Fix for Power-of-Two texture problem.

Work around for POTT-support problem - we now check for POTT support and convert if necessary.

Change-Id: I8121c9f86c137c28a24bc9b81231fb4f27b707e8
Reviewed-by: Christopher Ham <christopher.ham@nokia.com>
Reviewed-by: Danny Pope <daniel.pope@nokia.com>

2 files changed, 31 insertions, 0 deletions

diff --git a/src/threed/textures/qgltexture2d.cpp b/src/threed/textures/qgltexture2d.cpp
index 31f0ee6c..07fe9891 100644
--- a/src/threed/textures/qgltexture2d.cpp
+++ b/src/threed/textures/qgltexture2d.cpp
@@ -47,6 +47,7 @@
 #include "qabstractdownloadmanager.h"
 #include "qdownloadmanager.h"
 #include "qthreadeddownloadmanager.h"
+#include "qopenglfunctions.h"
 
 #include <QtCore/qfile.h>
 #include <QtCore/qfileinfo.h>
@@ -92,6 +93,8 @@ QT_BEGIN_NAMESPACE
 
 Q_GLOBAL_STATIC(QSize, getMaxImageSize)
 
+QGLTexture2DPrivate::ForcePowerOfTwo QGLTexture2DPrivate::forcePowerOfTwo = QGLTexture2DPrivate::ForcePowerOfTwoUndefined;
+
 QGLTexture2DPrivate::QGLTexture2DPrivate()
 {
     horizontalWrap = QGL::Repeat;
@@ -105,6 +108,13 @@ QGLTexture2DPrivate::QGLTexture2DPrivate()
     parameterGeneration = 0;
     infos = 0;
     downloadManager = 0;
+
+    if (forcePowerOfTwo == ForcePowerOfTwoUndefined) {
+        if (qgetenv("NPOT_MIPMAP_UNSUPPORTED").toInt() == 1)
+            forcePowerOfTwo = ForcePowerOfTwoTrue;
+        else
+            forcePowerOfTwo = ForcePowerOfTwoFalse;
+    }
 }
 
 QGLTexture2DPrivate::~QGLTexture2DPrivate()
@@ -606,6 +616,15 @@ bool QGLTexture2DPrivate::bind(GLenum target)
     if (!ctx)
         return false;
 
+    QOpenGLFunctions glFuncs(ctx);
+    if (!glFuncs.hasOpenGLFeature(QOpenGLFunctions::NPOTTextures))
+    {
+        QSize oldSize = size;
+        size = QGL::nextPowerOfTwo(size);
+        if (size != oldSize)
+            ++imageGeneration;
+    }
+
     // Find the information block for the context, or create one.
     QGLTexture2DTextureInfo *info = infos;
     QGLTexture2DTextureInfo *prev = 0;
@@ -664,6 +683,10 @@ void QGLTexture2DPrivate::bindImages(QGLTexture2DTextureInfo *info)
         scaledSize = QGL::nextPowerOfTwo(scaledSize);
     }
 #endif
+
+    if (forcePowerOfTwo == ForcePowerOfTwoTrue)
+        scaledSize = QGL::nextPowerOfTwo(scaledSize);
+
     if (!image.isNull())
         info->tex.uploadFace(GL_TEXTURE_2D, image, scaledSize);
     else if (size.isValid())
diff --git a/src/threed/textures/qgltexture2d_p.h b/src/threed/textures/qgltexture2d_p.h
index 7a401c68..0e9ac634 100644
--- a/src/threed/textures/qgltexture2d_p.h
+++ b/src/threed/textures/qgltexture2d_p.h
@@ -109,6 +109,14 @@ public:
     QGLTexture2DTextureInfo *infos;
     QAbstractDownloadManager *downloadManager;
 
+    enum ForcePowerOfTwo {
+        ForcePowerOfTwoUndefined = -1,
+        ForcePowerOfTwoFalse = 0,
+        ForcePowerOfTwoTrue = 1
+    };
+
+    static ForcePowerOfTwo forcePowerOfTwo;
+
     bool bind(GLenum target);
     virtual void bindImages(QGLTexture2DTextureInfo *info);
 };