rhi: Make the serialized srb layout description accessible

...by the Qt Quick renderer, for example.

A typical Qt Quick material binding set serializes to 8 uints. This
would not demand a container like QVector. However, being implicitly
shared is essential here due to the intended usage (query the
serialized blob, put it into a cache key, hash it, compare it, all
without any copying and new allocs; we can afford an extra alloc
upon each srb construction, but don't want more afterwards in the
rendering engines)

Also make it clear in the pipeline docs that the optimization Qt Quick
is (soon going to be) doing is legal. (the srb ref in the pipeline can
be dead and dangling as long as every call to setShaderResources()
specifies a layout-compatible alternative)

Change-Id: I97efbea1fa3516b10c9832adbab0a21b7bc0845d
Reviewed-by: Andy Nichols <andy.nichols@qt.io>
(cherry picked from commit b6b0c33058ba7f43661e316d9f27d4102f6a988f)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 16 insertions, 0 deletions

diff --git a/tests/auto/gui/rhi/qrhi/tst_qrhi.cpp b/tests/auto/gui/rhi/qrhi/tst_qrhi.cpp
index be825c8ac2..61e19434e0 100644
--- a/tests/auto/gui/rhi/qrhi/tst_qrhi.cpp
+++ b/tests/auto/gui/rhi/qrhi/tst_qrhi.cpp
@@ -3271,6 +3271,8 @@ void tst_QRhi::srbLayoutCompatibility()
 
         QVERIFY(srb1->isLayoutCompatible(srb2.data()));
         QVERIFY(srb2->isLayoutCompatible(srb1.data()));
+
+        QCOMPARE(srb1->serializedLayoutDescription(), srb2->serializedLayoutDescription());
     }
 
     // different count (not compatible)
@@ -3286,6 +3288,8 @@ void tst_QRhi::srbLayoutCompatibility()
 
         QVERIFY(!srb1->isLayoutCompatible(srb2.data()));
         QVERIFY(!srb2->isLayoutCompatible(srb1.data()));
+
+        QVERIFY(srb1->serializedLayoutDescription() != srb2->serializedLayoutDescription());
     }
 
     // full match (compatible)
@@ -3306,6 +3310,10 @@ void tst_QRhi::srbLayoutCompatibility()
 
         QVERIFY(srb1->isLayoutCompatible(srb2.data()));
         QVERIFY(srb2->isLayoutCompatible(srb1.data()));
+
+        QVERIFY(!srb1->serializedLayoutDescription().isEmpty());
+        QVERIFY(!srb2->serializedLayoutDescription().isEmpty());
+        QCOMPARE(srb1->serializedLayoutDescription(), srb2->serializedLayoutDescription());
     }
 
     // different visibility (not compatible)
@@ -3324,6 +3332,8 @@ void tst_QRhi::srbLayoutCompatibility()
 
         QVERIFY(!srb1->isLayoutCompatible(srb2.data()));
         QVERIFY(!srb2->isLayoutCompatible(srb1.data()));
+
+        QVERIFY(srb1->serializedLayoutDescription() != srb2->serializedLayoutDescription());
     }
 
     // different binding points (not compatible)
@@ -3342,6 +3352,8 @@ void tst_QRhi::srbLayoutCompatibility()
 
         QVERIFY(!srb1->isLayoutCompatible(srb2.data()));
         QVERIFY(!srb2->isLayoutCompatible(srb1.data()));
+
+        QVERIFY(srb1->serializedLayoutDescription() != srb2->serializedLayoutDescription());
     }
 
     // different buffer region offset and size (compatible)
@@ -3362,6 +3374,8 @@ void tst_QRhi::srbLayoutCompatibility()
 
         QVERIFY(srb1->isLayoutCompatible(srb2.data()));
         QVERIFY(srb2->isLayoutCompatible(srb1.data()));
+
+        QCOMPARE(srb1->serializedLayoutDescription(), srb2->serializedLayoutDescription());
     }
 
     // different resources (compatible)
@@ -3382,6 +3396,8 @@ void tst_QRhi::srbLayoutCompatibility()
 
         QVERIFY(srb1->isLayoutCompatible(srb2.data()));
         QVERIFY(srb2->isLayoutCompatible(srb1.data()));
+
+        QCOMPARE(srb1->serializedLayoutDescription(), srb2->serializedLayoutDescription());
     }
 }