Clean up example code.

+ Fix spartan path.
+ Fix triangle draw mode.

example-app/examplescene.cpp

@@ -11,7 +11,8 @@
 
 using namespace Qtk;
 
-ExampleScene::ExampleScene(Qtk::Scene * scene) : Qtk::SceneInterface(scene) {
+ExampleScene::ExampleScene()
+{
   setSceneName("Example Scene");
   getCamera().getTransform().setTranslation(-8.0f, 0.0f, 10.0f);
   getCamera().getTransform().setRotation(-5.0f, 0.0f, 1.0f, 0.0f);
@@ -19,18 +20,17 @@ ExampleScene::ExampleScene(Qtk::Scene * scene) : Qtk::SceneInterface(scene) {
 
 ExampleScene::~ExampleScene() = default;
 
-void ExampleScene::init() {
-  auto skybox = new Qtk::Skybox("Skybox");
-  setSkybox(skybox);
+void ExampleScene::init()
+{
+  setSkybox(new Qtk::Skybox("Skybox"));
 
   std::string spartanPath = QTK_EXAMPLE_SOURCE_DIR;
-  spartanPath += "/resources/models/spartan/spartan.obj";
-  auto spartan = new Model("spartan", spartanPath.c_str());
-  addObject(spartan);
+  spartanPath += "/../resources/models/spartan/spartan.obj";
+  auto spartan = addObject(new Model("spartan", spartanPath.c_str()));
   spartan->getTransform().setTranslation(-4.0f, 0.0f, 0.0f);
 
   auto mesh = addObject(
-      new Qtk::MeshRenderer("rightTriangle", Triangle(QTK_DRAW_ARRAYS)));
+      new Qtk::MeshRenderer("rightTriangle", Triangle(QTK_DRAW_ELEMENTS)));
   mesh->getTransform().setTranslation(-5.0f, 0.0f, -2.0f);
 
   // QTK_DRAW_ARRAYS is the default for generic shapes in qtk/shape.h
@@ -56,11 +56,17 @@ void ExampleScene::init() {
   mesh->setColor(GREEN);
 }
 
-void ExampleScene::draw() {
+void ExampleScene::draw()
+{
+  // No custom draw logic for this example.
   Scene::draw();
 }
 
-void ExampleScene::update() {
+void ExampleScene::update()
+{
+  auto top_triangle = MeshRenderer::getInstance("topTriangle");
+  auto bottom_triangle = MeshRenderer::getInstance("bottomTriangle");
+
   // Pitch forward and roll sideways
   MeshRenderer::getInstance("leftTriangle")
       ->getTransform()
@@ -69,29 +75,21 @@ void ExampleScene::update() {
       ->getTransform()
       .rotate(0.75f, 0.0f, 0.0f, 1.0f);
 
+  // Make the top and bottom triangles slide left-to-right.
   static float translateX = 0.025f;
   float limit = -9.0f;  // Origin position.x - 2.0f
-  float posX = MeshRenderer::getInstance("topTriangle")
-                   ->getTransform()
-                   .getTranslation()
-                   .x();
-  if(posX < limit || posX > limit + 4.0f) {
+  float posX = top_triangle->getTransform().getTranslation().x();
+  if (posX < limit || posX > limit + 4.0f) {
     translateX = -translateX;
   }
-  MeshRenderer::getInstance("topTriangle")
-      ->getTransform()
-      .translate(translateX, 0.0f, 0.0f);
-  MeshRenderer::getInstance("bottomTriangle")
-      ->getTransform()
-      .translate(-translateX, 0.0f, 0.0f);
-  MeshRenderer::getInstance("topTriangle")
-      ->getTransform()
-      .rotate(0.75f, 0.2f, 0.0f, 0.4f);
-  MeshRenderer::getInstance("bottomTriangle")
-      ->getTransform()
-      .rotate(0.75f, 0.0f, 0.2f, 0.4f);
 
