Generate spot light shadow maps (#2914)

Updated gazebo to generate shadow maps for spot lights.
This does not mean the spot lights will now start casting
shadows in gazebo - we still need to update the
RTShaderSystem code to actually render them.
This does however mean that the shadow maps are now
available and we can access them through custom
material shaders.

The spotlight_shadow_demo.world contains a shadow
receiver ground plane with custom material shaders to show
how to access the shadow texture generated by OGRE.

Signed-off-by: Ian Chen <ichen@osrfoundation.org>

gazebo/rendering/Heightmap.cc

@@ -3341,27 +3341,34 @@ Ogre::MaterialPtr TerrainMaterial::Profile::generate(
 
       // set up shadow split points in a way that is consistent with the
       // default ogre terrain material generator
-      Ogre::PSSMShadowCameraSetup* pssm =
-          RTShaderSystem::Instance()->GetPSSMShadowCameraSetup();
-      unsigned int numTextures =
-          static_cast<unsigned int>(pssm->getSplitCount());
-      Ogre::Vector4 splitPoints;
-      const Ogre::PSSMShadowCameraSetup::SplitPointList& splitPointList =
-          pssm->getSplitPoints();
-      // populate from split point 1 not 0, and include shadowFarDistance
-      for (unsigned int t = 0u; t < numTextures; ++t)
-        splitPoints[t] = splitPointList[t+1];
-      params->setNamedConstant("pssmSplitPoints", splitPoints);
-
-      // set up uv transform
-      double xTrans = static_cast<int>(gridCount / gridWidth) * factor;
-      double yTrans = (gridWidth - 1 - (gridCount % gridWidth)) * factor;
-      // explicitly set all matrix elements to avoid uninitialized values
-      Ogre::Matrix4 uvTransform(factor, 0.0, 0.0, xTrans,
-                                0.0, factor, 0.0, yTrans,
-                                0.0, 0.0, 1.0, 0.0,
-                                0.0, 0.0, 0.0, 1.0);
-      params->setNamedConstant("uvTransform", uvTransform);
+
+      if (params->_findNamedConstantDefinition("pssmSplitPoints"))
+      {
+        Ogre::PSSMShadowCameraSetup* pssm =
+            RTShaderSystem::Instance()->GetPSSMShadowCameraSetup();
+        unsigned int numTextures =
+            static_cast<unsigned int>(pssm->getSplitCount());
+        Ogre::Vector4 splitPoints;
+        const Ogre::PSSMShadowCameraSetup::SplitPointList& splitPointList =
+            pssm->getSplitPoints();
+        // populate from split point 1 not 0, and include shadowFarDistance
+        for (unsigned int t = 0u; t < numTextures; ++t)
+          splitPoints[t] = splitPointList[t+1];
+        params->setNamedConstant("pssmSplitPoints", splitPoints);
+      }
+
+      if (params->_findNamedConstantDefinition("uvTransform"))
+      {
+        // set up uv transform
+        double xTrans = static_cast<int>(gridCount / gridWidth) * factor;
+        double yTrans = (gridWidth - 1 - (gridCount % gridWidth)) * factor;
+        // explicitly set all matrix elements to avoid uninitialized values
+        Ogre::Matrix4 uvTransform(factor, 0.0, 0.0, xTrans,
+                                  0.0, factor, 0.0, yTrans,
+                                  0.0, 0.0, 1.0, 0.0,
+                                  0.0, 0.0, 0.0, 1.0);
+        params->setNamedConstant("uvTransform", uvTransform);
+      }
     }
   }
   gridCount++;

gazebo/rendering/Light.cc

@@ -30,6 +30,7 @@
 #include "gazebo/rendering/Visual.hh"
 #include "gazebo/rendering/Light.hh"
 #include "gazebo/rendering/LightPrivate.hh"
+#include "gazebo/rendering/RTShaderSystem.hh"
 
 using namespace gazebo;
 using namespace rendering;
@@ -573,12 +574,29 @@ void Light::SetRange(const double _range)
 //////////////////////////////////////////////////
 void Light::SetCastShadows(const bool _cast)
 {
+
   if (this->dataPtr->light->getType() == Ogre::Light::LT_DIRECTIONAL)
   {
+    // directional light uses PSSM shadow camera and should already be
+    // configured in RTShaderSystem
+    this->dataPtr->light->setCastShadows(_cast);
+  }
+  else if (this->dataPtr->light->getType() == Ogre::Light::LT_SPOTLIGHT)
+  {
+    // use different shadow camera for spot light
     this->dataPtr->light->setCastShadows(_cast);
+    if (_cast && this->dataPtr->shadowCameraSetup.isNull())
+    {
+      this->dataPtr->shadowCameraSetup =
+          Ogre::ShadowCameraSetupPtr(new Ogre::FocusedShadowCameraSetup());
+      this->dataPtr->light->setCustomShadowCameraSetup(
+          this->dataPtr->shadowCameraSetup);
+      RTShaderSystem::Instance()->UpdateShadows();
+    }
   }
   else
   {
+    // todo(anyone) make point light casts shadows
     this->dataPtr->light->setCastShadows(false);
   }
 }

gazebo/rendering/LightPrivate.hh

@@ -38,7 +38,7 @@ namespace gazebo
     class LightPrivate
     {
       /// \brief The ogre light source
-      public: Ogre::Light *light;
+      public: Ogre::Light *light = nullptr;
 
