started Porting from other frameworks

src/SUMMARY.md

@@ -15,6 +15,7 @@
     - [Basics - Anatomy of a Nannou App](./tutorials/basics/anatomy-of-a-nannou-app.md)
     - [Basics - Drawing 2D Shapes](./tutorials/basics/drawing-2d-shapes.md)
 - [Developer Reference](./developer_reference.md)
+- [Porting From Other Frameworks](./porting_from_other_frameworks.md)
 - [API Reference](./api_reference.md)
 - [Showcases](./showcases.md)
 

src/porting_from_other_frameworks.md

@@ -0,0 +1,45 @@
+# Porting from other frameworks
+
+Nannou is inspired by other creative coding frameworks inspired like [Processing](https://processing.org),
+[openFrameworks](https://openframeworks.cc), and [Cinder](https://libcinder.org/).
+This section is intended to help everyone making the switch to nannou and bringing their code with them.
+
+**note: This is very much a work in progress. It will be extended as we learn about porting issues.**
+
+## General
+**This section shall contain general information**
+
+## Processing
+Processing has two famous functions. The `setup()` function prepares everything and takes care of
+the initial setup. The `draw()` actuallly changes things on the screen.
+
+Most tasks of the `setup()` function in processing are taken care of by the `model()` function in nannou.
+This is where the inital state of the world (model) is created. This model information is then processed
+later by other functions.
+
+Sometimes the `setup()` function is used to prepare the screen. Sometimes code already draws
+in this phase (e.g. to set the background). This behaviour can be emulated using `.nth()`, which
+counts the number of frames displayed in the associated window.
+```rust
+fn view(app: &App, m: &Model, frame: &Frame) {
+    let draw = app.draw();
+    if frame.nth() == 0 {
+        // do one-time preparations of the screen here
+    }
+    // general drawing code
+    draw.to_frame(app, &frame).unwrap();
+}
+```
+
+The `draw()` function in processing is used to both draw on the screen and also to change the state
+of to be displayed. Nannou takes a more explicit approach here. The function `view()` in nannou
+displays things. Functions like `update()` or `event()` are used to (only) change the state of the
+model to be displayed. Thus there are dedicated places which take care of either showing things
+or changing things.
+
+
+## openFrameworks
+**This section shall contain openFrameworks-specific information**
+
+## Cinder
+**This section shall contain Cinder-specific information**