Planes should not receive shadows when rendered from behind.

Also refactors Renderables a bit to allow for additional use-cases.

PiperOrigin-RevId: 885527587
Change-Id: I4b17e097256de0356151a6d087bc01f11e3071b7

src/experimental/filament/filament/drawable.cc

@@ -88,7 +88,8 @@ static bool IsBehind(const mjtNum* headpos, const float* pos, const float* mat)
 Drawable::Drawable(ObjectManager* object_mgr, const mjvGeom& geom)
     : material_(object_mgr), renderables_(object_mgr->GetEngine()) {
   if (geom.category == mjCAT_DECOR) {
-    renderables_.DisableShadows();
+    renderables_.SetCastShadows(false);
+    renderables_.SetReceiveShadows(false);
   }
 
   switch ((mjtGeom)geom.type) {
@@ -346,8 +347,13 @@ void Drawable::UpdateMaterial(const mjvGeom& geom, bool use_segid_color,
   const mjModel* model = object_mgr->GetModel();
 
   float4 color = ReadFloat4(geom.rgba);
-  if (geom.type == mjGEOM_PLANE && IsBehind(headpos, geom.pos, geom.mat)) {
-    color[3] *= 0.3;
+  if (geom.type == mjGEOM_PLANE) {
+    if (IsBehind(headpos, geom.pos, geom.mat)) {
+      color[3] *= 0.3;
+      renderables_.SetReceiveShadows(false);
+    } else {
+      renderables_.SetReceiveShadows(true);
+    }
   }
 
   Material::Textures textures;

src/experimental/filament/filament/drawable.h

@@ -51,7 +51,6 @@ class Drawable {
   // beginFrame/endFrame.
   void SetDrawMode(Material::DrawMode mode);
 
-
  private:
   void AddMesh(int data_id);
   void AddHeightField(int hfield_id);

src/experimental/filament/filament/renderables.cc

@@ -14,6 +14,7 @@
 
 #include "experimental/filament/filament/renderables.h"
 
+#include <cstdint>
 #include <optional>
 
 #include <filament/Engine.h>
@@ -107,8 +108,9 @@ utils::Entity Renderables::CreateEntity(const FilamentBuffers& buffers) {
   builder.boundingBox(buffers.bounds)
       .culling(false)
       .castShadows(cast_shadows_)
-      .receiveShadows(true)
-      .layerMask(1, visible_ ? 1 : 0)
+      .receiveShadows(receive_shadows_)
+      .layerMask(0xff, layer_mask_)
+      .priority(priority_)
       .screenSpaceContactShadows(true);
 
   builder.build(*engine_, entity);
@@ -180,23 +182,47 @@ void Renderables::SetMaterialInstance(
   }
 }
 
-void Renderables::Hide() {
-  if (visible_) {
+void Renderables::SetLayerMask(std::uint8_t mask) {
+  if (mask != layer_mask_) {
+    layer_mask_ = mask;
+
     filament::RenderableManager& rm = engine_->getRenderableManager();
     for (utils::Entity& entity : entities_) {
-      rm.setLayerMask(rm.getInstance(entity), 1, 0);
+      rm.setLayerMask(rm.getInstance(entity), 0xff, layer_mask_);
     }
-    visible_ = false;
   }
 }
 
-void Renderables::Show() {
-  if (!visible_) {
+void Renderables::SetPriority(std::uint8_t priority) {
+  if (priority != priority_) {
+    priority_ = priority;
+
     filament::RenderableManager& rm = engine_->getRenderableManager();
     for (utils::Entity& entity : entities_) {
-      rm.setLayerMask(rm.getInstance(entity), 1, 1);
+      rm.setPriority(rm.getInstance(entity), priority_);
+    }
+  }
+}
+
+void Renderables::SetCastShadows(bool cast_shadows) {
+  if (cast_shadows_ != cast_shadows) {
+    cast_shadows_ = cast_shadows;
+
+    filament::RenderableManager& rm = engine_->getRenderableManager();
+    for (utils::Entity& entity : entities_) {
+      rm.setCastShadows(rm.getInstance(entity), cast_shadows_);
+    }
+  }
+}
+
+void Renderables::SetReceiveShadows(bool receive_shadows) {
+  if (receive_shadows_ != receive_shadows) {
+    receive_shadows_ = receive_shadows;
+
+    filament::RenderableManager& rm = engine_->getRenderableManager();
+    for (utils::Entity& entity : entities_) {
+      rm.setReceiveShadows(rm.getInstance(entity), receive_shadows_);
     }
-    visible_ = true;
   }
 }
 
