Choppy/Jittery fast motion - hardware or code?

Hello.

In the following example there is a stripped down version of everything I do in processing or have been doing since 2009, things moving across the screen at equal speed.

All this time I have never seen a movement like this look completely smooth on any system except maybe once in a mega gaming computer with top specs. That inspired me to purchase an eGPU a Nvidia GTX-1080 which is very good off course but this only helps a little bit.

I wonder if there is anything I can do to make continuous movements look smoother and less choppy. Is there something I can do to code this type of thing more efficiently and/or is there a way to utilize better my fancy eGPU. I have tried the P2D renderer and the results are not much different.

Do I just need to get the fanciest CPU available? What puzzles me is that it seems like a simple task. It seems to be easy to make much more complicated things look smooth and easy.

Any hints or tips would be greatly appreciated.

best regards,
Steini

int x;

void setup() {
  size(640, 360);
  noSmooth();
  fill(126);
  frameRate(30);
 
}

void draw() {
       background(102);
  
     x -= 4;
    stroke(255);
    rect(x+width, 30, 10, 10);
    rect(x+width+10, +70, 40, 10);
    rect(x+width+30, +120, 10, 30);      
    rect(x+width+50, +180, 20, 12);
    rect(x+width+90, +210, 33, 24); 


     if (x <= -850){
           x = 0;
          }

}
1 Like

Hey there!

Don’t worry, you don’t need the fanciest CPU available for tasks like these :slight_smile:

The choppy/jittery motion is likely a result of the way you coded your sketch. At a default frameRate of 60, you’re asking Processing to recalculate positions and sizes for 5 rectangles 60 times a second. Additionally all rectangles will be ‘redrawn from scratch’ at each frame.

Seeing the sizes of the shapes stay the same throughout your sketch, you could already improve your code by using PShapes. It enables you to store a shape as data which you can then reuse throughout your sketch, meaning your sketch won’t have to redraw it from scratch 60 times a second any more. Now it only has to recalculate the positions and place the existing shapes.

The PShape tutorial contains more examples and explanation. Another thing you can look into are classes, but for the example you showed us PShapes will probably suffice.

Hope that helps!

2 Likes

Yes thanks a lot!

I am using classes usually, yes, but I have never worked with PShapes, and yes, they usually stay the same throughout in my case.

I’ll check out the PShape

thanks again!

The P2D renderer, if not the default renderer, is likely to be locked to the vsync of the display. It’s worth trying a framerate at least as high as the display refresh rate, although potentially better set to 2x or more (eg. 120 for a 60Hz display). Of course, if your display is something like 75Hz then 30 or 60 fps will be jerky.

The other thing is that you might be better moving the rectangles based on time rather than a fixed amount per frame.

3 Likes

it helps to show the FPS
and to play with / compare modes: size(640, 360); // ,FX2D P2D P3D
( using low end hardware i found size(640, 360); most choppy )

int fr=30, x=0;

void setup() {
  size(640, 360);  // ,FX2D P2D  P3D  
  //noSmooth();
  fill(126);
  frameRate(fr);
  background(102);
}

void draw() {
  //  background(102);   // replace with:
  fill(102);
  stroke(102);
  rect(0, 0, width, height-120);
  // moving rects
  stroke(255);
  rect(x+2, 30, 10, 10);
  rect(x+10, 70, 40, 10);
  rect(x+30, 120, 10, 30);      
  rect(x+50, 180, 20, 12);
  rect(x+90, 210, 33, 24);
  // FPS scope
  stroke(0);
  line(x, height, x, height-120);
  stroke(200, 200, 0);
  line(x, height-60, x, height-60-(frameRate-fr)*5);
  x += 1;
  if ( x > width)  x = 0;
}

2 Likes

Wow, thank you guys.

I’ve been testing all of these things. I’m sure the PShape thing will be very helpful in my final result which has a lot of stuff, I’m already implementing it.

So I did try 120 fps and 60 30 and yes the screen I’m using is 60hz and yes, I have experienced phasing before. I had never tried the FX2D before, I ddin’t know about it, it’s much better actually, works really well with my setup apparently. I’m continuing to try this all out.

So I’m changing sizes and doing fps monitoring and even when it’s flatlined I still see the occasional jump/jitter although much much less than before.

So there is yet something other that is interrupting as well, which is not framerate or refresh rate related apparently. Some programmer who is not familiar with processing told me about hardware affinity or thread affinity, wondering if dual or multiple core processors etc, actually might cause such glitches in real-time renderings when things are being sent back and forth, while creating a hardware affinity you can link the whole code to one core or thread in the CPU. I wonder if anyone has experience with this or if it is at all possible in processing and if it’s even feasible at all.

And then maybe I’m just paranoid by looking at the screen for to long, seeing jitters everywhere I look.

Thanks again so much you guys.

3 Likes

You are not paranoid! Just mindful.

Sharing:

I have jitters at the startup of all my sketches as per my “FrameRate hiccups topic” including yours.

I tried your sketch with P2D and have the same jitters at start and then it seems fine with the occasional jitters.

You may want to explore your NVIDIA card settings:


I made some interesting observations investigating these and will share later.

Windows 10 has Graphics settings:


I set these but have not tested.

:slight_smile:

2 Likes

Ah, I have a mac with an eGPU and cannot seem to access these parameters. But they might be setup already. I’ll look into how to find them. Even if via terminal or whatever. It might change something.