move time-lapse frame grab from tick to rec_loop

src/canvas_layer.cpp

@@ -108,8 +108,10 @@ PBO Layer::gen_equirect_pbo(glm::ivec2 size /*= { 0, 0 }*/)
 
     PBO pbo;
     TextureCube cube = gen_cube();
+    std::this_thread::yield();
     RTT latlong;
     latlong.create(size.x * 4, size.y * 2);
+    std::this_thread::yield();
 
     App::I->render_task([&]
     {
@@ -129,9 +131,9 @@ PBO Layer::gen_equirect_pbo(glm::ivec2 size /*= { 0, 0 }*/)
 
         latlong.unbindFramebuffer();
     });
-
+    std::this_thread::yield();
     pbo.create(latlong);
-
+    std::this_thread::yield();
     latlong.destroy();
     cube.destroy();
     return pbo;