Create WRITEUP.md

WRITEUP.md

@@ -0,0 +1,25 @@
+# Seele Engine
+
+Seele is a Proof-of-Concept 3D render engine using Vulkan as it's primary graphics API, but other APIs could also be implemented.
+The focus of the project is to make the renderer use as many of the system resources as efficiently as possible to maximize the framerate 
+while minimizing resource usage.
+It does this by being designed to support multithreading for more recent APIs, like DX12 or Vulkan, while still providing an interface that could be implemented by an
+API that doesn't support it, like OpenGL. These APIs would suffer a significant performance loss, but would still work correctly.
+
+## Custom containers and other utilities
+
+Some of the basic containers are reimplemented, mostly not for any particular feature, but because that makes them more customizable and extendable for future uses and
+performance optimizations, like serialization for example. Due to them occuring in the code samples later, they will be quickly mentioned here.
+
+- `Array`: A heap-array backed dynamically resizable container, like `std::vector`
+- `StaticArray`: A static-array backed non-resizable container, like `std::array`
+- `Map`: A key-value splay-tree associative container, like `std::map`
+- `UniquePtr`: A smart pointer claiming ownership of an object, like `std::unique_pointer`
+- `RefPtr`: A reference counting smart pointer, similar to `std::shared_pointer`, with a few differences:
+  - global pointer-based reference counting
+  - this means a `RefPtr` can be constructed from a raw pointer and will retain its reference count correctly
+  - for example if you construct `RefPtr<HelloWorld> ptr = new HelloWorld();`, and in the constructor of HelloWorld create `RefPtr<HelloWorld ptr = this;`, both would have a reference count of 2.
+- `DEFINE_REF`/`DECLARE_REF`: Macros to automatically typedef different types of smart pointer for convenience, for example DEFINE_REF(HelloWorld) would typedef:
+  - `PHelloWorld`, the same as `RefPtr<HelloWorld>`
+  - `UPHelloWorld`, the same as `UniquePtr<HelloWorld>`
+