Examples: fix custom_scene_viewer for macOS

1. Add OpenGL context settings for macOS to the DemoWindow.
2. Move glutInit to main
3. Add command line option to set the ogre engine.

examples/custom_scene_viewer/DemoWindow.cc

@@ -15,10 +15,11 @@
  *
  */
 
-#if defined(__APPLE__)
+#if __APPLE__
   #include <OpenGL/gl.h>
+  #include <OpenGL/OpenGL.h>
   #include <GLUT/glut.h>
-#elif !defined(_WIN32)
+#else
   #include <GL/glew.h>
   #include <GL/gl.h>
   #include <GL/glut.h>
@@ -52,7 +53,11 @@ unsigned int imgh = 0;
 
 bool g_initContext = false;
 
-#if not (__APPLE__ || _WIN32)
+#if __APPLE__
+  CGLContextObj g_context;
+  CGLContextObj g_glutContext;
+#elif _WIN32
+#else
   GLXContext g_context;
   Display *g_display;
   GLXDrawable g_drawable;
@@ -159,7 +164,10 @@ void printFPS()
 //////////////////////////////////////////////////
 void displayCB()
 {
-#if not (__APPLE__ || _WIN32)
+#if __APPLE__
+  CGLSetCurrentContext(g_context);
+#elif _WIN32
+#else
   if (g_display)
   {
     glXMakeCurrent(g_display, g_drawable, g_context);
@@ -171,7 +179,10 @@ void displayCB()
 
   camera->Capture(*g_image);
 
-#if not (__APPLE__ || _WIN32)
+#if __APPLE__
+  CGLSetCurrentContext(g_glutContext);
+#elif _WIN32
+#else
   glXMakeCurrent(g_glutDisplay, g_glutDrawable, g_glutContext);
 #endif
 
@@ -198,7 +209,10 @@ void idleCB()
 //////////////////////////////////////////////////
 void keyboardCB(unsigned char _key, int, int)
 {
-#if not (__APPLE__ || _WIN32)
+#if __APPLE__
+    CGLSetCurrentContext(g_context);
+#elif _WIN32
+#else
   if (g_display)
   {
     glXMakeCurrent(g_display, g_drawable, g_context);
@@ -241,7 +255,10 @@ void keyboardCB(unsigned char _key, int, int)
     g_demo->SelectScene(index);
   }
 
-#if not (__APPLE__ || _WIN32)
+#if __APPLE__
+  CGLSetCurrentContext(g_glutContext);
+#elif _WIN32
+#else
   glXMakeCurrent(g_glutDisplay, g_glutDrawable, g_glutContext);
 #endif
 }
@@ -259,9 +276,6 @@ void initCamera(CameraPtr _camera)
 //////////////////////////////////////////////////
 void initContext()
 {
-  int argc = 0;
-  char **argv = 0;
-  glutInit(&argc, argv);
   glutInitDisplayMode(GLUT_DOUBLE);
   glutInitWindowPosition(0, 0);
   glutInitWindowSize(imgw, imgh);
@@ -278,6 +292,9 @@ void initContext()
 //////////////////////////////////////////////////
 void run(ManualSceneDemoPtr _demo)
 {
+#if __APPLE__
+  g_context = CGLGetCurrentContext();
+#endif
 #if not (__APPLE__ || _WIN32)
   g_context = glXGetCurrentContext();
   g_display = glXGetCurrentDisplay();
@@ -290,6 +307,9 @@ void run(ManualSceneDemoPtr _demo)
   initContext();
   printUsage();
 
+#if __APPLE__
+  g_glutContext = CGLGetCurrentContext();
+#endif
 #if not (__APPLE__ || _WIN32)
   g_glutDisplay = glXGetCurrentDisplay();
   g_glutDrawable = glXGetCurrentDrawable();

examples/custom_scene_viewer/ManualSceneDemo.cc

@@ -14,6 +14,16 @@
  * limitations under the License.
  *
  */
+
+#if defined(__APPLE__)
+  #include <OpenGL/gl.h>
+  #include <GLUT/glut.h>
+#elif not defined(_WIN32)
+  #include <GL/glew.h>
+  #include <GL/gl.h>
+  #include <GL/glut.h>
+#endif
+
 #include <iostream>
 #include <ignition/common/Console.hh>
 #include "ManualSceneDemo.hh"
@@ -169,8 +179,18 @@ void ManualSceneDemo::ChangeScene()
 
 //////////////////////////////////////////////////
 //////////////////////////////////////////////////
-int main(int, char**)
+int main(int _argc, char** _argv)
 {
+  glutInit(&_argc, _argv);
+
+  // Expose engine name to command line because we can't instantiate both
+  // ogre and ogre2 at the same time
+  std::string ogre_engine("ogre");
+  if (_argc > 1)
+  {
+    ogre_engine = _argv[1];
+  }
+
   common::Console::SetVerbosity(4);
 //! [add scenes]
   ManualSceneDemoPtr sceneDemo(new ManualSceneDemo);
@@ -188,7 +208,7 @@ int main(int, char**)
   sceneDemo->AddScene(SceneBuilderPtr(new ShadowSceneBuilder(4)));
   sceneDemo->AddScene(SceneBuilderPtr(new ShadowSceneBuilder(5)));
 //! [add scenes]
-  sceneDemo->AddCamera("ogre");
+  sceneDemo->AddCamera(ogre_engine);
   sceneDemo->AddCamera("optix");
   sceneDemo->Run();
   return 0;