<!--
    Copyright 2014 The Gfx-rs Developers.

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

        http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
-->

# Flowmap Example

A flowmap example. Flow mapping is often used to simulate water motion, by
encoding a flow direction using the red and green channel of an image. This
example uses three images to compose this effect:
* a flow map, which contains direction vector in the red and green channel
* a water diffuse texture, which will be distorted
* a noise texture, which fixes a common problem with flow maps mentioned in
the article *Animating Water Using Flow Maps* below

## Screenshot

![Flowmap Example](screenshot.png)

## Further reading

* [Water shader from source engine](https://developer.valvesoftware.com/wiki/Water_(shader))
* [Water Flow in Portal 2 – Valve paper](http://www.valvesoftware.com/publications/2010/siggraph2010_vlachos_waterflow.pdf)
* [Animating Water Using Flow Maps – Graphics Runner](http://graphicsrunner.blogspot.se/2010/08/water-using-flow-maps.html)
* [A Walkthrough of the Special FX of Uncharted 3: Drake's Deception – Page 57](http://twvideo01.ubm-us.net/o1/vault/gdc2012/slides/Missing%20Presentations/Added%20March%2026/Keith_Guerrette_VisualArts_TheTricksUp.pdf#page.57)
* [Water flow shader – icefall games](https://mtnphil.wordpress.com/2012/08/25/water-flow-shader/)