diff --git a/src/anim.cpp b/src/anim.cpp
index f6ab109..4141e88 100644
--- a/src/anim.cpp
+++ b/src/anim.cpp
@@ -123,7 +123,7 @@ Animation::streamReadLegacy(Stream *stream)
 		stream->read(&frames[i].t, 3*4);
 		frames[i].time = stream->readF32();
 		int32 prev = stream->readI32();
-		frames[i].prev = &frames[prev];
+		frames[i].prevFrame = &frames[prev];
 	}
 	return anim;
 }
@@ -153,7 +153,7 @@ Animation::streamWriteLegacy(Stream *stream)
 		stream->write(&frames[i].q, 4*4);
 		stream->write(&frames[i].t, 3*4);
 		stream->writeF32(frames[i].time);
-		stream->writeI32(frames[i].prev - frames);
+		stream->writeI32(frames[i].prevFrame - frames);
 	}
 	return true;
 }
diff --git a/src/base.cpp b/src/base.cpp
index 5458ccc..6630b10 100644
--- a/src/base.cpp
+++ b/src/base.cpp
@@ -82,6 +82,25 @@ mult(const Quat &q, const Quat &p)
 	                q.w*p.z + q.z*p.w + q.x*p.y - q.y*p.x);
 }
 
+
+Quat*
+Quat::rotate(const V3d *axis, float32 angle, CombineOp op)
+{
+	Quat rot = rotation(angle, *axis);
+	switch(op){
+	case COMBINEREPLACE:
+		*this = rot;
+		break;
+	case COMBINEPRECONCAT:
+		*this = mult(*this, rot);
+		break;
+	case COMBINEPOSTCONCAT:
+		*this = mult(rot, *this);
+		break;
+	}
+	return this;
+}
+
 Quat
 lerp(const Quat &q, const Quat &p, float32 r)
 {
diff --git a/src/charset.cpp b/src/charset.cpp
index 0001804..1ca88fc 100644
--- a/src/charset.cpp
+++ b/src/charset.cpp
@@ -60,7 +60,7 @@ Charset::close(void)
 }
 
 Charset*
-Charset::create(RGBA *foreground, RGBA *background)
+Charset::create(const RGBA *foreground, const RGBA *background)
 {
 	Charset *charset = (Charset*)rwMalloc(sizeof(Charset), MEMDUR_EVENT);
 	if(charset == nil){
@@ -91,7 +91,7 @@ Charset::destroy(void)
 }
 
 Charset*
-Charset::setColors(RGBA *foreground, RGBA *background)
+Charset::setColors(const RGBA *foreground, const RGBA *background)
 {
 	Image *img = Image::create(256, 256, 8);
 	if(img == nil)
diff --git a/src/hanim.cpp b/src/hanim.cpp
index b9efafd..e3893c4 100644
--- a/src/hanim.cpp
+++ b/src/hanim.cpp
@@ -35,7 +35,7 @@ HAnimHierarchy::create(int32 numNodes, int32 *nodeFlags, int32 *nodeIDs,
 		RWERROR((ERR_ALLOC, sizeof(*hier)));
 		return nil;
 	}
-	hier->currentAnim = AnimInterpolator::create(numNodes, maxKeySize);
+	hier->interpolator = AnimInterpolator::create(numNodes, maxKeySize);
 
 	hier->numNodes = numNodes;
 	hier->flags = flags;
@@ -68,6 +68,7 @@ HAnimHierarchy::create(int32 numNodes, int32 *nodeFlags, int32 *nodeIDs,
 void
 HAnimHierarchy::destroy(void)
 {
+	this->interpolator->destroy();
 	rwFree(this->matricesUnaligned);
 	rwFree(this->nodeInfo);
 	rwFree(this);
@@ -156,7 +157,7 @@ HAnimHierarchy::updateMatrices(void)
 	Matrix **sp, *stack[64];
 	Frame *frm, *parfrm;
 	int32 i;
-	AnimInterpolator *anim = this->currentAnim;
+	AnimInterpolator *anim = this->interpolator;
 
 	sp = stack;
 	curMat = this->matrices;
@@ -228,7 +229,7 @@ copyHAnim(void *dst, void *src, int32 offset, int32)
 	dsthanim->hierarchy = nil;
 	srchier = srchanim->hierarchy;
 	if(srchier && !(srchier->flags & HAnimHierarchy::SUBHIERARCHY)){
-		dsthier = HAnimHierarchy::create(srchier->numNodes, nil, nil, srchier->flags, srchier->currentAnim->maxInterpKeyFrameSize);
+		dsthier = HAnimHierarchy::create(srchier->numNodes, nil, nil, srchier->flags, srchier->interpolator->maxInterpKeyFrameSize);
 		for(i = 0; i < dsthier->numNodes; i++){
 			dsthier->nodeInfo[i].frame = nil;
 			dsthier->nodeInfo[i].flags = srchier->nodeInfo[i].flags;
@@ -286,7 +287,7 @@ writeHAnim(Stream *stream, int32, void *object, int32 offset, int32)
 	HAnimHierarchy *hier = hanim->hierarchy;
 	stream->writeI32(hier->numNodes);
 	stream->writeI32(hier->flags);
-	stream->writeI32(hier->currentAnim->maxInterpKeyFrameSize);
+	stream->writeI32(hier->interpolator->maxInterpKeyFrameSize);
 	for(int32 i = 0; i < hier->numNodes; i++){
 		stream->writeI32(hier->nodeInfo[i].id);
 		stream->writeI32(hier->nodeInfo[i].index);
@@ -316,7 +317,7 @@ hAnimFrameRead(Stream *stream, Animation *anim)
 		stream->read(&frames[i].q, 4*4);
 		stream->read(&frames[i].t, 3*4);
 		int32 prev = stream->readI32()/0x24;
-		frames[i].prev = &frames[prev];
+		frames[i].prevFrame = &frames[prev];
 	}
 }
 
