Basic working compressed texture atlas

This adds experimental automatic atlasing of ETC-compressed textures
(to be expanded to additional formats), similar to existing atlas
support of QImages. It is off by default, and can be enabled with
QSG_ENABLE_COMPRESSED_ATLAS=1.

[ChangeLog] Add experimental automatic atlasing of ETC-compressed
textures (can be enabled with QSG_ENABLE_COMPRESSED_ATLAS=1)

Change-Id: Ia66971f51299d082a569bdfaadb662a3e522bd79
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 14 insertions, 0 deletions

diff --git a/src/quick/scenegraph/qsgcontext.cpp b/src/quick/scenegraph/qsgcontext.cpp
index fb66a6ebb1..e5334d59e1 100644
--- a/src/quick/scenegraph/qsgcontext.cpp
+++ b/src/quick/scenegraph/qsgcontext.cpp
@@ -404,6 +404,20 @@ void QSGRenderContext::textureFactoryDestroyed(QObject *o)
     m_mutex.unlock();
 }
 
+/*!
+    Return the texture corresponding to a texture factory.
+
+    This may optionally manipulate the texture in some way; for example by returning
+    an atlased texture.
+
+    This function is not a replacement for textureForFactory; both should be used
+    for a single texture (this might atlas, while the other might cache).
+*/
+QSGTexture *QSGRenderContext::compressedTextureForFactory(const QSGCompressedTextureFactory *) const
+{
+    return nullptr;
+}
+
 #include "qsgcontext.moc"
 #include "moc_qsgcontext_p.cpp"