Hello! New to Processing and have been experimenting with the tutorials and videos a bit, and have a hit a hurdle I am sure someone will have some insight to.
Essentially, I am trying to take the colour tracking algorithm from Tutorial 11.5, and utilise the avgX variable to control the panning of a sine wave. My code is below...
// Daniel Shiffman
// http://codingtra.in
// http://patreon.com/codingtrain
// Code for: 
import processing.video.*;
import processing.sound.*;
SinOsc sine;
Capture video;
color trackColor;
float threshold = 25;
void setup() {
size(640, 360);
String[] cameras = Capture.list();
//printArray(cameras);
video = new Capture(this, cameras[3]);
video.start();
trackColor = color(255, 0, 0);
}
void captureEvent(Capture video) {
video.read();
}
void draw() {
video.loadPixels();
image(video, 0, 0);
//threshold = map(mouseX, 0, width, 0, 100);
threshold = 20;
float avgX = 0;
float avgY = 0;
int count = 0;
// Begin loop to walk through every pixel
for (int x = 0; x < video.width; x++ ) {
for (int y = 0; y < video.height; y++ ) {
int loc = x + y * video.width;
// What is current color
color currentColor = video.pixels[loc];
float r1 = red(currentColor);
float g1 = green(currentColor);
float b1 = blue(currentColor);
float r2 = red(trackColor);
float g2 = green(trackColor);
float b2 = blue(trackColor);
float d = distSq(r1, g1, b1, r2, g2, b2);
if (d < threshold*threshold) {
stroke(255);
strokeWeight(1);
point(x, y);
avgX += x;
avgY += y;
count++;
}
}
}
// We only consider the color found if its color distance is less than 10.
// This threshold of 10 is arbitrary and you can adjust this number depending on how accurate you require the tracking to be.
if (count > 0) {
avgX = avgX / count;
avgY = avgY / count;
// Draw a circle at the tracked pixel
fill(255);
strokeWeight(4.0);
stroke(0);
ellipse(avgX, avgY, 24, 24);
}
}
float distSq(float x1, float y1, float z1, float x2, float y2, float z2) {
float d = (x2-x1)*(x2-x1) + (y2-y1)*(y2-y1) +(z2-z1)*(z2-z1);
return d;
}
void mousePressed() {
// Save color where the mouse is clicked in trackColor variable
int loc = mouseX + mouseY*video.width;
trackColor = video.pixels[loc];
}
{
sine = new SinOsc(this);
sine.pan(map(avgX, 0, width, -1.0, 1.0));
sine.play();
}
The problem is that the variable avgX cannot exist outside the draw. It works if I place the Oscillator in Draw, but that causes a crash in a hurry!
Any help greatly appreciated!
Best, Matt