       /// \brief The visual used to visualize the light.
       public: VisualPtr visual;
@@ -63,6 +63,9 @@ namespace gazebo
 
       /// \brief Counter used to generate unique light names.
       public: static unsigned int lightCounter;
+
+      /// \brief Custom shadow camera setup for non-directional lights
+      public: Ogre::ShadowCameraSetupPtr shadowCameraSetup;
     };
   }
 }

gazebo/rendering/RTShaderSystem.cc

@@ -41,6 +41,7 @@
 #include "gazebo/common/SystemPaths.hh"
 #include "gazebo/rendering/ogre_gazebo.h"
 #include "gazebo/rendering/CustomPSSMShadowCameraSetup.hh"
+#include "gazebo/rendering/Light.hh"
 #include "gazebo/rendering/RenderEngine.hh"
 #include "gazebo/rendering/Scene.hh"
 #include "gazebo/rendering/Visual.hh"
@@ -242,6 +243,7 @@ void RTShaderSystem::DetachViewport(Ogre::Viewport *_viewport, ScenePtr _scene)
 void RTShaderSystem::UpdateShaders()
 {
   // shaders will be updated in the Update call on pre-render event.
+  std::lock_guard<std::mutex> lock(this->dataPtr->updateMutex);
   this->dataPtr->updateShaders = true;
 }
 
@@ -520,57 +522,7 @@ void RTShaderSystem::ApplyShadows(ScenePtr _scene)
     this->dataPtr->shaderGenerator->getRenderState(_scene->Name() +
         Ogre::RTShader::ShaderGenerator::DEFAULT_SCHEME_NAME);
 
-  sceneMgr->setShadowTechnique(Ogre::SHADOWTYPE_TEXTURE_ADDITIVE_INTEGRATED);
-
-  // 3 textures per directional light
-  sceneMgr->setShadowTextureCountPerLightType(Ogre::Light::LT_DIRECTIONAL, 3);
-  sceneMgr->setShadowTextureCountPerLightType(Ogre::Light::LT_POINT, 0);
-  sceneMgr->setShadowTextureCountPerLightType(Ogre::Light::LT_SPOTLIGHT, 0);
-  sceneMgr->setShadowTextureCount(3);
-
-  unsigned int texSize = this->dataPtr->shadowTextureSize;
-#if defined(__APPLE__)
-  // workaround a weird but on OSX if texture size at 2 and 3 splits are not
-  // halved
-  texSize = this->dataPtr->shadowTextureSize/2;
-#endif
-  sceneMgr->setShadowTextureConfig(0,
-      this->dataPtr->shadowTextureSize, this->dataPtr->shadowTextureSize,
-      Ogre::PF_FLOAT32_R);
-  sceneMgr->setShadowTextureConfig(1, texSize, texSize, Ogre::PF_FLOAT32_R);
-  sceneMgr->setShadowTextureConfig(2, texSize, texSize, Ogre::PF_FLOAT32_R);
-
-#if defined(HAVE_OPENGL)
-  // Enable shadow map comparison, so shader can use
-  // float texture(sampler2DShadow, vec3, [float]) instead of
-  // vec4 texture(sampler2D, vec2, [float]).
-  // NVidia, AMD, and Intel all take this as a cue to provide "hardware PCF",
-  // a driver hack that softens shadow edges with 4-sample interpolation.
-  for (size_t i = 0; i < sceneMgr->getShadowTextureCount(); ++i)
-  {
-    const Ogre::TexturePtr tex = sceneMgr->getShadowTexture(i);
-    // This will fail if not using OpenGL as the rendering backend.
-    GLuint texId;
-    tex->getCustomAttribute("GLID", &texId);
-    glBindTexture(GL_TEXTURE_2D, texId);
-    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE,
-        GL_COMPARE_R_TO_TEXTURE);
-  }
-#endif
-
-  sceneMgr->setShadowTextureSelfShadow(false);
-  sceneMgr->setShadowCasterRenderBackFaces(true);
-
-  // TODO: We have two different shadow caster materials, both taken from
-  // OGRE samples. They should be compared and tested.
-  // Set up caster material - this is just a standard depth/shadow map caster
-  // sceneMgr->setShadowTextureCasterMaterial("PSSM/shadow_caster");
-#if OGRE_VERSION_MAJOR == 1 && OGRE_VERSION_MINOR >= 11
-  sceneMgr->setShadowTextureCasterMaterial(
-      Ogre::MaterialManager::getSingleton().getByName("Gazebo/shadow_caster"));
-#else
-  sceneMgr->setShadowTextureCasterMaterial("Gazebo/shadow_caster");
-#endif
+  this->UpdateShadows(_scene);
 
