
+  mjtSize max_indices;          // maximum number of indices
+  int num_attributes;           // number of defined attributes
   mjrVertexAttribute attributes[mjMAX_VERTEX_ATTRIBUTES];  // per-vertex attribute information
   mjtBool interleaved;          // true if vertex attributes are interleaved
-  mjtSize num_indices;          // number of indices
-  const void* indices;          // indices data array
   int index_type;               // index data format (e.g. UINT16 or UINT32) [mjrIndexType]
   int primitive_type;           // index interpretation (e.g. TRIANGLES, etc.) [mjrMeshPrimitiveType]
+} mjrfMeshConfig;
+
+// Initializes the mjrfMeshConfig to default values.
+void mjrf_defaultMeshConfig(mjrfMeshConfig* config);
+
+// Creates an empty mesh with the given config.
+mjrfMesh* mjrf_createMesh(mjrfContext* ctx, const mjrfMeshConfig* config);
+
+// Destroys the mesh.
+void mjrf_destroyMesh(mjrfMesh* mesh);
+
+// Binary data used for creating a mesh (mjrfMesh).
+typedef struct mjrfMeshData_ {
+  mjtSize num_vertices;         // number of vertices
+  const void* vertices[mjMAX_VERTEX_ATTRIBUTES];  // per-vertex attribute data arrays
+  mjtSize num_indices;          // number of indices
+  const void* indices;          // indices data array
   mjtBool compute_bounds;       // if true, compute bounds from vertex positions
   float bounds_min[3];          // min/max bounds; assume unset if bounds_min == bounds_max
   float bounds_max[3];
@@ -202,11 +218,8 @@ typedef struct mjrfMeshData_ {
 // Initializes the mjrfMeshData to default values.
 void mjrf_defaultMeshData(mjrfMeshData* data);
 
-// Creates a mesh with the given data.
-mjrfMesh* mjrf_createMesh(mjrfContext* ctx, const mjrfMeshData* data);
-
-// Destroys the mesh.
-void mjrf_destroyMesh(mjrfMesh* mesh);
+// Uploads the given mesh data to the mesh.
+void mjrf_setMeshData(mjrfMesh* mesh, const mjrfMeshData* data);
 
 // Parameters for creating a scene (mjrfScene).
 typedef struct mjrfSceneParams_ {

python/mujoco/introspect/structs.py

@@ -11332,13 +11332,6 @@ STRUCTS: Mapping[str, StructDecl] = dict([
          name='mjrVertexAttribute',
          declname='struct mjrVertexAttribute_',
          fields=(
-             StructFieldDecl(
-                 name='bytes',
-                 type=PointerType(
-                     inner_type=ValueType(name='void', is_const=True),
-                 ),
-                 doc='vertex data',
-             ),
              StructFieldDecl(
                  name='usage',
                  type=ValueType(name='int'),

python/mujoco/structs.cc

@@ -1078,7 +1078,7 @@ This is useful for example when the MJB is not available as a file on disk.)"));
   py::class_<raw::MjrVertexAttribute> mjrVertexAttribute(m,
                                                          "MjrVertexAttribute");
   mjrVertexAttribute.def(py::init([](int usage, int type) {
-                           return raw::MjrVertexAttribute{nullptr, usage, type};
+                           return raw::MjrVertexAttribute{usage, type};
                          }),
                          py::arg("usage") = 0, py::arg("type") = 0);
   mjrVertexAttribute.def("__copy__", [](const raw::MjrVertexAttribute& other) {

src/experimental/filament/compat/scene_decorator.cc

@@ -243,27 +243,35 @@ void SceneDecorator::Update(mjData* data, const mjvOption* vis_option,
         const float* uvs =
             has_uvs ? mjv_scene_.flextexcoord + (6 * addr) : nullptr;
 
+        mjrfMeshConfig config;
+        mjrf_defaultMeshConfig(&config);
+        config.num_attributes = has_uvs ? 3 : 2;
+        config.max_vertices = 3 * mjv_scene_.flexfaceused[geom.objid];
+        config.max_indices = 3 * mjv_scene_.flexfaceused[geom.objid];
+        config.attributes[0].usage = mjVERTEX_ATTRIBUTE_USAGE_POSITION;
+        config.attributes[0].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT3;
+        config.attributes[1].usage = mjVERTEX_ATTRIBUTE_USAGE_NORMAL;
+        config.attributes[1].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT3;
+        config.attributes[2].usage = mjVERTEX_ATTRIBUTE_USAGE_UV;
+        config.attributes[2].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT2;
+        config.index_type = mjINDEX_TYPE_U32;
+        config.primitive_type = mjMESH_PRIMITIVE_TYPE_TRIANGLES;
+
         mjrfMeshData data;
         mjrf_defaultMeshData(&data);
-        data.num_attributes = has_uvs ? 3 : 2;
-        data.attributes[0].usage = mjVERTEX_ATTRIBUTE_USAGE_POSITION;
-        data.attributes[0].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT3;
-        data.attributes[0].bytes = positions;
-        data.attributes[1].usage = mjVERTEX_ATTRIBUTE_USAGE_NORMAL;
-        data.attributes[1].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT3;
-        data.attributes[1].bytes = normals;
-        data.attributes[2].usage = mjVERTEX_ATTRIBUTE_USAGE_UV;
-        data.attributes[2].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT2;
-        data.attributes[2].bytes = uvs;
+        data.vertices[0] = positions;
+        data.vertices[1] = normals;
+        data.vertices[2] = uvs;
         data.num_vertices = 3 * mjv_scene_.flexfaceused[geom.objid];
         data.num_indices = 3 * mjv_scene_.flexfaceused[geom.objid];
         data.indices = nullptr;
-        data.index_type = mjINDEX_TYPE_U32;
-        data.primitive_type = mjMESH_PRIMITIVE_TYPE_TRIANGLES;
         data.compute_bounds = true;
         data.release = nullptr;
         data.user_data = nullptr;
-        meshes_.push_back(CreateMesh(ctx, data));
+
+        auto mesh = CreateMesh(ctx, config);
+        mjrf_setMeshData(mesh.get(), &data);
+        meshes_.push_back(std::move(mesh));
 
         auto renderable = CreateRenderable(ctx, params);
         mjrf_setRenderableMesh(renderable.get(), meshes_.back().get(), 0, 0);

src/experimental/filament/compat/scene_objects.cc

@@ -103,8 +103,11 @@ static std::span<const int> GetIndices(const mjModel* model,
   }
 }
 
