class RcFilter
{
	public:
		RcFilter() {
			recalcCoeffs(0.5f);
		}
	
		// cutoff given = cutoff in Hz / sampleRate
		void recalcCoeffs(float cutoff, bool isHighPass = false) 
		{
			float	x = expf(-2.0f * M_PI * cutoff);
		
			if(isHighPass) {
				a0 = (1.0f + x) * 0.5f;
				a1 = -a0;
				b1 = x;
			} else {
				a0 = 1.0f - x;
				a1 = 0.0f;
				b1 = x;
			}
		}
		
		void process(float* buffer, unsigned int sampleFrames)
		{
			while(sampleFrames--) {
				float	x0 = *buffer;
				float	y0 = a0 * x0 + a1 * x1 + b1 * y1;
				y1 = y0; x1 = x0; 
				*buffer = y0; 
				buffer++;
			}
		}
	
	private:
		float	a0, a1, b1;
		float	y1, x1;
};