rhi: Add a way to tell an srb that only the resources have changed

Until now, after updating the bindings one had to always rebuild the
srb, which can be heavy esp. on Vulkan (release old objects, create
new layout object, descriptor sets). When updating the binding list in
a way that it is fully isLayoutCompatible() == true with the previous
list, this is an overkill. Internally, most notably in
setShaderResources(), we already should have everything in place in
all backends to recognize if the entries in the binding list refer to
QRhiBuffer/Texture/Sampler objects that are different than before, and
so apart from adding an alternative to create() in the API there is
not much else needed here.

Pick-to: 6.2
Change-Id: I2efdd4fd0b24c7ebba694a975ed83509744b044b
Reviewed-by: Andy Nichols <andy.nichols@qt.io>

1 files changed, 15 insertions, 0 deletions

diff --git a/src/gui/rhi/qrhid3d11.cpp b/src/gui/rhi/qrhid3d11.cpp
index bdbb6f538b..b2bc631569 100644
--- a/src/gui/rhi/qrhid3d11.cpp
+++ b/src/gui/rhi/qrhid3d11.cpp
@@ -3622,6 +3622,21 @@ bool QD3D11ShaderResourceBindings::create()
     return true;
 }
 
+void QD3D11ShaderResourceBindings::updateResources(UpdateFlags flags)
+{
+    sortedBindings.clear();
+    std::copy(m_bindings.cbegin(), m_bindings.cend(), std::back_inserter(sortedBindings));
+    if (!flags.testFlag(BindingsAreSorted)) {
+        std::sort(sortedBindings.begin(), sortedBindings.end(),
+                  [](const QRhiShaderResourceBinding &a, const QRhiShaderResourceBinding &b)
+        {
+            return a.data()->binding < b.data()->binding;
+        });
+    }
+
+    generation += 1;
+}
+
 QD3D11GraphicsPipeline::QD3D11GraphicsPipeline(QRhiImplementation *rhi)
     : QRhiGraphicsPipeline(rhi)
 {