-  MeshRenderer::getInstance("centerCube")
-      ->getTransform()
+  top_triangle->getTransform().translate(translateX, 0.0f, 0.0f);
+  bottom_triangle->getTransform().translate(-translateX, 0.0f, 0.0f);
+
+  // Apply some rotation to the triangles as they move left-to-right.
+  top_triangle->getTransform().rotate(0.75f, 0.2f, 0.0f, 0.4f);
+  bottom_triangle->getTransform().rotate(0.75f, 0.0f, 0.2f, 0.4f);
+
+  MeshRenderer::getInstance("centerCube")->getTransform()
       .rotate(0.75f, 0.2f, 0.4f, 0.6f);
 }

example-app/examplescene.h

@@ -11,16 +11,29 @@
 
 #include <qtk/scene.h>
 
-class ExampleScene : public Qtk::SceneInterface {
+class ExampleScene : public Qtk::Scene {
   public:
-    explicit ExampleScene(Qtk::Scene * scene);
+    explicit ExampleScene();
 
     ~ExampleScene();
 
+    /**
+     * Override the initialization logic for the scene.
+     * This method should up the scene's objects, skybox, etc.
+     */
     void init() override;
 
+    /**
+     * Optionally override the draw method for the scene.
+     *
+     * This is just here for example, it should be omitted entirely if we don't
+     * want to provide a custom implementation for the ExampleScene.
+     */
     void draw() override;
 
+    /**
+     * Update objects in the scene for translation or rotation.
+     */
     void update() override;
 };
 

example-app/examplewidget.cpp

@@ -11,7 +11,7 @@
 #include "examplewidget.h"
 
 ExampleWidget::ExampleWidget(QWidget * parent) :
-    QOpenGLWidget(parent), mScene(new ExampleScene(new Qtk::SceneEmpty)) {
+    QOpenGLWidget(parent), mScene(new ExampleScene) {
   // NOTE: The decorator pattern is used to save / load scenes in Qtk currently.
   // The initializer above sets mScene to the concrete decorator ExampleScene.
   // Qtk::SceneEmpty provides an empty scene as the concrete component.

src/qtk/scene.cpp

@@ -58,6 +58,8 @@ void Scene::draw() {
     mInit = true;
   }
 
+  // Check if there were new models added that still need to be loaded.
+  // This is for objects added at runtime via click-and-drag events, etc.
   while(!mModelLoadQueue.empty()) {
     auto modelSpec = mModelLoadQueue.front();
     // Load the model and add it to the scene.

src/qtk/scene.h

@@ -53,7 +53,7 @@ namespace Qtk {
 
       Scene();
 
-      virtual ~Scene();
+      ~Scene() override;
 
       /*************************************************************************
        * Public Methods
@@ -73,10 +73,13 @@ namespace Qtk {
 
       /**
        * Function called to update the QOpenGLWidget. Does not trigger a redraw.
-       *
+       * This method can translate or rotate objects to simulate movement.
        * Calling this several times will still result in only one repaint.
+       *
+       * It's very possible a client will not want to move objects in the scene
+       * using this method. This is intentially not pure virtual.
        */
-      virtual void update() {}
+      virtual void update() { }
 
       void loadModel(const QUrl & url) {
         auto fileName = url.fileName().replace(".obj", "").toStdString();
@@ -239,30 +242,6 @@ namespace Qtk {
       /* Track count of objects with same initial name. */
       std::unordered_map<std::string, uint64_t> mObjectCount;
   };
-
-  class SceneEmpty : public Scene {
-    public:
-      void init() override { setSceneName("Empty Scene"); }
-
-      void draw() override { Scene::draw(); }
-
-      void update() override { Scene::update(); }
-  };
-
-  class SceneInterface : public Scene {
-    public:
-      explicit SceneInterface(Scene * scene) : mScene(scene) {}
-
-      void init() override { mScene->init(); }
-
-      void draw() override { mScene->draw(); }
-
-      void update() override { mScene->update(); }
-
-    protected:
-      Scene * mScene;
-  };
-
 }  // namespace Qtk
 
 #endif  // QTK_SCENE_H