-static bool UpdateSkinFlexMeshData(mjrfMeshData* data, const mjModel* model,
-                                   const mjvScene* scene, const mjvGeom& geom) {
+SceneObjects::SceneObjects(mjrfContext* ctx) : ctx_(ctx) {}
+
+bool SceneObjects::CreateSkinFlexMesh(const mjvScene* scene,
+                                      const mjModel* model,
+                                      const mjvGeom& geom) {
   auto positions = GetPositions(model, scene, geom);
   if (positions.empty()) {
     return false;
@@ -119,41 +122,44 @@ static bool UpdateSkinFlexMeshData(mjrfMeshData* data, const mjModel* model,
     num_indices = 3 * scene->flexfaceused[geom.objid];
   }
 
-  data->num_attributes = uvs.data() ? 3 : 2;
-  data->attributes[0].usage = mjVERTEX_ATTRIBUTE_USAGE_POSITION;
-  data->attributes[0].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT3;
-  data->attributes[0].bytes = positions.data();
-  data->attributes[1].usage = mjVERTEX_ATTRIBUTE_USAGE_NORMAL;
-  data->attributes[1].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT3;
-  data->attributes[1].bytes = normals.data();
-  data->attributes[2].usage = mjVERTEX_ATTRIBUTE_USAGE_UV;
-  data->attributes[2].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT2;
-  data->attributes[2].bytes = uvs.data();
-  data->num_vertices = positions.size() / 3;
-  data->num_indices = num_indices;
-  data->indices = indices.data();
-  data->index_type = mjINDEX_TYPE_U32;
-  data->primitive_type = mjMESH_PRIMITIVE_TYPE_TRIANGLES;
-  data->compute_bounds = true;
-  data->release = nullptr;
-  data->user_data = nullptr;
-  return true;
-}
+  mjrfMeshConfig config;
+  mjrf_defaultMeshConfig(&config);
+  config.num_attributes = uvs.data() ? 3 : 2;
+  config.attributes[0].usage = mjVERTEX_ATTRIBUTE_USAGE_POSITION;
+  config.attributes[0].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT3;
+  config.attributes[1].usage = mjVERTEX_ATTRIBUTE_USAGE_NORMAL;
+  config.attributes[1].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT3;
+  config.attributes[2].usage = mjVERTEX_ATTRIBUTE_USAGE_UV;
+  config.attributes[2].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT2;
+  config.max_vertices = positions.size() / 3;
+  config.max_indices = num_indices;
+  config.index_type = mjINDEX_TYPE_U32;
+  config.primitive_type = mjMESH_PRIMITIVE_TYPE_TRIANGLES;
 
-SceneObjects::SceneObjects(mjrfContext* ctx) : ctx_(ctx) {}
-
-bool SceneObjects::CreateSkinFlexMesh(const mjvScene* scene,
-                                      const mjModel* model,
-                                      const mjvGeom& geom) {
   mjrfMeshData data;
   mjrf_defaultMeshData(&data);
-  if (!UpdateSkinFlexMeshData(&data, model, scene, geom)) {
-    return false;
-  }
+  data.vertices[0] = positions.data();
+  data.vertices[1] = normals.data();
+  data.vertices[2] = uvs.data();
+  data.num_vertices = positions.size() / 3;
+  data.num_indices = num_indices;
+  data.indices = indices.data();
+  data.compute_bounds = true;
+  data.release = nullptr;
+  data.user_data = nullptr;
+
   if (geom.type == mjGEOM_FLEX) {
-    flexes_.insert_or_assign(geom.objid, CreateMesh(ctx_, data));
+    auto iter = flexes_.find(geom.objid);
+    if (iter == flexes_.end()) {
+      iter = flexes_.insert({geom.objid, CreateMesh(ctx_, config)}).first;
+    }
+    mjrf_setMeshData(iter->second.get(), &data);
   } else if (geom.type == mjGEOM_SKIN) {
-    skins_.insert_or_assign(geom.objid, CreateMesh(ctx_, data));
+    auto iter = skins_.find(geom.objid);
+    if (iter == skins_.end()) {
+      iter = skins_.insert({geom.objid, CreateMesh(ctx_, config)}).first;
+    }
+    mjrf_setMeshData(iter->second.get(), &data);
   } else {
     mju_error("Unsupported dynamic mesh type: %d", geom.type);
   }

src/experimental/platform/ux/imgui_bridge.cc

@@ -219,27 +219,32 @@ void ImguiBridge::Update() {
   for (int n = 0; n < commands->CmdListsCount; ++n) {
     const ImDrawList* cmds = commands->CmdLists[n];
 
+    mjrfMeshConfig config;
+    mjrf_defaultMeshConfig(&config);
+    config.num_attributes = 3;
+    config.attributes[0].usage = mjVERTEX_ATTRIBUTE_USAGE_POSITION;
+    config.attributes[0].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT2;
+    config.attributes[1].usage = mjVERTEX_ATTRIBUTE_USAGE_UV;
+    config.attributes[1].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT2;
+    config.attributes[2].usage = mjVERTEX_ATTRIBUTE_USAGE_COLOR;
+    config.attributes[2].type = mjVERTEX_ATTRIBUTE_TYPE_UBYTE4;
+    config.max_vertices = cmds->VtxBuffer.Size;
+    config.max_indices = cmds->IdxBuffer.Size;
+    config.interleaved = true;
+    config.index_type = mjINDEX_TYPE_U16;
+    config.primitive_type = mjMESH_PRIMITIVE_TYPE_TRIANGLES;
+    meshes_.push_back(CreateMesh(ctx_, config));
+    mjrfMesh* mesh = meshes_.back().get();
+
     mjrfMeshData data;
     mjrf_defaultMeshData(&data);
-    data.num_attributes = 3;
-    data.attributes[0].usage = mjVERTEX_ATTRIBUTE_USAGE_POSITION;
-    data.attributes[0].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT2;
-    data.attributes[0].bytes = cmds->VtxBuffer.Data;
-    data.attributes[1].usage = mjVERTEX_ATTRIBUTE_USAGE_UV;
-    data.attributes[1].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT2;
-    data.attributes[1].bytes = cmds->VtxBuffer.Data + sizeof(float) * 2;
-    data.attributes[2].usage = mjVERTEX_ATTRIBUTE_USAGE_COLOR;
-    data.attributes[2].type = mjVERTEX_ATTRIBUTE_TYPE_UBYTE4;
-    data.attributes[2].bytes = cmds->VtxBuffer.Data + sizeof(float) * 4;
-    data.interleaved = true;
     data.num_vertices = cmds->VtxBuffer.Size;
+    data.vertices[0] = cmds->VtxBuffer.Data;
+    data.vertices[1] = cmds->VtxBuffer.Data + sizeof(float) * 2;
+    data.vertices[2] = cmds->VtxBuffer.Data + sizeof(float) * 4;
     data.num_indices = cmds->IdxBuffer.Size;
     data.indices = cmds->IdxBuffer.Data;
-    data.index_type = mjINDEX_TYPE_U16;
-    data.primitive_type = mjMESH_PRIMITIVE_TYPE_TRIANGLES;
-    meshes_.push_back(CreateMesh(ctx_, data));
-
-    const mjrfMesh* mesh = meshes_.back().get();
+    mjrf_setMeshData(mesh, &data);
 
     int index_offset = 0;
     for (const ImDrawCmd& command : cmds->CmdBuffer) {

src/render/filament/core/builtins.cc

@@ -27,6 +27,7 @@
 #include <math/vec3.h>
 #include <math/vec4.h>
 #include <mujoco/mjrfilament.h>
+#include <mujoco/mujoco.h>
 #include "render/filament/core/mesh.h"
 #include "render/filament/support/filament_util.h"
 
