Chapter 16: Example 16-3: Adjust Video Brightness

// Learning Processing
// Daniel Shiffman
// http://www.learningprocessing.com

// Example 16-3: Adjust video brightness

// Step 1. Import the video library
import processing.video.*;

// Step 2. Declare a Capture object
Capture video;

void setup() {
  size(320,240);
  
  // Step 3. Initialize Capture object via Constructor
  // video is 320 x 240, @15 fps
  video = new Capture(this,320,240,15); 
  background(0);
}

void draw() {
  
  // Check to see if a new frame is available
  if (video.available()) {
    // If so, read it.
    video.read();
  }
  
  loadPixels();
  video.loadPixels();
  
  for (int x = 0; x < video.width; x++) {
    for (int y = 0; y < video.height; y++) {
      
      // Calculate the 1D location from a 2D grid
      int loc = x + y*video.width;
      
      // Get the R,G,B values from image
      float r,g,b;
      r = red (video.pixels[loc]);
      g = green (video.pixels[loc]);
      b = blue (video.pixels[loc]);
      
      // Calculate an amount to change brightness based on proximity to the mouse
      float maxdist = 100;// dist(0,0,width,height);
      float d = dist(x,y,mouseX,mouseY);
      float adjustbrightness = (maxdist-d)/maxdist;
      r *= adjustbrightness;
      g *= adjustbrightness;
      b *= adjustbrightness;
      
      // Constrain RGB to make sure they are within 0-255 color range
      r = constrain(r,0,255);
      g = constrain(g,0,255);
      b = constrain(b,0,255);
      
      // Make a new color and set pixel in the window
      color c = color(r,g,b);
      pixels[loc] = c;
    }
  }
  updatePixels();
}