Class: Phlox::GradientGen::Node

Inherits:
Object
  • Object
show all
Defined in:
lib/phlox/gradient_gen.rb

Overview

A node in an expression tree for a pixel color calculation. Initializing a node also generates its child nodes, and you can use ‘Node#run` to evaluate the expression tree into a numerical value.

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Node

Returns a new instance of Node.



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# File 'lib/phlox/gradient_gen.rb', line 19

def initialize
  # calculate the node's value - it can either be a constant, one of the parameters,
  # a unary function invocation on another node, or a binary invocation on two other nodes
  types = [:param, :param, :const, :unary, :unary, :binary]
  @type = types.sample
  
  case @type
  when :const
    @val = const
  when :param
    @val = param
  when :unary
    unary_call
  when :binary
    binary_call
  end
end

Instance Method Details

#binary_call ⇒ Object 



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# File 'lib/phlox/gradient_gen.rb', line 75

def binary_call
  @val1 = Node.new
  @val2 = Node.new
  @fn = binary_fn
end

#binary_fn ⇒ Object

choose a random binary function



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# File 'lib/phlox/gradient_gen.rb', line 87

def binary_fn
  [:mul, :add, :and, :or, :xor, :pow, :sub, :div].sample
end

#const ⇒ Object

calculate a random constant, from 0 to 255



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# File 'lib/phlox/gradient_gen.rb', line 64

def const; rand 255; end

#param ⇒ Object

choose one of the parameters randomly



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# File 'lib/phlox/gradient_gen.rb', line 67

def param; [:x, :y].sample; end

#radians(n) ⇒ Object

converts a value from degrees to radians



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# File 'lib/phlox/gradient_gen.rb', line 118

def radians n
  Math::PI * (n / 180.0)
end

#run(x, y) ⇒ Object

Evaluate the node and its children into a number, given an x and y parameter. Any value that produce an error will equal 0.



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# File 'lib/phlox/gradient_gen.rb', line 39

def run x, y
  begin

    # try calculating the value
    case @type
    when :const
      return @val
    when :param
      return {x: x, y: y}[@val]
    when :unary
      v1 = @val1.run x, y
      return run_unary(v1).abs
    when :binary
      v1 = @val1.run x, y
      v2 = @val2.run x, y
      return run_binary(v1, v2).abs
    end
    
  # if something goes wrong, give up and just return 0
  rescue => e
    return 0
  end
end

#run_binary(v1, v2) ⇒ Object

run @fn on the arguments



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# File 'lib/phlox/gradient_gen.rb', line 104

def run_binary v1, v2
  case @fn
  when :mul then v1 * v2
  when :add then v1 + v2
  when :and then v1.to_i & v2.to_i
  when :or then v1.to_i | v2.to_i
  when :xor then v1.to_i ^ v2.to_i
  when :pow then v1 ** (v2 % 10)
  when :sub then v1 - v2
  when :div then v1 / v2.to_f
  end
end

#run_unary(v1) ⇒ Object

run @fn on the argument



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# File 'lib/phlox/gradient_gen.rb', line 92

def run_unary v1
  case @fn
  when :sq then v1 ** 2
  when :sin then 50 * Math::sin(radians v1)
  when :cos then 50 * Math::cos(radians v1)
  when :mod5 then 10 * (v1.abs % 5)
  when :log2 then 10 * Math::log2(v1.abs)
  when :tan then 50 * Math::tan(radians v1)
  end
end

#to_s ⇒ Object 



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# File 'lib/phlox/gradient_gen.rb', line 122

def to_s
  case @type
  when :const then @val.to_s
  when :param then @val.to_s
  when :unary then  "#@fn(#@val1)"
  when :binary then "#@fn(#@val1, #@val2)"
  end
end

#unary_call ⇒ Object

make a new argument node and choose a unary function to apply it to



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# File 'lib/phlox/gradient_gen.rb', line 70

def unary_call
  @val1 = Node.new
  @fn = unary_fn
end

#unary_fn ⇒ Object

choose a random unary function



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# File 'lib/phlox/gradient_gen.rb', line 82

def unary_fn
  [:sq, :sin, :cos, :mod5, :log2, :tan].sample
end