From 8bbbbfcafda418b47cf463c72568a8a84c90207f Mon Sep 17 00:00:00 2001
From: thechosenone124 <thechosenone124@gmail.com>
Date: Wed, 30 May 2018 23:36:37 -0700
Subject: [PATCH 1/3] Intermediate Function Is Improperly Done

The formula for calculating the intermediate for a SQUAD interpolation is

exp((log(next * invQuat) + log(prev * invQuat)) / static_cast<T>(-4)) * curr;

The current code uses addition instead of multiplication (based on http://web.mit.edu/2.998/www/QuaternionReport1.pdf)
---
 glm/gtx/quaternion.inl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/glm/gtx/quaternion.inl b/glm/gtx/quaternion.inl
index fde7a8fb..e2aa5102 100644
--- a/glm/gtx/quaternion.inl
+++ b/glm/gtx/quaternion.inl
@@ -45,7 +45,7 @@ namespace glm
 	)
 	{
 		tquat<T, Q> invQuat = inverse(curr);
-		return exp((log(next + invQuat) + log(prev + invQuat)) / static_cast<T>(-4)) * curr;
+		return exp((log(next * invQuat) + log(prev * invQuat)) / static_cast<T>(-4)) * curr;
 	}
 
 	template<typename T, qualifier Q>

From aa1728cde2dfc7d0f658227808c0cdb81f72efab Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Vladim=C3=ADr=20Vondru=C5=A1?= <mosra@centrum.cz>
Date: Fri, 1 Jun 2018 02:27:55 +0200
Subject: [PATCH 2/3] Make to_string(dualquat) actually work.

It segfaulted somewhere deep in strlen() due to a mismatch in printf()
argument count.
---
 glm/gtx/string_cast.inl      |  1 +
 test/gtx/gtx_string_cast.cpp | 12 ++++++++++++
 2 files changed, 13 insertions(+)

diff --git a/glm/gtx/string_cast.inl b/glm/gtx/string_cast.inl
index e237e8e5..09e4c5c6 100644
--- a/glm/gtx/string_cast.inl
+++ b/glm/gtx/string_cast.inl
@@ -467,6 +467,7 @@ namespace detail
 			char const * LiteralStr = literal<T, std::numeric_limits<T>::is_iec559>::value();
 			std::string FormatStr(detail::format("%sdualquat((%s, {%s, %s, %s}), (%s, {%s, %s, %s}))",
 				PrefixStr,
+				LiteralStr, LiteralStr, LiteralStr, LiteralStr,
 				LiteralStr, LiteralStr, LiteralStr, LiteralStr));
 
 			return detail::format(FormatStr.c_str(),
diff --git a/test/gtx/gtx_string_cast.cpp b/test/gtx/gtx_string_cast.cpp
index 9cfa48f6..e77c246b 100644
--- a/test/gtx/gtx_string_cast.cpp
+++ b/test/gtx/gtx_string_cast.cpp
@@ -129,12 +129,24 @@ int test_string_cast_quaternion()
 
 }
 
+int test_string_cast_dual_quaternion()
+{
+	int Error = 0;
+
+	glm::dualquat Q0 = glm::dualquat({1.0f, 2.0f, 3.0f, 4.0f}, {5.0f, 6.0f, 7.0f, 8.0f});
+	std::string S0 = glm::to_string(Q0);
+	Error += S0 != std::string("dualquat((1.000000, {2.000000, 3.000000, 4.000000}), (5.000000, {6.000000, 7.000000, 8.000000}))") ? 1 : 0;
+
+	return Error;
+}
+
 int main()
 {
 	int Error = 0;
 	Error += test_string_cast_vector();
 	Error += test_string_cast_matrix();
 	Error += test_string_cast_quaternion();
+	Error += test_string_cast_dual_quaternion();
 
 	return Error;
 }

From 89420dd1f5fdb618be94a7ac46794d6d009c9f00 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Vladim=C3=ADr=20Vondru=C5=A1?= <mosra@centrum.cz>
Date: Fri, 1 Jun 2018 12:01:25 +0200
Subject: [PATCH 3/3] Make the to_string(dualquat) test work under C++03.

I forgot this is still a thing, sorry.
---
 test/gtx/gtx_string_cast.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/gtx/gtx_string_cast.cpp b/test/gtx/gtx_string_cast.cpp
index e77c246b..2b7bb125 100644
--- a/test/gtx/gtx_string_cast.cpp
+++ b/test/gtx/gtx_string_cast.cpp
@@ -133,7 +133,7 @@ int test_string_cast_dual_quaternion()
 {
 	int Error = 0;
 
-	glm::dualquat Q0 = glm::dualquat({1.0f, 2.0f, 3.0f, 4.0f}, {5.0f, 6.0f, 7.0f, 8.0f});
+	glm::dualquat Q0 = glm::dualquat(glm::quat(1.0f, 2.0f, 3.0f, 4.0f), glm::quat(5.0f, 6.0f, 7.0f, 8.0f));
 	std::string S0 = glm::to_string(Q0);
 	Error += S0 != std::string("dualquat((1.000000, {2.000000, 3.000000, 4.000000}), (5.000000, {6.000000, 7.000000, 8.000000}))") ? 1 : 0;