1 files changed, 71 insertions, 0 deletions
diff --git a/src/org/usfirst/frc/team4272/robotlib/Pixy.java b/src/org/usfirst/frc/team4272/robotlib/Pixy.java
new file mode 100644
index 0000000..cc6cb58
--- /dev/null
+++ b/src/org/usfirst/frc/team4272/robotlib/Pixy.java
@@ -0,0 +1,71 @@
+package org.usfirst.frc.team4272.robotlib;
+
+import edu.wpi.first.wpilibj.SerialPort;
+import edu.wpi.first.wpilibj.SerialPort.Port;
+//Warning: if the pixy is plugged in through mini usb, this code WILL NOT WORK b/c the pixy is smart and detects where it should send data
+public class Pixy {
+		SerialPort pixy;
+		Port port = Port.kMXP;
+		PixyPacket[] packets;
+		PixyException pExc;
+		String print;
+		public Pixy() {
+			pixy = new SerialPort(19200, port);
+			pixy.setReadBufferSize(14);
+			packets = new PixyPacket[7];
+			pExc = new PixyException(print);
+		}	
+//This method parses raw data from the pixy into readable integers
+		public int cvt(byte upper, byte lower) {
+			return (((int)upper & 0xff) << 8) | ((int)lower & 0xff);
+		}
+		
+		public void pixyReset(){
+			pixy.reset();
+		}
+		
+//This method gathers data, then parses that data, and assigns the ints to global variables
+		public PixyPacket readPacket(int Signature) throws PixyException {
+			int Checksum;
+			int Sig;
+			byte[] rawData = new byte[32];
+			try{
+				rawData = pixy.read(32);
+			} catch (RuntimeException e){
+			}	
+			if(rawData.length < 32){
+				System.out.println("byte array length is broken");
+				return null;
+			}
+			for (int i = 0; i <= 16; i++) {
+				int syncWord = cvt(rawData[i+1], rawData[i+0]); //Parse first 2 bytes
+				if (syncWord == 0xaa55) { //Check is first 2 bytes equal a "sync word", which indicates the start of a packet of valid data
+					syncWord = cvt(rawData[i+3], rawData[i+2]); //Parse the next 2 bytes
+					if (syncWord != 0xaa55){ //Shifts everything in the case that one syncword is sent
+						i -= 2;
+					}
+//This next block parses the rest of the data
+					Checksum = cvt(rawData[i+5], rawData[i+4]);
+					Sig = cvt(rawData[i+7], rawData[i+6]);
+					if(Sig <= 0 || Sig > packets.length){
+						break;
+					}
+					packets[Sig - 1] = new PixyPacket();
+					packets[Sig - 1].X = cvt(rawData[i+9], rawData[i+8]);
+					packets[Sig - 1].Y = cvt(rawData[i+11], rawData[i+10]);
+					packets[Sig - 1].Width = cvt(rawData[i+13], rawData[i+12]);
+					packets[Sig - 1].Height = cvt(rawData[i+15], rawData[i+14]);
+//Checks whether the data is valid using the checksum *This if block should never be entered*
+					if (Checksum != Sig + packets[Sig - 1].X + packets[Sig - 1].Y + packets[Sig - 1].Width + packets[Sig - 1].Height) {
+						packets[Sig - 1] = null;
+						throw pExc;
+					}
+					break;
+				}
+			}
+//Assigns our packet to a temp packet, then deletes data so that we dont return old data
+			PixyPacket pkt = packets[Signature - 1];
+			packets[Signature - 1] = null;
+			return pkt;
+		}
+}
+\ No newline at end of file