Remove redundant code from quaternion class

git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@3699 dfc29bdd-3216-0410-991c-e03cc46cb475

include/quaternion.h

@@ -120,7 +120,10 @@ class quaternion
 		//! Inverts this quaternion
 		quaternion& makeInverse();
 
-		//! Set this quaternion to the result of the interpolation between two quaternions
+		//! Set this quaternion to the result of the linear interpolation between two quaternions
+		quaternion& quaternion::lerp(quaternion q1, quaternion q2, f32 time);
+
+		//! Set this quaternion to the result of the spherical interpolation between two quaternions
 		quaternion& slerp( quaternion q1, quaternion q2, f32 interpolate );
 
 		//! Create quaternion from rotation angle and rotation axis.
@@ -490,43 +493,37 @@ inline quaternion& quaternion::normalize()
 }
 
 
+// set this quaternion to the result of the linear interpolation between two quaternions
+inline quaternion& quaternion::lerp(quaternion q1, quaternion q2, f32 time)
+{
+	const f32 scale = 1.0f - time;
+	const f32 invscale = time;
+	return (*this = (q1*scale) + (q2*invscale));
+}
+
+
 // set this quaternion to the result of the interpolation between two quaternions
 inline quaternion& quaternion::slerp(quaternion q1, quaternion q2, f32 time)
 {
 	f32 angle = q1.dotProduct(q2);
 
+	// make sure we use the short rotation
 	if (angle < 0.0f)
 	{
 		q1 *= -1.0f;
 		angle *= -1.0f;
 	}
 
-	f32 scale;
+	if (angle <= 0.95f) // spherical interpolation
-	f32 invscale;
-
-	if ((angle + 1.0f) > 0.05f)
-	{
-		if ((1.0f - angle) >= 0.05f) // spherical interpolation
 	{
 		const f32 theta = acosf(angle);
 		const f32 invsintheta = reciprocal(sinf(theta));
-			scale = sinf(theta * (1.0f-time)) * invsintheta;
+		const f32 scale = sinf(theta * (1.0f-time)) * invsintheta;
-			invscale = sinf(theta * time) * invsintheta;
+		const f32 invscale = sinf(theta * time) * invsintheta;
+		return (*this = (q1*scale) + (q2*invscale));
 	}
 	else // linear interploation
-		{
+		return lerp(q1,q2,time);
-			scale = 1.0f - time;
-			invscale = time;
-		}
-	}
-	else
-	{
-		q2.set(-q1.Y, q1.X, -q1.W, q1.Z);
-		scale = sinf(PI * (0.5f - time));
-		invscale = sinf(PI * time);
-	}
-
-	return (*this = (q1*scale) + (q2*invscale));
 }
 
 

tests/testQuaternion.cpp

@@ -133,6 +133,88 @@ bool testRotationFromTo()
 	}
 	return result;
 }
+
+bool testInterpolation()
+{
+	bool result=true;
+	core::quaternion q(1.f,2.f,3.f,4.f);
+	core::quaternion q2;
+	q2.lerp(q,q,0);
+	if (q != q2)
+	{
+		logTestString("Quaternion lerp with same quaternion did not yield same quaternion back (with t==0).\n");
+		result = false;
+	}
+	q2.lerp(q,q,0.5f);
+	if (q != q2)
+	{
+		logTestString("Quaternion lerp with same quaternion did not yield same quaternion back (with t==0.5).\n");
+		result = false;
+	}
+	q2.lerp(q,q,1);
+	if (q != q2)
+	{
+		logTestString("Quaternion lerp with same quaternion did not yield same quaternion back (with t==1).\n");
+		result = false;
+	}
+	q2.lerp(q,q,0.2345f);
+	if (q != q2)
+	{
+		logTestString("Quaternion lerp with same quaternion did not yield same quaternion back (with t==0.2345).\n");
+		result = false;
+	}
+	q2.slerp(q,q,0);
+	if (q != q2)
+	{
+		logTestString("Quaternion slerp with same quaternion did not yield same quaternion back (with t==0).\n");
+		result = false;
+	}
+	q2.slerp(q,q,0.5f);
+	if (q != q2)
+	{
+		logTestString("Quaternion slerp with same quaternion did not yield same quaternion back (with t==0.5).\n");
+		result = false;
+	}
+	q2.slerp(q,q,1);
+	if (q != q2)
+	{
+		logTestString("Quaternion slerp with same quaternion did not yield same quaternion back (with t==1).\n");
+		result = false;
+	}
+	q2.slerp(q,q,0.2345f);
+	if (q != q2)
+	{
+		logTestString("Quaternion slerp with same quaternion did not yield same quaternion back (with t==0.2345).\n");
+		result = false;
+	}
+	core::quaternion q3(core::vector3df(45,135,85)*core::DEGTORAD);
+	q.set(core::vector3df(35,125,75)*core::DEGTORAD);
+	q2.slerp(q,q3,0);
+	if (q != q2)
+	{
+		logTestString("Quaternion slerp with different quaternions did not yield first quaternion back (with t==0).\n");
+		result = false;
+	}
+	q2.slerp(q,q3,1);
+	if (q3 != q2)
+	{
+		logTestString("Quaternion slerp with different quaternions did not yield second quaternion back (with t==1).\n");
+		result = false;
+	}
+	q2.slerp(q,q3,0.5);
+	if (!q2.equals(core::quaternion(-0.437f,0.742f,0.017f,0.506f),0.001f))
+	{
+		logTestString("Quaternion slerp with different quaternions did not yield correct result (with t==0.5).\n");
+		result = false;
+	}
+	q2.slerp(q,q3,0.2345f);
+	if (!q2.equals(core::quaternion(-0.4202f,0.7499f,0.03814f,0.5093f),0.0007f))
+	{
+		logTestString("Quaternion slerp with different quaternions did not yield correct result (with t==0.2345).\n");
+		result = false;
+	}
+	return result;
+}
 }
 
 bool testQuaternion(void)
@@ -172,7 +254,7 @@ bool testQuaternion(void)
 	}
 
 	result &= testRotationFromTo();
-
+	result &= testInterpolation();
 	result &= testEulerConversion();
 
 	return result;