DRWWrapper: Add StorageFlexibleBuffer

This buffer resizes on access.

1 files changed, 35 insertions, 0 deletions

diff --git a/source/blender/draw/intern/DRW_gpu_wrapper.hh b/source/blender/draw/intern/DRW_gpu_wrapper.hh
index d6ee50ff5aa..366dd40c220 100644
--- a/source/blender/draw/intern/DRW_gpu_wrapper.hh
+++ b/source/blender/draw/intern/DRW_gpu_wrapper.hh
@@ -31,6 +31,9 @@
  *   discarding all data inside it.
  *   Data can be accessed using the [] operator.
  *
+ * `draw::StorageFlexibleBuffer<T>`
+ *   Same as StorageArrayBuffer but will auto resize on access when using the [] operator.
+ *
  * `draw::StorageBuffer<T>`
  *   A storage buffer object class inheriting from T.
  *   Data can be accessed just like a normal T object.
@@ -340,6 +343,38 @@ template<
     typename T,
     /** True if created on device and no memory host memory is allocated. */
     bool device_only = false>
+class StorageFlexibleBuffer : public detail::StorageCommon<T, 1, device_only> {
+ public:
+  StorageFlexibleBuffer(const char *name = nullptr)
+      : detail::StorageCommon<T, 1, device_only>(name)
+  {
+    /* TODO(@fclem): We should map memory instead. */
+    this->data_ = (T *)MEM_mallocN_aligned(sizeof(T), 16, this->name_);
+  }
+  ~StorageFlexibleBuffer()
+  {
+    MEM_freeN(this->data_);
+  }
+
+  /* Resize on access. */
+  T &operator[](int64_t index)
+  {
+    BLI_STATIC_ASSERT(!device_only, "");
+    BLI_assert(index >= 0);
+    if (index >= this->len_) {
+      this->resize(this->len_ * 2);
+    }
+    return this->data_[index];
+  }
+
+  /* TODO(fclem): Implement shrinking. */
+};
+
+template<
+    /** Type of the values stored in this uniform buffer. */
+    typename T,
+    /** True if created on device and no memory host memory is allocated. */
+    bool device_only = false>
 class StorageBuffer : public T, public detail::StorageCommon<T, 1, device_only> {
  public:
   StorageBuffer(const char *name = nullptr) : detail::StorageCommon<T, 1, device_only>(name)