diff --git a/apps/openmw/mwrender/pingpongcanvas.cpp b/apps/openmw/mwrender/pingpongcanvas.cpp
index 6782bdddfd..b96b40ff3f 100644
--- a/apps/openmw/mwrender/pingpongcanvas.cpp
+++ b/apps/openmw/mwrender/pingpongcanvas.cpp
@@ -10,9 +10,11 @@
 
 namespace MWRender
 {
-    PingPongCanvas::PingPongCanvas(Shader::ShaderManager& shaderManager)
+    PingPongCanvas::PingPongCanvas(
+        Shader::ShaderManager& shaderManager, const std::shared_ptr<LuminanceCalculator>& luminanceCalculator)
         : mFallbackStateSet(new osg::StateSet)
         , mMultiviewResolveStateSet(new osg::StateSet)
+        , mLuminanceCalculator(luminanceCalculator)
     {
         setUseDisplayList(false);
         setUseVertexBufferObjects(true);
@@ -26,8 +28,7 @@ namespace MWRender
 
         addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::TRIANGLES, 0, 3));
 
-        mLuminanceCalculator = LuminanceCalculator(shaderManager);
-        mLuminanceCalculator.disable();
+        mLuminanceCalculator->disable();
 
         Shader::ShaderManager::DefineMap defines;
         Stereo::shaderStereoDefines(defines);
@@ -142,7 +143,7 @@ namespace MWRender
                         .getTexture());
             }
 
-            mLuminanceCalculator.dirty(mTextureScene->getTextureWidth(), mTextureScene->getTextureHeight());
+            mLuminanceCalculator->dirty(mTextureScene->getTextureWidth(), mTextureScene->getTextureHeight());
 
             if (Stereo::getStereo())
                 mRenderViewport
@@ -158,11 +159,11 @@ namespace MWRender
                 { GL_COLOR_ATTACHMENT0_EXT, GL_COLOR_ATTACHMENT2_EXT },
                 { GL_COLOR_ATTACHMENT0_EXT, GL_COLOR_ATTACHMENT1_EXT } } };
 
-        (mAvgLum) ? mLuminanceCalculator.enable() : mLuminanceCalculator.disable();
+        (mAvgLum) ? mLuminanceCalculator->enable() : mLuminanceCalculator->disable();
 
         // A histogram based approach is superior way to calculate scene luminance. Using mipmaps is more broadly
         // supported, so that's what we use for now.
-        mLuminanceCalculator.draw(*this, renderInfo, state, ext, frameId);
+        mLuminanceCalculator->draw(*this, renderInfo, state, ext, frameId);
 
         auto buffer = buffers[0];
 
@@ -202,8 +203,8 @@ namespace MWRender
             node.mRootStateSet->setTextureAttribute(PostProcessor::Unit_Depth, mTextureDepth);
 
             if (mAvgLum)
-                node.mRootStateSet->setTextureAttribute(
-                    PostProcessor::TextureUnits::Unit_EyeAdaptation, mLuminanceCalculator.getLuminanceTexture(frameId));
+                node.mRootStateSet->setTextureAttribute(PostProcessor::TextureUnits::Unit_EyeAdaptation,
+                    mLuminanceCalculator->getLuminanceTexture(frameId));
 
             if (mTextureNormals)
                 node.mRootStateSet->setTextureAttribute(PostProcessor::TextureUnits::Unit_Normals, mTextureNormals);
@@ -258,8 +259,6 @@ namespace MWRender
                         texture->setTextureSize(w, h);
                         texture->setNumMipmapLevels(pass.mRenderTexture->getNumMipmapLevels());
                         texture->dirtyTextureObject();
-
-                        mDirtyAttachments = false;
                     }
 