   // Disable fog on the caster pass.
   //  Ogre::MaterialPtr passCaterMaterial =
@@ -649,18 +601,39 @@ Ogre::PSSMShadowCameraSetup *RTShaderSystem::GetPSSMShadowCameraSetup() const
 void RTShaderSystem::Update()
 {
   IGN_PROFILE("rendering::RTShaderSystem::Update");
-  if (!this->dataPtr->initialized || !this->dataPtr->updateShaders)
+  if (!this->dataPtr->initialized)
+  {
     return;
+  }
+
+  bool updateShaders, updateShadows = false;
+  {
+    std::lock_guard<std::mutex> lock(this->dataPtr->updateMutex);
+    updateShaders = this->dataPtr->updateShaders;
+    updateShadows = this->dataPtr->updateShadows;
+    this->dataPtr->updateShaders = false;
+    this->dataPtr->updateShadows = false;
+  }
 
-  for (const auto &scene : this->dataPtr->scenes)
+  if (updateShadows)
   {
-    VisualPtr vis = scene->WorldVisual();
-    if (vis)
+    for (const auto &scene : this->dataPtr->scenes)
     {
-      this->UpdateShaders(vis);
+      this->UpdateShadows(scene);
+    }
+  }
+
+  if (updateShaders)
+  {
+    for (const auto &scene : this->dataPtr->scenes)
+    {
+      VisualPtr vis = scene->WorldVisual();
+      if (vis)
+      {
+        this->UpdateShaders(vis);
+      }
     }
   }
-  this->dataPtr->updateShaders = false;
 }
 
 /////////////////////////////////////////////////
@@ -728,3 +701,97 @@ double RTShaderSystem::ShadowSplitPadding() const
 {
   return this->dataPtr->shadowSplitPadding;
 }
+
+/////////////////////////////////////////////////
+void RTShaderSystem::UpdateShadows()
+{
+  std::lock_guard<std::mutex> lock(this->dataPtr->updateMutex);
+  this->dataPtr->updateShadows = true;
+}
+
+/////////////////////////////////////////////////
+void RTShaderSystem::UpdateShadows(ScenePtr _scene)
+{
+  if (!this->dataPtr->initialized)
+    return;
+
+  Ogre::SceneManager *sceneMgr = _scene->OgreSceneManager();
+
+  sceneMgr->setShadowTechnique(Ogre::SHADOWTYPE_TEXTURE_ADDITIVE_INTEGRATED);
+
+  // directional: assume there can only be one dir light and we always create
+  //              the shadow map for the dir light
+  // spot: update number of shadow textures based on number of shadow casting
+  //       spot lights
+  // point: not working yet
+  unsigned int dirLightCount = 1u;
+  unsigned int spotLightCount = 0u;
+  for (unsigned int i = 0; i < _scene->LightCount(); ++i)
+  {
+    LightPtr light = _scene->LightByIndex(i);
+
+    if (!light->CastShadows())
+      continue;
+
+    if (light->Type() == "spot")
+      spotLightCount++;
+  }
+
+  // 3 textures per directional light
+  sceneMgr->setShadowTextureCountPerLightType(Ogre::Light::LT_DIRECTIONAL, 3);
+
+  // spot light shadow count
+  sceneMgr->setShadowTextureCountPerLightType(Ogre::Light::LT_SPOTLIGHT, 1);
+
+  // \todo(anyone) make point light shadows work
+  sceneMgr->setShadowTextureCountPerLightType(Ogre::Light::LT_POINT, 0);
+
+  // \todo(anyone) include point light shadows when it is working
+  unsigned int dirShadowCount = 3 * dirLightCount;
+  unsigned int spotShadowCount = spotLightCount;
+  sceneMgr->setShadowTextureCount(dirShadowCount + spotShadowCount);
+
+  unsigned int texSize = this->dataPtr->shadowTextureSize;
+#if defined(__APPLE__)
+  // workaround a weird but on OSX if texture size at 2 and 3 splits are not
+  // halved
+  texSize = this->dataPtr->shadowTextureSize/2;
+#endif
+  sceneMgr->setShadowTextureConfig(0,
+      this->dataPtr->shadowTextureSize, this->dataPtr->shadowTextureSize,
+      Ogre::PF_FLOAT32_R);
+  sceneMgr->setShadowTextureConfig(1, texSize, texSize, Ogre::PF_FLOAT32_R);
+  sceneMgr->setShadowTextureConfig(2, texSize, texSize, Ogre::PF_FLOAT32_R);
+
+#if defined(HAVE_OPENGL)
+  // Enable shadow map comparison, so shader can use
+  // float texture(sampler2DShadow, vec3, [float]) instead of
+  // vec4 texture(sampler2D, vec2, [float]).
+  // NVidia, AMD, and Intel all take this as a cue to provide "hardware PCF",
+  // a driver hack that softens shadow edges with 4-sample interpolation.
+  for (size_t i = 0u; i < dirShadowCount; ++i)
+  {
+    const Ogre::TexturePtr tex = sceneMgr->getShadowTexture(i);
+    // This will fail if not using OpenGL as the rendering backend.
+    GLuint texId;
+    tex->getCustomAttribute("GLID", &texId);
+    glBindTexture(GL_TEXTURE_2D, texId);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE,
+        GL_COMPARE_R_TO_TEXTURE);
+  }
+#endif
+
+  sceneMgr->setShadowTextureSelfShadow(false);
+  sceneMgr->setShadowCasterRenderBackFaces(true);
+
+  // TODO: We have two different shadow caster materials, both taken from
+  // OGRE samples. They should be compared and tested.
+  // Set up caster material - this is just a standard depth/shadow map caster
+  // sceneMgr->setShadowTextureCasterMaterial("PSSM/shadow_caster");
+#if OGRE_VERSION_MAJOR == 1 && OGRE_VERSION_MINOR >= 11
+  sceneMgr->setShadowTextureCasterMaterial(
+      Ogre::MaterialManager::getSingleton().getByName("Gazebo/shadow_caster"));
+#else
+  sceneMgr->setShadowTextureCasterMaterial("Gazebo/shadow_caster");
+#endif
+}

