vulkan: Use view of null buffer for texel buffers if nullDescriptor not supported. (#1231)

src/video_core/buffer_cache/buffer_cache.cpp

@@ -36,6 +36,17 @@ BufferCache::BufferCache(const Vulkan::Instance& instance_, Vulkan::Scheduler& s
     ASSERT(null_id.index == 0);
     const vk::Buffer& null_buffer = slot_buffers[null_id].buffer;
     Vulkan::SetObjectName(instance.GetDevice(), null_buffer, "Null Buffer");
+
+    const vk::BufferViewCreateInfo null_view_ci = {
+        .buffer = null_buffer,
+        .format = vk::Format::eR8Unorm,
+        .offset = 0,
+        .range = VK_WHOLE_SIZE,
+    };
+    const auto [null_view_result, null_view] = instance.GetDevice().createBufferView(null_view_ci);
+    ASSERT_MSG(null_view_result == vk::Result::eSuccess, "Failed to create null buffer view.");
+    null_buffer_view = null_view;
+    Vulkan::SetObjectName(instance.GetDevice(), null_buffer_view, "Null Buffer View");
 }
 
 BufferCache::~BufferCache() = default;

src/video_core/buffer_cache/buffer_cache.h

@@ -67,6 +67,10 @@ public:
         return slot_buffers[id];
     }
 
+    [[nodiscard]] vk::BufferView& NullBufferView() {
+        return null_buffer_view;
+    }
+
     /// Invalidates any buffer in the logical page range.
     void InvalidateMemory(VAddr device_addr, u64 size);
 
@@ -146,6 +150,7 @@ private:
     Buffer gds_buffer;
     std::mutex mutex;
     Common::SlotVector<Buffer> slot_buffers;
+    vk::BufferView null_buffer_view;
     MemoryTracker memory_tracker;
     PageTable page_table;
 };