                     pass.mRenderTarget->apply(state, osg::FrameBufferObject::DRAW_FRAMEBUFFER);
@@ -336,5 +335,8 @@ namespace MWRender
         {
             bindDestinationFbo();
         }
+
+        if (mDirtyAttachments)
+            mDirtyAttachments = false;
     }
 }
diff --git a/apps/openmw/mwrender/pingpongcanvas.hpp b/apps/openmw/mwrender/pingpongcanvas.hpp
index 557813b816..0d53fd049a 100644
--- a/apps/openmw/mwrender/pingpongcanvas.hpp
+++ b/apps/openmw/mwrender/pingpongcanvas.hpp
@@ -22,7 +22,8 @@ namespace MWRender
     class PingPongCanvas : public osg::Geometry
     {
     public:
-        PingPongCanvas(Shader::ShaderManager& shaderManager);
+        PingPongCanvas(
+            Shader::ShaderManager& shaderManager, const std::shared_ptr<LuminanceCalculator>& luminanceCalculator);
 
         void drawGeometry(osg::RenderInfo& renderInfo) const;
 
@@ -72,7 +73,7 @@ namespace MWRender
         mutable osg::ref_ptr<osg::FrameBufferObject> mMultiviewResolveFramebuffer;
         mutable osg::ref_ptr<osg::FrameBufferObject> mDestinationFBO;
         mutable std::array<osg::ref_ptr<osg::FrameBufferObject>, 3> mFbos;
-        mutable LuminanceCalculator mLuminanceCalculator;
+        mutable std::shared_ptr<LuminanceCalculator> mLuminanceCalculator;
     };
 }
 
diff --git a/apps/openmw/mwrender/postprocessor.cpp b/apps/openmw/mwrender/postprocessor.cpp
index 66ade9495c..2527f52df1 100644
--- a/apps/openmw/mwrender/postprocessor.cpp
+++ b/apps/openmw/mwrender/postprocessor.cpp
@@ -118,9 +118,14 @@ namespace MWRender
         , mUsePostProcessing(Settings::postProcessing().mEnabled)
         , mSamples(Settings::video().mAntialiasing)
         , mPingPongCull(new PingPongCull(this))
-        , mCanvases({ new PingPongCanvas(mRendering.getResourceSystem()->getSceneManager()->getShaderManager()),
-              new PingPongCanvas(mRendering.getResourceSystem()->getSceneManager()->getShaderManager()) })
     {
+        auto& shaderManager = mRendering.getResourceSystem()->getSceneManager()->getShaderManager();
+
+        std::shared_ptr<LuminanceCalculator> luminanceCalculator = std::make_shared<LuminanceCalculator>(shaderManager);
+
+        for (auto& canvas : mCanvases)
+            canvas = new PingPongCanvas(shaderManager, luminanceCalculator);
+
         mHUDCamera->setReferenceFrame(osg::Camera::ABSOLUTE_RF);
         mHUDCamera->setRenderOrder(osg::Camera::POST_RENDER);
         mHUDCamera->setClearColor(osg::Vec4(0.45, 0.45, 0.14, 1.0));
@@ -139,8 +144,7 @@ namespace MWRender
         if (Settings::shaders().mSoftParticles || Settings::postProcessing().mTransparentPostpass)
         {
             mTransparentDepthPostPass
-                = new TransparentDepthBinCallback(mRendering.getResourceSystem()->getSceneManager()->getShaderManager(),
-                    Settings::postProcessing().mTransparentPostpass);
+                = new TransparentDepthBinCallback(shaderManager, Settings::postProcessing().mTransparentPostpass);
             osgUtil::RenderBin::getRenderBinPrototype("DepthSortedBin")->setDrawCallback(mTransparentDepthPostPass);
         }
 
@@ -617,8 +621,6 @@ namespace MWRender
                     subPass.mSize = renderTarget.mSize;
                     subPass.mRenderTexture = renderTarget.mTarget;
                     subPass.mMipMap = renderTarget.mMipMap;
-                    subPass.mStateSet->setAttributeAndModes(new osg::Viewport(
-                        0, 0, subPass.mRenderTexture->getTextureWidth(), subPass.mRenderTexture->getTextureHeight()));
 
                     subPass.mRenderTarget = new osg::FrameBufferObject;
                     subPass.mRenderTarget->setAttachment(osg::FrameBufferObject::BufferComponent::COLOR_BUFFER0,