gazebo/rendering/RTShaderSystem.hh

@@ -91,6 +91,9 @@ namespace gazebo
       /// \brief Queue a call to update the shaders.
       public: void UpdateShaders();
 
+      /// \brief Queue a call to update the shadows.
+      public: void UpdateShadows();
+
       /// \brief Set a viewport to use shaders.
       /// \param[in] _viewport The viewport to add.
       /// \param[in] _scene The scene that the viewport uses.
@@ -177,6 +180,10 @@ namespace gazebo
       /// \param[in] _vis Pointer to the visual to update.
       private: void UpdateShaders(VisualPtr _vis);
 
+      /// \brief Update the shadows for a scene
+      /// \param[in] _scene Pointer to the scene to update
+      private: void UpdateShadows(ScenePtr _scene);
+
       /// \brief Re-apply shadows. Call this if a shadow paramenter is changed.
       private: void ReapplyShadows();
 

gazebo/rendering/RTShaderSystemPrivate.hh

@@ -18,6 +18,7 @@
 #ifndef _GAZEBO_RTSHADERSYSTEM_PRIVATE_HH_
 #define _GAZEBO_RTSHADERSYSTEM_PRIVATE_HH_
 
+#include <mutex>
 #include <string>
 #include <vector>
 
@@ -56,6 +57,9 @@ namespace gazebo
       /// \brief Flag to indicate that shaders need to be updated.
       public: bool updateShaders;
 
+      /// \brief Flag to indicate that shadows need to be updated.
+      public: bool updateShadows = false;
+
       /// \brief Size of the Parallel Split Shadow Map (PSSM) shadow texture
       /// at closest layer.
       public: unsigned int shadowTextureSize = 2048u;
@@ -79,6 +83,9 @@ namespace gazebo
 
       /// \brief Flag to indicate if normal map should be enabled
       public: bool enableNormalMap = true;
+
+      /// \brief Mutex to protect shaders and shadows update
+      public: std::mutex updateMutex;
     };
   }
 }

gazebo/rendering/RenderingLight_TEST.cc

@@ -115,8 +115,9 @@ TEST_F(Light_TEST, CastShadows)
   msg.set_cast_shadows(true);
   spotLight->LoadFromMsg(msg);
   EXPECT_EQ(spotLight->LightType(), "spot");
-  // issue #2083: spot light does not cast shadows
-  EXPECT_FALSE(spotLight->CastShadows());
+  // issue #2083: spot light generates shadow maps but they are not currently
+  // being rendered
+  EXPECT_TRUE(spotLight->CastShadows());
   scene->RemoveLight(spotLight);
   spotLight.reset();