video_core: Use sampler IDs instead pointers in the pipeline config

The previous approach of storing pointers returned by `GetGraphicsSampler`/`GetComputeSampler` caused UB, as these functions can cause reallocation of the sampler slot vector and therefore invalidate the pointers

src/video_core/texture_cache/image_view_base.cpp

@@ -46,7 +46,6 @@ ImageViewBase::ImageViewBase(const ImageInfo& info, const ImageViewInfo& view_in
 ImageViewBase::ImageViewBase(const NullImageViewParams&) : image_id{NULL_IMAGE_ID} {}
 
 bool ImageViewBase::SupportsAnisotropy() const noexcept {
-    using namespace VideoCommon;
     switch (format) {
     case PixelFormat::R8_UNORM:
     case PixelFormat::R8_SNORM:

src/video_core/texture_cache/texture_cache.h

@@ -222,30 +222,50 @@ void TextureCache<P>::CheckFeedbackLoop(std::span<const ImageViewInOut> views) {
 
 template <class P>
 typename P::Sampler* TextureCache<P>::GetGraphicsSampler(u32 index) {
+    return &slot_samplers[GetGraphicsSamplerId(index)];
+}
+
+template <class P>
+typename P::Sampler* TextureCache<P>::GetComputeSampler(u32 index) {
+    return &slot_samplers[GetComputeSamplerId(index)];
+}
+
+template <class P>
+SamplerId TextureCache<P>::GetGraphicsSamplerId(u32 index) {
     if (index > channel_state->graphics_sampler_table.Limit()) {
         LOG_DEBUG(HW_GPU, "Invalid sampler index={}", index);
-        return &slot_samplers[NULL_SAMPLER_ID];
+        return NULL_SAMPLER_ID;
     }
     const auto [descriptor, is_new] = channel_state->graphics_sampler_table.Read(index);
     SamplerId& id = channel_state->graphics_sampler_ids[index];
     if (is_new) {
         id = FindSampler(descriptor);
     }
-    return &slot_samplers[id];
+    return id;
 }
 
 template <class P>
-typename P::Sampler* TextureCache<P>::GetComputeSampler(u32 index) {
+SamplerId TextureCache<P>::GetComputeSamplerId(u32 index) {
     if (index > channel_state->compute_sampler_table.Limit()) {
         LOG_DEBUG(HW_GPU, "Invalid sampler index={}", index);
-        return &slot_samplers[NULL_SAMPLER_ID];
+        return NULL_SAMPLER_ID;
     }
     const auto [descriptor, is_new] = channel_state->compute_sampler_table.Read(index);
     SamplerId& id = channel_state->compute_sampler_ids[index];
     if (is_new) {
         id = FindSampler(descriptor);
     }
-    return &slot_samplers[id];
+    return id;
+}
+
+template <class P>
+const typename P::Sampler& TextureCache<P>::GetSampler(SamplerId id) const noexcept {
+    return slot_samplers[id];
+}
+
+template <class P>
+typename P::Sampler& TextureCache<P>::GetSampler(SamplerId id) noexcept {
+    return slot_samplers[id];
 }
 
 template <class P>

src/video_core/texture_cache/texture_cache_base.h

@@ -159,6 +159,18 @@ public:
     /// Get the sampler from the compute descriptor table in the specified index
     Sampler* GetComputeSampler(u32 index);
 
+    /// Get the sampler id from the graphics descriptor table in the specified index
+    SamplerId GetGraphicsSamplerId(u32 index);
+
+    /// Get the sampler id from the compute descriptor table in the specified index
+    SamplerId GetComputeSamplerId(u32 index);
+
+    /// Return a constant reference to the given sampler id
+    [[nodiscard]] const Sampler& GetSampler(SamplerId id) const noexcept;
+
+    /// Return a reference to the given sampler id
+    [[nodiscard]] Sampler& GetSampler(SamplerId id) noexcept;
+
     /// Refresh the state for graphics image view and sampler descriptors
     void SynchronizeGraphicsDescriptors();