Merge pull request #1324 from MRPT/feature/assimp-better-transparent-…

…render

OpenGL render engine: smarter z-ordering for transparent Assimp models

apps/SceneViewer3D/_DSceneViewerMain.cpp

@@ -320,6 +320,7 @@ const long _DSceneViewerFrame::ID_BUTTON5 = wxNewId();
 const long _DSceneViewerFrame::ID_STATICLINE2 = wxNewId();
 const long _DSceneViewerFrame::ID_BUTTON6 = wxNewId();
 const long _DSceneViewerFrame::ID_BUTTON7 = wxNewId();
+const long _DSceneViewerFrame::ID_BUTTON_SHADOWS = wxNewId();
 const long _DSceneViewerFrame::ID_BUTTON8 = wxNewId();
 const long _DSceneViewerFrame::ID_BUTTON9 = wxNewId();
 const long _DSceneViewerFrame::ID_STATICLINE3 = wxNewId();
@@ -480,6 +481,17 @@ _DSceneViewerFrame::_DSceneViewerFrame(wxWindow* parent, wxWindowID id) : maxv(0
       wxArtProvider::GetBitmap(wxART_MAKE_ART_ID_FROM_STR(_T("wxART_TICK_MARK")), wxART_TOOLBAR));
   btnOrtho->SetMargins(wxSize(5, 5));
   FlexGridSizer2->Add(btnOrtho, 1, wxEXPAND, 1);
+
+  btnShadows = new wxCustomButton(
+      this, ID_BUTTON_SHADOWS, _(" Shadows "),
+      wxArtProvider::GetBitmap(wxART_MAKE_ART_ID_FROM_STR(_T("wxART_TICK_MARK")), wxART_TOOLBAR),
+      wxDefaultPosition, wxDefaultSize, wxCUSTBUT_TOGGLE | wxCUSTBUT_BOTTOM, wxDefaultValidator,
+      _T("ID_BUTTON_SHADOWS"));
+  btnShadows->SetBitmapDisabled(
+      wxArtProvider::GetBitmap(wxART_MAKE_ART_ID_FROM_STR(_T("wxART_TICK_MARK")), wxART_TOOLBAR));
+  btnShadows->SetMargins(wxSize(5, 5));
+  FlexGridSizer2->Add(btnShadows, 1, wxEXPAND, 1);
+
   btnAutoplay = new wxCustomButton(
       this, ID_BUTTON8, _("  Autoplay  "),
       wxArtProvider::GetBitmap(wxART_MAKE_ART_ID_FROM_STR(_T("wxART_REMOVABLE")), wxART_TOOLBAR),
@@ -657,6 +669,7 @@ _DSceneViewerFrame::_DSceneViewerFrame(wxWindow* parent, wxWindowID id) : maxv(0
   Bind(wxEVT_BUTTON, &svf::OnReload, this, ID_BUTTON5);
   Bind(wxEVT_BUTTON, &svf::OnMenuOptions, this, ID_BUTTON6);
   Bind(wxEVT_COMMAND_TOGGLEBUTTON_CLICKED, &svf::OnbtnOrthoClicked, this, ID_BUTTON7);
+  Bind(wxEVT_COMMAND_TOGGLEBUTTON_CLICKED, &svf::OnbtnShadowsClicked, this, ID_BUTTON_SHADOWS);
   Bind(wxEVT_COMMAND_TOGGLEBUTTON_CLICKED, &svf::OnbtnAutoplayClicked, this, ID_BUTTON8);
   Bind(wxEVT_COMMAND_TOGGLEBUTTON_CLICKED, &svf::OnBtnRecordClicked, this, ID_BUTTON9);
   Bind(wxEVT_BUTTON, &svf::OnAbout, this, ID_BUTTON10);
@@ -891,34 +904,39 @@ void _DSceneViewerFrame::OntimLoadFileCmdLineTrigger(wxTimerEvent&)
 {
   timLoadFileCmdLine.Stop();  // One shot only.
   // Open file if passed by the command line:
-  if (!global_fileToOpen.empty())
+  if (global_fileToOpen.empty()) return;
+
+  if (mrpt::system::strCmpI(
+          "3Dscene", mrpt::system::extractFileExtension(global_fileToOpen, true /*ignore .gz*/)))
   {
-    if (mrpt::system::strCmpI(
-            "3Dscene", mrpt::system::extractFileExtension(global_fileToOpen, true /*ignore .gz*/)))
+    loadFromFile(global_fileToOpen);
+  }
+  else
+  {
+    std::cout << "Filename extension does not match `3Dscene`, "
+                 "importing as an ASSIMP model...\n";
+    try
     {
-      loadFromFile(global_fileToOpen);
+      auto obj3D = mrpt::opengl::CAssimpModel::Create();
+      obj3D->loadScene(global_fileToOpen);
+      // obj3D->setPose(mrpt::math::TPose3D(0, 0, 0, .0_deg,
+      // 0._deg, 90.0_deg));
+      m_canvas->getOpenGLSceneRef()->insert(obj3D);
+
+      // TODO: make optional?
+      obj3D->split_triangles_rendering_bbox(0.25);
+
+      m_canvas->Refresh();
     }
-    else
+    catch (const std::exception& e)
     {
-      std::cout << "Filename extension does not match `3Dscene`, "
-                   "importing as an ASSIMP model...\n";
-      try
-      {
-        auto obj3D = mrpt::opengl::CAssimpModel::Create();
-        obj3D->loadScene(global_fileToOpen);
-        // obj3D->setPose(mrpt::math::TPose3D(0, 0, 0, .0_deg,
-        // 0._deg, 90.0_deg));
-        m_canvas->getOpenGLSceneRef()->insert(obj3D);
-
-        m_canvas->Refresh();
-      }
-      catch (const std::exception& e)
-      {
-        std::cerr << mrpt::exception_to_str(e) << std::endl;
-        wxMessageBox(mrpt::exception_to_str(e), _("Exception"), wxOK, this);
-      }
+      std::cerr << mrpt::exception_to_str(e) << std::endl;
+      wxMessageBox(mrpt::exception_to_str(e), _("Exception"), wxOK, this);
     }
   }
+
+  // Enable shadows?
+  applyShadowsOptions();
 }
 
