Fixed a problem where QPixmaps where re-bound in non-sharing contexts.

If you have two non-sharing GL contexts and try to draw the same
QPixmap in both of them, they will wind up competing for a spot in the
texture cache. Make the context group a part of the cache key to avoid
that.

Task-number: QT-3462
Reviewed-by: Kim

2 files changed, 67 insertions, 20 deletions

diff --git a/src/opengl/qgl.cpp b/src/opengl/qgl.cpp
index 922a96c..c8502c2 100644
--- a/src/opengl/qgl.cpp
+++ b/src/opengl/qgl.cpp
@@ -91,6 +91,7 @@
 #include "qcolormap.h"
 #include "qfile.h"
 #include "qlibrary.h"
+#include <qmutex.h>
 
 
 QT_BEGIN_NAMESPACE
@@ -1515,10 +1516,33 @@ bool operator!=(const QGLFormat& a, const QGLFormat& b)
     return !(a == b);
 }
 
+struct QGLContextGroupList {
+    void append(QGLContextGroup *group) {
+        QMutexLocker locker(&m_mutex);
+        m_list.append(group);
+    }
+
+    void remove(QGLContextGroup *group) {
+        QMutexLocker locker(&m_mutex);
+        m_list.removeOne(group);
+    }
+
+    QList<QGLContextGroup *> m_list;
+    QMutex m_mutex;
+};
+
+Q_GLOBAL_STATIC(QGLContextGroupList, qt_context_groups)
+
 /*****************************************************************************
   QGLContext implementation
  *****************************************************************************/
 
+QGLContextGroup::QGLContextGroup(const QGLContext *context)
+    : m_context(context), m_guards(0), m_refs(1)
+{
+    qt_context_groups()->append(this);
+}
+
 QGLContextGroup::~QGLContextGroup()
 {
     // Clear any remaining QGLSharedResourceGuard objects on the group.
@@ -1528,6 +1552,7 @@ QGLContextGroup::~QGLContextGroup()
         guard->m_id = 0;
         guard = guard->m_next;
     }
+    qt_context_groups()->remove(this);
 }
 
 void QGLContextGroup::addGuard(QGLSharedResourceGuard *guard)
@@ -1736,7 +1761,7 @@ void QGLTextureCache::insert(QGLContext* ctx, qint64 key, QGLTexture* texture, i
     QWriteLocker locker(&m_lock);
     if (m_cache.totalCost() + cost > m_cache.maxCost()) {
         // the cache is full - make an attempt to remove something
-        const QList<qint64> keys = m_cache.keys();
+        const QList<QGLTextureCacheKey> keys = m_cache.keys();
         int i = 0;
         while (i < m_cache.count()
                && (m_cache.totalCost() + cost > m_cache.maxCost())) {
@@ -1746,13 +1771,26 @@ void QGLTextureCache::insert(QGLContext* ctx, qint64 key, QGLTexture* texture, i
             ++i;
         }
     }
-    m_cache.insert(key, texture, cost);
+    const QGLTextureCacheKey cacheKey = {key, QGLContextPrivate::contextGroup(ctx)};
+    m_cache.insert(cacheKey, texture, cost);
+}
+
+void QGLTextureCache::remove(qint64 key)
+{
+    QWriteLocker locker(&m_lock);
+    QMutexLocker groupLocker(&qt_context_groups()->m_mutex);
+    QList<QGLContextGroup *>::const_iterator it = qt_context_groups()->m_list.constBegin();
+    while (it != qt_context_groups()->m_list.constEnd()) {
+        const QGLTextureCacheKey cacheKey = {key, *it};
+        m_cache.remove(cacheKey);
+        ++it;
+    }
 }
 
