Do not delay cleanup of backend Texture instances

If we delay the cleanup of backend Texture instances, in the case of a texture
being reparented from an existing node with backend to a node with no
backend, the resulting node destroyed, node created changes delivered in the
same loop would result in the Texture still being marked for destruction and
eventually being destroyed even though it was recreated.

This patch now still marks textures that were destroyed (by storing their
ids), so that the GL Texture managers can update the resources
accordingly. However, we now cleanup Textures immediately. We also remove
textures ids marked for destruction in the GL texture managers if we detect a
Texture with the same id is readded.

Change-Id: I29092d7dff9f70bb9fb4b15f4e9419ee1791b6e2
Task-number: QTBUG-69379
Reviewed-by: Mike Krus <mike.krus@kdab.com>
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

1 files changed, 5 insertions, 8 deletions

diff --git a/src/render/renderers/opengl/renderer/renderer.cpp b/src/render/renderers/opengl/renderer/renderer.cpp
index f04b864a3..27d46cc81 100644
--- a/src/render/renderers/opengl/renderer/renderer.cpp
+++ b/src/render/renderers/opengl/renderer/renderer.cpp
@@ -1191,16 +1191,13 @@ void Renderer::updateGLResources()
                 glTexture->getOrCreateGLTexture();
         }
     }
-    // When Textures are cleaned up, their id is saved
-    // so that they can be cleaned up in the render thread
-    // Note: we perform this step in second so that the previous updateTexture call
-    // has a chance to find a shared texture
+    // When Textures are cleaned up, their id is saved so that they can be
+    // cleaned up in the render thread Note: we perform this step in second so
+    // that the previous updateTexture call has a chance to find a shared
+    // texture and avoid possible destroying recreating a new texture
     const QVector<Qt3DCore::QNodeId> cleanedUpTextureIds = m_nodesManager->textureManager()->takeTexturesIdsToCleanup();
-    for (const Qt3DCore::QNodeId textureCleanedUpId: cleanedUpTextureIds) {
+    for (const Qt3DCore::QNodeId textureCleanedUpId: cleanedUpTextureIds)
         cleanupTexture(m_nodesManager->textureManager()->lookupResource(textureCleanedUpId));
-        // We can really release the texture at this point
-        m_nodesManager->textureManager()->releaseResource(textureCleanedUpId);
-    }
 }
 
 // Render Thread