@@ -59,59 +60,69 @@ static std::size_t NumIndicesPerSide(int num_quads_per_axis) {
   return kNumIndicesPerQuad * num_quads_per_axis * num_quads_per_axis;
 }
 
-class BuiltinBuilder : public mjrfMeshData {
+class BuiltinBuilder {
  public:
-  BuiltinBuilder() { mjrf_defaultMeshData(this); }
+  BuiltinBuilder() {}
   virtual ~BuiltinBuilder() = default;
 
   template <typename T, typename... Args>
   static std::unique_ptr<Mesh> Create(filament::Engine* engine,
                                       Args&&... args) {
     auto builder = new T(std::forward<Args>(args)...);
-    mjrfMeshData* mesh_data = builder->PrepareMeshData();
-    mesh_data->release = +[](void* user_data) {
+
+    mjrfMeshConfig config;
+    mjrf_defaultMeshConfig(&config);
+    config.max_vertices = builder->positions_.size();
+    config.max_indices = builder->indices_.size();
+    config.index_type = mjINDEX_TYPE_U16;
+    config.primitive_type = builder->primitive_type_;
+    config.num_attributes = 2;
+    config.attributes[0].usage = mjVERTEX_ATTRIBUTE_USAGE_POSITION;
+    config.attributes[0].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT3;
+    config.attributes[1].usage = mjVERTEX_ATTRIBUTE_USAGE_TANGENTS;
+    config.attributes[1].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT4;
+
+    mjrfMeshData data;
+    mjrf_defaultMeshData(&data);
+    data.num_vertices = builder->positions_.size();
+    data.vertices[0] = builder->positions_.data();
+    data.vertices[1] = builder->orientations_.data();
+    data.num_indices = builder->indices_.size();
+    data.indices = builder->indices_.data();
+    data.bounds_min[0] = builder->bounds_min_.x;
+    data.bounds_min[1] = builder->bounds_min_.y;
+    data.bounds_min[2] = builder->bounds_min_.z;
+    data.bounds_max[0] = builder->bounds_max_.x;
+    data.bounds_max[1] = builder->bounds_max_.y;
+    data.bounds_max[2] = builder->bounds_max_.z;
+    data.release = +[](void* user_data) {
       delete static_cast<BuiltinBuilder*>(user_data);
     };
-    mesh_data->user_data = builder;
-    return std::make_unique<Mesh>(engine, *mesh_data);
-  }
+    data.user_data = builder;
 
-  mjrfMeshData* PrepareMeshData() {
-    // Update the `mjrfMeshData` fields.
-    num_attributes = 2;
-    attributes[0].usage = mjVERTEX_ATTRIBUTE_USAGE_POSITION;
-    attributes[0].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT3;
-    attributes[0].bytes = reinterpret_cast<const void*>(positions_.data());
-    attributes[1].usage = mjVERTEX_ATTRIBUTE_USAGE_TANGENTS;
-    attributes[1].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT4;
-    attributes[1].bytes = reinterpret_cast<const void*>(orientations_.data());
-    num_vertices = positions_.size();
-
-    indices = indices_.data();
-    num_indices = indices_.size();
-    index_type = mjINDEX_TYPE_U16;
-    return this;
+    auto mesh = std::make_unique<Mesh>(engine, config);
+    mesh->Upload(data);
+    return mesh;
   }
 
  protected:
   void SetBounds(const float3& min, const float3& max) {
-    bounds_min[0] = min.x;
-    bounds_min[1] = min.y;
-    bounds_min[2] = min.z;
-    bounds_max[0] = max.x;
-    bounds_max[1] = max.y;
-    bounds_max[2] = max.z;
+    bounds_min_ = min;
+    bounds_max_ = max;
   }
 
+  int primitive_type_ = mjMESH_PRIMITIVE_TYPE_TRIANGLES;
   std::vector<float3> positions_;
   std::vector<float4> orientations_;
   std::vector<uint16_t> indices_;
+  float3 bounds_min_ = {0, 0, 0};
+  float3 bounds_max_ = {0, 0, 0};
 };
 
 class LineBuilder : public BuiltinBuilder {
  public:
   LineBuilder() {
-    primitive_type = mjMESH_PRIMITIVE_TYPE_LINES;
+    primitive_type_ = mjMESH_PRIMITIVE_TYPE_LINES;
 
     positions_.reserve(2);
     positions_.emplace_back(0, 0, 0);
@@ -183,7 +194,7 @@ class TriangleBuilder : public BuiltinBuilder {
 class LineBoxBuilder : public BuiltinBuilder {
  public:
   explicit LineBoxBuilder() {
-    primitive_type = mjMESH_PRIMITIVE_TYPE_LINES;
+    primitive_type_ = mjMESH_PRIMITIVE_TYPE_LINES;
 
     positions_.reserve(8);
     positions_.emplace_back(-1.0f, -1.0f, -1.0f);

src/render/filament/core/mesh.cc

@@ -102,21 +102,43 @@ int FillSequence(std::byte* buffer, std::size_t num_bytes) {
   return num;
 }
 
