diff --git a/src/matrix.cpp b/src/matrix.cpp
index e6d05117..204abde1 100644
--- a/src/matrix.cpp
+++ b/src/matrix.cpp
@@ -12,6 +12,10 @@
 #   include "config.h"
 #endif
 
+#ifdef ANDROID_NDK
+#   include <android/log.h>
+#endif
+
 #include <cstdio>
 #include <cstdlib> /* free() */
 #include <cstring> /* strdup() */
@@ -65,6 +69,31 @@ template<> mat4 mat4::invert() const
     return ret;
 }
 
+template<> void mat4::printf() const
+{
+    mat4 const &p = *this;
+
+#ifdef ANDROID_NDK
+    __android_log_print(ANDROID_LOG_INFO, "LOL",
+        "[ %6.6f %6.6f %6.6f %6.6f", p[0][0], p[1][0], p[2][0], p[3][0]);
+    __android_log_print(ANDROID_LOG_INFO, "LOL",
+        "  %6.6f %6.6f %6.6f %6.6f", p[0][1], p[1][1], p[2][1], p[3][1]);
+    __android_log_print(ANDROID_LOG_INFO, "LOL",
+        "  %6.6f %6.6f %6.6f %6.6f", p[0][2], p[1][2], p[2][2], p[3][2]);
+    __android_log_print(ANDROID_LOG_INFO, "LOL",
+        "  %6.6f %6.6f %6.6f %6.6f ]", p[0][3], p[1][3], p[2][3], p[3][3]);
+#else
+    fprintf(stderr, "[ %6.6f %6.6f %6.6f %6.6f\n",
+            p[0][0], p[1][0], p[2][0], p[3][0]);
+    fprintf(stderr, "  %6.6f %6.6f %6.6f %6.6f\n",
+            p[0][1], p[1][1], p[2][1], p[3][1]);
+    fprintf(stderr, "  %6.6f %6.6f %6.6f %6.6f\n",
+            p[0][2], p[1][2], p[2][2], p[3][2]);
+    fprintf(stderr, "  %6.6f %6.6f %6.6f %6.6f ]\n",
+            p[0][3], p[1][3], p[2][3], p[3][3]);
+#endif
+}
+
 template<> mat4 mat4::ortho(float left, float right, float bottom,
                             float top, float near, float far)
 {
diff --git a/src/matrix.h b/src/matrix.h
index 51ce7663..69accb43 100644
--- a/src/matrix.h
+++ b/src/matrix.h
@@ -215,6 +215,8 @@ template <typename T> struct Mat4
     static Mat4<T> translate(T x, T y, T z);
     static Mat4<T> rotate(T theta, T x, T y, T z);
 
+    void printf() const;
+
     inline Mat4<T> operator +(Mat4<T> const val) const
     {
         Mat4<T> ret;