 void _DSceneViewerFrame::OnbtnAutoplayClicked(wxCommandEvent& event)
@@ -1037,6 +1055,24 @@ void _DSceneViewerFrame::OnbtnOrthoClicked(wxCommandEvent& event)
   m_canvas->Refresh(false);
 }
 
+void _DSceneViewerFrame::OnbtnShadowsClicked(wxCommandEvent& event)
+{
+  applyShadowsOptions();
+  m_canvas->Refresh(false);
+}
+
+void _DSceneViewerFrame::applyShadowsOptions()
+{
+  bool shadowsEnabled = btnShadows->GetValue();
+  auto scene = m_canvas->getOpenGLSceneRef();
+  if (!scene) return;
+
+  auto vw = scene->getViewport();
+  if (!vw) return;
+
+  vw->enableShadowCasting(shadowsEnabled);
+}
+
 void _DSceneViewerFrame::OnReload(wxCommandEvent& event)
 {
   if (fileExists(loadedFileName)) loadFromFile(loadedFileName);

apps/SceneViewer3D/_DSceneViewerMain.h

@@ -76,6 +76,7 @@ class _DSceneViewerFrame : public wxFrame
   void OnClose(wxCloseEvent& event);
   void OnBtnRecordClicked(wxCommandEvent& event);
   void OnbtnOrthoClicked(wxCommandEvent& event);
+  void OnbtnShadowsClicked(wxCommandEvent& event);
   void OnReload(wxCommandEvent& event);
   void OnInsert3DS(wxCommandEvent& event);
   void OnMenuSave(wxCommandEvent& event);
@@ -104,6 +105,8 @@ class _DSceneViewerFrame : public wxFrame
 
   void OntimAutoplay(wxTimerEvent& event);
 