-Mesh::Mesh(filament::Engine* engine, const mjrfMeshData& data)
-    : engine_(engine), shared_state_(std::make_shared<SharedState>()) {
-  type_ = data.primitive_type == mjMESH_PRIMITIVE_TYPE_TRIANGLES
-              ? filament::RenderableManager::PrimitiveType::TRIANGLES
-              : filament::RenderableManager::PrimitiveType::LINES;
-
-  // If the user has provided a release callback, then we need to ensure we
-  // call is when filament is done with the mesh data.
-  if (data.release) {
-    shared_state_->callbacks.push_back([=]() { data.release(data.user_data); });
+Mesh::Mesh(filament::Engine* engine, const mjrfMeshConfig& config)
+    : engine_(engine),
+      config_(config),
+      shared_state_(std::make_shared<SharedState>()) {
+  // Perform some validation on the config.
+  const mjrVertexAttribute* positions = nullptr;
+  const mjrVertexAttribute* normals = nullptr;
+  const mjrVertexAttribute* tangents = nullptr;
+  for (int i = 0; i < config_.num_attributes; ++i) {
+    if (config_.attributes[i].usage == mjVERTEX_ATTRIBUTE_USAGE_POSITION) {
+      positions = &config_.attributes[i];
+    } else if (config_.attributes[i].usage == mjVERTEX_ATTRIBUTE_USAGE_NORMAL) {
+      normals = &config_.attributes[i];
+    } else if (config_.attributes[i].usage == mjVERTEX_ATTRIBUTE_USAGE_TANGENTS) {
+      tangents = &config_.attributes[i];
+    }
+  }
+  if (config_.max_vertices == 0) {
+    mju_error("Mesh has no vertices.");
+  }
+  if (!positions) {
+    mju_error("Mesh has no positions.");
+  }
+  if (config_.attributes[0].usage != mjVERTEX_ATTRIBUTE_USAGE_POSITION) {
+    mju_error("Positions must be the first attribute.");
+  }
+  if (normals && tangents) {
+    mju_error("Mesh has both normals and tangents.");
+  }
+  if (normals && config_.interleaved) {
+    // We need to build orientations from normals and so we require each
+    // attribute to be in a separate buffer.
+    mju_error("Cannot support normals with interleaved vertex attributes.");
   }
 
-  BuildVertexBuffer(data);
-  BuildIndexBuffer(data);
-  UpdateBounds(data);
+  InitVertexBuffer();
+  InitIndexBuffer();
 }
 
 Mesh::~Mesh() {
@@ -129,9 +151,84 @@ Mesh::~Mesh() {
   }
 }
 
-void Mesh::BuildVertexBuffer(const mjrfMeshData& data) {
-  if (data.num_vertices == 0) {
-    mju_error("mjrfMeshData has no vertices.");
+void Mesh::Upload(const mjrfMeshData& data) {
+  // If the user has provided a release callback, then we need to ensure we
+  // call is when filament is done with the mesh data.
+  if (data.release) {
+    shared_state_->callbacks.push_back([=]() { data.release(data.user_data); });
+  }
+
+  UpdateVertexBuffer(data);
+  UpdateIndexBuffer(data);
+  UpdateBounds(data);
+}
+
+void Mesh::InitVertexBuffer() {
+  filament::VertexBuffer::Builder vb_builder;
+  vb_builder.vertexCount(config_.max_vertices);
+
+  if (config_.interleaved) {
+    // For an interleaved vertex buffer, we will create a single buffer which
+    // contains the data in the order specified by the attributes array,
+    // starting from the first attribute's payload.
+    vb_builder.bufferCount(1);
+    int total_vertex_size = 0;
+    for (int i = 0; i < config_.num_attributes; ++i) {
+      total_vertex_size += VertexAttributeTypeSize(config_.attributes[i]);
+    }
+
+    // We assume the buffer is tightly packed with no padding between
+    // attributes. As such, the stride is equal to the total vertex size and
+    // each offset is the sum of the sizes of the preceding attributes.
+    int offset = 0;
+    for (int i = 0; i < config_.num_attributes; ++i) {
+      const mjrVertexAttribute& attrib = config_.attributes[i];
+      const filament::VertexAttribute usage = GetUsage(attrib);
+      filament::VertexBuffer::AttributeType type = GetType(attrib);
+      vb_builder.attribute(usage, 0, type, offset, total_vertex_size);
+      if (usage == filament::VertexAttribute::COLOR) {
+        vb_builder.normalized(usage);
+      }
+      offset += VertexAttributeTypeSize(attrib);
+    }
+    vertex_buffer_ = vb_builder.build(*engine_);
+  } else {
+    // For a non-interleaved vertex buffer, we assign a separate buffer to each
+    // attribute.
+    vb_builder.bufferCount(config_.num_attributes);
+    for (int i = 0; i < config_.num_attributes; ++i) {
+      const mjrVertexAttribute& attrib = config_.attributes[i];
+      const filament::VertexAttribute usage = GetUsage(attrib);
+      filament::VertexBuffer::AttributeType type = GetType(attrib);
+      if (attrib.usage == mjVERTEX_ATTRIBUTE_USAGE_NORMAL) {
+        // We will replace normals with orientations.
+        type = filament::VertexBuffer::AttributeType::FLOAT4;
+      }
+      vb_builder.attribute(usage, i, type);
+      if (usage == filament::VertexAttribute::COLOR) {
+        vb_builder.normalized(usage);
+      }
+    }
+    vertex_buffer_ = vb_builder.build(*engine_);
+  }
+}
+
+void Mesh::InitIndexBuffer() {
+  if (config_.max_indices == 0) {
+    return;
+  }
+
+  filament::IndexBuffer::Builder ib_builder;
+  ib_builder.indexCount(config_.max_indices);
+  ib_builder.bufferType(config_.index_type == mjINDEX_TYPE_U16
+                            ? filament::IndexBuffer::IndexType::USHORT
+                            : filament::IndexBuffer::IndexType::UINT);
+  index_buffer_ = ib_builder.build(*engine_);
+}
+
+void Mesh::UpdateVertexBuffer(const mjrfMeshData& data) {
+  if (config_.max_vertices != data.num_vertices) {
+    mju_error("Vertex count does not match config.");
   }
 
   // The filament BufferDescriptor callback for releasing the memory.
@@ -151,100 +248,27 @@ void Mesh::BuildVertexBuffer(const mjrfMeshData& data) {
     }
   };
 
-  // Pointers to specific attributes in the mesh data, used for additional
-  // validation and processing.
-  const mjrVertexAttribute* positions = nullptr;
-  const mjrVertexAttribute* normals = nullptr;
-  const mjrVertexAttribute* tangents = nullptr;
-  for (int i = 0; i < data.num_attributes; ++i) {
-    if (data.attributes[i].usage == mjVERTEX_ATTRIBUTE_USAGE_POSITION) {
-      positions = &data.attributes[i];
-    } else if (data.attributes[i].usage == mjVERTEX_ATTRIBUTE_USAGE_NORMAL) {
-      normals = &data.attributes[i];
-    } else if (data.attributes[i].usage == mjVERTEX_ATTRIBUTE_USAGE_TANGENTS) {
-      tangents = &data.attributes[i];
-    }
-  }
-  if (!positions) {
-    mju_error("mjrfMeshData has no positions.");
-  }
-  if (data.attributes[0].usage != mjVERTEX_ATTRIBUTE_USAGE_POSITION) {
-    mju_error("Positions must be the first attribute.");
-  }
-  if (normals && tangents) {
-    mju_error("mjrfMeshData has both normals and tangents.");
-  }
-  if (normals && data.interleaved) {
-    // We need to build orientations from normals and so we require each
-    // attribute to be in a separate buffer.
-    mju_error("Cannot support normals with interleaved vertex attributes.");
-  }
-
-  // Build the vertex buffer.
-  filament::VertexBuffer::Builder vb_builder;
-  vb_builder.vertexCount(data.num_vertices);
-
-  if (data.interleaved) {
-    // For an interleaved vertex buffer, we will create a single buffer which
-    // contains the data in the order specified by the attributes array,
-    // starting from the first attribute's payload.
-    vb_builder.bufferCount(1);
+  if (config_.interleaved) {
     int total_vertex_size = 0;
-    for (int i = 0; i < data.num_attributes; ++i) {
-      total_vertex_size += VertexAttributeTypeSize(data.attributes[i]);
+    for (int i = 0; i < config_.num_attributes; ++i) {
+      total_vertex_size += VertexAttributeTypeSize(config_.attributes[i]);
     }
-    const void* bytes = data.attributes[0].bytes;
-    const size_t nbytes = data.num_vertices * total_vertex_size;
 
