rhi: Improve srb layout serialization helpers

Be idiomatic and return the output iterator one past the last element.
Otherwise passing in a plain pointer (as exercised by the autotest now)
fails to function because we write over the same 4 elements again and
again for each binding.

Pick-to: 6.2
Change-Id: If74463fa5140ffa2b1d5be97b71868848ad46614
Reviewed-by: Andy Nichols <andy.nichols@qt.io>

1 files changed, 3 insertions, 2 deletions

diff --git a/src/gui/rhi/qrhi_p.h b/src/gui/rhi/qrhi_p.h
index 81b00cd07f..527d72e486 100644
--- a/src/gui/rhi/qrhi_p.h
+++ b/src/gui/rhi/qrhi_p.h
@@ -413,13 +413,14 @@ public:
         } u;
 
         template<typename Output>
-        void serialize(Output dst) const
+        Output serialize(Output dst) const
         {
             // must write out exactly LAYOUT_DESC_ENTRIES_PER_BINDING elements here
             *dst++ = quint32(binding);
             *dst++ = quint32(stage);
             *dst++ = quint32(type);
             *dst++ = quint32(type == QRhiShaderResourceBinding::SampledTexture ? u.stex.count : 1);
+            return dst;
         }
     };
 
@@ -434,7 +435,7 @@ public:
                                            Output dst)
     {
         while (first != last) {
-            first->data()->serialize(dst);
+            dst = first->data()->serialize(dst);
             ++first;
         }
     }