From 2568f119a4e31ed192e54e3fecb8bd62f33194f3 Mon Sep 17 00:00:00 2001
From: Bo Svensson <90132211+bosvensson1@users.noreply.github.com>
Date: Fri, 1 Oct 2021 08:11:00 +0000
Subject: [PATCH] reapplies PR without npe (#3137)

* avoids creating empty statesets on drawables

Currently, we attempt to skip creating state on drawable nodes when this state matches the default state. This attempt is incomplete because we still create an avoidable empty stateset in the default case.

* renderingmanager.cpp

* nifloader.cpp

* nifloader.cpp

* shadervisitor.cpp
---
 apps/openmw/mwrender/renderingmanager.cpp |  1 +
 components/nifosg/nifloader.cpp           | 20 +++++++++-----------
 components/shader/shadervisitor.cpp       |  6 ++++--
 3 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/apps/openmw/mwrender/renderingmanager.cpp b/apps/openmw/mwrender/renderingmanager.cpp
index 07b0418f2b..be143510b2 100644
--- a/apps/openmw/mwrender/renderingmanager.cpp
+++ b/apps/openmw/mwrender/renderingmanager.cpp
@@ -486,6 +486,7 @@ namespace MWRender
         defaultMat->setDiffuse(osg::Material::FRONT_AND_BACK, osg::Vec4f(1,1,1,1));
         defaultMat->setSpecular(osg::Material::FRONT_AND_BACK, osg::Vec4f(0.f, 0.f, 0.f, 0.f));
         sceneRoot->getOrCreateStateSet()->setAttribute(defaultMat);
+        sceneRoot->getOrCreateStateSet()->addUniform(new osg::Uniform("emissiveMult", 1.f));
 
         mFog.reset(new FogManager());
 
diff --git a/components/nifosg/nifloader.cpp b/components/nifosg/nifloader.cpp
index 0432aef5b4..a564844ce6 100644
--- a/components/nifosg/nifloader.cpp
+++ b/components/nifosg/nifloader.cpp
@@ -1134,8 +1134,6 @@ namespace NifOsg
                 trans->addChild(toAttach);
                 parentNode->addChild(trans);
             }
-            // create partsys stateset in order to pass in ShaderVisitor like all other Drawables
-            partsys->getOrCreateStateSet();
         }
 
         void handleNiGeometryData(osg::Geometry *geometry, const Nif::NiGeometryData* data, const std::vector<unsigned int>& boundTextures, const std::string& name)
@@ -1923,8 +1921,6 @@ namespace NifOsg
         void applyDrawableProperties(osg::Node* node, const std::vector<const Nif::Property*>& properties, SceneUtil::CompositeStateSetUpdater* composite,
                                              bool hasVertexColors, int animflags)
         {
-            osg::StateSet* stateset = node->getOrCreateStateSet();
-
             // Specular lighting is enabled by default, but there's a quirk...
             bool specEnabled = true;
             osg::ref_ptr<osg::Material> mat (new osg::Material);
@@ -2006,15 +2002,15 @@ namespace NifOsg
                         if (blendFunc->getDestination() == GL_DST_ALPHA)
                             blendFunc->setDestination(GL_ONE);
                         blendFunc = shareAttribute(blendFunc);
-                        stateset->setAttributeAndModes(blendFunc, osg::StateAttribute::ON);
+                        node->getOrCreateStateSet()->setAttributeAndModes(blendFunc, osg::StateAttribute::ON);
 
                         bool noSort = (alphaprop->flags>>13)&1;
                         if (!noSort)
-                            stateset->setRenderingHint(osg::StateSet::TRANSPARENT_BIN);
+                            node->getOrCreateStateSet()->setRenderingHint(osg::StateSet::TRANSPARENT_BIN);
                         else
-                            stateset->setRenderBinToInherit();
+                            node->getOrCreateStateSet()->setRenderBinToInherit();
                     }
-                    else
+                    else if (osg::StateSet* stateset = node->getStateSet())
                     {
                         stateset->removeAttribute(osg::StateAttribute::BLENDFUNC);
                         stateset->removeMode(GL_BLEND);
@@ -2025,9 +2021,9 @@ namespace NifOsg
                     {
                         osg::ref_ptr<osg::AlphaFunc> alphaFunc (new osg::AlphaFunc(getTestMode((alphaprop->flags>>10)&0x7), alphaprop->data.threshold/255.f));
                         alphaFunc = shareAttribute(alphaFunc);
-                        stateset->setAttributeAndModes(alphaFunc, osg::StateAttribute::ON);
+                        node->getOrCreateStateSet()->setAttributeAndModes(alphaFunc, osg::StateAttribute::ON);
                     }
-                    else
+                    else if (osg::StateSet* stateset = node->getStateSet())
                     {
                         stateset->removeAttribute(osg::StateAttribute::ALPHAFUNC);
                         stateset->removeMode(GL_ALPHA_TEST);
@@ -2083,8 +2079,10 @@ namespace NifOsg
 
             mat = shareAttribute(mat);
 
+            osg::StateSet* stateset = node->getOrCreateStateSet();
             stateset->setAttributeAndModes(mat, osg::StateAttribute::ON);
-            stateset->addUniform(new osg::Uniform("emissiveMult", emissiveMult));
+            if (emissiveMult != 1.f)
+                stateset->addUniform(new osg::Uniform("emissiveMult", emissiveMult));
         }
 
     };
diff --git a/components/shader/shadervisitor.cpp b/components/shader/shadervisitor.cpp
index 0d0710853f..cc2b781cfd 100644
--- a/components/shader/shadervisitor.cpp
+++ b/components/shader/shadervisitor.cpp
@@ -116,7 +116,6 @@ namespace Shader
         , mImageManager(imageManager)
         , mDefaultShaderPrefix(defaultShaderPrefix)
     {
-        mRequirements.emplace_back();
     }
 
     void ShaderVisitor::setForceShaders(bool force)
@@ -421,7 +420,10 @@ namespace Shader
 
     void ShaderVisitor::pushRequirements(osg::Node& node)
     {
-        mRequirements.push_back(mRequirements.back());
+        if (mRequirements.empty())
+            mRequirements.emplace_back();
+        else
+            mRequirements.push_back(mRequirements.back());
         mRequirements.back().mNode = &node;
     }