Add test case for glm::angle() sign bug introduced by #946

test/ext/ext_quaternion_trigonometric.cpp

@@ -21,6 +21,12 @@ static int test_angle()
 		Error += glm::equal(A, 90.0f, Epsilon) ? 0 : 1;
 	}
 
+	{
+		glm::quat const Q = glm::angleAxis(glm::two_pi<float>() - 1.0f, glm::vec3(1, 0, 0));
+		float const A = glm::angle(Q);
+		Error += glm::equal(A, 1.0f, Epsilon) ? 1 : 0;
+	}
+
 	return Error;
 }