Limit number of shadow casting lights in ogre2 (#155)

* limit num of shadow casting lights Signed-off-by: Ian Chen <[email protected]> * add warning about limit Signed-off-by: Ian Chen <[email protected]>
gazebosim · Oct 5, 2020 · 7253594 · 7253594
1 parent 8f049ce
commit 7253594
Showing 1 changed file with 19 additions and 0 deletions.
diff --git a/ogre2/src/Ogre2RenderTarget.cc b/ogre2/src/Ogre2RenderTarget.cc
@@ -346,6 +346,24 @@ void Ogre2RenderTarget::UpdateShadowNode()
     }
   }
 
+  // limit number of shadow maps
+  // shaders dynamically generated by ogre produce compile error at runtime if
+  // the number of shadow maps exceeds certain number. The error seems to
+  // suggest that the number of uniform variables has exceeded the max number
+  // allowed
+  unsigned int maxShadowMaps = 25u;
+  if (dirLightCount * 3 + spotPointLightCount > maxShadowMaps)
+  {
+    dirLightCount = std::min(static_cast<unsigned int>(maxShadowMaps / 3),
+        dirLightCount);
+    spotPointLightCount = std::min(
+        std::max(maxShadowMaps - dirLightCount * 3, 0u), spotPointLightCount);
+    ignwarn << "Number of shadow-casting lights exceeds the limit supported by "
+            << "the underlying rendering engine ogre2. Limiting to "
+            << dirLightCount << " directional lights and "
+            << spotPointLightCount << " point / spot lights" << std::endl;
+  }
+
   auto engine = Ogre2RenderEngine::Instance();
   Ogre::CompositorManager2 *compositorManager =
       engine->OgreRoot()->getCompositorManager2();
@@ -386,6 +404,7 @@ void Ogre2RenderTarget::UpdateShadowNode()
   unsigned int colIdx = 0;
   unsigned int rowSize = maxTexSize / texSize;
   unsigned int colSize = rowSize;
+
   for (unsigned int i = 0; i < spotPointLightCount; ++i)
   {
     shadowParam.technique = Ogre::SHADOWMAP_FOCUSED;