PImage img;
  
void setup() {
	size(500, 500);
	img = createImage(500, 500, RGB);
	for (int i = 0; i < img.pixels.length/2; i++) {
		img.pixels[i] = color(0, 150, 102);
	}
	for (int i = img.pixels.length/2; i < img.pixels.length; i++) {
		img.pixels[i] = color(200, 100, 32);
	}
	image(img, 0, 0);
}

void draw(){
	loadPixels();
	for (int x = 0; x < img.width; x++) {
		for (int y = 0; y < img.height; y++ ) {
			int loc = x + y*img.width;
			float r = red   (img.pixels[loc]);
			float g = green (img.pixels[loc]);
			float b = blue  (img.pixels[loc]);
			float distance = dist(x,y,mouseX,mouseY);
			float adjustBrightness = (100-distance)/100;
			r *= adjustBrightness;
			g *= adjustBrightness;
			b *= adjustBrightness;
			r = constrain(r,0,255);
			g = constrain(g,0,255);
			b = constrain(b,0,255);
			color c = color(r,g,b);
			pixels[loc] = c;
		}
	}
	updatePixels();
}