Zack Elliott - Distribution Functions

src/distribution.js

@@ -1,32 +1,91 @@
+function fract(x) {
+    return x - Math.floor(x);
+}
+
+function bias(b, x) {
+    return Math.pow(x, Math.log(b) / Math.log(0.5));
+}
+
+function impulse(i, x) {
+    var j = i * x;
+    return j * Math.exp(1.0 - j);
+}
+
+function cubicPulse(c, w, x) {
+    x = Math.abs(x - c);
+
+    if (x > w) return 0.0;
+
+    x /= w;
+
+    return 1.0 - x * x * (3.0 - (2.0 * x));
+}
 
 export function func1(mesh, settings) {
     var abs_y = settings.pos;
     var height = settings.max - settings.min;
     var rel_y = (settings.pos - settings.min) / height;
-
+
+    var y = (height - abs_y);
+
+    var fnA = y * 0.5;
+    var fnB = 0.25 * Math.sin(6.0 * y);
+    var fnC = Math.sin(0.35 * y) * fnA + fnB;
+    var fn = fnC;
+
     mesh.position.set(0, abs_y, 0);
+    mesh.scale.set(fn, settings.size, fn);
 }
 
-export function sawtooth(mesh, settings) {
+export function func2(mesh, settings) {
     var abs_y = settings.pos;
     var height = settings.max - settings.min;
     var rel_y = (settings.pos - settings.min) / height;
-
+
+    var y = (height - abs_y);
+
+    var fnA = (Math.pow(y, 3.0) / 2000.0);
+    var fnB = fract(y / 5.0) * fnA;
+    var fn = fnB;
+
     mesh.position.set(0, abs_y, 0);
+    mesh.scale.set(fn, settings.size, fn);
 }
 
-export function triangle(mesh, settings) {
+export function func3(mesh, settings) {
     var abs_y = settings.pos;
     var height = settings.max - settings.min;
     var rel_y = (settings.pos - settings.min) / height;
-
+
+    var y = (height - abs_y);
+
+    var freq = 0.2;
+    var amplitude = 2.0;
+
+    var fnA = Math.abs((y * freq) % amplitude - (0.5 * amplitude));
+    var fnB = Math.pow(fnA, 2.0) * y;
+    var fn = fnB;
+
     mesh.position.set(0, abs_y, 0);
+    mesh.scale.set(fn, settings.size, fn);
 }
 
-export function step(mesh, settings) {
+// NOTE:
+// This one isn't as good as the rest, struggled a bit trying
+// to find an impulse curve to fit the outer shape, settled on a sine
+// wave but it clearly isn't perfect.
+
+export function func4(mesh, settings) {
     var abs_y = settings.pos;
     var height = settings.max - settings.min;
     var rel_y = (settings.pos - settings.min) / height;
-
+
+    var y = (height - abs_y);
+
+    var fnA = Math.sin((y / 16.0) - 1.5) * 25.0;
+    var fnB = (2.0 * (1.0 - fract(y / 4.0))) + fnA + 25.0;
+    var fn = fnB;
+
     mesh.position.set(0, abs_y, 0);
+    mesh.scale.set(fn, settings.size, fn);
 }

src/main.js

@@ -13,7 +13,7 @@ function onLoad(framework) {
   var stats = framework.stats;
 
   // LOOK: the line below is synyatic sugar for the code above. Optional, but I sort of recommend it.
-  // var {scene, camera, renderer, gui, stats} = framework; 
+  // var {scene, camera, renderer, gui, stats} = framework;
 
   // initialize a simple box and material
   var cylinder = new THREE.CylinderGeometry(0.5, 0.5, 1, 32, 32);
@@ -22,7 +22,7 @@ function onLoad(framework) {
 
   var light1 = new THREE.DirectionalLight(0xffffff, 0.8);
   light1.position.set(10, 10, 10);
-  
+
   var light2 = new THREE.DirectionalLight(0xffffff, 0.2);
   light2.position.set(-10, 5, -10);
 
@@ -59,11 +59,11 @@ function onLoad(framework) {
         size: settings.leafHeight
       };
 
-      func1(mesh, params);
-      // func2(mesh, settings);
-      // func3(mesh, settings);
-      // func4(mesh, settings);
-      
+      // func1(mesh, params);
+      // func2(mesh, params);
+      // func3(mesh, params);
+      func4(mesh, params);
+
       scene.add(mesh);
       tree_items.push(mesh);
     }