undefined method `abs' but isnt absolute a function in ruby?-CodePudding

I tried to call abs for my math in the code but the terminal reports that abs is unidentified when it is supposed to be in the language itself. The error message: customcode.rb:58:in <class:Survivor>: undefined method abs for nil:NilClass (NoMethodError)

        vel_sum = (@vel_x).abs   (@vel_y).abs\r
                          ^^^^

This is the part of the code where the error lies

  def acceleration(direction)
            case direction
                when :forwards  
                    @vel_x  = Math.sin(@sprite.rotate*Math::PI/180) 
                    @vel_y -= Math.cos(@sprite.rotate*Math::PI/180) 
                when :backwards  
                    @vel_x -= Math.sin(@sprite.rotate*Math::PI/180) 
                    @vel_y  = Math.cos(@sprite.rotate*Math::PI/180) 
            end
        end

            vel_sum = @vel_x.abs   @vel_y.abs
        if vel_sum > 2
            @vel_x = @vel_x*2
            @vel_y = @vel_y*2
        end

vel_sum = @vel_x.abs @vel_y.abs @vel_x and y should be integers so I honestly do not know why It does not work. I hope some passerby could help me with this one.

CodePudding user response：

The vel_sum... code is outside of the def acceleration method, therefore the program does not understand @vel_x and @vel_y when it is called.

def acceleration(direction)
            case direction
                when :forwards  
                    @vel_x  = Math.sin(@sprite.rotate*Math::PI/180) 
                    @vel_y -= Math.cos(@sprite.rotate*Math::PI/180) 
                when :backwards  
                    @vel_x -= Math.sin(@sprite.rotate*Math::PI/180) 
                    @vel_y  = Math.cos(@sprite.rotate*Math::PI/180) 
            end

            vel_sum = @vel_x.abs   @vel_y.abs
            if vel_sum > 2
                @vel_x = @vel_x*(2/vel_sum)
                @vel_y = @vel_y*(2/vel_sum)
            end
end

This fix should work..