euglena/lib/video/examples/Capture/Spatiotemporal/Spatiotemporal.pde

/**
 * Spatiotemporal
 * by David Muth
 * 
 * Records a number of video frames into memory, then plays back the video
 * buffer by turning the time axis into the x-axis and vice versa
 */ 

import processing.video.*;

Capture video;
int signal = 0;

//the buffer for storing video frames
ArrayList frames;

//different program modes for recording and playback
int mode = 0;
int MODE_NEWBUFFER = 0;
int MODE_RECORDING = 1;
int MODE_PLAYBACK = 2;

int currentX = 0;

void setup() {
  size(640, 480);
  
  // This the default video input, see the GettingStartedCapture 
  // example if it creates an error
  video = new Capture(this, width, height);
  
  // Start capturing the images from the camera
  video.start();  
}

void captureEvent(Capture c) {
  c.read();

  //create a new buffer in case one is needed
  if (mode == MODE_NEWBUFFER) {
    frames = new ArrayList();
    mode = MODE_RECORDING;
  }

  //record into the buffer until there are enough frames
  if (mode == MODE_RECORDING) {
    //copy the current video frame into an image, so it can be stored in the buffer
    PImage img = createImage(width, height, RGB);
    video.loadPixels();
    arrayCopy(video.pixels, img.pixels);

    frames.add(img);

    //in case enough frames have been recorded, switch to playback mode
    if (frames.size() >= width) {
      mode = MODE_PLAYBACK;
    }
  }
}

void draw() { 
  loadPixels();

  //code for the recording mode 
  if (mode == MODE_RECORDING) {
    //set the image counter to 0
    int currentImage = 0;

    //begin a loop for displaying pixel columns
    for (int x = 0; x < video.width; x++) {
      //go through the frame buffer and pick an image using the image counter
      if (currentImage < frames.size()) {
        PImage img = (PImage)frames.get(currentImage);
        
        //display a pixel column of the current image
        if (img != null) {
          img.loadPixels();

          for (int y = 0; y < video.height; y++) {
            pixels[x + y * width] = img.pixels[x + y * video.width];
          }  
        }
        
        //increase the image counter
        currentImage++;
        
      } 
      else {
        break;
      }
    }
  }

  //code for displaying the spatiotemporal transformation
  if (mode == MODE_PLAYBACK) {  
    
    //begin a loop for displaying pixel columns
    for (int x = 0; x < video.width; x++) {
      //get an image from the buffer using loopcounter x as the index
      PImage img = (PImage)frames.get(x);

      if (img != null) {
        img.loadPixels();
        
        //pick the same column from each image for display, 
        //then distribute the columns over the x-axis on the screen
        for(int y = 0; y < video.height; y++) {
          pixels[x + y * width] = img.pixels[currentX + y * video.width];
        }  
      }
    } 

    //a different column shall be used next time draw() is being called
    currentX++;
    
    //if the end of the buffer is reached
    if(currentX >= video.width) {
      //create a new buffer when the next video frame arrives
      mode = MODE_NEWBUFFER;
      //reset the column counter
      currentX = 0;
    }
  }
  
  updatePixels();
}