+  void applyShadowsOptions();
+
   //(*Identifiers(_DSceneViewerFrame)
   static const long ID_BUTTON1;
   static const long ID_BUTTON2;
@@ -114,6 +117,7 @@ class _DSceneViewerFrame : public wxFrame
   static const long ID_STATICLINE2;
   static const long ID_BUTTON6;
   static const long ID_BUTTON7;
+  static const long ID_BUTTON_SHADOWS;
   static const long ID_BUTTON8;
   static const long ID_BUTTON9;
   static const long ID_STATICLINE3;
@@ -187,6 +191,7 @@ class _DSceneViewerFrame : public wxFrame
   wxMenuItem* mnuSelectionScale;
   wxMenuItem* mnuImportLAS;
   wxCustomButton* btnOrtho;
+  wxCustomButton* btnShadows;
   wxStatusBar* StatusBar1;
   wxMenuItem* MenuItem6;
   wxStaticLine* StaticLine3;

doc/source/doxygen-docs/changelog.md

@@ -1,7 +1,12 @@
 \page changelog Change Log
 
 # Version 2.14.1: UNRELEASED
-(None yet)
+- Changes in apps:
+  - SceneViewer3D: New button to enable shadow casting.
+- Changes in libraries:
+  - \ref mrpt_opengl_grp:
+    - New method mrpt::opengl::CAssimpModel::split_triangles_rendering_bbox() to enable a new feature in Assimp 3D models: splitting into smaller triangle sets for correct z-ordering of semitransparent objects; e.g. required for trees with masked leaves.
+    - SkyBox shader changed its internal ID so it gets rendered before potentially transparent elements, fixing render artifacts.
 
 # Version 2.14.0: Released Sep 15th, 2024
 - Changes in libraries:

libs/opengl/include/mrpt/opengl/CAssimpModel.h

@@ -120,6 +120,16 @@ class CAssimpModel :
 
   mrpt::math::TBoundingBoxf internalBoundingBoxLocal() const override;
 
+  /** Enable (or disable if set to .0f) a feature in which textured triangles
+   *  are split into different renderizable smaller objects.
+   *  This is required only for semitransparent objects with overlaping regions.
+   */
+  void split_triangles_rendering_bbox(const float bbox_size);
+  [[nodiscard]] float split_triangles_rendering_bbox() const
+  {
+    return m_split_triangles_rendering_bbox;
+  }
+
   struct TInfoPerTexture
   {
     // indices in \a m_texturedObjects. string::npos for non-initialized
@@ -152,6 +162,7 @@ class CAssimpModel :
   mutable std::vector<CSetOfTexturedTriangles::Ptr> m_texturedObjects;
   bool m_verboseLoad = false;
   bool m_ignoreMaterialColor = false;
+  float m_split_triangles_rendering_bbox = .0f;
 
   void recursive_render(
       const aiScene* sc,

libs/opengl/include/mrpt/opengl/DefaultShaders.h

@@ -26,19 +26,19 @@ struct DefaultShaderID
   static constexpr shader_id_t POINTS = 0;
   static constexpr shader_id_t WIREFRAME = 1;
   static constexpr shader_id_t TEXT = 2;
-  static constexpr shader_id_t TRIANGLES_LIGHT = 3;
-  static constexpr shader_id_t TEXTURED_TRIANGLES_LIGHT = 4;
-  static constexpr shader_id_t TRIANGLES_NO_LIGHT = 5;
-  static constexpr shader_id_t TEXTURED_TRIANGLES_NO_LIGHT = 6;
+  static constexpr shader_id_t TRIANGLES_LIGHT = 10;
+  static constexpr shader_id_t TEXTURED_TRIANGLES_LIGHT = 11;
+  static constexpr shader_id_t TRIANGLES_NO_LIGHT = 12;
+  static constexpr shader_id_t TEXTURED_TRIANGLES_NO_LIGHT = 13;
 
