ResourceAccessor: allow read-only access to textures

Change-Id: I0a8d20081912f3ff9a037cab74702581b3b02613
Reviewed-by: Christian Stromme <christian.stromme@qt.io>

3 files changed, 14 insertions, 5 deletions

diff --git a/src/quick3d/quick3dscene2d/items/scene2d.cpp b/src/quick3d/quick3dscene2d/items/scene2d.cpp
index c29f741ae..b5c25431f 100644
--- a/src/quick3d/quick3dscene2d/items/scene2d.cpp
+++ b/src/quick3d/quick3dscene2d/items/scene2d.cpp
@@ -336,7 +336,7 @@ void Scene2D::render()
 
         if (resourceAccessor()->accessResource(RenderBackendResourceAccessor::OutputAttachment,
                                                m_outputId, (void**)&attachmentData, nullptr)) {
-            if (!resourceAccessor()->accessResource(RenderBackendResourceAccessor::OGLTexture,
+            if (!resourceAccessor()->accessResource(RenderBackendResourceAccessor::OGLTextureWrite,
                                                     attachmentData->m_textureUuid,
                                                        (void**)&texture, &textureLock)) {
                 // Need to call sync even if the texture is not in use
diff --git a/src/render/backend/resourceaccessor.cpp b/src/render/backend/resourceaccessor.cpp
index e69907f3f..c6496976a 100644
--- a/src/render/backend/resourceaccessor.cpp
+++ b/src/render/backend/resourceaccessor.cpp
@@ -73,7 +73,10 @@ bool ResourceAccessor::accessResource(ResourceType type, Qt3DCore::QNodeId nodeI
 {
     switch (type) {
 
-    case RenderBackendResourceAccessor::OGLTexture: {
+    case RenderBackendResourceAccessor::OGLTextureWrite:
+        Q_FALLTHROUGH();
+    case RenderBackendResourceAccessor::OGLTextureRead:
+    {
         Texture *tex = m_textureManager->lookupResource(nodeId);
         if (!tex)
             return false;
@@ -85,10 +88,15 @@ bool ResourceAccessor::accessResource(ResourceType type, Qt3DCore::QNodeId nodeI
         if (glTex->isDirty())
             return false;
 
-        glTex->setExternalRenderingEnabled(true);
+        if (type == RenderBackendResourceAccessor::OGLTextureWrite)
+            glTex->setExternalRenderingEnabled(true);
+
         QOpenGLTexture **glTextureHandle = reinterpret_cast<QOpenGLTexture **>(handle);
         *glTextureHandle = glTex->getGLTexture();
-        *lock = glTex->externalRenderingLock();
+
+        if (type == RenderBackendResourceAccessor::OGLTextureWrite)
+            *lock = glTex->externalRenderingLock();
+
         return true;
     }
 
diff --git a/src/render/backend/resourceaccessor_p.h b/src/render/backend/resourceaccessor_p.h
index 10e4abaa9..627efcb0d 100644
--- a/src/render/backend/resourceaccessor_p.h
+++ b/src/render/backend/resourceaccessor_p.h
@@ -73,7 +73,8 @@ class RenderBackendResourceAccessor
 {
 public:
     enum ResourceType {
-        OGLTexture,
+        OGLTextureWrite,
+        OGLTextureRead,
         OutputAttachment,
         EntityHandle,
     };