I'm trying to render to texture using FBO using OpenTK in C#. When I try to render, everything show up and just fine except the texture is shown on bottom-left corner, I'm expecting it shown on the top left corner.
Also the Texture appear flipped in Y axis, So I need to modify the Texture Matrix after binding the Texture Target.
If I just bind my texture and draw the vertices, the sprite will appear on top-left corner.
The codes I use is looks exactly same from the official documentation.
I got 2 questions:
1. Am I doing it right to make the target texture show up properly by modifying the Texture Matrix?
2. How to make the texture target appear on top left corner?
Thanks in advance!
I encountered similar problems when the first time I tried FBO, so here my answer:
Although there several ways to workaround against this Upside down problem, Modifying Texture Matrix isn't bad idea at all. Sometimes modifying Texture matrix could be handy in certain situation, e.g: Use non normalized texture coordinate, So you can add such features to your bind texture function.
It's seems projection / viewport issue, if you are sure that the normal sprite appear on top-left coordinate, try to re-setup your projection / view / camera before unbind the FBO handle.