fix construct_from_angle_axis

CMakeLists.txt

@@ -436,10 +436,10 @@ if(ENABLE_TESTING)
 
 		add_custom_command(
 			OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/Run${CIFPP_TEST}.touch
-			COMMAND $<TARGET_FILE:${CIFPP_TEST}> -- ${PROJECT_SOURCE_DIR}/test)
+			COMMAND $<TARGET_FILE:${CIFPP_TEST}> -- ${CMAKE_CURRENT_SOURCE_DIR}/test)
 
 		add_test(NAME ${CIFPP_TEST}
-			COMMAND $<TARGET_FILE:${CIFPP_TEST}> -- ${PROJECT_SOURCE_DIR}/test)
+			COMMAND $<TARGET_FILE:${CIFPP_TEST}> -- ${CMAKE_CURRENT_SOURCE_DIR}/test)
 	endforeach()
 endif()
 

src/point.cpp

@@ -299,13 +299,25 @@ quaternion_type<T> normalize(quaternion_type<T> q)
 
 quaternion construct_from_angle_axis(float angle, point axis)
 {
-	auto q = std::cos((angle * kPI / 180) / 2);
-	auto s = std::sqrt(1 - q * q);
+	// auto q = std::cos((angle * kPI / 180) / 2);
+	// auto s = std::sqrt(1 - q * q);
+
+	// axis.normalize();
+
+	// return normalize(quaternion{
+	// 	static_cast<float>(q),
+	// 	static_cast<float>(s * axis.m_x),
+	// 	static_cast<float>(s * axis.m_y),
+	// 	static_cast<float>(s * axis.m_z) });
+
+	angle = (angle * kPI / 180) / 2;
+	auto s = std::sin(angle);
+	auto c = std::cos(angle);
 
 	axis.normalize();
 
 	return normalize(quaternion{
-		static_cast<float>(q),
+		static_cast<float>(c),
 		static_cast<float>(s * axis.m_x),
 		static_cast<float>(s * axis.m_y),
 		static_cast<float>(s * axis.m_z) });
@@ -364,33 +376,10 @@ quaternion construct_for_dihedral_angle(point p1, point p2, point p3, point p4,
 	p3 -= p3;
 
 	quaternion q;
-	auto axis = p2;
+	auto axis = -p2;
 
 	float dh = dihedral_angle(p1, p2, p3, p4);
-	for (int iteration = 0; iteration < 100; ++iteration)
-	{
-		float delta = std::fmod(angle - dh, 360.0f);
-
-		if (delta < -180)
-			delta += 360;
-		if (delta > 180)
-			delta -= 360;
-
-		if (std::abs(delta) < esd)
-			break;
-
-		// if (iteration > 0)
-		// 	std::cout << cif::coloured(("iteration " + std::to_string(iteration)).c_str(), cif::scBLUE, cif::scBLACK) << " delta: " << delta << std::endl;
-
-		auto q2 = construct_from_angle_axis(delta, axis);
-		q = iteration == 0 ? q2 : q * q2;
-			
-		p4.rotate(q2);
-
-		dh = dihedral_angle(p1, p2, p3, p4);
-	}
-
-	return q;
+	return construct_from_angle_axis(angle - dh, axis);
 }
 
 point centroid(const std::vector<point> &pts)

test/unit-3d-test.cpp

@@ -168,6 +168,46 @@ BOOST_AUTO_TEST_CASE(t3)
 	BOOST_TEST(a == 45, tt::tolerance(0.01));
 }
 
+BOOST_AUTO_TEST_CASE(dh_q_0)
+{
+	cif::point axis(1, 0, 0);
+
+	cif::point p(1, 1, 0);
+	
+	cif::point t[3] =
+	{
+		{ 0, 1, 0 },
+		{ 0, 0, 0 },
+		{ 1, 0, 0 }
+	};
+
+	auto a = cif::dihedral_angle(t[0], t[1], t[2], p);
+	BOOST_TEST(a == 0, tt::tolerance(0.01f));
+
+	auto q = cif::construct_from_angle_axis(90, axis);
+
+	p.rotate(q);
+
+	BOOST_TEST(p.m_x == 1, tt::tolerance(0.01f));
+	BOOST_TEST(p.m_y == 0, tt::tolerance(0.01f));
+	BOOST_TEST(p.m_z == 1, tt::tolerance(0.01f));
+
+	a = cif::dihedral_angle(t[0], t[1], t[2], p);
+	BOOST_TEST(a == 90, tt::tolerance(0.01f));
+
+	q = cif::construct_from_angle_axis(-90, axis);
+
+	p.rotate(q);
+
+	BOOST_TEST(p.m_x == 1, tt::tolerance(0.01f));
+	BOOST_TEST(p.m_y == 1, tt::tolerance(0.01f));
+	BOOST_TEST(p.m_z == 0, tt::tolerance(0.01f));
+
+	a = cif::dihedral_angle(t[0], t[1], t[2], p);
+	BOOST_TEST(a == 0, tt::tolerance(0.01f));
+
+}
+
 BOOST_AUTO_TEST_CASE(dh_q_1)
 {
 	struct
@@ -204,9 +244,7 @@ BOOST_AUTO_TEST_CASE(dh_q_1)
 	{
 		auto q = cif::construct_for_dihedral_angle(pts[0], pts[1], pts[2], pts[3], angle, 1);
 
-		pts[3] -= pts[2];
-		pts[3].rotate(q);
-		pts[3] += pts[2];
+		pts[3].rotate(q, pts[2]);
 
 		auto dh = cif::dihedral_angle(pts[0], pts[1], pts[2], pts[3]);
 		BOOST_TEST(dh == angle, tt::tolerance(0.1f));