 bool QGLTextureCache::remove(QGLContext* ctx, GLuint textureId)
 {
     QWriteLocker locker(&m_lock);
-    QList<qint64> keys = m_cache.keys();
+    QList<QGLTextureCacheKey> keys = m_cache.keys();
     for (int i = 0; i < keys.size(); ++i) {
         QGLTexture *tex = m_cache.object(keys.at(i));
         if (tex->id == textureId && tex->context == ctx) {
@@ -1767,9 +1805,9 @@ bool QGLTextureCache::remove(QGLContext* ctx, GLuint textureId)
 void QGLTextureCache::removeContextTextures(QGLContext* ctx)
 {
     QWriteLocker locker(&m_lock);
-    QList<qint64> keys = m_cache.keys();
+    QList<QGLTextureCacheKey> keys = m_cache.keys();
     for (int i = 0; i < keys.size(); ++i) {
-        const qint64 &key = keys.at(i);
+        const QGLTextureCacheKey &key = keys.at(i);
         if (m_cache.object(key)->context == ctx)
             m_cache.remove(key);
     }
@@ -1782,7 +1820,6 @@ void QGLTextureCache::removeContextTextures(QGLContext* ctx)
 void QGLTextureCache::cleanupTexturesForCacheKey(qint64 cacheKey)
 {
     qt_gl_texture_cache()->remove(cacheKey);
-    Q_ASSERT(qt_gl_texture_cache()->getTexture(cacheKey) == 0);
 }
 
 
@@ -2425,7 +2462,7 @@ QGLTexture* QGLContextPrivate::bindTexture(const QImage &image, GLenum target, G
 QGLTexture *QGLContextPrivate::textureCacheLookup(const qint64 key, GLenum target)
 {
     Q_Q(QGLContext);
-    QGLTexture *texture = QGLTextureCache::instance()->getTexture(key);
+    QGLTexture *texture = QGLTextureCache::instance()->getTexture(q, key);
     if (texture && texture->target == target
         && (texture->context == q || QGLContext::areSharing(q, texture->context)))
     {
diff --git a/src/opengl/qgl_p.h b/src/opengl/qgl_p.h
index d92f963..16c225f 100644
--- a/src/opengl/qgl_p.h
+++ b/src/opengl/qgl_p.h
@@ -230,7 +230,7 @@ public:
     static void addShare(const QGLContext *context, const QGLContext *share);
     static void removeShare(const QGLContext *context);
 private:
-    QGLContextGroup(const QGLContext *context) : m_context(context), m_guards(0), m_refs(1) { }
+    QGLContextGroup(const QGLContext *context);
 
     QGLExtensionFuncs m_extensionFuncs;
     const QGLContext *m_context; // context group's representative
@@ -522,17 +522,33 @@ public:
     QSize bindCompressedTexturePVR(const char *buf, int len);
 };
 
+struct QGLTextureCacheKey {
+    qint64 key;
+    QGLContextGroup *group;
+};
+
+inline bool operator==(const QGLTextureCacheKey &a, const QGLTextureCacheKey &b)
+{
+    return a.key == b.key && a.group == b.group;
+}
+
+inline uint qHash(const QGLTextureCacheKey &key)
+{
+    return qHash(key.key) ^ qHash(key.group);
+}
+
+
 class Q_AUTOTEST_EXPORT QGLTextureCache {
 public:
     QGLTextureCache();
     ~QGLTextureCache();
 
     void insert(QGLContext *ctx, qint64 key, QGLTexture *texture, int cost);
-    inline void remove(quint64 key);
+    void remove(qint64 key);
     inline int size();
     inline void setMaxCost(int newMax);
     inline int maxCost();
-    inline QGLTexture* getTexture(quint64 key);
+    inline QGLTexture* getTexture(QGLContext *ctx, qint64 key);
 
     bool remove(QGLContext *ctx, GLuint textureId);
     void removeContextTextures(QGLContext *ctx);
@@ -542,7 +558,7 @@ public:
     static void cleanupBeforePixmapDestruction(QPixmapData* pixmap);
 
 private:
-    QCache<qint64, QGLTexture> m_cache;
+    QCache<QGLTextureCacheKey, QGLTexture> m_cache;
     QReadWriteLock m_lock;
 };
 
@@ -563,19 +579,13 @@ int QGLTextureCache::maxCost()
     return m_cache.maxCost();
 }
 
-QGLTexture* QGLTextureCache::getTexture(quint64 key)
+QGLTexture* QGLTextureCache::getTexture(QGLContext *ctx, qint64 key)
 {
     QReadLocker locker(&m_lock);
-    return m_cache.object(key);
+    const QGLTextureCacheKey cacheKey = {key, QGLContextPrivate::contextGroup(ctx)};
+    return m_cache.object(cacheKey);
 }
 
-void QGLTextureCache::remove(quint64 key)
-{
-    QWriteLocker locker(&m_lock);
-    m_cache.remove(key);
-}
-
-
 extern Q_OPENGL_EXPORT QPaintEngine* qt_qgl_paint_engine();
 
 bool qt_gl_preferGL2Engine();