[dxvk] Only merge clears when framebuffer size matches view size

Otherwise, we'll only clear a smaller portion of the view, which is
incorrect. Fixes a rendering issue in Fallout New Vegas with DXUP.

src/dxvk/dxvk_context.cpp

@@ -532,11 +532,12 @@ namespace dxvk {
     }
     
     // Check whether the render target view is an attachment
-    // of the current framebuffer. If not, we need to create
-    // a temporary framebuffer.
+    // of the current framebuffer and is included entirely.
+    // If not, we need to create a temporary framebuffer.
     int32_t attachmentIndex = -1;
     
-    if (m_state.om.framebuffer != nullptr)
+    if (m_state.om.framebuffer != nullptr
+     && m_state.om.framebuffer->isFullSize(imageView))
       attachmentIndex = m_state.om.framebuffer->findAttachment(imageView);
     
     if (attachmentIndex < 0) {

src/dxvk/dxvk_framebuffer.cpp

@@ -71,6 +71,13 @@ namespace dxvk {
   }
   
   
+  bool DxvkFramebuffer::isFullSize(const Rc<DxvkImageView>& view) const {
+    return m_renderSize.width  == view->mipLevelExtent(0).width
+        && m_renderSize.height == view->mipLevelExtent(0).height
+        && m_renderSize.layers == view->info().numLayers;
+  }
+
+
   DxvkRenderPassFormat DxvkFramebuffer::getRenderPassFormat(const DxvkRenderTargets& renderTargets) {
     DxvkRenderPassFormat format;
     

src/dxvk/dxvk_framebuffer.h

@@ -176,8 +176,19 @@ namespace dxvk {
      * \returns \c true if the render targets are the same
      *          as the ones used for this framebuffer object.
      */
-    bool hasTargets(
-      const DxvkRenderTargets&  renderTargets);
+    bool hasTargets(const DxvkRenderTargets& renderTargets);
+    
+    /**
+     * \brief Checks whether view and framebuffer sizes match
+     *
+     * Tests whether the size of the framebuffer is the same
+     * as the size of one of its views. This may be \c false
+     * when mixing attachments with mismatched dimensions.
+     * \param [in] view Image view to test
+     * \returns \c true if \c view has the same size as
+     *          the framebuffer.
+     */
+    bool isFullSize(const Rc<DxvkImageView>& view) const;
     
     /**
      * \brief Generatess render pass format