Initial Commit

Java/Processing/processing-3.3.6/modes/java/examples/Topics/Simulate/Springs/Springs.pde

@@ -0,0 +1,151 @@
+/**
+ * Springs. 
+ * 
+ * Move the mouse over one of the circles and click to re-position. 
+ * When you release the mouse, it will snap back into position. 
+ * Each circle has a slightly different behavior.  
+ */
+
+
+int num = 3; 
+Spring[] springs = new Spring[num]; 
+
+void setup() {
+  size(640, 360);
+  noStroke(); 
+  springs[0] = new Spring(240, 260, 40, 0.98, 8.0, 0.1, springs, 0); 
+  springs[1] = new Spring(320, 210, 120, 0.95, 9.0, 0.1, springs, 1); 
+  springs[2] = new Spring(180, 170, 200, 0.90, 9.9, 0.1, springs, 2);
+}
+
+void draw() {
+  background(51); 
+
+  for (Spring spring : springs) { 
+    spring.update(); 
+    spring.display();
+  }
+}
+
+void mousePressed() {
+  for (Spring spring : springs) { 
+    spring.pressed();
+  }
+}
+
+void mouseReleased() {
+  for (Spring spring : springs) { 
+    spring.released();
+  }
+}
+
+class Spring { 
+  // Screen values 
+  float xpos, ypos;
+  float tempxpos, tempypos; 
+  int size = 20; 
+  boolean over = false; 
+  boolean move = false; 
+
+  // Spring simulation constants 
+  float mass;       // Mass 
+  float k = 0.2;    // Spring constant 
+  float damp;       // Damping 
+  float rest_posx;  // Rest position X 
+  float rest_posy;  // Rest position Y 
+
+  // Spring simulation variables 
+  //float pos = 20.0; // Position 
+  float velx = 0.0;   // X Velocity 
+  float vely = 0.0;   // Y Velocity 
+  float accel = 0;    // Acceleration 
+  float force = 0;    // Force 
+
+  Spring[] friends;
+  int me;
+
+  // Constructor
+  Spring(float x, float y, int s, float d, float m, 
+  float k_in, Spring[] others, int id) { 
+    xpos = tempxpos = x; 
+    ypos = tempypos = y;
+    rest_posx = x;
+    rest_posy = y;
+    size = s;
+    damp = d; 
+    mass = m; 
+    k = k_in;
+    friends = others;
+    me = id;
+  } 
+
+  void update() { 
+    if (move) { 
+      rest_posy = mouseY; 
+      rest_posx = mouseX;
+    } 
+
+    force = -k * (tempypos - rest_posy);  // f=-ky 
+    accel = force / mass;                 // Set the acceleration, f=ma == a=f/m 
+    vely = damp * (vely + accel);         // Set the velocity 
+    tempypos = tempypos + vely;           // Updated position 
+
+    force = -k * (tempxpos - rest_posx);  // f=-ky 
+    accel = force / mass;                 // Set the acceleration, f=ma == a=f/m 
+    velx = damp * (velx + accel);         // Set the velocity 
+    tempxpos = tempxpos + velx;           // Updated position 
+
+
+    if ((overEvent() || move) && !otherOver() ) { 
+      over = true;
+    } else { 
+      over = false;
+    }
+  } 
+
+  // Test to see if mouse is over this spring
+  boolean overEvent() {
+    float disX = tempxpos - mouseX;
+    float disY = tempypos - mouseY;
+    if (sqrt(sq(disX) + sq(disY)) < size/2 ) {
+      return true;
+    } else {
+      return false;
+    }
+  }
+
+  // Make sure no other springs are active
+  boolean otherOver() {
+    for (int i=0; i<num; i++) {
+      if (i != me) {
+        if (friends[i].over == true) {
+          return true;
+        }
+      }
+    }
+    return false;
+  }
+
+  void display() { 
+    if (over) { 
+      fill(153);
+    } else { 
+      fill(255);
+    } 
+    ellipse(tempxpos, tempypos, size, size);
+  } 
+
+  void pressed() { 
+    if (over) { 
+      move = true;
+    } else { 
+      move = false;
+    }
+  } 
+
+  void released() { 
+    move = false; 
+    rest_posx = xpos;
+    rest_posy = ypos;
+  }
+}