4 files changed, 75 insertions, 14 deletions

diff --git a/src/quick/scenegraph/qsgdefaultrendercontext.cpp b/src/quick/scenegraph/qsgdefaultrendercontext.cpp
index 1b0753e9ae..6b0a8d6556 100644
--- a/src/quick/scenegraph/qsgdefaultrendercontext.cpp
+++ b/src/quick/scenegraph/qsgdefaultrendercontext.cpp
@@ -101,6 +101,14 @@ void QSGDefaultRenderContext::invalidate()
     qDeleteAll(m_textures);
     m_textures.clear();
 
+    for (auto it = m_depthStencilBuffers.cbegin(), end = m_depthStencilBuffers.cend(); it != end; ++it) {
+        QSharedPointer<QSGDepthStencilBuffer> buf = it.value().toStrongRef();
+        delete buf->ds;
+        buf->ds = nullptr;
+        buf->rc = nullptr;
+    }
+    m_depthStencilBuffers.clear();
+
     /* The cleanup of the atlas textures is a bit intriguing.
        As part of the cleanup in the threaded render loop, we
        do:
@@ -296,6 +304,44 @@ void QSGDefaultRenderContext::resetGlyphCacheResources()
     m_pendingGlyphCacheTextures.clear();
 }
 
+QSGDepthStencilBuffer::~QSGDepthStencilBuffer()
+{
+    if (rc && ds) {
+        const auto key = std::pair(ds->pixelSize(), ds->sampleCount());
+        rc->m_depthStencilBuffers.remove(key);
+    }
+    delete ds;
+}
+
+QSharedPointer<QSGDepthStencilBuffer> QSGDefaultRenderContext::getDepthStencilBuffer(const QSize &size, int sampleCount)
+{
+    const auto key = std::pair(size, sampleCount);
+    auto it = m_depthStencilBuffers.constFind(key);
+    if (it != m_depthStencilBuffers.cend()) {
+        if (it.value())
+            return it.value().toStrongRef();
+    }
+
+    QRhiRenderBuffer *ds = m_rhi->newRenderBuffer(QRhiRenderBuffer::DepthStencil, size, sampleCount);
+    if (!ds->create()) {
+        qWarning("Failed to build depth-stencil buffer for layer");
+        delete ds;
+        return {};
+    }
+    QSharedPointer<QSGDepthStencilBuffer> buf(new QSGDepthStencilBuffer(ds));
+    addDepthStencilBuffer(buf);
+    return buf;
+}
+
+void QSGDefaultRenderContext::addDepthStencilBuffer(const QSharedPointer<QSGDepthStencilBuffer> &ds)
+{
+    if (ds) {
+        const auto key = std::pair(ds->ds->pixelSize(), ds->ds->sampleCount());
+        ds->rc = this;
+        m_depthStencilBuffers.insert(key, ds.toWeakRef());
+    }
+}
+
 QT_END_NAMESPACE
 
 #include "moc_qsgdefaultrendercontext_p.cpp"
diff --git a/src/quick/scenegraph/qsgdefaultrendercontext_p.h b/src/quick/scenegraph/qsgdefaultrendercontext_p.h
index c3352aa89f..be3d1c1312 100644
--- a/src/quick/scenegraph/qsgdefaultrendercontext_p.h
+++ b/src/quick/scenegraph/qsgdefaultrendercontext_p.h
@@ -25,13 +25,25 @@ class QRhiCommandBuffer;
 class QRhiRenderPassDescriptor;
 class QRhiResourceUpdateBatch;
 class QRhiTexture;
+class QRhiRenderBuffer;
 class QSGMaterialShader;
 class QSurface;
+class QSGDefaultRenderContext;
 
 namespace QSGRhiAtlasTexture {
     class Manager;
 }
 
+class QSGDepthStencilBuffer
+{
+public:
+    QSGDepthStencilBuffer() { }
+    QSGDepthStencilBuffer(QRhiRenderBuffer *ds) : ds(ds) { }
+    ~QSGDepthStencilBuffer();
+    QRhiRenderBuffer *ds = nullptr;
+    QSGDefaultRenderContext *rc = nullptr;
+};
+
 class Q_QUICK_EXPORT QSGDefaultRenderContext : public QSGRenderContext
 {
     Q_OBJECT
@@ -107,6 +119,9 @@ public:
     void deferredReleaseGlyphCacheTexture(QRhiTexture *texture);
     void resetGlyphCacheResources();
 
+    QSharedPointer<QSGDepthStencilBuffer> getDepthStencilBuffer(const QSize &size, int sampleCount);
+    void addDepthStencilBuffer(const QSharedPointer<QSGDepthStencilBuffer> &ds);
+
 protected:
     InitParams m_initParams;
     QRhi *m_rhi;
@@ -119,6 +134,9 @@ protected:
     QRhiResourceUpdateBatch *m_glyphCacheResourceUpdates;
     QSet<QRhiTexture *> m_pendingGlyphCacheTextures;
     QHash<FontKey, QSGCurveGlyphAtlas *> m_curveGlyphAtlases;
+    QHash<std::pair<QSize, int>, QWeakPointer<QSGDepthStencilBuffer>> m_depthStencilBuffers;
+
+    friend class QSGDepthStencilBuffer;
 };
 
