Refactor out duplicated RTT setup code

apps/openmw/mwrender/localmap.cpp

@@ -18,6 +18,7 @@
 #include <components/settings/settings.hpp>
 #include <components/sceneutil/visitor.hpp>
 #include <components/sceneutil/shadow.hpp>
+#include <components/sceneutil/util.hpp>
 #include <components/files/memorystream.hpp>
 
 #include "../mwbase/environment.hpp"
@@ -237,17 +238,7 @@ void LocalMap::setupRenderToTexture(osg::ref_ptr<osg::Camera> camera, int x, int
     texture->setWrap(osg::Texture::WRAP_S, osg::Texture::CLAMP_TO_EDGE);
     texture->setWrap(osg::Texture::WRAP_T, osg::Texture::CLAMP_TO_EDGE);
 
-    unsigned int samples = 0;
-    unsigned int colourSamples = 0;
-    if (Settings::Manager::getBool("antialias alpha test", "Shaders") && Settings::Manager::getInt("antialiasing", "Video") > 1)
-    {
-        // Alpha-to-coverage requires a multisampled framebuffer.
-        // OSG will set that up automatically and resolve it to the specified single-sample texture for us.
-        // For some reason, two samples are needed, at least with some drivers.
-        samples = 2;
-        colourSamples = 1;
-    }
-    camera->attach(osg::Camera::COLOR_BUFFER, texture, 0, 0, false, samples, colourSamples);
+    SceneUtil::attachAlphaToCoverageFriendlyFramebufferToCamera(camera, osg::Camera::COLOR_BUFFER, texture);
 
     camera->addChild(mSceneRoot);
     mRoot->addChild(camera);

apps/openmw/mwrender/water.cpp

@@ -26,6 +26,7 @@
 #include <components/resource/scenemanager.hpp>
 
 #include <components/sceneutil/shadow.hpp>
+#include <components/sceneutil/util.hpp>
 #include <components/sceneutil/waterutil.hpp>
 
 #include <components/misc/constants.hpp>
@@ -271,17 +272,7 @@ public:
         mRefractionTexture->setFilter(osg::Texture::MIN_FILTER, osg::Texture::LINEAR);
         mRefractionTexture->setFilter(osg::Texture::MAG_FILTER, osg::Texture::LINEAR);
 
-        unsigned int samples = 0;
-        unsigned int colourSamples = 0;
-        if (Settings::Manager::getBool("antialias alpha test", "Shaders") && Settings::Manager::getInt("antialiasing", "Video") > 1)
-        {
-            // Alpha-to-coverage requires a multisampled framebuffer.
-            // OSG will set that up automatically and resolve it to the specified single-sample texture for us.
-            // For some reason, two samples are needed, at least with some drivers.
-            samples = 2;
-            colourSamples = 1;
-        }
-        attach(osg::Camera::COLOR_BUFFER, mRefractionTexture, 0, 0, false, samples, colourSamples);
+        SceneUtil::attachAlphaToCoverageFriendlyFramebufferToCamera(this, osg::Camera::COLOR_BUFFER, mRefractionTexture);
 
         mRefractionDepthTexture = new osg::Texture2D;
         mRefractionDepthTexture->setTextureSize(rttSize, rttSize);
@@ -366,17 +357,7 @@ public:
         mReflectionTexture->setWrap(osg::Texture::WRAP_S, osg::Texture::CLAMP_TO_EDGE);
         mReflectionTexture->setWrap(osg::Texture::WRAP_T, osg::Texture::CLAMP_TO_EDGE);
 
-        unsigned int samples = 0;
-        unsigned int colourSamples = 0;
-        if (Settings::Manager::getBool("antialias alpha test", "Shaders") && Settings::Manager::getInt("antialiasing", "Video") > 1)
-        {
-            // Alpha-to-coverage requires a multisampled framebuffer.
-            // OSG will set that up automatically and resolve it to the specified single-sample texture for us.
-            // For some reason, two samples are needed, at least with some drivers.
-            samples = 2;
-            colourSamples = 1;
-        }
-        attach(osg::Camera::COLOR_BUFFER, mReflectionTexture, 0, 0, false, samples, colourSamples);
+        SceneUtil::attachAlphaToCoverageFriendlyFramebufferToCamera(this, osg::Camera::COLOR_BUFFER, mReflectionTexture);
 
         // XXX: should really flip the FrontFace on each renderable instead of forcing clockwise.
         osg::ref_ptr<osg::FrontFace> frontFace (new osg::FrontFace);

components/sceneutil/util.cpp

@@ -11,6 +11,7 @@
 
 #include <components/resource/imagemanager.hpp>
 #include <components/resource/scenemanager.hpp>
+#include <components/settings/settings.hpp>
 
 namespace SceneUtil
 {
@@ -260,4 +261,19 @@ osg::ref_ptr<GlowUpdater> addEnchantedGlow(osg::ref_ptr<osg::Node> node, Resourc
     return glowUpdater;
 }
 
+bool attachAlphaToCoverageFriendlyFramebufferToCamera(osg::Camera* camera, osg::Camera::BufferComponent buffer, osg::Texture * texture, unsigned int level, unsigned int face, bool mipMapGeneration)
+{
+    unsigned int samples = 0;
+    unsigned int colourSamples = 0;
+    if (Settings::Manager::getBool("antialias alpha test", "Shaders") && Settings::Manager::getInt("antialiasing", "Video") > 1)
+    {
+        // Alpha-to-coverage requires a multisampled framebuffer.
+        // OSG will set that up automatically and resolve it to the specified single-sample texture for us.
+        // For some reason, two samples are needed, at least with some drivers.
+        samples = 2;
+        colourSamples = 1;
+    }
+    camera->attach(buffer, texture, level, face, mipMapGeneration, samples, colourSamples);
+}
+
 }

components/sceneutil/util.hpp

@@ -3,6 +3,7 @@
 
 #include <osg/Matrix>
 #include <osg/BoundingSphere>
+#include <osg/Camera>
 #include <osg/NodeCallback>
 #include <osg/Texture2D>
 #include <osg/Vec4f>
@@ -60,6 +61,9 @@ namespace SceneUtil
     bool hasUserDescription(const osg::Node* node, const std::string pattern);
 
     osg::ref_ptr<GlowUpdater> addEnchantedGlow(osg::ref_ptr<osg::Node> node, Resource::ResourceSystem* resourceSystem, osg::Vec4f glowColor, float glowDuration=-1);
+
+    // Alpha-to-coverage requires a multisampled framebuffer, so we need to set that up for RTTs
+    bool attachAlphaToCoverageFriendlyFramebufferToCamera(osg::Camera* camera, osg::Camera::BufferComponent buffer, osg::Texture* texture, unsigned int level = 0, unsigned int face = 0, bool mipMapGeneration = false);
 }
 
 #endif