Initial Commit

Java/Processing/processing-3.3.6/modes/java/examples/Basics/Math/Graphing2DEquation/Graphing2DEquation.pde

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+/**
+ * Graphing 2D Equations
+ * by Daniel Shiffman. 
+ * 
+ * Graphics the following equation: 
+ * sin(n*cos(r) + 5*theta) 
+ * where n is a function of horizontal mouse location.  
+ */
+ 
+void setup() {
+  size(640, 360);
+}
+
+void draw() {
+  loadPixels();
+  float n = (mouseX * 10.0) / width;
+  float w = 16.0;         // 2D space width
+  float h = 16.0;         // 2D space height
+  float dx = w / width;    // Increment x this amount per pixel
+  float dy = h / height;   // Increment y this amount per pixel
+  float x = -w/2;          // Start x at -1 * width / 2
+  for (int i = 0; i < width; i++) {
+    float y = -h/2;        // Start y at -1 * height / 2
+    for (int j = 0; j < height; j++) {
+      float r = sqrt((x*x) + (y*y));    // Convert cartesian to polar
+      float theta = atan2(y,x);         // Convert cartesian to polar
+      // Compute 2D polar coordinate function
+      float val = sin(n*cos(r) + 5 * theta);           // Results in a value between -1 and 1
+      //float val = cos(r);                            // Another simple function
+      //float val = sin(theta);                        // Another simple function
+      // Map resulting vale to grayscale value
+      pixels[i+j*width] = color((val + 1.0) * 255.0/2.0);     // Scale to between 0 and 255
+      y += dy;                // Increment y
+    }
+    x += dx;                  // Increment x
+  }
+  updatePixels();
+}
+