Processing 1.0 - Processing Discourse - Help with Delay/Break/Pause

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Index › Programming Questions & Help › Syntax Questions › Help with Delay/Break/Pause

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Help with Delay/Break/Pause (Read 1303 times)

Winglets747

Help with Delay/Break/Pause
Feb 26^th, 2007, 4:31am

Hi all,
I'm trying to create a sketch where a random image is displayed, then automatically changes after a brief period of time (in the code below, I have it at 2 seconds).

I thought I could do this with the Delay function, but that does not seem to work. I thought about the Loop/No Loop option, but everything I saw there required the user to input when to resume the sketch.

In the end, I'll have approximately 400 images to cycle through.

If it helps, here is a brief version of my current code:
###

int pic_counter;
PImage Afghanistan1;
PImage Afghanistan2;

void setup(){
size(240,240);
Afghanistan1 = loadImage("Afghanistan11.jpg");
Afghanistan2 = loadImage("Afghanistan21.jpg");
}

void draw(){
if(pic_counter == 1){
image(Afghanistan1,0,0);
}

if(pic_counter == 2){
image(Afghanistan2,0,0);
}

for(int i = 0; i<20; i++){
drawPicture();
}
}

void drawPicture(){
pic_counter = int(random(1,2));
//delay(2000);
//pic_counter = int(random(2,2));
}

###
Thanks,
Will

jaylfk

Re: Help with Delay/Break/Pause
Reply #1 - Feb 26^th, 2007, 6:39am

Here is an example of a slide show code i'm using

Quote:

// Modified Code from bodytag.org/tp02/tp02.pde (Glen Murphy)

PImage scene, im1, im2, im3;
int sloop = 0;
int WIDTH=640;
int HEIGHT=480;
int WH = WIDTH*HEIGHT;

int blend(int org, int col, int alpha) {
int r1=(org&0x0000ff);
int g1=(org&0x00ff00);
int b1=(org&0xff0000);
int r2=(col&0x0000ff);
int g2=(col&0x00ff00);
int b2=(col&0xff0000);

int r3=(((alpha*(r1-r2)) >>8 )+r2)&0x000000ff;
int g3=(((alpha*(g1-g2)) >>8 )+g2)&0x0000ff00;
int b3=(((alpha*(b1-b2)) >>8 )+b2)&0x00ff0000;

return (r3)|(g3)|(b3);
}

void setup() {
size(640,480,P3D);
frameRate(15);
loadPixels();
scene = loadImage("myimage01.jpg");
im1 = loadImage("myimage01.jpg");
im2 = loadImage("myimage02.jpg");
im3 = loadImage("myimage03.jpg");
background(0);
}

void draw() {
for(int i = 0; i < WH-1; i++) {
if(sloop < 255) {
scene.pixels[i] = blend(im1.pixels[i], im2.pixels[i], 255-sloop);
}
else if(sloop < 510) {
scene.pixels[i] = blend(im2.pixels[i], im3.pixels[i], 255-sloop%255);
}
else if(sloop < 765) {
scene.pixels[i] = blend(im3.pixels[i], im1.pixels[i], 255-sloop%255);
}
else sloop = 0;
pixels[i] = scene.pixels[i];
updatePixels();
}
sloop++;
}

There is no pause between images, but the fading effect is slow/smooth enough to enjoy the slide. Wink

JohnG

Re: Help with Delay/Break/Pause
Reply #2 - Feb 26^th, 2007, 11:04am

One way you could simulate a 2 second delay, would be to only change the image, if the value of millis has increased by 2000 since the last image change;
Code:

int lastMillis;

void setup()
{
  //normal setup
  lastMillis=0;
}

void draw()
{
  if(lastMillis==0 || millis() > (lastMillis+2000))
  {
    lastMillis=millis();
    //move to next image
  }
}

However, it should be noted that you're going to have problems with 400 images, though it may not affect the final output with some tweaking.

400 images will take up too much memory to load them all in setup, and loading images in draw can be slow.. so, you may not need to have a 2000 millis delay, since the image loading could take about the same length of time, depending if it's being run as an applet, or a local version.

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