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Index › Programming Questions & Help › Syntax Questions › Image array speed

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Image array speed (Read 739 times)

pauline YaBB Newbies Offline Posts: 6	Image array speed Apr 12^th, 2010, 11:17pm Howdy, Is there a way to have an image array that moves at a different frame rate from the one defined in void draw? the only way I can think of is duplicating the same frame so it appears to Any suggestions or comments will be GREATLY appreciated

Bejoscha

Re: Image array speed
Reply #1 - Apr 13^th, 2010, 1:24am

Not sure I got your question.
You have several options:
1) You can change the frame-rate of your sketch, but that would cause ALL drawings to change speed.
2) You act on one of your images only ever x-th frame, so that the value of x slows the movement.
3) The "speed" (the offset) you are moving your image with each redraw is different for your objects.

Sketch 1: 2 balls moving left-right with same speed. Pressing +/- changes the framerate.

Quote:

PVector Pos1;
PVector Pos2;
void setup()
{
   size(600,100);
   stroke(255);
   strokeWeight(10);
   Pos1 = new PVector(20,30); // just a starting position
   Pos2 = new PVector(20,80); // just a starting position
}
void draw()
{
  background(0);
  point(Pos1.x,Pos1.y);
  point(Pos2.x,Pos2.y);
  Pos1.x+=5;  // shift position 5 pixels to the right by adding 5
  Pos2.x+=5;  // shift position 5 pixels to the right by adding 5
  if (Pos1.x>=width) Pos1.x-=width; // warp at right boarder
  if (Pos2.x>=width) Pos2.x-=width; // warp at right boarder
}

void keyPressed()
{
   if (key=='+') frameRate(min(30,frameRate+5));
   if (key=='-') frameRate(max(1,frameRate-5));
}

Seketch 2: Two balls at different speed by adding different "velocity"

Quote:

PVector Pos1;
PVector Pos2;
void setup()
{
   size(600,100);
   stroke(255);
   strokeWeight(10);
   Pos1 = new PVector(20,30); // just a starting position
   Pos2 = new PVector(20,80); // just a starting position
}
void draw()
{
  background(0);
  point(Pos1.x,Pos1.y);
  point(Pos2.x,Pos2.y);
  Pos1.x+=5;  // shift position 5 pixels to the right by adding 5
  Pos2.x+=1;  // shift position 1 pixel to the right by adding 1
  if (Pos1.x>=width) Pos1.x-=width; // warp at right boarder
  if (Pos2.x>=width) Pos2.x-=width; // warp at right boarder
}

void keyPressed()
{
   if (key=='+') frameRate(min(30,frameRate+5));
   if (key=='-') frameRate(max(1,frameRate-5));
}

Sketch 3: Different speed by acting every 5th frame only.
Quote:

PVector Pos1;
PVector Pos2;
void setup()
{
   size(600,100);
   stroke(255);
   strokeWeight(10);
   Pos1 = new PVector(20,30); // just a starting position
   Pos2 = new PVector(20,80); // just a starting position
}
void draw()
{
  background(0);
  point(Pos1.x,Pos1.y);
  point(Pos2.x,Pos2.y);
  Pos1.x+=5;  // shift position 5 pixels to the right by adding 5
  if (frameCount%5==0) Pos2.x+=5; // shift every 5th update only
  if (Pos1.x>=width) Pos1.x-=width; // warp at right boarder
  if (Pos2.x>=width) Pos2.x-=width; // warp at right boarder
}

void keyPressed()
{
   if (key=='+') frameRate(min(30,frameRate+5));
   if (key=='-') frameRate(max(1,frameRate-5));
}

blindfish

Re: Image array speed
Reply #2 - Apr 13^th, 2010, 1:39am

Presumably you're talking about an array of images that forms an animation... In which case you'd be interested in the speed at which you move from one image to the next to control the framerate of the animation.

I haven't tried any of the animation libraries but you may find one of them suits your needs. Otherwise the best approach would actually be to use a time-based approach where you count millis() and trigger a new frame based on the time ellapsed... Unless you're relying on the Processing framerate to control something else it's often recommended to set it to some arbitraryily high number (e.g. 999) to force the sketch to run as fast as possible - since at the default I guess there's the chance that the framerate of the sketch doesn't coincide with the framerate of the animation meaning a frame might get triggered a few milliseconds later than it should have; though TBH I'm not convinced this would be visible unless the sketch was running at a very slow rate...

Just make sure the images are preloaded in setup rather than trying to load each one in draw Wink

Where is the what if the what is in why?

pauline YaBB Newbies Offline Posts: 6	Re: Image array speed Reply #3 - Apr 13^th, 2010, 2:25am I am aware of speed changing speed of moving objects, but not in regards to an image array without affecting everything in the sketch. Thanks for the responses

Bejoscha Full Member Offline Posts: 120	Re: Image array speed Reply #4 - Apr 13^th, 2010, 3:16am @Pauline: Maybe it's best you post/share some basic-script and explain what you want to achieve? If it is about "cycling" through an image array at different speeds you could use the sketch #3 method of cycling through one image array only every x-th frame...

blindfish

Re: Image array speed
Reply #5 - Apr 13^th, 2010, 10:01am

Bejoscha wrote on Apr 13^th, 2010, 3:16am:

@Pauline: Maybe it's best you post/share some basic-script and explain what you want to achieve
If it is about "cycling" through an image array at different speeds you could use the sketch #3 method of cycling through one image array only every x-th frame...

The only potential problem with that is that the sketch framerate is not necessarily consistent, so if you push the processor too hard you may encounter slowdown in your animation when using this approach. Using a time-based approach you have the option to drop frames if the sketch can't keep up...

Where is the what if the what is in why?

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