Add AddressableLED (#2092)

wpilibj/src/main/java/edu/wpi/first/wpilibj/AddressableLED.java

@@ -0,0 +1,122 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2019 FIRST. All Rights Reserved.                             */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+package edu.wpi.first.wpilibj;
+
+import edu.wpi.first.hal.AddressableLEDJNI;
+
+/**
+ * A class for driving addressable LEDs, such as WS2812s and NeoPixels.
+ */
+public class AddressableLED implements AutoCloseable {
+  private final PWM m_pwmOutput;
+  private int m_handle;
+  private final boolean m_ownsPwm;
+
+  /**
+   * Constructs a new driver from a PWM output.
+   *
+   * @param output the pwm output to use
+   */
+  public AddressableLED(PWM output) {
+    m_pwmOutput = output;
+    m_ownsPwm = false;
+    init();
+  }
+
+  /**
+   * Constructs a new driver for a specific port.
+   *
+   * @param port the output port to use (Must be a PWM port)
+   */
+  public AddressableLED(int port) {
+    m_pwmOutput = new PWM(port);
+    m_ownsPwm = true;
+    init();
+  }
+
+  private void init() {
+    m_handle = AddressableLEDJNI.initialize(m_pwmOutput.m_handle);
+  }
+
+  @Override
+  public void close() {
+    if (m_handle != 0) {
+      AddressableLEDJNI.free(m_handle);
+    }
+    if (m_ownsPwm) {
+      m_pwmOutput.close();
+    }
+  }
+
+  /**
+   * Sets the length of the LED strip.
+   *
+   * <p>Calling this is an expensive call, so its best to call it once, then just update data.
+   *
+   * @param length the strip length
+   */
+  public void setLength(int length) {
+    AddressableLEDJNI.setLength(m_handle, length);
+  }
+
+  /**
+   * Sets the led output data.
+   *
+   * <p>If the output is enabled, this will start writing the next data cycle.
+   * It is safe to call, even while output is enabled.
+   *
+   * @param buffer the buffer to write
+   */
+  public void setData(AddressableLEDBuffer buffer) {
+    AddressableLEDJNI.setData(m_handle, buffer.m_buffer);
+  }
+
+  /**
+   * Sets the bit timing.
+   *
+   * <p>By default, the driver is set up to drive WS2812s, so nothing needs to be set for those.
+   *
+   * @param lowTime0NanoSeconds low time for 0 bit
+   * @param highTime0NanoSeconds high time for 0 bit
+   * @param lowTime1NanoSeconds low time for 1 bit
+   * @param highTime1NanoSeconds high time for 1 bit
+   */
+  public void setBitTiming(int lowTime0NanoSeconds, int highTime0NanoSeconds,
+      int lowTime1NanoSeconds, int highTime1NanoSeconds) {
+    AddressableLEDJNI.setBitTiming(m_handle, lowTime0NanoSeconds,
+        highTime0NanoSeconds, lowTime1NanoSeconds,
+        highTime1NanoSeconds);
+  }
+
+  /**
+   * Sets the sync time.
+   *
+   * <p>The sync time is the time to hold output so LEDs enable. Default set for WS2812.
+   *
+   * @param syncTimeMicroSeconds the sync time
+   */
+  public void setSyncTime(int syncTimeMicroSeconds) {
+    AddressableLEDJNI.setSyncTime(m_handle, syncTimeMicroSeconds);
+  }
+
+  /**
+   * Starts the output.
+   *
+   * <p>The output writes continously.
+   */
+  public void start() {
+    AddressableLEDJNI.start(m_handle);
+  }
+
+  /**
+   * Stops the output.
+   */
+  public void stop() {
+    AddressableLEDJNI.stop(m_handle);
+  }
+}

wpilibj/src/main/java/edu/wpi/first/wpilibj/AddressableLEDBuffer.java

@@ -0,0 +1,40 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2019 FIRST. All Rights Reserved.                             */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+package edu.wpi.first.wpilibj;
+
+/**
+ * Buffer storage for Addressable LEDs.
+ */
+public class AddressableLEDBuffer {
+  byte[] m_buffer;
+
+  /**
+   * Constructs a new LED buffer with the specified length.
+   *
+   * @param length The length of the buffer in pixels
+   */
+  public AddressableLEDBuffer(int length) {
+    m_buffer = new byte[length * 4];
+  }
+
+  /**
+   * Sets a specific led in the buffer.
+   *
+   * @param index the index to write
+   * @param r the r value
+   * @param g the g value
+   * @param b the b value
+   */
+  @SuppressWarnings("ParameterName")
+  public void setLED(int index, int r, int g, int b) {
+    m_buffer[index * 4] = (byte) b;
+    m_buffer[(index * 4) + 1] = (byte) g;
+    m_buffer[(index * 4) + 2] = (byte) r;
+    m_buffer[(index * 4) + 3] = 0;
+  }
+}

wpilibj/src/main/java/edu/wpi/first/wpilibj/PWM.java

@@ -46,7 +46,9 @@ public class PWM extends MotorSafety implements Sendable, AutoCloseable {
   }
 
   private final int m_channel;
-  private int m_handle;
+
+  // Package private to use from AddressableLED
+  int m_handle;
 
   /**
    * Allocate a PWM given a channel.