1 files changed, 67 insertions, 0 deletions
diff --git a/source/blender/blenlib/intern/math_rotation.c b/source/blender/blenlib/intern/math_rotation.c
index b8cef511293..3b58fe88bf5 100644
--- a/source/blender/blenlib/intern/math_rotation.c
+++ b/source/blender/blenlib/intern/math_rotation.c
@@ -1530,6 +1530,73 @@ void copy_dq_dq(DualQuat *dq1, DualQuat *dq2)
 	memcpy(dq1, dq2, sizeof(DualQuat));
 }
 
+/* axis matches eTrackToAxis_Modes */
+void quat_apply_track(float quat[4], short axis, short upflag)
+{	
+	/* rotations are hard coded to match vec_to_quat */
+	const float quat_track[][4]= {{0.70710676908493, 0.0, -0.70710676908493, 0.0},  /* pos-y90 */ 
+	                              {0.5, 0.5, 0.5, 0.5},  /* Quaternion((1,0,0), radians(90)) * Quaternion((0,1,0), radians(90)) */ 
+	                              {0.70710676908493, 0.0, 0.0, 0.70710676908493},  /* pos-z90 */ 
+	                              {0.70710676908493, 0.0, 0.70710676908493, 0.0}, /* neg-y90 */ 
+	                              {0.5, -0.5, -0.5, 0.5}, /* Quaternion((1,0,0), radians(-90)) * Quaternion((0,1,0), radians(-90)) */ 
+	                              {-3.0908619663705394e-08, 0.70710676908493, 0.70710676908493, 3.0908619663705394e-08}}; /* no rotation */
+
+	mul_qt_qtqt(quat, quat, quat_track[axis]);
+
+	if(axis>2)
+		axis= axis-3;
+
+	/* there are 2 possible up-axis for each axis used, the 'quat_track' applies so the first
+	 * up axis is used X->Y, Y->X, Z->X, if this first up axis isn used then rotate 90d
+	 * the strange bit shift below just find the low axis {X:Y, Y:X, Z:X} */
+	if(upflag != (2-axis)>>1) {
+		float q[4]= {0.70710676908493, 0.0, 0.0, 0.0}; /* assign 90d rotation axis */
+		q[axis+1] = ((axis==1)) ? 0.70710676908493 : -0.70710676908493; /* flip non Y axis */
+		mul_qt_qtqt(quat, quat, q);
+	}
+}
+
+
+void vec_apply_track(float vec[3], short axis)
+{
+	float tvec[3];
+
+	copy_v3_v3(tvec, vec);
+
+	switch(axis) {
+	case 0: /* pos-x */
+		/* vec[0]=  0.0; */
+		vec[1]=  tvec[2];
+		vec[2]=  -tvec[1];
+		break;
+	case 1: /* pos-y */
+		/* vec[0]= tvec[0]; */
+		/* vec[1]=  0.0; */
+		/* vec[2]= tvec[2]; */ 
+		break;
+	case 2: /* pos-z */
+		/* vec[0]= tvec[0]; */
+		/* vec[1]= tvec[1]; */
+		// vec[2]=  0.0; */
+		break;
+	case 3: /* neg-x */
+		/* vec[0]=  0.0; */
+		vec[1]=  tvec[2];
+		vec[2]= -tvec[1];
+		break;
+	case 4: /* neg-y */
+		vec[0]= -tvec[2];
+		/* vec[1]=  0.0; */
+		vec[2]= tvec[0];
+		break;
+	case 5: /* neg-z */
+		vec[0]= -tvec[0];
+		vec[1]= -tvec[1];
+		/* vec[2]=  0.0; */
+		break;
+	}
+}
+
 /* lense/angle conversion (radians) */
 float lens_to_angle(float lens)
 {