add length noise

lindenmayer-system/lindenmeyer-system.html

@@ -190,7 +190,7 @@ function sierpinski() {
      project.clear();
      if(typeof num_defects == 'undefined') { num_defects = 0 };
      var r = generate(
-         'iIjX'.split(''),
+         'iIjJX'.split(''),
          [
              ['X'.split(''), 'F[-lfX][cfX][+rfX]'.split('')],
              //['F'.split(''), 'FF'.split('')],
@@ -231,6 +231,7 @@ function sierpinski() {
              'i': draw_set_dir(Math.PI),
              'I': draw_angle_init(25/180 * Math.PI),
              'j': draw_set_turn_noise(1),
+             'J': draw_set_length_noise(1),
 
              '*': draw_angle_add((Math.random() - 0.5) * 0.01),
              '-': draw_angle_turn(-1),

lindenmayer-system/lindenmeyer-system.js

@@ -51,6 +51,7 @@ function draw_initstate(p, state) {
     if(!('dir' in state)) {
         state.dir = 0;
         state.turnnoise = 0;
+        state.lennoise = 0;
     }
     if(!('stepsize' in state)) {
         state.stepsize = 1;
@@ -76,6 +77,13 @@ function draw_set_turn_noise(level) {
 }
 
 
+function draw_set_length_noise(level) {
+    return function(p, state) {
+        state.lennoise = level;
+    }
+}
+
+
 function draw_forward(factor=1) {
     return function(p, state) {
         draw_initstate(p, state);
@@ -84,10 +92,11 @@ function draw_forward(factor=1) {
             console.log('---------------------------');
         }
         var lastp = state.curpath.segments[state.curpath.segments.length - 1].point;
-        state.curpath.add(lastp.add(
-            new paper.Point(Math.sin(state.dir) * state.stepsize * factor,
-                            Math.cos(state.dir) * state.stepsize * factor)
-        ));
+        var noise = 1 + (Math.random() - 0.5) * state.lennoise;
+        state.curpath.add(lastp.add(new paper.Point(
+              Math.sin(state.dir) * state.stepsize * factor * noise,
+              Math.cos(state.dir) * state.stepsize * factor * noise
+        )));
     }
 }