// Learning Processing
// Daniel Shiffman
// http://www.learningprocessing.com
// Example 15-9: Adjusting image brightness based on pixel location (Flashlight effect)
PImage img;
void setup() {
size(200,200);
img = loadImage( "sunflower.jpg" );
}
void draw() {
loadPixels();
// We must also call loadPixels() on the PImage since we are going to read its pixels. img.loadPixels();
for (int x = 0; x < img.width; x++ ) {
for (int y = 0; y < img.height; y++ ) {
// Calculate the 1D pixel location
int loc = x + y*img.width;
// Get the R,G,B values from image
float r = red (img.pixels[loc]);
float g = green (img.pixels[loc]);
float b = blue (img.pixels[loc]);
// Calculate an amount to change brightness
// based on proximity to the mouse
float distance = dist(x,y,mouseX,mouseY);
// The closer the pixel is to the mouse, the lower the value of "distance"
// We want closer pixels to be brighter, however, so we invert the value with the formula: adjustBrightness = (50-distance)/50
// Pixels with a distance of 50 (or greater) have a brightness of 0.0 (or negative which is equivalent to 0 here)
// Pixels with a distance of 0 have a brightness of 1.0.
float adjustBrightness = (50-distance)/50;
r *= adjustBrightness;
g *= adjustBrightness;
b *= adjustBrightness;
// Constrain RGB to between 0-255
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();
}
