Destroy FBOs when RenderTarget node is destroyed

It appears we never destroyed FBOs which lead to bugs
when destroying and recreating a RenderTarget

Change-Id: I507b045d9b9e1088ff49f719c8846cc43c4fc8f2
Reviewed-by: Mike Krus <mike.krus@kdab.com>

3 files changed, 16 insertions, 0 deletions

diff --git a/src/plugins/renderers/opengl/graphicshelpers/submissioncontext.cpp b/src/plugins/renderers/opengl/graphicshelpers/submissioncontext.cpp
index e4b223185..c8d459b01 100644
--- a/src/plugins/renderers/opengl/graphicshelpers/submissioncontext.cpp
+++ b/src/plugins/renderers/opengl/graphicshelpers/submissioncontext.cpp
@@ -500,6 +500,14 @@ void SubmissionContext::activateRenderTarget(Qt3DCore::QNodeId renderTargetNodeI
     activateDrawBuffers(attachments);
 }
 
+void SubmissionContext::releaseRenderTarget(const Qt3DCore::QNodeId id)
+{
+    if (m_renderTargets.contains(id)) {
+        const GLuint fboId = m_renderTargets.take(id);
+        m_glHelper->releaseFrameBufferObject(fboId);
+    }
+}
+
 GLuint SubmissionContext::createRenderTarget(Qt3DCore::QNodeId renderTargetNodeId, const AttachmentPack &attachments)
 {
     const GLuint fboId = m_glHelper->createFrameBufferObject();
diff --git a/src/plugins/renderers/opengl/graphicshelpers/submissioncontext_p.h b/src/plugins/renderers/opengl/graphicshelpers/submissioncontext_p.h
index b663e47ec..5e3a0c04b 100644
--- a/src/plugins/renderers/opengl/graphicshelpers/submissioncontext_p.h
+++ b/src/plugins/renderers/opengl/graphicshelpers/submissioncontext_p.h
@@ -113,6 +113,7 @@ public:
     // FBO
     GLuint activeFBO() const { return m_activeFBO; }
     void activateRenderTarget(const Qt3DCore::QNodeId id, const AttachmentPack &attachments, GLuint defaultFboId);
+    void releaseRenderTarget(const Qt3DCore::QNodeId id);
     QSize renderTargetSize(const QSize &surfaceSize) const;
     QImage readFramebuffer(const QRect &rect);
     void blitFramebuffer(Qt3DCore::QNodeId outputRenderTargetId, Qt3DCore::QNodeId inputRenderTargetId,
diff --git a/src/plugins/renderers/opengl/renderer/renderer.cpp b/src/plugins/renderers/opengl/renderer/renderer.cpp
index af43a4fe5..79eca16fa 100644
--- a/src/plugins/renderers/opengl/renderer/renderer.cpp
+++ b/src/plugins/renderers/opengl/renderer/renderer.cpp
@@ -1434,6 +1434,13 @@ void Renderer::updateGLResources()
 
     // Record list of buffer that might need uploading
     lookForDownloadableBuffers();
+
+    // Remove destroyed FBOs
+    {
+        const QNodeIdVector destroyedRenderTargetIds = m_nodesManager->renderTargetManager()->takeRenderTargetIdsToCleanup();
+        for (const Qt3DCore::QNodeId &renderTargetId : destroyedRenderTargetIds)
+            m_submissionContext->releaseRenderTarget(renderTargetId);
+    }
 }
 
 // Render Thread