Factor out more resources.

+ Use QOpenGLShader to get compiled shader code in TreeView.
+ Remove last remaining Qt resources dependency in libqtk.
+ shaders.h in libqtk to define default GLSL shader programs.

src/designer-plugins/toolbox.cpp

@@ -130,13 +130,8 @@ void ToolBox::createPageShader(const Object * object)
 
   auto shaderView = new QTextEdit;
   shaderView->setReadOnly(true);
-  auto vertexFile = QFile(object->getVertexShader().c_str());
-  if (vertexFile.exists()) {
-    vertexFile.open(QIODeviceBase::ReadOnly);
-    shaderView->setText(vertexFile.readAll());
-    vertexFile.close();
-    mainLayout->addRow(shaderView);
-  }
+  shaderView->setText(object->getVertexShaderSourceCode().c_str());
+  mainLayout->addRow(shaderView);
 
   rowLayout = new QHBoxLayout;
   rowLayout->addWidget(new QLabel("Fragment Shader:"));
@@ -145,13 +140,8 @@ void ToolBox::createPageShader(const Object * object)
 
   shaderView = new QTextEdit;
   shaderView->setReadOnly(true);
-  auto fragmentfile = QFile(object->getFragmentShader().c_str());
-  if (fragmentfile.exists()) {
-    fragmentfile.open(QIODeviceBase::ReadOnly);
-    shaderView->setText(fragmentfile.readAll());
-    fragmentfile.close();
-    mainLayout->addRow(shaderView);
-  }
+  shaderView->setText(object->getFragmentShaderSourceCode().c_str());
+  mainLayout->addRow(shaderView);
 
   widget->setLayout(mainLayout);
 }