@@ -204,29 +230,19 @@ void Renderables::SetWireframe(bool wireframe) {
   static constexpr auto kWireframeType =
       filament::RenderableManager::PrimitiveType::LINES;
 
-  if (wireframe == wireframe_) {
-    return;
-  }
-  wireframe_ = wireframe;
+  if (wireframe != wireframe_) {
+    wireframe_ = wireframe;
 
-  filament::RenderableManager& rm = engine_->getRenderableManager();
-  for (int i = 0; i < entities_.size(); ++i) {
-    utils::Entity& entity = entities_[i];
-    FilamentBuffers& buffers = owned_buffers_[i].buffers;
-    rm.setGeometryAt(rm.getInstance(entity), 0,
-                     wireframe ? kWireframeType : buffers.type,
-                     buffers.vertex_buffer, buffers.index_buffer, 0,
-                     buffers.index_buffer->getIndexCount());
+    filament::RenderableManager& rm = engine_->getRenderableManager();
+    for (int i = 0; i < entities_.size(); ++i) {
+      utils::Entity& entity = entities_[i];
+      FilamentBuffers& buffers = owned_buffers_[i].buffers;
+      rm.setGeometryAt(rm.getInstance(entity), 0,
+                      wireframe_ ? kWireframeType : buffers.type,
+                      buffers.vertex_buffer, buffers.index_buffer, 0,
+                      buffers.index_buffer->getIndexCount());
+    }
   }
 }
 
-
-void Renderables::DisableShadows() {
-  filament::RenderableManager& rm = engine_->getRenderableManager();
-  for (utils::Entity& entity : entities_) {
-    rm.setCastShadows(rm.getInstance(entity), false);
-  }
-  cast_shadows_ = false;
-}
-
 }  // namespace mujoco

src/experimental/filament/filament/renderables.h

@@ -15,8 +15,8 @@
 #ifndef MUJOCO_SRC_EXPERIMENTAL_FILAMENT_FILAMENT_RENDERABLES_H_
 #define MUJOCO_SRC_EXPERIMENTAL_FILAMENT_FILAMENT_RENDERABLES_H_
 
+#include <cstdint>
 #include <optional>
-#include <span>
 #include <vector>
 
 #include <filament/Engine.h>
@@ -29,6 +29,10 @@ namespace mujoco {
 // Manages a collection of related filament Renderable Entities.
 class Renderables {
  public:
+  // Default filament values for priority and layer mask.
+  static constexpr std::uint8_t kDefaultPriority = 4;
+  static constexpr std::uint8_t kDefaultLayerMask = 0x01;
+
   Renderables(filament::Engine* engine);
   ~Renderables() noexcept;
 
@@ -53,16 +57,19 @@ class Renderables {
   int GetNumEntities() const { return entities_.size(); }
 
   // Hides all managed entities.
-  void Hide();
+  void SetLayerMask(std::uint8_t mask);
 
-  // Shows all managed entities.
-  void Show();
-
-  // Returns true if the entities are visible.
-  bool IsVisible() const { return visible_; }
+  // Sets the priority of all managed entities.
+  void SetPriority(std::uint8_t priority);
 
   // Disables the renderables from casting shadows.
-  void DisableShadows();
+  void SetCastShadows(bool cast_shadows);
+
+  // Disables the renderables from receiving shadows.
+  void SetReceiveShadows(bool receive_shadows);
+
+  // If true, forces all entities to be rendered as lines.
+  void SetWireframe(bool wireframe);
 
   // Adds all managed entities to the given filament Scene.
   void AddToScene(filament::Scene* scene);
@@ -73,9 +80,6 @@ class Renderables {
   // Sets the material instance for all managed entities.
   void SetMaterialInstance(filament::MaterialInstance* material_instance);
 
-  // If true, forces all entities to be rendered as lines.
-  void SetWireframe(bool wireframe);
-
   // Returns the filament Engine managing the entities in this collection.
   filament::Engine* GetEngine() { return engine_; }
 
@@ -96,9 +100,11 @@ class Renderables {
   filament::MaterialInstance* material_instance_ = nullptr;
   std::vector<utils::Entity> entities_;
   std::vector<OwnedBuffers> owned_buffers_;
-  bool visible_ = true;
+  std::uint8_t priority_ = kDefaultPriority;
+  std::uint8_t layer_mask_ = kDefaultLayerMask;
   bool wireframe_ = false;
   bool cast_shadows_ = true;
+  bool receive_shadows_ = true;
 };
 
 }  // namespace mujoco