   // Shadow generation 1st/2nd pass shaders:
-  static constexpr shader_id_t TRIANGLES_SHADOW_1ST = 10;
-  static constexpr shader_id_t TRIANGLES_SHADOW_2ND = 11;
-  static constexpr shader_id_t TEXTURED_TRIANGLES_SHADOW_1ST = 12;
-  static constexpr shader_id_t TEXTURED_TRIANGLES_SHADOW_2ND = 13;
+  static constexpr shader_id_t TRIANGLES_SHADOW_1ST = 20;
+  static constexpr shader_id_t TRIANGLES_SHADOW_2ND = 21;
+  static constexpr shader_id_t TEXTURED_TRIANGLES_SHADOW_1ST = 22;
+  static constexpr shader_id_t TEXTURED_TRIANGLES_SHADOW_2ND = 23;
 
   // Special effects:
-  static constexpr shader_id_t SKYBOX = 20;
+  static constexpr shader_id_t SKYBOX = 5;  // render *before* potentially transparent triangles
   static constexpr shader_id_t DEBUG_TEXTURE_TO_SCREEN = 30;
   static constexpr shader_id_t NONE = 31;  //!< Skip rendering
 };

libs/opengl/src/CAssimpModel.cpp

@@ -33,6 +33,7 @@
 #endif
 
 #include <mrpt/core/lock_helper.h>
+#include <mrpt/core/round.h>
 #include <mrpt/opengl/opengl_api.h>
 #include <mrpt/serialization/CArchive.h>
 #include <mrpt/system/filesystem.h>
@@ -273,8 +274,65 @@ void CAssimpModel::onUpdateBuffers_all()
 
   process_textures(m_assimp_scene->scene);
 
+  // Model -> 3D primitives:
   const auto transf = mrpt::poses::CPose3D();
   recursive_render(m_assimp_scene->scene, m_assimp_scene->scene->mRootNode, transf, re);
+
+  // Handle split:
+  if (m_split_triangles_rendering_bbox > .0f)
+  {
+    const float voxel = m_split_triangles_rendering_bbox;
+
+    ASSERT_EQUAL_(m_texturedObjects.size(), m_textureIdMap.size());
+    const std::vector<CSetOfTexturedTriangles::Ptr> origTexturedObjects = m_texturedObjects;
+    m_texturedObjects.clear();
+
+    std::unordered_map<int64_t, std::map<size_t /*textId*/, CSetOfTexturedTriangles::Ptr>>
+        newTextObjs;
+
+    for (size_t textId = 0; textId < m_textureIdMap.size(); textId++)
+    {
+      const auto& glTris = origTexturedObjects.at(textId);
+      const std::vector<mrpt::opengl::TTriangle>& iTris = glTris->shaderTexturedTrianglesBuffer();
+      for (const auto& t : iTris)
+      {
+        const auto midPt = 0.333f * (t.vertices[0].xyzrgba.pt + t.vertices[1].xyzrgba.pt +
+                                     t.vertices[2].xyzrgba.pt);
+        // hash for "voxels":
+        const int64_t vxlCoord = mrpt::round(midPt.x / voxel) +           //
+                                 mrpt::round(midPt.y / voxel) * 10'000 +  //
+                                 mrpt::round(midPt.z / voxel) * 100'000'000;
+
+        auto& trgObj = newTextObjs[vxlCoord][textId];
+        if (!trgObj)
+        {
+          // Create
+          trgObj = CSetOfTexturedTriangles::Create();
+
+          // Set representative point: the MOST FUNDAMENTAL property
+          // to ensure proper z ordering for transparent rendering:
+          trgObj->setLocalRepresentativePoint(midPt);
+
+          // copy texture
+          const auto& texRGB = glTris->getTextureImage();
+          const auto& texAlpha = glTris->getTextureAlphaImage();
+          if (!texAlpha.isEmpty())
+            trgObj->assignImage(texRGB, texAlpha);
+          else
+            trgObj->assignImage(texRGB);
+        }
+        // Add triangle:
+        trgObj->insertTriangle(t);
+      }
+    }
+
+    // replace list of objects:
+    m_texturedObjects.clear();
+    for (const auto& m : newTextObjs)
+      for (const auto& [k, v] : m.second)  //
+        m_texturedObjects.push_back(v);
+  }  // end: split into subobjects:
+
 #endif
 }
 
@@ -297,14 +355,15 @@ void CAssimpModel::enqueueForRenderRecursive(
   mrpt::opengl::enqueueForRendering(lst, state, rq, wholeInView, is1stShadowMapPass);
 }
 
