SkyGradientLayer.java

// Copyright 2008 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package com.google.android.stardroid.layers;

import com.google.android.stardroid.R;
import com.google.android.stardroid.base.TimeConstants;
import com.google.android.stardroid.control.AstronomerModel;
import com.google.android.stardroid.provider.ephemeris.SolarPositionCalculator;
import com.google.android.stardroid.renderer.RendererController;
import com.google.android.stardroid.search.SearchResult;
import com.google.android.stardroid.units.GeocentricCoordinates;
import com.google.android.stardroid.units.RaDec;
import com.google.android.stardroid.util.MiscUtil;

import android.content.res.Resources;
import android.util.Log;

import java.util.Collections;
import java.util.Date;
import java.util.List;
import java.util.Set;
import java.util.concurrent.locks.ReentrantLock;

/**
 * If enabled, keeps the sky gradient up to date.
 *
 * @author John Taylor
 * @author Brent Bryan
 */
public class SkyGradientLayer implements Layer {
  private static final String TAG = MiscUtil.getTag(SkyGradientLayer.class);
  private static final long UPDATE_FREQUENCY_MS = 5L * TimeConstants.MILLISECONDS_PER_MINUTE;

  private final ReentrantLock rendererLock = new ReentrantLock();
  private final AstronomerModel model;
  private final Resources resources;

  private RendererController renderer;
  private long lastUpdateTimeMs = 0L;

  public SkyGradientLayer(AstronomerModel model, Resources resources) {
    this.model = model;
    this.resources = resources;
  }

  @Override
  public void initialize() {}

  @Override
  public void registerWithRenderer(RendererController controller) {
    this.renderer = controller;
    redraw();
  }

  @Override
  public void setVisible(boolean visible) {
    Log.d(TAG, "Setting showSkyGradient " + visible);
    if (visible) {
      redraw();
    } else {
      rendererLock.lock();
      try {
        renderer.queueDisableSkyGradient();
      } finally {
        rendererLock.unlock();
      }
    }
  }

  /** Redraws the sky shading gradient using the model's current time. */
  protected void redraw() {
    Date modelTime = model.getTime();
    if (Math.abs(modelTime.getTime() - lastUpdateTimeMs) > UPDATE_FREQUENCY_MS) {
      lastUpdateTimeMs = modelTime.getTime();

      RaDec sunPosition = SolarPositionCalculator.getSolarPosition(modelTime);
      // Log.d(TAG, "Enabling sky gradient with sun position " + sunPosition);
      rendererLock.lock();
      try {
        renderer.queueEnableSkyGradient(GeocentricCoordinates.getInstance(sunPosition));
      } finally {
        rendererLock.unlock();
      }
    }
  }

  @Override
  public int getLayerId() {
    return 0;
  }

  public String getPreferenceId() {
    return "source_provider." + getLayerNameId();
  }

  public String getLayerName() {
    return resources.getString(getLayerNameId());
  }

  private int getLayerNameId() {
    return R.string.show_sky_gradient;
  }

  @Override
  public List<SearchResult> searchByObjectName(String name) {
    return Collections.emptyList();
  }

  @Override
  public Set<String> getObjectNamesMatchingPrefix(String prefix) {
    return Collections.emptySet();
  }
}