edu.wpi.first.wpilibj.vision.GripRunner.java Source code

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Here is the source code for edu.wpi.first.wpilibj.vision.GripRunner.java

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/*----------------------------------------------------------------------------*/
/* Copyright (c) FIRST 2016-2017. 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.vision;

import org.opencv.videoio.VideoCapture;
import org.opencv.videoio.Videoio;
import org.opencv.core.Core;
import org.opencv.core.Mat;

/**
 * A GRIP runner is a convenient wrapper object to make it easy to run vision
 * pipelines from robot code.
 *
 * @see VisionPipeline
 */
public class GripRunner<P extends VisionPipeline> {

    static {
        System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
    }

    public static final boolean DEBUG = Boolean.valueOf(System.getProperty("debug", "false"));
    public static final boolean HEADLESS = Boolean.valueOf(System.getProperty("headless", "false"));
    final static int FRAME_COUNT_SPAN = 3;

    private final VideoCapture m_cvSink;
    private final P m_pipeline;
    private final Mat m_image = new Mat();
    private final Listener<? super P> m_listener;
    private int frameCount = 0;
    private long frameCountTimeout = System.currentTimeMillis() + 1000L * FRAME_COUNT_SPAN;

    /**
     * Listener interface for a callback that should run after a pipeline has
     * processed its input.
     *
     * @param <P> the type of the pipeline this listener is for
     */
    @FunctionalInterface
    public interface Listener<P extends VisionPipeline> {

        /**
         * Called when the pipeline has run. This shouldn't take much time to
         * run because it will delay later calls to the pipeline's
         * {@link VisionPipeline#process process} method. Copying the outputs
         * and code that uses the copies should be <i>synchronized</i> on the
         * same mutex to prevent multiple threads from reading and writing to
         * the same memory at the same time.
         *
         * @param pipeline
         *            the vision pipeline that ran
         */
        void copyPipelineOutputs(P pipeline);

    }

    /**
     * Creates a new vision runner. It will take images from the
     * {@code videoSource}, send them to the {@code pipeline}, and call the
     * {@code listener} when the pipeline has finished to alert user code when
     * it is safe to access the pipeline's outputs.
     *
     * @param camera the video source to use to supply images for the pipeline
     * @param pipeline the vision pipeline to run
     * @param listener a function to call after the pipeline has finished running
     */
    public GripRunner(VideoCapture camera, P pipeline, Listener<? super P> listener) {
        this.m_pipeline = pipeline;
        this.m_listener = listener;
        m_cvSink = camera;
    }

    /**
     * Runs the pipeline one time, giving it the next image from the video
     * source specified in the constructor. This will block until the source
     * either has an image or throws an error. If the source successfully
     * supplied a frame, the pipeline's image input will be set, the pipeline
     * will run, and the listener specified in the constructor will be called to
     * notify it that the pipeline ran.
     *
     * <p>
     * This method is exposed to allow teams to add additional functionality or
     * have their own ways to run the pipeline. Most teams, however, should just
     * use {@link #runForever} in its own thread using a {@link VisionThread}.
     * </p>
     */
    public void runOnce() {
        m_cvSink.read(m_image);
        m_pipeline.process(m_image);
        if (m_listener != null) {
            m_listener.copyPipelineOutputs(m_pipeline);
        }
    }

    /**
     * A convenience method that calls {@link #runOnce()} in an infinite loop.
     * This must be run in a dedicated thread, and cannot be used in the main
     * robot thread because it will freeze the robot program.
     * 
     * @see VisionThread
     */
    public void runForever() {
        while (!Thread.currentThread().isInterrupted()) {
            runOnce();
            if (DEBUG) {
                frameCount++;
                if (System.currentTimeMillis() > frameCountTimeout) {
                    System.out.println("fps: " + (frameCount / FRAME_COUNT_SPAN));
                    frameCount = 0;
                    frameCountTimeout = System.currentTimeMillis() + 1000L * FRAME_COUNT_SPAN;
                }
            }
        }
    }

    /**
     * Make a connection to a camera.
     * 
     * @param device  Camera number.
     * @param width  Window width in pixels.
     * @param height Window height in pixels.
     * @param exposure Relative exposure.
     * @return
     */
    public static VideoCapture makeCamera(int device, int width, int height, double exposure) {
        VideoCapture camera = new VideoCapture(0);
        camera.set(Videoio.CAP_PROP_FRAME_WIDTH, width);
        camera.set(Videoio.CAP_PROP_FRAME_HEIGHT, height);
        if (exposure > -1.0) {
            System.out.println("\t" + exposure);
            camera.set(Videoio.CAP_PROP_AUTO_EXPOSURE, 0);
            camera.set(Videoio.CAP_PROP_EXPOSURE, exposure);
        }
        if (!camera.isOpened()) {
            throw new RuntimeException("Camera will not open");
        }
        return camera;
    }

    /**
     * Make a GUI window on which to display a {@link Mat} image.
     * 
     * @param title Title on the window.
     * @param width  Window width in pixels.
     * @param height Window height in pixels.
     * @return a new {@link VideoViewer}
     */
    public static VideoViewer makeWindow(String title, int width, int height) {
        if (HEADLESS) {
            return null;
        }
        return new VideoViewer("GRIP", width, height);
    }

}