-uint8_t CAssimpModel::serializeGetVersion() const { return 2; }
+uint8_t CAssimpModel::serializeGetVersion() const { return 3; }
 void CAssimpModel::serializeTo(mrpt::serialization::CArchive& out) const
 {
   writeToStreamRender(out);
 #if (MRPT_HAS_OPENGL_GLUT || MRPT_HAS_EGL) && MRPT_HAS_ASSIMP
   const bool empty = m_assimp_scene->scene == nullptr;
   out << empty;
-  out << m_modelPath;  // v2
+  out << m_modelPath;                       // v2
+  out << m_split_triangles_rendering_bbox;  // v3
   if (!empty)
   {
 #if 0
@@ -348,6 +407,8 @@ void CAssimpModel::serializeFrom(mrpt::serialization::CArchive& in, uint8_t vers
       {
         const bool empty = in.ReadAs<bool>();
         in >> m_modelPath;
+        if (version >= 3) in >> m_split_triangles_rendering_bbox;
+
         if (!empty)
         {
           const auto blobSize = in.ReadAs<uint32_t>();
@@ -439,6 +500,7 @@ void CAssimpModel::after_load_model()
   // Evaluate overall bbox:
   {
     aiVector3D scene_min, scene_max;
+    ASSERT_(m_assimp_scene->scene);
     get_bounding_box(m_assimp_scene->scene, &scene_min, &scene_max);
     m_bbox_min.x = scene_min.x;
     m_bbox_min.y = scene_min.y;
@@ -460,6 +522,16 @@ auto CAssimpModel::internalBoundingBoxLocal() const -> mrpt::math::TBoundingBoxf
   return mrpt::math::TBoundingBoxf::FromUnsortedPoints(m_bbox_min, m_bbox_max);
 }
 
+void CAssimpModel::split_triangles_rendering_bbox(const float bbox_size)
+{
+  m_split_triangles_rendering_bbox = bbox_size;
+
+#if (MRPT_HAS_OPENGL_GLUT || MRPT_HAS_EGL) && MRPT_HAS_ASSIMP
+  CRenderizable::notifyChange();
+  if (m_assimp_scene->scene) after_load_model();
+#endif
+}
+
 bool CAssimpModel::traceRay(
     [[maybe_unused]] const mrpt::poses::CPose3D& o, [[maybe_unused]] double& dist) const
 {

libs/ros2bridge/src/point_cloud2.cpp

@@ -126,7 +126,7 @@ bool mrpt::ros2bridge::fromROS(const sensor_msgs::msg::PointCloud2& msg, CSimple
     {
       const unsigned char* msg_data = row_data + col * msg.point_step;
 
-      float x, y, z;
+      float x = 0, y = 0, z = 0;
       get_float_from_field(x_field, msg_data, x);
       get_float_from_field(y_field, msg_data, y);
       get_float_from_field(z_field, msg_data, z);
@@ -165,7 +165,7 @@ bool mrpt::ros2bridge::fromROS(const sensor_msgs::msg::PointCloud2& msg, CPoints
     {
       const unsigned char* msg_data = row_data + col * msg.point_step;
 
-      float x, y, z, i;
+      float x = 0, y = 0, z = 0, i = 0;
       get_float_from_field(x_field, msg_data, x);
       get_float_from_field(y_field, msg_data, y);
       get_float_from_field(z_field, msg_data, z);
@@ -212,15 +212,15 @@ bool mrpt::ros2bridge::fromROS(const sensor_msgs::msg::PointCloud2& msg, CPoints
     {
       const unsigned char* msg_data = row_data + col * msg.point_step;
 
-      float x, y, z;
+      float x = 0, y = 0, z = 0;
       get_float_from_field(x_field, msg_data, x);
       get_float_from_field(y_field, msg_data, y);
       get_float_from_field(z_field, msg_data, z);
       obj.setPointFast(idx, x, y, z);
 
       if (i_field)
       {
-        float i;
+        float i = 0;
         get_float_from_field(i_field, msg_data, i);
         obj.setPointIntensity(idx, i);
       }