diff --git a/include/ui/mat3.h b/include/ui/mat3.h
new file mode 100644
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--- /dev/null
+++ b/include/ui/mat3.h
@@ -0,0 +1,435 @@
+/*
+ * Copyright 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef UI_MAT3_H_
+#define UI_MAT3_H_
+
+#include <ui/quat.h>
+#include <ui/TMatHelpers.h>
+#include <ui/vec3.h>
+#include <stdint.h>
+#include <sys/types.h>
+
+#define PURE __attribute__((pure))
+
+namespace android {
+// -------------------------------------------------------------------------------------
+namespace details {
+
+template<typename T>
+class TQuaternion;
+
+/**
+ * A 3x3 column-major matrix class.
+ *
+ * Conceptually a 3x3 matrix is a an array of 3 column vec3:
+ *
+ * mat3 m =
+ *      \f$
+ *      \left(
+ *      \begin{array}{ccc}
+ *      m[0] & m[1] & m[2] \\
+ *      \end{array}
+ *      \right)
+ *      \f$
+ *      =
+ *      \f$
+ *      \left(
+ *      \begin{array}{ccc}
+ *      m[0][0] & m[1][0] & m[2][0] \\
+ *      m[0][1] & m[1][1] & m[2][1] \\
+ *      m[0][2] & m[1][2] & m[2][2] \\
+ *      \end{array}
+ *      \right)
+ *      \f$
+ *      =
+ *      \f$
+ *      \left(
+ *      \begin{array}{ccc}
+ *      m(0,0) & m(0,1) & m(0,2) \\
+ *      m(1,0) & m(1,1) & m(1,2) \\
+ *      m(2,0) & m(2,1) & m(2,2) \\
+ *      \end{array}
+ *      \right)
+ *      \f$
+ *
+ * m[n] is the \f$ n^{th} \f$ column of the matrix and is a vec3.
+ *
+ */
+template <typename T>
+class TMat33 :  public TVecUnaryOperators<TMat33, T>,
+                public TVecComparisonOperators<TMat33, T>,
+                public TVecAddOperators<TMat33, T>,
+                public TMatProductOperators<TMat33, T>,
+                public TMatSquareFunctions<TMat33, T>,
+                public TMatTransform<TMat33, T>,
+                public TMatHelpers<TMat33, T>,
+                public TMatDebug<TMat33, T> {
+public:
+    enum no_init { NO_INIT };
+    typedef T value_type;
+    typedef T& reference;
+    typedef T const& const_reference;
+    typedef size_t size_type;
+    typedef TVec3<T> col_type;
+    typedef TVec3<T> row_type;
+
+    static constexpr size_t COL_SIZE = col_type::SIZE;  // size of a column (i.e.: number of rows)
+    static constexpr size_t ROW_SIZE = row_type::SIZE;  // size of a row (i.e.: number of columns)
+    static constexpr size_t NUM_ROWS = COL_SIZE;
+    static constexpr size_t NUM_COLS = ROW_SIZE;
+
+private:
+    /*
+     *  <--  N columns  -->
+     *
+     *  a[0][0] a[1][0] a[2][0] ... a[N][0]    ^
+     *  a[0][1] a[1][1] a[2][1] ... a[N][1]    |
+     *  a[0][2] a[1][2] a[2][2] ... a[N][2]  M rows
+     *  ...                                    |
+     *  a[0][M] a[1][M] a[2][M] ... a[N][M]    v
+     *
+     *  COL_SIZE = M
+     *  ROW_SIZE = N
+     *  m[0] = [ a[0][0] a[0][1] a[0][2] ... a[0][M] ]
+     */
+
+    col_type m_value[NUM_COLS];
+
+public:
+    // array access
+    inline constexpr col_type const& operator[](size_t column) const {
+#if __cplusplus >= 201402L
+        // only possible in C++0x14 with constexpr
+        assert(column < NUM_COLS);
+#endif
+        return m_value[column];
+    }
+
+    inline col_type& operator[](size_t column) {
+        assert(column < NUM_COLS);
+        return m_value[column];
+    }
+
+    // -----------------------------------------------------------------------
+    // we want the compiler generated versions for these...
+    TMat33(const TMat33&) = default;
+    ~TMat33() = default;
+    TMat33& operator = (const TMat33&) = default;
+
+    /**
+     *  constructors
+     */
+
+    /**
+     * leaves object uninitialized. use with caution.
+     */
+    explicit
+    constexpr TMat33(no_init)
+            : m_value{ col_type(col_type::NO_INIT),
+                       col_type(col_type::NO_INIT),
+                       col_type(col_type::NO_INIT) } {}
+
+
+    /**
+     * initialize to identity.
