core: rename mbgl directories to mln (#4511)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

include/mln/gfx/vertex_buffer.hpp

@@ -0,0 +1,42 @@
+#pragma once
+
+#include <memory>
+#include <cassert>
+
+namespace mln {
+namespace gfx {
+
+class VertexBufferResource {
+protected:
+    VertexBufferResource() noexcept = default;
+
+public:
+    virtual ~VertexBufferResource() noexcept = default;
+};
+
+using UniqueVertexBufferResource = std::unique_ptr<VertexBufferResource>;
+
+// This class has a template argument that we use to specify the vertex type. It
+// is not used by the implementation, but serves type checking purposes during
+// build time.
+template <class>
+class VertexBuffer {
+public:
+    VertexBuffer(const std::size_t elements_, UniqueVertexBufferResource&& resource_)
+        : elements(elements_),
+          resource(std::move(resource_)) {}
+
+    std::size_t elements;
+
+    template <typename T = VertexBufferResource>
+    T& getResource() const {
+        assert(resource);
+        return static_cast<T&>(*resource);
+    }
+
+protected:
+    UniqueVertexBufferResource resource;
+};
+
+} // namespace gfx
+} // namespace mln