Add: documents

Author: nutti

README.md

@@ -1,2 +1,61 @@
-# UE4-kd-tree
-kd-tree plugin for UE4
+# UE4 Plugin: kd-tree
+
+This is a UE4 plugin to provide utility functions for building kd-tree as Blueprint Function Library.
+
+
+## Supported Environment
+
+This plugin is tested on the below environment.
+
+* UE4 Version: 4.22 
+* OS: Windows/Mac
+
+
+## Installation
+
+#### 1. Download source codes
+
+Download whole project's source codes from [GitHub](https://github.com/nutti/UE4-Kdtree/archive/master.zip) and unzip them.
+
+
+#### 2. Copy the plugin source codes
+
+Copy the plugin source codes (`Kdtree` directory) into the plugin directory (`Plugin` directory) on your UE4 project.
+
+
+#### 3. Generate a project file for each IDE
+
+Generate a project file for Visual Studio (Windows) or XCode (Mac).
+
+
+#### 4. Build
+
+Build whole source codes including plugin source codes.
+
+
+#### 5. Launch UE4 editor and enable plugin
+
+Launch .uproject file and enable plugin via *Settings* > *Plugins* > *Project* > *Other* > *kd-tree*.
+
+
+## Features / Tutorials
+
+### Build kdtree and radius search
+
+1. `Build Kdtree` builds a kd-tree (`Kdtree` object in Blueprint) from `Vector` objects.
+   * `Dump Kdtree to Console` outputs the internal information of `Kdtree` object to the console for debugging.
+   * `Validate Kdtree` checks the `Kdtree` object and halts the game play if there is a incorrect in it. 
+2. `Collect from Kdtree` collects `Vector` objects in the sphere (center location is `Center`, radius is `Radius`). `Collect from Kdtree` also returns indicies of list that is input argument of `Build Kdtree`.
+3. If you don't use `Kdtree` any more, you can destroy `Kdtree` object and free memories by `Clear Kdtree`.
+
+![](docs/images/kdtree.png)
+
+
+### Build Actor kdtree and radius search
+
+Same as [Build kdtree and radius search](#Build-kdtree-and-radius-search) except for below things.
+
+* Build a kd-tree from `Actor` objects.
+* The name of all functions and data structures need to be changed as `kdtree` -> `Actor kdtree`.
+
+![](docs/images/actor_kdtree.png)