+     *
+     *      \f$
+     *      \left(
+     *      \begin{array}{ccc}
+     *      1 & 0 & 0 \\
+     *      0 & 1 & 0 \\
+     *      0 & 0 & 1 \\
+     *      \end{array}
+     *      \right)
+     *      \f$
+     */
+    TMat33();
+
+    /**
+     * initialize to Identity*scalar.
+     *
+     *      \f$
+     *      \left(
+     *      \begin{array}{ccc}
+     *      v & 0 & 0 \\
+     *      0 & v & 0 \\
+     *      0 & 0 & v \\
+     *      \end{array}
+     *      \right)
+     *      \f$
+     */
+    template<typename U>
+    explicit TMat33(U v);
+
+    /**
+     * sets the diagonal to a vector.
+     *
+     *      \f$
+     *      \left(
+     *      \begin{array}{ccc}
+     *      v[0] & 0 & 0 \\
+     *      0 & v[1] & 0 \\
+     *      0 & 0 & v[2] \\
+     *      \end{array}
+     *      \right)
+     *      \f$
+     */
+    template <typename U>
+    explicit TMat33(const TVec3<U>& v);
+
+    /**
+     * construct from another matrix of the same size
+     */
+    template <typename U>
+    explicit TMat33(const TMat33<U>& rhs);
+
+    /**
+     * construct from 3 column vectors.
+     *
+     *      \f$
+     *      \left(
+     *      \begin{array}{ccc}
+     *      v0 & v1 & v2 \\
+     *      \end{array}
+     *      \right)
+     *      \f$
+     */
+    template <typename A, typename B, typename C>
+    TMat33(const TVec3<A>& v0, const TVec3<B>& v1, const TVec3<C>& v2);
+
+    /** construct from 9 elements in column-major form.
+     *
+     *      \f$
+     *      \left(
+     *      \begin{array}{ccc}
+     *      m[0][0] & m[1][0] & m[2][0] \\
+     *      m[0][1] & m[1][1] & m[2][1] \\
+     *      m[0][2] & m[1][2] & m[2][2] \\
+     *      \end{array}
+     *      \right)
+     *      \f$
+     */
+    template <
+        typename A, typename B, typename C,
+        typename D, typename E, typename F,
+        typename G, typename H, typename I>
+    TMat33(A m00, B m01, C m02,
+           D m10, E m11, F m12,
+           G m20, H m21, I m22);
+
+    /**
+     * construct from a quaternion
+     */
+    template <typename U>
+    explicit TMat33(const TQuaternion<U>& q);
+
+    /**
+     * construct from a C array in column major form.
+     */
+    template <typename U>
+    explicit TMat33(U const* rawArray);
+
+    /**
+     * orthogonalize only works on matrices of size 3x3
+     */
+    friend inline
+    TMat33 orthogonalize(const TMat33& m) {
+        TMat33 ret(TMat33::NO_INIT);
+        ret[0] = normalize(m[0]);
+        ret[2] = normalize(cross(ret[0], m[1]));
+        ret[1] = normalize(cross(ret[2], ret[0]));
+        return ret;
+    }
+};
+
+// ----------------------------------------------------------------------------------------
+// Constructors
+// ----------------------------------------------------------------------------------------
+
+// Since the matrix code could become pretty big quickly, we don't inline most
+// operations.
+
+template <typename T>
+TMat33<T>::TMat33() {
+    m_value[0] = col_type(1, 0, 0);
+    m_value[1] = col_type(0, 1, 0);
+    m_value[2] = col_type(0, 0, 1);
+}
+
+template <typename T>
+template <typename U>
+TMat33<T>::TMat33(U v) {
+    m_value[0] = col_type(v, 0, 0);
+    m_value[1] = col_type(0, v, 0);
+    m_value[2] = col_type(0, 0, v);
+}
+
+template<typename T>
+template<typename U>
+TMat33<T>::TMat33(const TVec3<U>& v) {
+    m_value[0] = col_type(v.x, 0, 0);
+    m_value[1] = col_type(0, v.y, 0);
+    m_value[2] = col_type(0, 0, v.z);
+}
+
+// construct from 16 scalars. Note that the arrangement
+// of values in the constructor is the transpose of the matrix
+// notation.
+template<typename T>
+template <
+    typename A, typename B, typename C,
+    typename D, typename E, typename F,
+    typename G, typename H, typename I>
+TMat33<T>::TMat33(A m00, B m01, C m02,
+                  D m10, E m11, F m12,
+                  G m20, H m21, I m22) {
+    m_value[0] = col_type(m00, m01, m02);
+    m_value[1] = col_type(m10, m11, m12);
+    m_value[2] = col_type(m20, m21, m22);
+}
+
+template <typename T>
+template <typename U>
+TMat33<T>::TMat33(const TMat33<U>& rhs) {
+    for (size_t col = 0; col < NUM_COLS; ++col) {
+        m_value[col] = col_type(rhs[col]);
+    }
+}
+
+// Construct from 3 column vectors.