-    // We assume the buffer is tightly packed with no padding between
-    // attributes. As such, the stride is equal to the total vertex size and
-    // each offset is the sum of the sizes of the preceding attributes.
-    int offset = 0;
-    for (int i = 0; i < data.num_attributes; ++i) {
-      const mjrVertexAttribute& attrib = data.attributes[i];
-      const filament::VertexAttribute usage = GetUsage(attrib);
-      filament::VertexBuffer::AttributeType type = GetType(attrib);
-      vb_builder.attribute(usage, 0, type, offset, total_vertex_size);
-      if (usage == filament::VertexAttribute::COLOR) {
-        vb_builder.normalized(usage);
-      }
-      offset += VertexAttributeTypeSize(attrib);
-      attributes_[i] = usage;
-    }
-    vertex_buffer_ = vb_builder.build(*engine_);
     auto* user_data = new std::shared_ptr<SharedState>(shared_state_);
+    const void* bytes = data.vertices[0];
+    const size_t nbytes = data.num_vertices * total_vertex_size;
     vertex_buffer_->setBufferAt(*engine_, 0,
                                 {bytes, nbytes, callback, user_data});
   } else {
-    // For a non-interleaved vertex buffer, we assign a separate buffer to each
-    // attribute.
-    vb_builder.bufferCount(data.num_attributes);
-    for (int i = 0; i < data.num_attributes; ++i) {
-      const mjrVertexAttribute& attrib = data.attributes[i];
-      const filament::VertexAttribute usage = GetUsage(attrib);
-      filament::VertexBuffer::AttributeType type = GetType(attrib);
-      if (attrib.usage == mjVERTEX_ATTRIBUTE_USAGE_NORMAL) {
-        // We will replace normals with orientations.
-        type = filament::VertexBuffer::AttributeType::FLOAT4;
-      }
-      vb_builder.attribute(usage, i, type);
-      if (usage == filament::VertexAttribute::COLOR) {
-        vb_builder.normalized(usage);
-      }
-      attributes_[i] = usage;
-    }
-    num_attributes_ = data.num_attributes;
-    vertex_buffer_ = vb_builder.build(*engine_);
-
     // Assign the individual data buffers.
-    for (int i = 0; i < data.num_attributes; ++i) {
-      const mjrVertexAttribute& attrib = data.attributes[i];
-      const void* bytes = attrib.bytes;
+    for (int i = 0; i < config_.num_attributes; ++i) {
+      const mjrVertexAttribute& attrib = config_.attributes[i];
+      const void* bytes = data.vertices[i];
       size_t nbytes = data.num_vertices * VertexAttributeTypeSize(attrib);
       if (attrib.usage == mjVERTEX_ATTRIBUTE_USAGE_NORMAL) {
         // Replace normals with orientations.
         nbytes = data.num_vertices * sizeof(float4);
-        bytes = BuildOrientationsFromNormals(data.num_vertices, attrib);
+        bytes = BuildOrientationsFromNormals(data.num_vertices, bytes);
       }
       auto* user_data = new std::shared_ptr<SharedState>(shared_state_);
       vertex_buffer_->setBufferAt(*engine_, i,
@@ -253,14 +277,17 @@ void Mesh::BuildVertexBuffer(const mjrfMeshData& data) {
   }
 }
 
-void Mesh::BuildIndexBuffer(const mjrfMeshData& data) {
+void Mesh::UpdateIndexBuffer(const mjrfMeshData& data) {
   if (data.num_indices == 0) {
     return;
   }
+  if (data.num_indices != config_.max_indices) {
+    mju_error("Index count does not match config.");
+  }
 
   const int element_size =
-      data.index_type == mjINDEX_TYPE_U16 ? sizeof(uint16_t) : sizeof(uint32_t);
-  const int num_bytes = data.num_indices * element_size;
+      config_.index_type == mjINDEX_TYPE_U16 ? sizeof(uint16_t) : sizeof(uint32_t);
+  const int num_bytes = config_.max_indices * element_size;
 
   // If indices == 0 and num_indices > 0, then the user is specifying that the
   // vertices are provided "in order", i.e. the indices are 0, 1, 2, 3, ...
@@ -270,37 +297,19 @@ void Mesh::BuildIndexBuffer(const mjrfMeshData& data) {
     std::byte* sequence = new std::byte[num_bytes];
     shared_state_->callbacks.push_back([=]() { delete[] sequence; });
 
-    if (data.index_type == mjINDEX_TYPE_U16) {
+    if (config_.index_type == mjINDEX_TYPE_U16) {
       FillSequence<uint16_t>(sequence, num_bytes);
     } else {
       FillSequence<uint32_t>(sequence, num_bytes);
     }
     indices = sequence;
   }
-
-  filament::IndexBuffer::Builder ib_builder;
-  ib_builder.indexCount(data.num_indices);
-  ib_builder.bufferType(data.index_type == mjINDEX_TYPE_U16
-                            ? filament::IndexBuffer::IndexType::USHORT
-                            : filament::IndexBuffer::IndexType::UINT);
-  index_buffer_ = ib_builder.build(*engine_);
   // We don't worry about setting a release callback here because the release
   // callback for the vertex buffer will call release_callbacks_.
   filament::backend::BufferDescriptor desc(indices, num_bytes);
   index_buffer_->setBuffer(*engine_, std::move(desc));
 }
 
