4 files changed, 56 insertions, 6 deletions

diff --git a/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp b/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
index 1dcb773..3ddc15a 100644
--- a/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
+++ b/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
@@ -1212,6 +1212,9 @@ void QGL2PaintEngineExPrivate::stroke(const QVectorPath &path, const QPen &pen)
         stroker.process(dashStroke, pen, clip);
     }
 
+    if (!stroker.vertexCount())
+        return;
+
     if (opaque) {
         prepareForDraw(opaque);
         setVertexAttributePointer(QT_VERTEX_COORDS_ATTR, stroker.vertices());
@@ -1479,6 +1482,8 @@ void QGL2PaintEngineExPrivate::drawCachedGlyphs(QFontEngineGlyphCache::Type glyp
     if (!cache || cache->cacheType() != glyphType) {
         cache = new QGLTextureGlyphCache(ctx, glyphType, QTransform());
         staticTextItem->fontEngine()->setGlyphCache(ctx, cache);
+    } else if (cache->context() == 0) { // Old context has been destroyed, new context has same ptr value
+        cache->setContext(ctx);
     }
 
     bool recreateVertexArrays = false;
@@ -1494,8 +1499,13 @@ void QGL2PaintEngineExPrivate::drawCachedGlyphs(QFontEngineGlyphCache::Type glyp
     // cache so this text is performed before we test if the cache size has changed.
     if (recreateVertexArrays) {
         cache->setPaintEnginePrivate(this);
-        cache->populate(staticTextItem->fontEngine(), staticTextItem->numGlyphs,
-                        staticTextItem->glyphs, staticTextItem->glyphPositions);
+        if (!cache->populate(staticTextItem->fontEngine(), staticTextItem->numGlyphs,
+			     staticTextItem->glyphs, staticTextItem->glyphPositions)) {
+	    // No space in cache. We need to clear the cache and try again
+            cache->clear();
+            cache->populate(staticTextItem->fontEngine(), staticTextItem->numGlyphs,
+			    staticTextItem->glyphs, staticTextItem->glyphPositions);
+	}
     }
 
     if (cache->width() == 0 || cache->height() == 0)
diff --git a/src/opengl/gl2paintengineex/qtextureglyphcache_gl.cpp b/src/opengl/gl2paintengineex/qtextureglyphcache_gl.cpp
index 919c542..705ad09 100644
--- a/src/opengl/gl2paintengineex/qtextureglyphcache_gl.cpp
+++ b/src/opengl/gl2paintengineex/qtextureglyphcache_gl.cpp
@@ -54,11 +54,18 @@ extern Q_GUI_EXPORT bool qt_cleartype_enabled;
 
 QGLTextureGlyphCache::QGLTextureGlyphCache(QGLContext *context, QFontEngineGlyphCache::Type type, const QTransform &matrix)
     : QImageTextureGlyphCache(type, matrix)
-    , ctx(context)
+    , ctx(0)
     , m_width(0)
     , m_height(0)
     , m_filterMode(Nearest)
 {
+    setContext(context);
+}
+
+void QGLTextureGlyphCache::setContext(QGLContext *context)
+{
+    ctx = context;
+
     // broken FBO readback is a bug in the SGX 1.3 and 1.4 drivers for the N900 where
     // copying between FBO's is broken if the texture is either GL_ALPHA or POT. The
     // workaround is to use a system-memory copy of the glyph cache for this device.
@@ -71,7 +78,7 @@ QGLTextureGlyphCache::QGLTextureGlyphCache(QGLContext *context, QFontEngineGlyph
             SLOT(contextDestroyed(const QGLContext*)));
 }
 
-QGLTextureGlyphCache::~QGLTextureGlyphCache()
+void QGLTextureGlyphCache::clear() 
 {
     if (ctx) {
         QGLShareContextScope scope(ctx);
@@ -81,7 +88,24 @@ QGLTextureGlyphCache::~QGLTextureGlyphCache()
 
         if (m_width || m_height)
             glDeleteTextures(1, &m_texture);
+
+        m_fbo = 0;
+        m_texture = 0;
+        m_width = 0;
+        m_height = 0;
+        m_w = 0;
+        m_h = 0;
+        m_cx = 0;
+        m_cy = 0;
+        m_currentRowHeight = 0;
+        coords.clear();
     }
+  
+}
+
+QGLTextureGlyphCache::~QGLTextureGlyphCache()
+{
+    clear();
 }
 
 void QGLTextureGlyphCache::createTextureData(int width, int height)
diff --git a/src/opengl/gl2paintengineex/qtextureglyphcache_gl_p.h b/src/opengl/gl2paintengineex/qtextureglyphcache_gl_p.h
index e22146d..aaef350 100644
--- a/src/opengl/gl2paintengineex/qtextureglyphcache_gl_p.h
+++ b/src/opengl/gl2paintengineex/qtextureglyphcache_gl_p.h
@@ -90,6 +90,9 @@ public:
     FilterMode filterMode() const { return m_filterMode; }
     void setFilterMode(FilterMode m) { m_filterMode = m; }
 
+    void setContext(QGLContext *context);
+    QGLContext *context() const { return ctx; }
+
 public Q_SLOTS:
     void contextDestroyed(const QGLContext *context) {
         if (context == ctx) {
@@ -98,10 +101,20 @@ public Q_SLOTS:
                 // the context may not be current, so we cannot directly
                 // destroy the fbo and texture here, but since the context
                 // is about to be destroyed, the GL server will do the
-                // clean up for us anyway
+                // clean up for us anyway. We reset everything, so that the
+                // glyph cache object can be reused later by setting a new
+                // context on it.
                 m_fbo = 0;
                 m_texture = 0;
                 ctx = 0;
+                m_width = 0;
+                m_height = 0;
+                m_w = 0;
+                m_h = 0;
+                m_cx = 0;
+                m_cy = 0;
+                m_currentRowHeight = 0;
+                coords.clear();
             } else {
                 // since the context holding the texture is shared, and
                 // about to be destroyed, we have to transfer ownership
@@ -111,6 +124,8 @@ public Q_SLOTS:
         }
     }
 
+    void clear();
+
 private:
     QGLContext *ctx;
 
diff --git a/src/opengl/qgl_p.h b/src/opengl/qgl_p.h
index 4742bdb..b46d428 100644
--- a/src/opengl/qgl_p.h
+++ b/src/opengl/qgl_p.h
@@ -506,7 +506,8 @@ private slots:
             // when you come to delete the context.
             QGLContextPrivate::unbindPixmapFromTexture(boundPixmap);
             glDeleteTextures(1, &id);
-            oldContext->makeCurrent();
+            if (oldContext)
+                oldContext->makeCurrent();
             return;
         }
 #endif