rhi: gl: Avoid a copy in partial texture uploads

Pick-to: 6.7 6.6 6.5
Task-number: QTBUG-120565
Change-Id: I7f1f8c42b98c5743708c4ff80e401070d8ab24ac
Reviewed-by: Andy Nichols <andy.nichols@qt.io>

1 files changed, 9 insertions, 1 deletions

diff --git a/src/gui/rhi/qrhigles2.cpp b/src/gui/rhi/qrhigles2.cpp
index f54371da66..dcaa87a5ff 100644
--- a/src/gui/rhi/qrhigles2.cpp
+++ b/src/gui/rhi/qrhigles2.cpp
@@ -2377,7 +2377,15 @@ void QRhiGles2::enqueueSubresUpload(QGles2Texture *texD, QGles2CommandBuffer *cb
             const QPoint sp = subresDesc.sourceTopLeft();
             if (!subresDesc.sourceSize().isEmpty())
                 size = subresDesc.sourceSize();
-            img = img.copy(sp.x(), sp.y(), size.width(), size.height());
+
+            if (caps.unpackRowLength) {
+                cbD->retainImage(img);
+                // create a non-owning wrapper for the subimage
+                const uchar *data = img.constBits() + sp.y() * img.bytesPerLine() + sp.x() * (qMax(1, img.depth() / 8));
+                img = QImage(data, size.width(), size.height(), img.bytesPerLine(), img.format());
+            } else {
+                img = img.copy(sp.x(), sp.y(), size.width(), size.height());
+            }
         }
 
         setCmdByNotCompressedData(cbD->retainImage(img), size, img.bytesPerLine());