-float4* Mesh::BuildOrientationsFromNormals(int num_vertices,
-                                           const mjrVertexAttribute& normals) {
-  float4* orientations = new float4[num_vertices];
-  shared_state_->callbacks.push_back([=]() { delete[] orientations; });
-  const float* normals_ptr = reinterpret_cast<const float*>(normals.bytes);
-  for (int i = 0; i < num_vertices; ++i) {
-    orientations[i] = CalculateOrientation(ReadFloat3(normals_ptr, i));
-  }
-  return orientations;
-}
-
 void Mesh::UpdateBounds(const mjrfMeshData& data) {
   float3 bounds_min = ReadFloat3(data.bounds_min);
   float3 bounds_max = ReadFloat3(data.bounds_max);
@@ -310,11 +319,11 @@ void Mesh::UpdateBounds(const mjrfMeshData& data) {
     bounds_min = float3(FLT_MAX, FLT_MAX, FLT_MAX);
     bounds_max = float3(-FLT_MAX, -FLT_MAX, -FLT_MAX);
 
-    if (data.attributes[0].usage != mjVERTEX_ATTRIBUTE_USAGE_POSITION) {
+    if (config_.attributes[0].usage != mjVERTEX_ATTRIBUTE_USAGE_POSITION) {
       mju_error("mjrfMeshData has no positions.");
     }
     const float* positions =
-        reinterpret_cast<const float*>(data.attributes[0].bytes);
+        reinterpret_cast<const float*>(data.vertices[0]);
 
     for (int i = 0; i < data.num_vertices; ++i) {
       const float3 position = ReadFloat3(positions, i);
@@ -336,6 +345,18 @@ void Mesh::ReleaseResources() {
   }
 }
 
+float4* Mesh::BuildOrientationsFromNormals(int num_vertices,
+                                           const void* normals) {
+  float4* orientations = new float4[num_vertices];
+  shared_state_->callbacks.push_back([=]() { delete[] orientations; });
+
+  const float* normals_ptr = reinterpret_cast<const float*>(normals);
+  for (int i = 0; i < num_vertices; ++i) {
+    orientations[i] = CalculateOrientation(ReadFloat3(normals_ptr, i));
+  }
+  return orientations;
+}
+
 filament::IndexBuffer* Mesh::GetFilamentIndexBuffer() const {
   return index_buffer_;
 }
@@ -345,13 +366,18 @@ filament::VertexBuffer* Mesh::GetFilamentVertexBuffer() const {
 }
 
 filament::RenderableManager::PrimitiveType Mesh::GetPrimitiveType() const {
-  return type_;
+  return config_.primitive_type == mjMESH_PRIMITIVE_TYPE_TRIANGLES
+             ? filament::RenderableManager::PrimitiveType::TRIANGLES
+             : filament::RenderableManager::PrimitiveType::LINES;
 }
 
 bool Mesh::HasVertexAttribute(mjrVertexAttributeUsage attrib) const {
-  auto fattrib = GetUsage(mjrVertexAttribute{.usage = attrib});
-  auto it = std::find(attributes_.begin(), attributes_.end(), fattrib);
-  return it != attributes_.end();
+  for (int i = 0; i < config_.num_attributes; ++i) {
+    if (config_.attributes[i].usage == attrib) {
+      return true;
+    }
+  }
+  return false;
 }
 
 bool Mesh::HasBounds() const { return bounds_.has_value(); }

src/render/filament/core/mesh.h

@@ -37,12 +37,15 @@ namespace mujoco {
 class Mesh : public mjrfMesh {
  public:
   // Creates a Mesh from the given MeshData.
-  Mesh(filament::Engine* engine, const mjrfMeshData& data);
+  Mesh(filament::Engine* engine, const mjrfMeshConfig& config);
   ~Mesh();
 
   Mesh(const Mesh&) = delete;
   Mesh& operator=(const Mesh&) = delete;
 
+  // Uploads the given MeshData to the mesh.
+  void Upload(const mjrfMeshData& data);
+
   // Returns the filament IndexBuffer for the mesh.
   filament::IndexBuffer* GetFilamentIndexBuffer() const;
 
@@ -67,29 +70,31 @@ class Mesh : public mjrfMesh {
   }
 
  private:
-  void BuildVertexBuffer(const mjrfMeshData& data);
-  void BuildIndexBuffer(const mjrfMeshData& data);
+  void InitVertexBuffer();
+  void InitIndexBuffer();
+
+  void UpdateVertexBuffer(const mjrfMeshData& data);
+  void UpdateIndexBuffer(const mjrfMeshData& data);
   void UpdateBounds(const mjrfMeshData& data);
 
-  filament::math::float4* BuildOrientationsFromNormals(
-      int num_vertices, const mjrVertexAttribute& normals);
+  filament::math::float4* BuildOrientationsFromNormals(int num_vertices,
+                                                       const void* normals);
 
   void ReleaseResources();
 
   filament::Engine* engine_ = nullptr;
+  mjrfMeshConfig config_;
+
   filament::IndexBuffer* index_buffer_ = nullptr;
   filament::VertexBuffer* vertex_buffer_ = nullptr;
-  filament::RenderableManager::PrimitiveType type_ =
-      filament::RenderableManager::PrimitiveType::TRIANGLES;
   std::optional<filament::Box> bounds_;
+
   struct SharedState {
     std::vector<std::function<void()>> callbacks;
     std::mutex mutex;
     bool called = false;
   };
   std::shared_ptr<SharedState> shared_state_;
-  std::array<filament::VertexAttribute, mjMAX_VERTEX_ATTRIBUTES> attributes_;
-  int num_attributes_ = 0;
 };
 
 }  // namespace mujoco

src/render/filament/mjrfilament.cc

@@ -62,6 +62,10 @@ void mjrf_defaultTextureConfig(mjrfTextureConfig* config) {
   memset(config, 0, sizeof(mjrfTextureConfig));
 }
 
+void mjrf_defaultMeshConfig(mjrfMeshConfig* config) {
+  memset(config, 0, sizeof(mjrfMeshConfig));
+}
+
 void mjrf_defaultMeshData(mjrfMeshData* data) {
   memset(data, 0, sizeof(mjrfMeshData));
 }
@@ -151,9 +155,9 @@ void mjrf_destroyTexture(mjrfTexture* texture) {
   delete mujoco::Texture::downcast(texture);
 }
 
-mjrfMesh* mjrf_createMesh(mjrfContext* ctx, const mjrfMeshData* data) {
+mjrfMesh* mjrf_createMesh(mjrfContext* ctx, const mjrfMeshConfig* config) {
   return new mujoco::Mesh(mujoco::FilamentContext::downcast(ctx)->GetEngine(),
-                          *data);
+                          *config);
 }
 
 void mjrf_destroyMesh(mjrfMesh* mesh) { delete mujoco::Mesh::downcast(mesh); }
@@ -202,6 +206,10 @@ void mjrf_setTextureData(mjrfTexture* texture, const mjrfTextureData* data) {
   mujoco::Texture::downcast(texture)->Upload(*data);
 }
 
