1 files changed, 25 insertions, 0 deletions
diff --git a/o3d/samples/o3d-webgl/transform.js b/o3d/samples/o3d-webgl/transform.js
index 640592c..a569dc2 100644
--- a/o3d/samples/o3d-webgl/transform.js
+++ b/o3d/samples/o3d-webgl/transform.js
@@ -626,6 +626,31 @@ o3d.Transform.transformPoint = function(m, v) {
 
 
 /**
+ * Takes a 4-by-4 matrix and a vector with 4 entries,
+ * interprets the vector as a point, transforms that point by the matrix, and
+ * returns the result as a vector with 4 entries.
+ * @param {!o3djs.math.Matrix4} m The matrix.
+ * @param {!o3djs.math.Vector4} v The vector.
+ * @return {!o3djs.math.Vector4} The transformed vector.
+ */
+o3d.Transform.multiplyVector = function(m, v) {
+  var v0 = v[0];
+  var v1 = v[1];
+  var v2 = v[2];
+  var v3 = v[3];
+  var m0 = m[0];
+  var m1 = m[1];
+  var m2 = m[2];
+  var m3 = m[3];
+
+  return [(v0 * m0[0] + v1 * m1[0] + v2 * m2[0] + v3 * m3[0]),
+          (v0 * m0[1] + v1 * m1[1] + v2 * m2[1] + v3 * m3[1]),
+          (v0 * m0[2] + v1 * m1[2] + v2 * m2[2] + v3 * m3[2]),
+          (v0 * m0[3] + v1 * m1[3] + v2 * m2[3] + v3 * m3[3])];
+};
+
+
+/**
  * Takes a 4-by-4 matrix and a vector with 3 entries,
  * interprets the vector as a point, transforms that point by the matrix,
  * returning the z-component of the result only.