documented and completed viewer GL widget

app/widget/viewer/viewerglwidget.cpp

@@ -8,28 +8,44 @@
 #include "render/gl/shadergenerators.h"
 
 ViewerGLWidget::ViewerGLWidget(QWidget *parent) :
-  QOpenGLWidget(parent)
+  QOpenGLWidget(parent),
+  texture_(0)
 {
 }
 
+void ViewerGLWidget::SetTexture(GLuint tex)
+{
+  // Update the texture
+  texture_ = tex;
+
+  // Paint the texture
+  update();
+}
+
+void ViewerGLWidget::initializeGL()
+{
+  // Re-retrieve pipeline pertaining to this context
+  pipeline_ = olive::gl::GetDefaultPipeline();
+}
+
 void ViewerGLWidget::paintGL()
 {
-  /*
+  // Get functions attached to this context (they will already be initialized)
   QOpenGLFunctions* f = context()->functions();
 
-  f->glClearColor(1.0f, 0.0f, 0.0f, 1.0f);
+  // Clear background to empty
+  f->glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
   f->glClear(GL_COLOR_BUFFER_BIT);
 
-  QOpenGLTexture* tex = new QOpenGLTexture(img);
+  // Check if we have a texture to draw
+  if (texture_ > 0) {
+    // Bind retrieved texture
+    f->glBindTexture(GL_TEXTURE_2D, texture_);
 
-  ShaderPtr pipeline = olive::gl::GetDefaultPipeline();
+    // Blit using the pipeline retrieved in initializeGL()
+    olive::gl::Blit(pipeline_, true);
 
-  tex->bind();
-
-  olive::gl::Blit(pipeline, true);
-
-  tex->release();
-
-  delete tex;
-  */
+    // Release retrieved texture
+    f->glBindTexture(GL_TEXTURE_2D, 0);
+  }
 }