+void mjrf_setMeshData(mjrfMesh* mesh, const mjrfMeshData* data) {
+  mujoco::Mesh::downcast(mesh)->Upload(*data);
+}
+
 int mjrf_getTextureWidth(const mjrfTexture* texture) {
   return mujoco::Texture::downcast(texture)->GetWidth();
 }

src/render/filament/mjrfilament_cpp.h

@@ -38,8 +38,8 @@ inline UniquePtr<mjrfTexture> CreateTexture(mjrfContext* ctx,
 }
 
 inline UniquePtr<mjrfMesh> CreateMesh(mjrfContext* ctx,
-                                      const mjrfMeshData& data) {
-  mjrfMesh* mesh = mjrf_createMesh(ctx, &data);
+                                      const mjrfMeshConfig& config) {
+  mjrfMesh* mesh = mjrf_createMesh(ctx, &config);
   return UniquePtr<mjrfMesh>(mesh, mjrf_destroyMesh);
 }
 

src/render/filament/support/mesh_util.cc

@@ -362,43 +362,47 @@ static void FillSkinVertices(T* vertices, const mjModel* model,
   }
 }
 
-static mjrfMeshData PrepareMeshData(int num_vertices, bool has_uvs) {
-  mjrfMeshData mesh_data;
-  mjrf_defaultMeshData(&mesh_data);
+static void PrepareMeshData(mjrfMeshConfig* config, mjrfMeshData* data,
+                            int num_vertices, bool has_uvs) {
+  mjrf_defaultMeshConfig(config);
+  config->max_vertices = num_vertices;
+  config->num_attributes = has_uvs ? 3 : 2;
+  config->interleaved = true;
+  config->primitive_type = mjMESH_PRIMITIVE_TYPE_TRIANGLES;
+  config->max_indices = num_vertices;
+  config->index_type = mjINDEX_TYPE_U32;
+  config->attributes[0].usage = mjVERTEX_ATTRIBUTE_USAGE_POSITION;
+  config->attributes[0].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT3;
+  config->attributes[1].usage = mjVERTEX_ATTRIBUTE_USAGE_TANGENTS;
+  config->attributes[1].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT4;
+  if (has_uvs) {
+    config->attributes[2].usage = mjVERTEX_ATTRIBUTE_USAGE_UV;
+    config->attributes[2].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT2;
+  }
 
+  mjrf_defaultMeshData(data);
   if (has_uvs) {
     const int nbytes = sizeof(VertexWithUv) * num_vertices;
-    mesh_data.user_data = new char[nbytes];
-    std::memset(mesh_data.user_data, 0, nbytes);
+    data->user_data = new char[nbytes];
+    std::memset(data->user_data, 0, nbytes);
   } else {
     const int nbytes = sizeof(VertexNoUv) * num_vertices;
-    mesh_data.user_data = new char[nbytes];
-    std::memset(mesh_data.user_data, 0, nbytes);
+    data->user_data = new char[nbytes];
+    std::memset(data->user_data, 0, nbytes);
   }
-  mesh_data.release = [](void* user_data) {
+  data->release = [](void* user_data) {
     delete[] (char*)(user_data);
   };
 
-  char* buf = reinterpret_cast<char*>(mesh_data.user_data);
-  mesh_data.num_vertices = num_vertices;
-  mesh_data.num_attributes = has_uvs ? 3 : 2;
-  mesh_data.interleaved = true;
-  mesh_data.attributes[0].usage = mjVERTEX_ATTRIBUTE_USAGE_POSITION;
-  mesh_data.attributes[0].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT3;
-  mesh_data.attributes[0].bytes = buf;
-  mesh_data.attributes[1].usage = mjVERTEX_ATTRIBUTE_USAGE_TANGENTS;
-  mesh_data.attributes[1].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT4;
-  mesh_data.attributes[1].bytes = buf + sizeof(float[3]);
+  char* buf = reinterpret_cast<char*>(data->user_data);
+  data->num_vertices = num_vertices;
+  data->vertices[0] = buf;
+  data->vertices[1] = buf + sizeof(float[3]);
   if (has_uvs) {
-    mesh_data.attributes[2].usage = mjVERTEX_ATTRIBUTE_USAGE_UV;
-    mesh_data.attributes[2].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT2;
-    mesh_data.attributes[2].bytes = buf + sizeof(float[7]);
+    data->vertices[2] = buf + sizeof(float[7]);
   }
-  mesh_data.primitive_type = mjMESH_PRIMITIVE_TYPE_TRIANGLES;
-  mesh_data.num_indices = num_vertices;
-  mesh_data.index_type = mjINDEX_TYPE_U32;
-  mesh_data.indices = nullptr;
-  return mesh_data;
+  data->num_indices = num_vertices;
+  data->indices = nullptr;
 }
 
 static void SetBounds(mjrfMeshData* mesh_data, const float3& min_pt,
@@ -428,7 +432,10 @@ UniquePtr<mjrfMesh> CreateFlexMesh(mjrfContext* ctx, const mjModel* model,
 
   const int num_vertices = num_faces * 3;
   const bool has_uvs = model->flex_texcoordadr[flex_id] >= 0;
-  mjrfMeshData mesh_data = PrepareMeshData(num_vertices, has_uvs);
+
+  mjrfMeshConfig mesh_config;
+  mjrfMeshData mesh_data;
+  PrepareMeshData(&mesh_config, &mesh_data, num_vertices, has_uvs);
 
   float3 min_pt = float3(FLT_MAX);
   float3 max_pt = float3(FLT_MIN);
@@ -440,14 +447,21 @@ UniquePtr<mjrfMesh> CreateFlexMesh(mjrfContext* ctx, const mjModel* model,
     FillFlexVertices(vertices, model, data, flex_id, &min_pt, &max_pt);
   }
   SetBounds(&mesh_data, min_pt, max_pt);
-  return CreateMesh(ctx, mesh_data);
+
+  auto mesh = CreateMesh(ctx, mesh_config);
+  mjrf_setMeshData(mesh.get(), &mesh_data);
+  return mesh;
 }
 
