Merge pull request #682 from CaptainCarrot/Quaternion-Look-At

quatLookAt: removed internal normalization of input direction #682

glm/gtx/quaternion.hpp

@@ -185,7 +185,7 @@ namespace glm
 
 	/// Build a look at quaternion based on the default handedness.
 	///
-	/// @param direction Desired direction of the camera.
+	/// @param direction Desired forward direction. Needs to be normalized.
 	/// @param up Up vector, how the camera is oriented. Typically (0, 1, 0).
 	template<typename T, qualifier Q>
 	GLM_FUNC_DECL tquat<T, Q> quatLookAt(
@@ -194,7 +194,7 @@ namespace glm
 
 	/// Build a right-handed look at quaternion.
 	///
-	/// @param direction Desired direction of the camera.
+	/// @param direction Desired forward direction onto which the -z-axis gets mapped. Needs to be normalized.
 	/// @param up Up vector, how the camera is oriented. Typically (0, 1, 0).
 	template<typename T, qualifier Q>
 	GLM_FUNC_DECL tquat<T, Q> quatLookAtRH(
@@ -203,7 +203,7 @@ namespace glm
 
 	/// Build a left-handed look at quaternion.
 	///
-	/// @param direction Desired direction onto which the +z-axis gets mapped
+	/// @param direction Desired forward direction onto which the +z-axis gets mapped. Needs to be normalized.
 	/// @param up Up vector, how the camera is oriented. Typically (0, 1, 0).
 	template<typename T, qualifier Q>
 	GLM_FUNC_DECL tquat<T, Q> quatLookAtLH(

glm/gtx/quaternion.inl

@@ -230,7 +230,7 @@ namespace glm
 	{
 		mat<3, 3, T, Q> Result;
 
-		Result[2] = -normalize(direction);
+		Result[2] = -direction;
 		Result[0] = normalize(cross(up, Result[2]));
 		Result[1] = cross(Result[2], Result[0]);
 
@@ -242,7 +242,7 @@ namespace glm
 	{
 		mat<3, 3, T, Q> Result;
 
-		Result[2] = normalize(direction);
+		Result[2] = direction;
 		Result[0] = normalize(cross(up, Result[2]));
 		Result[1] = cross(Result[2], Result[0]);
 

test/gtx/gtx_quaternion.cpp

@@ -99,9 +99,9 @@ int test_quat_lookAt()
 
 	glm::vec3 eye(0.0f);
 	glm::vec3 center(1.1f, -2.0f, 3.1416f);
-	glm::vec3 up = glm::vec3(-0.17f, 7.23f, -1.744f);
+	glm::vec3 up(-0.17f, 7.23f, -1.744f);
 
-	glm::quat test_quat = glm::quatLookAt(center - eye, up);
+	glm::quat test_quat = glm::quatLookAt(glm::normalize(center - eye), up);
 	glm::quat test_mat = glm::conjugate(glm::quat_cast(glm::lookAt(eye, center, up)));
 
 	Error += static_cast<int>(glm::abs(glm::length(test_quat) - 1.0f) > glm::epsilon<float>());