Adding the shader examples

java/examples/Topics/Shaders/EdgeDetect/EdgeDetect.pde

@@ -0,0 +1,31 @@
+/**
+ * Edge Detection
+ * 
+ * Change the default shader to apply a simple, custom edge detection filter.
+ * 
+ * Press the mouse to switch between the custom and default shader.
+ */
+
+PShader edges;  
+PImage img;
+boolean enabled = true;
+    
+void setup() {
+  size(640, 360, P2D);
+  img = loadImage("leaves.jpg");      
+  edges = loadShader("edges.glsl");
+}
+
+void draw() {
+  if (enabled == true) {
+    shader(edges);
+  }
+  image(img, 0, 0);
+}
+    
+void mousePressed() {
+  enabled = !enabled;
+  if (!enabled == true) {
+    resetShader();
+  }
+}