 QT_END_NAMESPACE
diff --git a/src/quick/scenegraph/qsgrhilayer.cpp b/src/quick/scenegraph/qsgrhilayer.cpp
index 3ce7e5e81a..e802805d0d 100644
--- a/src/quick/scenegraph/qsgrhilayer.cpp
+++ b/src/quick/scenegraph/qsgrhilayer.cpp
@@ -5,7 +5,6 @@
 
 #include <private/qqmlglobal_p.h>
 #include <private/qsgrenderer_p.h>
-#include <private/qsgdefaultrendercontext_p.h>
 
 QSGRhiLayer::QSGRhiLayer(QSGRenderContext *context)
     : QSGLayer(*(new QSGTexturePrivate(this)))
@@ -210,8 +209,7 @@ void QSGRhiLayer::releaseResources()
     delete m_rtRp;
     m_rtRp = nullptr;
 
-    delete m_ds;
-    m_ds = nullptr;
+    m_ds.clear();
 
     delete m_msaaColorBuffer;
     m_msaaColorBuffer = nullptr;
@@ -278,9 +276,8 @@ void QSGRhiLayer::grab()
                 return;
             }
             if (depthBufferEnabled) {
-                m_ds = m_rhi->newRenderBuffer(QRhiRenderBuffer::DepthStencil, m_pixelSize, effectiveSamples);
-                if (!m_ds->create()) {
-                    qWarning("Failed to build depth-stencil buffer for layer");
+                m_ds = m_context->getDepthStencilBuffer(m_pixelSize, effectiveSamples);
+                if (!m_ds) {
                     releaseResources();
                     return;
                 }
@@ -290,7 +287,7 @@ void QSGRhiLayer::grab()
             color0.setResolveTexture(m_texture);
             desc.setColorAttachments({ color0 });
             if (depthBufferEnabled)
-                desc.setDepthStencilBuffer(m_ds);
+                desc.setDepthStencilBuffer(m_ds->ds);
             m_rt = m_rhi->newTextureRenderTarget(desc);
             m_rtRp = m_rt->newCompatibleRenderPassDescriptor();
             if (!m_rtRp) {
@@ -313,9 +310,8 @@ void QSGRhiLayer::grab()
                 return;
             }
             if (depthBufferEnabled) {
-                m_ds = m_rhi->newRenderBuffer(QRhiRenderBuffer::DepthStencil, m_pixelSize);
-                if (!m_ds->create()) {
-                    qWarning("Failed to build depth-stencil buffer for layer");
+                m_ds = m_context->getDepthStencilBuffer(m_pixelSize, 1);
+                if (!m_ds) {
                     releaseResources();
                     return;
                 }
@@ -332,10 +328,10 @@ void QSGRhiLayer::grab()
                 }
                 color0.setTexture(m_secondaryTexture);
             }
+            QRhiTextureRenderTargetDescription desc({ color0 });
             if (depthBufferEnabled)
-                m_rt = m_rhi->newTextureRenderTarget({ color0, m_ds });
-            else
-                m_rt = m_rhi->newTextureRenderTarget({ color0 });
+                desc.setDepthStencilBuffer(m_ds->ds);
+            m_rt = m_rhi->newTextureRenderTarget(desc);
             m_rtRp = m_rt->newCompatibleRenderPassDescriptor();
             if (!m_rtRp) {
                 qWarning("Failed to build render pass descriptor for layer");
diff --git a/src/quick/scenegraph/qsgrhilayer_p.h b/src/quick/scenegraph/qsgrhilayer_p.h
index 922192ec5e..d6d9165123 100644
--- a/src/quick/scenegraph/qsgrhilayer_p.h
+++ b/src/quick/scenegraph/qsgrhilayer_p.h
@@ -17,6 +17,7 @@
 #include <private/qsgadaptationlayer_p.h>
 #include <private/qsgcontext_p.h>
 #include <private/qsgtexture_p.h>
+#include <private/qsgdefaultrendercontext_p.h>
 #include <rhi/qrhi.h>
 
 QT_BEGIN_NAMESPACE
@@ -73,7 +74,7 @@ private:
 
     QSGRenderer *m_renderer = nullptr;
     QRhiTexture *m_texture = nullptr;
-    QRhiRenderBuffer *m_ds = nullptr;
+    QSharedPointer<QSGDepthStencilBuffer> m_ds;
     QRhiRenderBuffer *m_msaaColorBuffer = nullptr;
     QRhiTexture *m_secondaryTexture = nullptr;
     QRhiTextureRenderTarget *m_rt = nullptr;