Expose renderpass from QSGRendererInterface

Important for Vulkan and (upcoming) examples like vulkanunderqml.

Change-Id: I5b6c978f38175eca76efe059aa83bb7158724752
Reviewed-by: Andy Nichols <andy.nichols@qt.io>

5 files changed, 30 insertions, 4 deletions

diff --git a/src/quick/scenegraph/coreapi/qsgrendererinterface.cpp b/src/quick/scenegraph/coreapi/qsgrendererinterface.cpp
index e504fe1c62..bc68199e08 100644
--- a/src/quick/scenegraph/coreapi/qsgrendererinterface.cpp
+++ b/src/quick/scenegraph/coreapi/qsgrendererinterface.cpp
@@ -134,6 +134,10 @@ QT_BEGIN_NAMESPACE
 
     \value VulkanInstanceResource The resource is a pointer to the
     QVulkanInstance used by the scenegraph, when applicable.
+
+    \value RenderPassResource The resource is a pointer to the render pass used
+    by the scenegraph, describing the color and depth/stecil attachments and
+    how they are used. For example, a \c{VkRenderPass *}.
  */
 
 /*!
diff --git a/src/quick/scenegraph/coreapi/qsgrendererinterface.h b/src/quick/scenegraph/coreapi/qsgrendererinterface.h
index 3052c81f6c..7aa7d0e769 100644
--- a/src/quick/scenegraph/coreapi/qsgrendererinterface.h
+++ b/src/quick/scenegraph/coreapi/qsgrendererinterface.h
@@ -72,7 +72,8 @@ public:
         OpenGLContextResource,
         DeviceContextResource,
         CommandEncoderResource,
-        VulkanInstanceResource
+        VulkanInstanceResource,
+        RenderPassResource
     };
 
     enum ShaderType {
diff --git a/src/quick/scenegraph/qsgdefaultrendercontext.cpp b/src/quick/scenegraph/qsgdefaultrendercontext.cpp
index b6f35b8580..4ccaa91cce 100644
--- a/src/quick/scenegraph/qsgdefaultrendercontext.cpp
+++ b/src/quick/scenegraph/qsgdefaultrendercontext.cpp
@@ -68,6 +68,7 @@ QSGDefaultRenderContext::QSGDefaultRenderContext(QSGContext *context)
     , m_glAtlasManager(nullptr)
     , m_rhiAtlasManager(nullptr)
     , m_currentFrameCommandBuffer(nullptr)
+    , m_currentFrameRenderPass(nullptr)
 {
 }
 
@@ -239,6 +240,7 @@ void QSGDefaultRenderContext::beginNextRhiFrame(QSGRenderer *renderer, QRhiRende
     renderer->setRenderPassRecordingCallbacks(mainPassRecordingStart, mainPassRecordingEnd, callbackUserData);
 
     m_currentFrameCommandBuffer = cb;
+    m_currentFrameRenderPass = rp;
 }
 
 void QSGDefaultRenderContext::renderNextRhiFrame(QSGRenderer *renderer)
@@ -250,6 +252,7 @@ void QSGDefaultRenderContext::endNextRhiFrame(QSGRenderer *renderer)
 {
     Q_UNUSED(renderer);
     m_currentFrameCommandBuffer = nullptr;
+    m_currentFrameRenderPass = nullptr;
 }
 
 /*!
diff --git a/src/quick/scenegraph/qsgdefaultrendercontext_p.h b/src/quick/scenegraph/qsgdefaultrendercontext_p.h
index 79bc9dd76d..6a3462ae2b 100644
--- a/src/quick/scenegraph/qsgdefaultrendercontext_p.h
+++ b/src/quick/scenegraph/qsgdefaultrendercontext_p.h
@@ -62,6 +62,7 @@ QT_BEGIN_NAMESPACE
 
 class QRhi;
 class QRhiCommandBuffer;
+class QRhiRenderPassDescriptor;
 class QOpenGLContext;
 class QSGMaterialShader;
 class QSGMaterialRhiShader;
@@ -145,6 +146,10 @@ public:
         // may be null if not in an active frame, but returning null is valid then
         return m_currentFrameCommandBuffer;
     }
+    QRhiRenderPassDescriptor *currentFrameRenderPass() const {
+        // may be null if not in an active frame, but returning null is valid then
+        return m_currentFrameRenderPass;
+    }
 
 protected:
     static QString fontKey(const QRawFont &font);
@@ -160,6 +165,7 @@ protected:
     QSGOpenGLAtlasTexture::Manager *m_glAtlasManager;
     QSGRhiAtlasTexture::Manager *m_rhiAtlasManager;
     QRhiCommandBuffer *m_currentFrameCommandBuffer;
+    QRhiRenderPassDescriptor *m_currentFrameRenderPass;
 };
 
 QT_END_NAMESPACE
diff --git a/src/quick/scenegraph/qsgrhisupport.cpp b/src/quick/scenegraph/qsgrhisupport.cpp
index a92b6b0c84..e050938cc9 100644
--- a/src/quick/scenegraph/qsgrhisupport.cpp
+++ b/src/quick/scenegraph/qsgrhisupport.cpp
@@ -279,12 +279,16 @@ QSurface::SurfaceType QSGRhiSupport::windowSurfaceType() const
 }
 
 #if QT_CONFIG(vulkan)
-static const void *qsgrhi_vk_rifResource(QSGRendererInterface::Resource res, const QRhiNativeHandles *nat,
-                                   const QRhiNativeHandles *cbNat)
+static const void *qsgrhi_vk_rifResource(QSGRendererInterface::Resource res,
+                                         const QRhiNativeHandles *nat,
+                                         const QRhiNativeHandles *cbNat,
+                                         const QRhiNativeHandles *rpNat)
 {
     const QRhiVulkanNativeHandles *vknat = static_cast<const QRhiVulkanNativeHandles *>(nat);
     const QRhiVulkanCommandBufferNativeHandles *maybeVkCbNat =
             static_cast<const QRhiVulkanCommandBufferNativeHandles *>(cbNat);
+    const QRhiVulkanRenderPassNativeHandles *maybeVkRpNat =
+            static_cast<const QRhiVulkanRenderPassNativeHandles *>(rpNat);
 
     switch (res) {
     case QSGRendererInterface::DeviceResource:
@@ -298,6 +302,11 @@ static const void *qsgrhi_vk_rifResource(QSGRendererInterface::Resource res, con
             return nullptr;
     case QSGRendererInterface::PhysicalDeviceResource:
         return &vknat->physDev;
+    case QSGRendererInterface::RenderPassResource:
+        if (maybeVkRpNat)
+            return &maybeVkRpNat->renderPass;
+        else
+            return nullptr;
     default:
         return nullptr;
     }
@@ -376,7 +385,10 @@ const void *QSGRhiSupport::rifResource(QSGRendererInterface::Resource res, const
     case QRhi::Vulkan:
     {
         QRhiCommandBuffer *cb = rc->currentFrameCommandBuffer();
-        return qsgrhi_vk_rifResource(res, nat, cb ? cb->nativeHandles() : nullptr);
+        QRhiRenderPassDescriptor *rp = rc->currentFrameRenderPass();
+        return qsgrhi_vk_rifResource(res, nat,
+                                     cb ? cb->nativeHandles() : nullptr,
+                                     rp ? rp->nativeHandles() : nullptr);
     }
 #endif
 #if QT_CONFIG(opengl)