Fix segfault binding unloaded texture.

example-app/examplescene.cpp

@@ -22,18 +22,7 @@ ExampleScene::~ExampleScene() = default;
 
 void ExampleScene::init()
 {
-  setSkybox(new Qtk::Skybox(":/textures/skybox/right.png",
+  setSkybox(new Qtk::Skybox);
-                            ":/textures/skybox/top.png",
-                            ":/textures/skybox/front.png",
-                            ":/textures/skybox/left.png",
-                            ":/textures/skybox/bottom.png",
-                            ":/textures/skybox/back.png",
-                            "Skybox"));
-
-  std::string spartanPath = QTK_EXAMPLE_SOURCE_DIR;
-  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_ELEMENTS)));

src/qtk/meshrenderer.cpp

@@ -121,9 +121,7 @@ void MeshRenderer::draw()
   bindShaders();
   mVAO.bind();
 
-  if (mTexture.hasTexture()) {
+  mTexture.bind();
-    mTexture.getOpenGLTexture().bind();
-  }
 
   // TODO: Automate uniforms some other way
   setUniformMVP();
@@ -138,9 +136,7 @@ void MeshRenderer::draw()
                    mShape.mIndices.data());
   }
 
-  if (mTexture.hasTexture()) {
+  mTexture.bind();
-    mTexture.getOpenGLTexture().release();
-  }
 
   mVAO.release();
   releaseShaders();

src/qtk/skybox.cpp

@@ -17,9 +17,28 @@ using namespace Qtk;
  * Constructors / Destructors
  ******************************************************************************/
 
-Skybox::Skybox(QOpenGLTexture * cubeMap, const std::string & name)
+Skybox::Skybox(const std::string & name) :
+    mVBO(QOpenGLBuffer::VertexBuffer),
+    mVertices(Cube(QTK_DRAW_ELEMENTS).getVertices()),
+    mIndices(Cube(QTK_DRAW_ELEMENTS).getIndexData())
 {
-  mTexture.setTexture(cubeMap);
+  QImage image({1024, 1024}, QImage::Format_RGBA8888);
+  image.fill(Qt::darkGray);
+  mTexture.setCubeMap(image, image, image, image, image, image);
+  init();
+}
+
+Skybox::Skybox(QOpenGLTexture * cubeMap, const std::string & name) :
+    mVBO(QOpenGLBuffer::VertexBuffer),
+    mVertices(Cube(QTK_DRAW_ELEMENTS).getVertices()),
+    mIndices(Cube(QTK_DRAW_ELEMENTS).getIndexData())
+{
+  if (cubeMap == Q_NULLPTR) {
+    qDebug()
+        << "[Qtk] Failed to set cubemap for skybox with null QOpenGLTexture.";
+  } else {
+    mTexture.setTexture(cubeMap);
+  }
   init();
 }
 
@@ -34,13 +53,13 @@ Skybox::Skybox(const std::string & right,
     mVertices(Cube(QTK_DRAW_ELEMENTS).getVertices()),
     mIndices(Cube(QTK_DRAW_ELEMENTS).getIndexData())
 {
-  init();
   mTexture.setCubeMap(QImage(right.c_str()).mirrored(),
                       QImage(top.c_str()),
                       QImage(front.c_str()),
                       QImage(left.c_str()),
                       QImage(bottom.c_str()),
                       QImage(back.c_str()));
+  init();
 }
 
 /*******************************************************************************
@@ -54,7 +73,7 @@ void Skybox::draw()
 
   mVAO.bind();
   mProgram.bind();
-  mTexture.getOpenGLTexture().bind();
+  mTexture.bind();
 
   mProgram.setUniformValue("uProjectionMatrix", Scene::getProjectionMatrix());
   mProgram.setUniformValue("uViewMatrix", Scene::getCamera().toMatrix());
@@ -62,7 +81,7 @@ void Skybox::draw()
   glDrawElements(
       GL_TRIANGLES, mIndices.size(), GL_UNSIGNED_INT, mIndices.data());
 
-  mTexture.getOpenGLTexture().bind();
+  mTexture.bind();
   mProgram.release();
   mVAO.release();
 

src/qtk/skybox.h

@@ -34,7 +34,12 @@ namespace Qtk
        * Constructors / Destructors
        ************************************************************************/
 
-      // Delegate this constructor to use default skybox images
+      /**
+       * Construct a skybox with a default texture.
+       *
+       * @param name The objectName to use for the Skybox.
+       */
+      explicit Skybox(const std::string & name = "Skybox");
 
       /**
        * Construct a skybox with an existing QOpenGLTexture.

src/qtk/texture.cpp

@@ -104,9 +104,9 @@ QOpenGLTexture * OpenGLTextureFactory::initCubeMap(const QImage & right,
       QOpenGLTexture::CubeMapNegativeZ};
   int i = 0;
   for (const auto & face : faces) {
-    QImage faceImage(faceTextures[i]);
+    QImage & faceImage = faceTextures[i];
     if (faceImage.isNull()) {
-      qDebug() << "Error loading cube map image\n";
+      qDebug() << "[libqtk] Error loading cube map image\n";
       faceImage = defaultTexture();
     }
     faceImage = faceImage.convertToFormat(QImage::Format_RGBA8888);

src/qtk/texture.h

@@ -217,6 +217,20 @@ namespace Qtk
         return mOpenGLTexture != Q_NULLPTR;
       }
 
+      /**
+       * Bind the OpenGL texture if it exists, avoiding segmentation faults.
+       */
+      bool bind() const
+      {
+        if (hasTexture()) {
+          // TODO: It would be nice to warn here but some objects may not have
+          // a texture. Factor Texture out of those objects so we don't bind.
+          mOpenGLTexture->bind();
+          return true;
+        }
+        return false;
+      }
+
       /*************************************************************************
        * Accessors
        ************************************************************************/
@@ -300,12 +314,12 @@ namespace Qtk
       /**
        * Sets this Texture to be a cube map with provided sides.
        *
-       * @param right Path to texture to use for right cube map side.
+       * @param right QImage texture to use for right cube map side.
-       * @param top Path to texture to use for top cube map side.
+       * @param top QImage texture to use for top cube map side.
-       * @param front Path to texture to use for front cube map side.
+       * @param front QImage texture to use for front cube map side.
-       * @param left Path to texture to use for left cube map side.
+       * @param left QImage texture to use for left cube map side.
-       * @param bottom Path to texture to use for bottom cube map side.
+       * @param bottom QImage texture to use for bottom cube map side.
-       * @param back Path to texture to use for back cube map side.
+       * @param back QImage texture to use for back cube map side.
        */
       virtual inline void setCubeMap(const QImage & right,
                                      const QImage & top,