From c4866bdfc63e28ceff2573dabb643fafc4283360 Mon Sep 17 00:00:00 2001
From: scrawl <scrawl@baseoftrash.de>
Date: Mon, 13 Jul 2015 19:13:26 +0200
Subject: [PATCH] Disable mipmaps for GUI textures

For some reason, the mipmap generator seems to be broken on Linux Intel graphics (works on Nvidia). This was breaking the scrollbar arrows, which are minified enough to show using a mipmap.
---
 components/myguiplatform/myguitexture.cpp |  2 ++
 components/resource/texturemanager.cpp    | 25 ++++++++++++++++++++++-
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/components/myguiplatform/myguitexture.cpp b/components/myguiplatform/myguitexture.cpp
index 0a846b227..50ac5c1f3 100644
--- a/components/myguiplatform/myguitexture.cpp
+++ b/components/myguiplatform/myguitexture.cpp
@@ -87,6 +87,8 @@ namespace osgMyGUI
             throw std::runtime_error("No texturemanager set");
 
         mTexture = mTextureManager->getTexture2D(fname, osg::Texture2D::CLAMP_TO_EDGE, osg::Texture2D::CLAMP_TO_EDGE);
+        // disable mip-maps
+        mTexture->setFilter(osg::Texture2D::MIN_FILTER, osg::Texture2D::LINEAR);
 
         // FIXME
         mFormat = MyGUI::PixelFormat::R8G8B8;
diff --git a/components/resource/texturemanager.cpp b/components/resource/texturemanager.cpp
index 62cbd6bb3..ae8d16102 100644
--- a/components/resource/texturemanager.cpp
+++ b/components/resource/texturemanager.cpp
@@ -64,7 +64,30 @@ namespace Resource
         for (std::map<MapKey, osg::ref_ptr<osg::Texture2D> >::iterator it = mTextures.begin(); it != mTextures.end(); ++it)
         {
             osg::ref_ptr<osg::Texture2D> tex = it->second;
-            tex->setFilter(osg::Texture::MIN_FILTER, mMinFilter);
+
+            // Keep mip-mapping disabled if the texture creator explicitely requested it.
+            osg::Texture::FilterMode oldMin = tex->getFilter(osg::Texture::MIN_FILTER);
+            if (oldMin == osg::Texture::LINEAR || oldMin == osg::Texture::NEAREST)
+            {
+                osg::Texture::FilterMode newMin = osg::Texture::LINEAR;
+                switch (mMinFilter)
+                {
+                case osg::Texture::LINEAR:
+                case osg::Texture::LINEAR_MIPMAP_LINEAR:
+                case osg::Texture::LINEAR_MIPMAP_NEAREST:
+                    newMin = osg::Texture::LINEAR;
+                    break;
+                case osg::Texture::NEAREST:
+                case osg::Texture::NEAREST_MIPMAP_LINEAR:
+                case osg::Texture::NEAREST_MIPMAP_NEAREST:
+                    newMin = osg::Texture::NEAREST;
+                    break;
+                }
+                tex->setFilter(osg::Texture::MIN_FILTER, newMin);
+            }
+            else
+                tex->setFilter(osg::Texture::MIN_FILTER, mMinFilter);
+
             tex->setFilter(osg::Texture::MAG_FILTER, mMagFilter);
             tex->setMaxAnisotropy(static_cast<float>(mMaxAnisotropy));
         }