From 0a6323c2de23bd7a23e44ff3a534b06f7be994c6 Mon Sep 17 00:00:00 2001
From: Laszlo Agocs <laszlo.agocs@theqtcompany.com>
Date: Fri, 16 Jan 2015 11:01:58 +0100
Subject: [PATCH] Scale mipmapped npot images when not supported

Task-number: QTBUG-43847
Task-number: QTBUG-40789
Change-Id: Iceacaa49bafffb31752a9fb26c896df570153fec
Reviewed-by: Gunnar Sletta <gunnar@sletta.org>
---
 src/quick/scenegraph/util/qsgtexture.cpp | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/quick/scenegraph/util/qsgtexture.cpp b/src/quick/scenegraph/util/qsgtexture.cpp
index fc50500..bfc9212 100644
--- a/src/quick/scenegraph/util/qsgtexture.cpp
+++ b/src/quick/scenegraph/util/qsgtexture.cpp
@@ -35,6 +35,7 @@
 #include <qopenglfunctions.h>
 #include <QtQuick/private/qsgcontext_p.h>
 #include <qthread.h>
+#include <qmath.h>
 #include <private/qquickprofiler_p.h>
 #include <private/qqmlglobal_p.h>
 #include <QtGui/qguiapplication.h>
@@ -75,13 +76,11 @@ static bool qsg_leak_check = !qgetenv("QML_LEAK_CHECK").isEmpty();
 
 QT_BEGIN_NAMESPACE
 
-#ifndef QT_NO_DEBUG
 inline static bool isPowerOfTwo(int x)
 {
     // Assumption: x >= 1
     return x == (x & -x);
 }
-#endif
 
 QSGTexturePrivate::QSGTexturePrivate()
     : wrapChanged(false)
@@ -686,6 +685,16 @@ void QSGPlainTexture::bind()
         m_texture_size = tmp.size();
     }
 
+    // Scale to a power of two size if mipmapping is requested and the
+    // texture is npot and npot textures are not properly supported.
+    if (mipmapFiltering() != QSGTexture::None
+        && (!isPowerOfTwo(m_texture_size.width()) || !isPowerOfTwo(m_texture_size.height()))
+        && !funcs->hasOpenGLFeature(QOpenGLFunctions::NPOTTextures)) {
+        tmp = tmp.scaled(qNextPowerOfTwo(m_texture_size.width()), qNextPowerOfTwo(m_texture_size.height()),
+                         Qt::IgnoreAspectRatio, Qt::SmoothTransformation);
+        m_texture_size = tmp.size();
+    }
+
     if (tmp.width() * 4 != tmp.bytesPerLine())
         tmp = tmp.copy();
 
-- 
2.7.4