Avoid redundant VkImageView recreation

There are a lot of cases of `VkImageView` being recreated arbitrarily due to it being tied to the ephemeral object `TextureView` rather than `Texture`, this commit flips that by storing all `VkImageView`s inside `Texture` with `TextureView` simply holding a copy of the handle to them. Additionally, this change results in stable `VkImageView` handles and helps in paving the path for framebuffer caching when `VK_KHR_imageless_framebuffer` is unavailable.

app/src/main/cpp/skyline/gpu/texture/texture.cpp

@@ -24,10 +24,16 @@ namespace skyline::gpu {
 
     TextureView::TextureView(std::shared_ptr<Texture> texture, vk::ImageViewType type, vk::ImageSubresourceRange range, texture::Format format, vk::ComponentMapping mapping) : texture(std::move(texture)), type(type), format(format), mapping(mapping), range(range) {}
 
-    vk::ImageView TextureView::GetView() {
+    Texture::TextureViewStorage::TextureViewStorage(vk::ImageViewType type, texture::Format format, vk::ComponentMapping mapping, vk::ImageSubresourceRange range, vk::raii::ImageView &&vkView) : type(type), format(format), mapping(mapping), range(range), vkView(std::move(vkView)) {}
-        if (view)
-            return **view;
 
+    vk::ImageView TextureView::GetView() {
+        if (vkView)
+            return vkView;
+
+        auto it{std::find_if(texture->views.begin(), texture->views.end(), [this](const Texture::TextureViewStorage &view) {
+            return view.type == type && view.format == format && view.mapping == mapping && view.range == range;
+        })};
+        if (it == texture->views.end()) {
             vk::ImageViewCreateInfo createInfo{
                 .image = texture->GetBacking(),
                 .viewType = type,
@@ -36,7 +42,10 @@ namespace skyline::gpu {
                 .subresourceRange = range,
             };
 
-        return *view.emplace(texture->gpu.vkDevice, createInfo);
+            it = texture->views.emplace(texture->views.end(), type, format, mapping, range, vk::raii::ImageView{texture->gpu.vkDevice, createInfo});
+        }
+
+        return vkView = *it->vkView;
     }
 
     void TextureView::lock() {
@@ -530,22 +539,10 @@ namespace skyline::gpu {
         if (!pFormat)
             pFormat = format;
 
-        for (auto viewIt{views.begin()}; viewIt != views.end();) {
-            auto view{viewIt->lock()};
-            if (view && type == view->type && pFormat == view->format && range == view->range && mapping == view->mapping)
-                return view;
-            else if (!view)
-                viewIt = views.erase(viewIt);
-            else
-                ++viewIt;
-        }
-
         if (gpu.traits.quirks.vkImageMutableFormatCostly && pFormat->vkFormat != format->vkFormat)
             Logger::Warn("Creating a view of a texture with a different format without mutable format: {} - {}", vk::to_string(pFormat->vkFormat), vk::to_string(format->vkFormat));
 
-        auto view{std::make_shared<TextureView>(shared_from_this(), type, range, pFormat, mapping)};
+        return std::make_shared<TextureView>(shared_from_this(), type, range, pFormat, mapping);
-        views.push_back(view);
-        return view;
     }
 
     void Texture::CopyFrom(std::shared_ptr<Texture> source, const vk::ImageSubresourceRange &subresource) {

app/src/main/cpp/skyline/gpu/texture/texture.h

@@ -284,7 +284,7 @@ namespace skyline::gpu {
      */
     class TextureView : public FenceCycleDependency, public std::enable_shared_from_this<TextureView> {
       private:
-        std::optional<vk::raii::ImageView> view;
+        vk::ImageView vkView{};
 
       public:
         std::shared_ptr<Texture> texture;
@@ -348,7 +348,20 @@ namespace skyline::gpu {
             GpuDirty, //!< The GPU texture has been modified but the CPU mappings have not been updated
         } dirtyState{DirtyState::CpuDirty}; //!< The state of the CPU mappings with respect to the GPU texture
 
-        std::vector<std::weak_ptr<TextureView>> views; //!< TextureView(s) that are backed by this Texture, used for repointing to a new Texture on deletion
+        /**
+         * @brief Storage for all metadata about a specific view into the buffer, used to prevent redundant view creation and duplication of VkBufferView(s)
+         */
+        struct TextureViewStorage {
+            vk::ImageViewType type;
+            texture::Format format;
+            vk::ComponentMapping mapping;
+            vk::ImageSubresourceRange range;
+            vk::raii::ImageView vkView;
+
+            TextureViewStorage(vk::ImageViewType type, texture::Format format, vk::ComponentMapping mapping, vk::ImageSubresourceRange range, vk::raii::ImageView&& vkView);
+        };
+
+        std::vector<TextureViewStorage> views;
 
         friend TextureManager;
         friend TextureView;