content: /*
   * Copyright 2019 Gustl22
   * Copyright 2019 devemux86
   *
   * This program is free software: you can redistribute it and/or modify it under the
   * terms of the GNU Lesser General Public License as published by the Free Software
   * Foundation, either version 3 of the License, or (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful, but WITHOUT ANY
   * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
   * PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public License along with
   * this program. If not, see <http://www.gnu.org/licenses/>.
   */
  /*
   * Copyright (C) 2009 The Android Open Source Project
   *
   * 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 org.oscim.android.gl;
  
  import android.opengl.GLSurfaceView;
  import org.oscim.android.MapView;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import javax.microedition.khronos.egl.EGL10;
  import javax.microedition.khronos.egl.EGLConfig;
  import javax.microedition.khronos.egl.EGLContext;
  import javax.microedition.khronos.egl.EGLDisplay;
  
  /**
   * https://developer.android.com/guide/topics/graphics/opengl.html#version-check
   * <p>
   * https://github.com/libgdx/libgdx/blob/master/backends/gdx-backend-android/src/com/badlogic/gdx/backends/android/surfaceview/GLSurfaceView20.java
   */
  public class GlContextFactory implements GLSurfaceView.EGLContextFactory {
  
      private static final Logger log = LoggerFactory.getLogger(GlContextFactory.class);
  
      private static final int EGL_CONTEXT_CLIENT_VERSION = 0x3098;
  
      @Override
      public EGLContext createContext(EGL10 egl, EGLDisplay display, EGLConfig eglConfig) {
          log.info("creating OpenGL ES " + MapView.OPENGL_VERSION + " context");
          checkEglError("Before eglCreateContext " + MapView.OPENGL_VERSION, egl);
          int[] attrib_list = {EGL_CONTEXT_CLIENT_VERSION, (int) MapView.OPENGL_VERSION, EGL10.EGL_NONE};
          EGLContext context = egl.eglCreateContext(display, eglConfig, EGL10.EGL_NO_CONTEXT, attrib_list);
          boolean success = checkEglError("After eglCreateContext " + MapView.OPENGL_VERSION, egl);
  
          if ((!success || context == null) && MapView.OPENGL_VERSION > 2) {
              log.warn("Falling back to GLES 2");
              MapView.OPENGL_VERSION = 2.0;
              return createContext(egl, display, eglConfig);
          }
          log.info("Returning a GLES " + MapView.OPENGL_VERSION + " context");
          return context;
      }
  
      @Override
      public void destroyContext(EGL10 egl, EGLDisplay display, EGLContext context) {
          egl.eglDestroyContext(display, context);
      }
  
      private static boolean checkEglError(String prompt, EGL10 egl) {
          int error;
          boolean result = true;
          while ((error = egl.eglGetError()) != EGL10.EGL_SUCCESS) {
              result = false;
              log.error(String.format("%s: EGL error: 0x%x", prompt, error));
          }
          return result;
      }
  }
  