Playing with this all day, still no clue where this lag is coming from and how to eliminate it.
Here is an example which is a bit closer to my actual project:
Let me explain what you’re seeing here. There is a ring of points (where the pink circle is), and a corresponding ring of points further back whose positions are calculated based on the current camera position. Essentially, these ‘far points’ are always a continuation of the line between the camera and near point. I am using the resulting grid of lines to create a portal which changes the appearance of the material behind the portal. Since the calculations each frame are based on the camera position, this portal effect should always be behind the pink disc.
However, as you can see from the video above (which has been slowed down to 5% speed), there is a delay between the actual position of the camera and the position which is being used to drive the calculations for the portal.
The lines you see being drawn are line traces - the fact that you can see them like this shows that something is going wrong, because they should be drawn straight at the camera. We can see them as vertical lines going up the screen because they are being drawn to a point above the current camera position. Additionally, the little red dots you see are the ‘far points’. If there were being drawn correctly, they would always been behind the pink disc.
I am also printing to screen three things: (1) tick counter, (2) whether the camera is moving or static, and (3) whether the far points are moving or static. Again, if this were working properly, there would never be a discrepancy between the camera and far points being moving/static. However, on tick 786 you can see that the camera has stopped moving while the far points are still moving:
This is because, as can be seen, they are catching up with the position of the camera.
Please can someone, anyone, explain to me why this is the case, and what I can do to fix it?!
Note that I am doing a fair few calculations on tick based on the camera position, but this lag is the same whether I am doing this with one point, or 200.
I’m sorry if I’m sounding like a broken record here, but no-one is responding, and I’m totally stuck until I fix this!