+template <typename T>
+template <typename A, typename B, typename C>
+TMat33<T>::TMat33(const TVec3<A>& v0, const TVec3<B>& v1, const TVec3<C>& v2) {
+    m_value[0] = v0;
+    m_value[1] = v1;
+    m_value[2] = v2;
+}
+
+// Construct from raw array, in column-major form.
+template <typename T>
+template <typename U>
+TMat33<T>::TMat33(U const* rawArray) {
+    for (size_t col = 0; col < NUM_COLS; ++col) {
+        for (size_t row = 0; row < NUM_ROWS; ++row) {
+            m_value[col][row] = *rawArray++;
+        }
+    }
+}
+
+template <typename T>
+template <typename U>
+TMat33<T>::TMat33(const TQuaternion<U>& q) {
+    const U n = q.x*q.x + q.y*q.y + q.z*q.z + q.w*q.w;
+    const U s = n > 0 ? 2/n : 0;
+    const U x = s*q.x;
+    const U y = s*q.y;
+    const U z = s*q.z;
+    const U xx = x*q.x;
+    const U xy = x*q.y;
+    const U xz = x*q.z;
+    const U xw = x*q.w;
+    const U yy = y*q.y;
+    const U yz = y*q.z;
+    const U yw = y*q.w;
+    const U zz = z*q.z;
+    const U zw = z*q.w;
+    m_value[0] = col_type(1-yy-zz,    xy+zw,    xz-yw);  // NOLINT
+    m_value[1] = col_type(  xy-zw,  1-xx-zz,    yz+xw);  // NOLINT
+    m_value[2] = col_type(  xz+yw,    yz-xw,  1-xx-yy);  // NOLINT
+}
+
+// ----------------------------------------------------------------------------------------
+// Arithmetic operators outside of class
+// ----------------------------------------------------------------------------------------
+
+/* We use non-friend functions here to prevent the compiler from using
+ * implicit conversions, for instance of a scalar to a vector. The result would
+ * not be what the caller expects.
+ *
+ * Also note that the order of the arguments in the inner loop is important since
+ * it determines the output type (only relevant when T != U).
+ */
+
+// matrix * column-vector, result is a vector of the same type than the input vector
+template <typename T, typename U>
+typename TMat33<U>::col_type PURE operator *(const TMat33<T>& lhs, const TVec3<U>& rhs) {
+    // Result is initialized to zero.
+    typename TMat33<U>::col_type result;
+    for (size_t col = 0; col < TMat33<T>::NUM_COLS; ++col) {
+        result += lhs[col] * rhs[col];
+    }
+    return result;
+}
+
+// row-vector * matrix, result is a vector of the same type than the input vector
+template <typename T, typename U>
+typename TMat33<U>::row_type PURE operator *(const TVec3<U>& lhs, const TMat33<T>& rhs) {
+    typename TMat33<U>::row_type result(TMat33<U>::row_type::NO_INIT);
+    for (size_t col = 0; col < TMat33<T>::NUM_COLS; ++col) {
+        result[col] = dot(lhs, rhs[col]);
+    }
+    return result;
+}
+
+// matrix * scalar, result is a matrix of the same type than the input matrix
+template<typename T, typename U>
+constexpr typename std::enable_if<std::is_arithmetic<U>::value, TMat33<T>>::type PURE
+operator*(TMat33<T> lhs, U rhs) {
+    return lhs *= rhs;
+}
+
+// scalar * matrix, result is a matrix of the same type than the input matrix
+template<typename T, typename U>
+constexpr typename std::enable_if<std::is_arithmetic<U>::value, TMat33<T>>::type PURE
+operator*(U lhs, const TMat33<T>& rhs) {
+    return rhs * lhs;
+}
+
+//------------------------------------------------------------------------------
+template <typename T>
+TMat33<T> orthogonalize(const TMat33<T>& m) {
+    TMat33<T> ret(TMat33<T>::NO_INIT);
+    ret[0] = normalize(m[0]);
+    ret[2] = normalize(cross(ret[0], m[1]));
+    ret[1] = normalize(cross(ret[2], ret[0]));
+    return ret;
+}
+
+// ----------------------------------------------------------------------------------------
+
+/* FIXME: this should go into TMatSquareFunctions<> but for some reason
+ * BASE<T>::col_type is not accessible from there (???)
+ */
+template<typename T>
+typename TMat33<T>::col_type PURE diag(const TMat33<T>& m) {
+    return matrix::diag(m);
+}
+
+}  // namespace details
+
+// ----------------------------------------------------------------------------------------
+
+typedef details::TMat33<double> mat3d;
+typedef details::TMat33<float> mat3;
+typedef details::TMat33<float> mat3f;
+
+// ----------------------------------------------------------------------------------------
+}  // namespace android
+
+#undef PURE
+
+#endif  // UI_MAT3_H_