Update on resize instead of pre-render / render (gazebosim#1028)

Signed-off-by: Ian Chen <ichen@osrfoundation.org>
Signed-off-by: William Lew <WilliamMilesLew@gmail.com>

src/gui/plugins/scene3d/Scene3D.cc

@@ -600,8 +600,7 @@ void IgnRenderer::Render(RenderSync *_renderSync)
     // setting the size should cause the render texture to be rebuilt
     {
       IGN_PROFILE("IgnRenderer::Render Pre-render camera");
-      this->dataPtr->camera->PreRender();
-      this->dataPtr->camera->Render();
+      this->dataPtr->camera->Update();
     }
     this->textureDirty = false;