circular buffer to store and plot values

plot.pde

// this code is not a working sketch

int   circularBufferSize;
int   circularBufferIndex;
int [][] circularBuffer;

circularBufferSize    = 512;
circularBufferIndex	  = 0;
circularBuffer        = new int [6][circularBufferSize];

// write values to circular buffer when received from Arduino analog

for (int i=0; i<6; i++)
{
	circularBuffer[i][circularBufferIndex] = 0; //valueFromArduino

	if(circularBufferIndex<circularBufferSize-1) circularBufferIndex++;
	else                                         circularBufferIndex=0;
}


void drawDataPlot(int xPos, int yPos, int w, int h, int buffer)
{	
	float x;
	float y;

	// draw eggshell background
	fill(255, 253, 248);
	rect(xPos, yPos, w, h);

	// add position in width and height.
	// for mapping (after drawing the background)
   	w = xPos+w;
	h = yPos+h;

	int padding = 5;

	noFill();
	strokeWeight(1);
	stroke(120); 

		// beginShape is a fast way to draw lines!   
		beginShape();       
		
		for (int i=0; i<circularBufferSize-1; i++)
		{        			 
			x = map(i, 0, circularBufferSize, xPos+padding, w-padding);
			// use sensorAvgMinValue and sensorAvgMaxValue to scale
			y = map(getValueFromCircularBuffer(buffer, i), 0, 1023, h-padding, yPos+padding);                          
			vertex(x,y); 
		}
		
		endShape();  
	
	noStroke();		
}

int getValueFromCircularBuffer(int buffer, int index)
{	
	// circularBufferIndex +1 is the smallest (the oldest in the array)
	int idx = (circularBufferIndex + 1 + index) % circularBufferSize;
	return circularBuffer[buffer][idx];
}