docs for noise_mode

Author: monkstone

docs/_methods/noise_mode.md

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+---
+layout: post
+title:  "noise_mode"
+---
+
+### Name ###
+
+`noise_mode` _NB: not currently available in vanilla processing_.
+
+### Examples ###
+
+```ruby
+#!/usr/bin/env jruby -w
+require 'picrate'
+
+class TestNoise < Processing::App
+  attr_reader :z
+
+  def setup
+    stroke(255, 64)
+    @z = 0
+  end
+
+  def draw
+    noise_scale = 0.01
+    background(0)
+    grid(width, height, 10, 10) do |x, y|
+      arrow(x, y, noise(x * noise_scale, y * noise_scale, z * noise_scale) * TWO_PI * 2)
+    end
+    @z += 1
+  end
+
+  def mouse_pressed
+    mode = Processing::SIMPLEX
+    noise_mode mode
+    sketch_title "#{mode}"
+  end
+
+  def mouse_released
+    mode = Processing::VALUE # default mode "Perlin Noise" in vanilla processing
+    noise_mode(mode)
+    sketch_title "#{mode}"
+  end
+
+
+  def arrow(x, y, ang)
+    pushMatrix()
+    translate(x, y)
+    rotate(ang)
+    line(0, 0, 20, 0)
+    translate(20, 0)
+    rotate(PI + 0.4)
+    line(0, 0, 5, 0)
+    rotate(-0.8)
+    line(0, 0, 5, 0)
+    popMatrix()
+  end
+
+  def settings
+    size(600, 400, P2D)
+  end
+end
+
+TestNoise.new
+
+```
+
+### Description	###
+
+Currently supports two implementations of noise ValueNoise (Perlin noise in vanilla processing), up to 3D and SimplexNoise up to 4D.
+
+### Syntax ###
+
+```ruby
+noise_mode(mode) # default mode is Processing::VALUE, and Processing::SIMPLEX
+```
+
+### Related ###
+
+`noise(x, y, z, w)` SimplexNoise only
+
+`noise(x, y, z)` ValueNoise and SimplexNoise