free resources on app destruction

src/node_stroke_preview.cpp

@@ -30,7 +30,6 @@ void NodeStrokePreview::clone_finalize(Node* dest) const
 
 void NodeStrokePreview::init_controls()
 {
-    m_mesh.create();
     m_sampler_linear.create();
     m_sampler_linear_repeat.create(GL_LINEAR, GL_REPEAT);
     m_sampler_mipmap.create();
@@ -470,3 +469,14 @@ void NodeStrokePreview::handle_resize(glm::vec2 old_size, glm::vec2 new_size)
 
     draw_stroke();
 }
+
+void NodeStrokePreview::destroy_immediate()
+{
+    Node::destroy_immediate();
+    m_rtt.destroy();
+    m_rtt_mixer.destroy();
+    m_tex.destroy();
+    m_tex_dual.destroy();
+    m_tex_background.destroy();
+    m_brush_shape.destroy();
+}