@@ -328,7 +329,7 @@ hAnimFrameWrite(Stream *stream, Animation *anim)
 		stream->writeF32(frames[i].time);
 		stream->write(&frames[i].q, 4*4);
 		stream->write(&frames[i].t, 3*4);
-		stream->writeI32((frames[i].prev - frames)*0x24);
+		stream->writeI32((frames[i].prevFrame - frames)*0x24);
 	}
 }
 
diff --git a/src/rwbase.h b/src/rwbase.h
index 1a06d0b..d486849 100644
--- a/src/rwbase.h
+++ b/src/rwbase.h
@@ -235,19 +235,33 @@ struct V4d
 };
 inline bool32 equal(const V4d &v1, const V4d &v2) { return v1.x == v2.x && v1.y == v2.y && v1.z == v2.z && v1.w == v2.w; }
 
+enum CombineOp
+{
+	COMBINEREPLACE,
+	COMBINEPRECONCAT,
+	COMBINEPOSTCONCAT
+};
+
+
 Quat makeQuat(float32 w, float32 x, float32 y, float32 z);
 Quat makeQuat(float32 w, const V3d &vec);
 
 struct Quat
 {
 	// order is important for streaming
-	float32 x, y, z, w;
+	union {
+		struct { float32 x, y, z, w; };
+		// needed for RW compatibility
+		struct { V3d imag; float32 real; };
+	};
 
 	static Quat rotation(float32 angle, const V3d &axis){
-		return makeQuat(cos(angle/2.0f), scale(axis, sin(angle/2.0f))); }
+		return makeQuat(cos(angle/2.0f), scale(normalize(axis), sin(angle/2.0f))); }
 	void set(float32 w, float32 x, float32 y, float32 z){
 		this->w = w; this->x = x; this->y = y; this->z = z; }
 	V3d vec(void){ return makeV3d(x, y, z); }
+
+	Quat *rotate(const V3d *axis, float32 angle, CombineOp op);
 };
 
 inline Quat makeQuat(float32 w, float32 x, float32 y, float32 z) { Quat q = { x, y, z, w }; return q; }
@@ -265,13 +279,6 @@ inline V3d rotate(const V3d &v, const Quat &q) { return mult(mult(q, makeQuat(0.
 Quat lerp(const Quat &q, const Quat &p, float32 r);
 Quat slerp(const Quat &q, const Quat &p, float32 a);
 
-enum CombineOp
-{
-	COMBINEREPLACE,
-	COMBINEPRECONCAT,
-	COMBINEPOSTCONCAT
-};
-
 struct RawMatrix
 {
 	V3d right;
diff --git a/src/rwcharset.h b/src/rwcharset.h
index 3616603..d4576ed 100644
--- a/src/rwcharset.h
+++ b/src/rwcharset.h
@@ -12,9 +12,9 @@ struct Charset
 
 	static bool32 open(void);
 	static void close(void);
-	static Charset *create(RGBA *foreground, RGBA *background);
+	static Charset *create(const RGBA *foreground, const RGBA *background);
 	void destroy(void);
-	Charset *setColors(RGBA *foreground, RGBA *background);
+	Charset *setColors(const RGBA *foreground, const RGBA *background);
 	void print(const char *str, int32 x, int32 y, bool32 hideSpaces);
 	void printBuffered(const char *str, int32 x, int32 y, bool32 hideSpaces);
 	static void flushBuffer(void);
diff --git a/src/rwplugins.h b/src/rwplugins.h
index b26046a..af23303 100644
--- a/src/rwplugins.h
+++ b/src/rwplugins.h
@@ -6,7 +6,7 @@ namespace rw {
 
 struct HAnimKeyFrame
 {
-	HAnimKeyFrame *prev;
+	HAnimKeyFrame *prevFrame;
 	float32        time;
 	Quat           q;
 	V3d            t;
@@ -37,7 +37,7 @@ struct HAnimHierarchy
 	HAnimNodeInfo *nodeInfo;
 	Frame *parentFrame;
 	HAnimHierarchy *parentHierarchy;	// mostly unused
-	AnimInterpolator *currentAnim;
+	AnimInterpolator *interpolator;
 
 	static HAnimHierarchy *create(int32 numNodes, int32 *nodeFlags,
 			int32 *nodeIDs, int32 flags, int32 maxKeySize);