Added quat.random

toji · Jul 29, 2017 · 83b3152 · 83b3152
1 parent a8540ce
commit 83b3152
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Showing 4 changed files with 58 additions and 1 deletion.
diff --git a/dist/gl-matrix-min.js b/dist/gl-matrix-min.js
diff --git a/dist/gl-matrix.js b/dist/gl-matrix.js
@@ -5570,6 +5570,7 @@ exports.rotateY = rotateY;
 exports.rotateZ = rotateZ;
 exports.calculateW = calculateW;
 exports.slerp = slerp;
+exports.random = random;
 exports.invert = invert;
 exports.conjugate = conjugate;
 exports.fromMat3 = fromMat3;
@@ -5875,6 +5876,29 @@ function slerp(out, a, b, t) {
   return out;
 }
 
+/**
+ * Generates a random quaternion
+ *
+ * @param {quat} out the receiving quaternion
+ * @returns {quat} out
+ */
+function random(out) {
+  // Implementation of http://planning.cs.uiuc.edu/node198.html
+  // TODO: Calling random 3 times is probably not the fastest solution
+  var u1 = glMatrix.RANDOM();
+  var u2 = glMatrix.RANDOM();
+  var u3 = glMatrix.RANDOM();
+
+  var sqrt1MinusU1 = Math.sqrt(1 - u1);
+  var sqrtU1 = Math.sqrt(u1);
+
+  out[0] = sqrt1MinusU1 * Math.sin(2.0 * Math.PI * u2);
+  out[1] = sqrt1MinusU1 * Math.cos(2.0 * Math.PI * u2);
+  out[2] = sqrtU1 * Math.sin(2.0 * Math.PI * u3);
+  out[3] = sqrtU1 * Math.cos(2.0 * Math.PI * u3);
+  return out;
+}
+
 /**
  * Calculates the inverse of a quat
  *

diff --git a/spec/gl-matrix/quat-spec.js b/spec/gl-matrix/quat-spec.js
@@ -582,6 +582,16 @@ describe("quat", function() {
 
     // TODO: slerp, calcuateW, rotateX, rotateY, rotateZ
 
+    describe("random", function() {
+        beforeEach(function() { result = quat.random(out); });
+
+        it("should result in a normalized quaternion", function() {
+            let copy = quat.clone(out);
+            expect(quat.normalize(out, out)).toBeEqualish(copy);
+        });
+        it("should return out", function() { expect(result).toBe(out); });
+    });
+
     describe("invert", function() {
         describe("with a separate output quaternion", function() {
             beforeEach(function() { result = quat.invert(out, quatA); });

diff --git a/src/gl-matrix/quat.js b/src/gl-matrix/quat.js
@@ -254,6 +254,29 @@ export function slerp(out, a, b, t) {
   return out;
 }
 
+/**
+ * Generates a random quaternion
+ *
+ * @param {quat} out the receiving quaternion
+ * @returns {quat} out
+ */
+export function random(out) {
+  // Implementation of http://planning.cs.uiuc.edu/node198.html
+  // TODO: Calling random 3 times is probably not the fastest solution
+  let u1 = glMatrix.RANDOM();
+  let u2 = glMatrix.RANDOM();
+  let u3 = glMatrix.RANDOM();
+
+  let sqrt1MinusU1 = Math.sqrt(1 - u1);
+  let sqrtU1 = Math.sqrt(u1);
+
+  out[0] = sqrt1MinusU1 * Math.sin(2.0 * Math.PI * u2);
+  out[1] = sqrt1MinusU1 * Math.cos(2.0 * Math.PI * u2);
+  out[2] = sqrtU1 * Math.sin(2.0 * Math.PI * u3);
+  out[3] = sqrtU1 * Math.cos(2.0 * Math.PI * u3);
+  return out;
+}
+
 /**
  * Calculates the inverse of a quat
  *