 UniquePtr<mjrfMesh> CreateSkinMesh(mjrfContext* ctx, const mjModel* model,
                                    const mjData* data, int skin_id) {
   const int num_vertices = model->skin_vertnum[skin_id];
   const bool has_uvs = model->skin_texcoordadr[skin_id] >= 0;
-  mjrfMeshData mesh_data = PrepareMeshData(num_vertices, has_uvs);
+
+
+  mjrfMeshConfig mesh_config;
+  mjrfMeshData mesh_data;
+  PrepareMeshData(&mesh_config, &mesh_data, num_vertices, has_uvs);
 
   float3 min_pt = float3(FLT_MAX);
   float3 max_pt = float3(FLT_MIN);
@@ -461,7 +475,10 @@ UniquePtr<mjrfMesh> CreateSkinMesh(mjrfContext* ctx, const mjModel* model,
   mesh_data.num_indices = 3 * model->skin_facenum[skin_id];
   mesh_data.indices = model->skin_face + 3 * model->skin_faceadr[skin_id];
   SetBounds(&mesh_data, min_pt, max_pt);
-  return CreateMesh(ctx, mesh_data);
+
+  auto mesh = CreateMesh(ctx, mesh_config);
+  mjrf_setMeshData(mesh.get(), &mesh_data);
+  return mesh;
 }
 
 void GatherSpatialTendonPoints(const mjModel* model, const mjData* data,

src/render/filament/support/model_objects.cc

@@ -329,8 +329,8 @@ static int GetNumVertices(const mjModel* model, int id, MeshType mesh_type) {
   }
 }
 
-static void UpdateMeshData(mjrfMeshData* data, const mjModel* model, int id,
-                           MeshType mesh_type) {
+static void UpdateMeshData(mjrfMeshConfig* config, mjrfMeshData* data,
+                           const mjModel* model, int id, MeshType mesh_type) {
   if (!IsValidIndex(model, id, mesh_type)) {
     mju_error("Invalid index %d for type %d", id, mesh_type);
     return;
@@ -357,24 +357,29 @@ static void UpdateMeshData(mjrfMeshData* data, const mjModel* model, int id,
       break;
   }
 
-  data->primitive_type = mjMESH_PRIMITIVE_TYPE_TRIANGLES;
-  data->num_vertices = num_vertices;
-  data->num_indices = data->num_vertices;
-  data->indices = nullptr;
-  data->index_type = data->num_vertices >= std::numeric_limits<uint16_t>::max()
-                         ? mjINDEX_TYPE_U32
-                         : mjINDEX_TYPE_U16;
-  data->num_attributes = has_uvs ? 3 : 2;
-  data->attributes[0].usage = mjVERTEX_ATTRIBUTE_USAGE_POSITION;
-  data->attributes[0].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT3;
-  data->attributes[0].bytes = builder->positions.data();
-  data->attributes[1].usage = mjVERTEX_ATTRIBUTE_USAGE_TANGENTS;
-  data->attributes[1].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT4;
-  data->attributes[1].bytes = builder->orientations.data();
+  config->max_vertices = num_vertices;
+  config->max_indices = num_vertices;
+  config->primitive_type = mjMESH_PRIMITIVE_TYPE_TRIANGLES;
+  config->index_type = num_vertices >= std::numeric_limits<uint16_t>::max()
+                           ? mjINDEX_TYPE_U32
+                           : mjINDEX_TYPE_U16;
+  config->num_attributes = has_uvs ? 3 : 2;
+  config->attributes[0].usage = mjVERTEX_ATTRIBUTE_USAGE_POSITION;
+  config->attributes[0].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT3;
+  config->attributes[1].usage = mjVERTEX_ATTRIBUTE_USAGE_TANGENTS;
+  config->attributes[1].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT4;
   if (has_uvs) {
-    data->attributes[2].usage = mjVERTEX_ATTRIBUTE_USAGE_UV;
-    data->attributes[2].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT2;
-    data->attributes[2].bytes = builder->uvs.data();
+    config->attributes[2].usage = mjVERTEX_ATTRIBUTE_USAGE_UV;
+    config->attributes[2].type = mjVERTEX_ATTRIBUTE_TYPE_FLOAT2;
+  }
+
+  data->num_vertices = num_vertices;
+  data->num_indices = num_vertices;
+  data->indices = nullptr;
+  data->vertices[0] = builder->positions.data();
+  data->vertices[1] = builder->orientations.data();
+  if (has_uvs) {
+    data->vertices[2] = builder->uvs.data();
   }
   data->bounds_min[0] = builder->bounds_min.x;
   data->bounds_min[1] = builder->bounds_min.y;
@@ -415,16 +420,27 @@ void ModelObjects::UploadMesh(const mjModel* model, int id) {
   meshes_.erase(id);
   convex_hulls_.erase(id);
 
+  mjrfMeshConfig config;
+  mjrf_defaultMeshConfig(&config);
   mjrfMeshData data;
   mjrf_defaultMeshData(&data);
-  UpdateMeshData(&data, model, id, MeshType::kNormal);
-  meshes_.insert_or_assign(id, CreateMesh(ctx_, data));
+  UpdateMeshData(&config, &data, model, id, MeshType::kNormal);
+
+  auto mesh = CreateMesh(ctx_, config);
+  mjrf_setMeshData(mesh.get(), &data);
+  meshes_.insert_or_assign(id, std::move(mesh));
 
   if (model->mesh_graphadr[id] >= 0) {
+    mjrfMeshConfig convex_hull_config;
+    mjrf_defaultMeshConfig(&convex_hull_config);
     mjrfMeshData convex_hull_data;
     mjrf_defaultMeshData(&convex_hull_data);
-    UpdateMeshData(&convex_hull_data, model, id, MeshType::kConvexHull);
-    convex_hulls_.insert_or_assign(id, CreateMesh(ctx_, convex_hull_data));
+    UpdateMeshData(&convex_hull_config, &convex_hull_data, model, id,
+                   MeshType::kConvexHull);
+
+    auto convex_hull = CreateMesh(ctx_, convex_hull_config);
+    mjrf_setMeshData(convex_hull.get(), &convex_hull_data);
+    convex_hulls_.insert_or_assign(id, std::move(convex_hull));
   }
 }
 
@@ -484,10 +500,15 @@ void ModelObjects::UploadHeightField(const mjModel* model, int id) {
 
   height_fields_.erase(id);
 
+  mjrfMeshConfig config;
+  mjrf_defaultMeshConfig(&config);
   mjrfMeshData data;
   mjrf_defaultMeshData(&data);
-  UpdateMeshData(&data, model, id, MeshType::kHeightField);
-  height_fields_.insert_or_assign(id, CreateMesh(ctx_, data));
+  UpdateMeshData(&config, &data, model, id, MeshType::kHeightField);
+
+  auto mesh = CreateMesh(ctx_, config);
+  mjrf_setMeshData(mesh.get(), &data);
+  height_fields_.insert_or_assign(id, std::move(mesh));
 }
 
 const mjrfMesh* ModelObjects::GetMesh(int data_id) const {

unity/Runtime/Bindings/MjBindings.cs

@@ -6240,7 +6240,6 @@ public unsafe struct mjrRendererInfo_ {
 
 [StructLayout(LayoutKind.Sequential)]
 public unsafe struct mjrVertexAttribute_ {
-  public void* bytes;
   public int usage;
   public int type;
 }