Merge pull request #1588 from tildearrow/doc-xyosc

XY-osc doc

doc/8-advanced/README.md

@@ -18,6 +18,7 @@ as listed in the "Window" menu:
 
 - [piano](piano.md)
 - [oscilloscope](osc.md)
+- [oscilloscope (X-Y)](xyosc.md)
 - [oscilloscopes (per-channel)](chanosc.md)
 - [clock](clock.md)
 - [register view](regview.md)

doc/8-advanced/osc.md

@@ -1,6 +1,6 @@
 # oscilloscope
 
-the Oscilloscope shows the waveform of the mix of all currently playing sounds.
+the Oscilloscope shows the audio output as a waveform.
 
 ![oscilloscope view](osc.png)
 

doc/8-advanced/xyosc.md

@@ -0,0 +1,17 @@
+# oscilloscope (X-Y)
+
+also called "vectorscope", this is similar to the normal oscilloscope in that it draws audio output as a waveform, but instead of being one-dimensional and going from left to right, it is plotted in two dimensions (usually X represents left output and Y represents right output).
+
+(TODO: image)
+
+right-clicking the X-Y oscilloscope window displays settings:
+- **X Channel**: the output channel which will affect the X (left-right) axis. 1 is left.
+  - **Invert**: flips the axis.
+- **Y Channel**: the output channel which will affect the Y (up-down) axis. 2 is right.
+  - **Invert**: flips the axis.
+- **Zoom**: changes amplitude, making the plot bigger or smaller.
+- **Samples**: the maximum number of samples to use for plotting.
+  - this setting may be replaced by another or removed in a future version.
+- **Decay Time (ms)**: sets how long it takes for the points/lines to fade away.
+- **Intensity**: changes the brightness of the dots/lines.
+- **Line Thickness**: sets how thick lines are.