more example moving

java/examples/Books/Processing Handbook/Extensions/Vision/Ex_03/Ex_03.pde

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+// Determines whether a test location (such as the cursor) is contained within
+// the silhouette of a dark object
+import processing.video.*;
+
+color black = color(0);
+color white = color(255);
+int numPixels;
+Capture video;
+
+void setup() {
+  size(640, 480); // Change size to 320 x 240 if too slow at 640 x 480
+  strokeWeight(5);
+  video = new Capture(this, width, height, 24);
+  numPixels = video.width * video.height;
+  noCursor();
+  smooth();
+}
+
+void draw() {
+  if (video.available()) {
+    video.read();
+    video.loadPixels();
+    int threshold = 127; // Set the threshold value
+    float pixelBrightness; // Declare variable to store a pixel's color
+    // Turn each pixel in the video frame black or white depending on its brightness
+    loadPixels();
+    for (int i = 0; i < numPixels; i++) {
+      pixelBrightness = brightness(video.pixels[i]);
+      if (pixelBrightness > threshold) { // If the pixel is brighter than the
+        pixels[i] = white; // threshold value, make it white
+      } 
+      else { // Otherwise,
+        pixels[i] = black; // make it black
+      }
+    }
+    updatePixels();
+    // Test a location to see where it is contained. Fetch the pixel at the test
+    // location (the cursor), and compute its brightness
+    int testValue = get(mouseX, mouseY);
+    float testBrightness = brightness(testValue);
+    if (testBrightness > threshold) { // If the test location is brighter than
+      fill(black); // the threshold set the fill to black
+    } 
+    else { // Otherwise,
+      fill(white); // set the fill to white
+    }
+    ellipse(mouseX, mouseY, 20, 20);
+  }
+}