I had a bit of a hard time to follow this. There's a bunch of things that changed from the last lecture. Jumping to the outline code, it's not really obvious what to replace and where to place it. Some things changed without much explanation, such as the Size which was a float and became a Vector 2.
What is the purpose of making it a vec2? Don't we assume pixels are square? Is it for being supported to some particular devices?
Hm, I must've done an earlier version of the outline, I see the previous version is now updated to match with this lecture. I guess I'm a bit outdated, never mind then..!