C++ FA2CSPose::LocalBlendCSBoneTransforms方法代码示例

//.........这里部分代码省略.........
				// We just have the two limbs double back on themselves, and EndPos will not equal the desired EffectorLocation.
				if ((CosAngle > 1.f) || (CosAngle < -1.f))
				{
					// Because we want the effector to be a positive distance down DesiredDir, we go back by the smaller section.
					if (UpperLimbLength > LowerLimbLength)
					{
						OutJointPos = RootPos + (UpperLimbLength * DesiredDir);
						OutEndPos = OutJointPos - (LowerLimbLength * DesiredDir);
					}
					else
					{
						OutJointPos = RootPos - (UpperLimbLength * DesiredDir);
						OutEndPos = OutJointPos + (LowerLimbLength * DesiredDir);
					}
				}
				else
				{
					// Angle between upper limb and DesiredDir
					const float Angle = FMath::Acos(CosAngle);

					// Now we calculate the distance of the joint from the root -> effector line.
					// This forms a right-angle triangle, with the upper limb as the hypotenuse.
					const float JointLineDist = UpperLimbLength * FMath::Sin(Angle);

					// And the final side of that triangle - distance along DesiredDir of perpendicular.
					// ProjJointDistSqr can't be neg, because JointLineDist must be <= UpperLimbLength because appSin(Angle) is <= 1.
					const float ProjJointDistSqr = (UpperLimbLength*UpperLimbLength) - (JointLineDist*JointLineDist);
					// although this shouldn't be ever negative, sometimes Xbox release produces -0.f, causing ProjJointDist to be NaN
					// so now I branch it.
					float ProjJointDist = (ProjJointDistSqr>0.f) ? FMath::Sqrt(ProjJointDistSqr) : 0.f;
					if (bReverseUpperBone)
					{
						ProjJointDist *= -1.f;
					}

					// So now we can work out where to put the joint!
					OutJointPos = RootPos + (ProjJointDist * DesiredDir) + (JointLineDist * JointBendDir);
				}
			}

			// Update transform for upper bone.
			{
				// Get difference in direction for old and new joint orientations
				FVector const OldDir = (InitialJointPos - RootPos).GetSafeNormal();
				FVector const NewDir = (OutJointPos - RootPos).GetSafeNormal();
				// Find Delta Rotation take takes us from Old to New dir
				FQuat const DeltaRotation = FQuat::FindBetween(OldDir, NewDir);
				// Rotate our Joint quaternion by this delta rotation
				UpperLimbCSTransform.SetRotation(DeltaRotation * UpperLimbCSTransform.GetRotation());
				// And put joint where it should be.
				UpperLimbCSTransform.SetTranslation(RootPos);

				// Order important. First bone is upper limb.
				OutBoneTransforms.Add(FBoneTransform(UpperLimbIndex, UpperLimbCSTransform));
			}

			// Update transform for lower bone.
			{
				// Get difference in direction for old and new joint orientations
				FVector const OldDir = (InitialEndPos - InitialJointPos).GetSafeNormal();
				FVector const NewDir = (OutEndPos - OutJointPos).GetSafeNormal();

				// Find Delta Rotation take takes us from Old to New dir
				FQuat const DeltaRotation = FQuat::FindBetween(OldDir, NewDir);
				// Rotate our Joint quaternion by this delta rotation
				LowerLimbCSTransform.SetRotation(DeltaRotation * LowerLimbCSTransform.GetRotation());
				// And put joint where it should be.
				LowerLimbCSTransform.SetTranslation(OutJointPos);

				// Order important. Second bone is lower limb.
				OutBoneTransforms.Add(FBoneTransform(LowerLimbIndex, LowerLimbCSTransform));

			}

			// Update transform for end bone.
			{

				// Set correct location for end bone.
				EndBoneCSTransform.SetTranslation(OutEndPos);

				// Order important. Third bone is End Bone.
				OutBoneTransforms.Add(FBoneTransform(EndBoneIndex, EndBoneCSTransform));
			}

			OutBoneTransforms.Sort([](const FBoneTransform& A, const FBoneTransform& B)
			{
				return A.BoneIndex < B.BoneIndex;
			});

			if (OutBoneTransforms.Num() > 0)
			{
				MeshBases.LocalBlendCSBoneTransforms(OutBoneTransforms, BlendWeight);
				OutBoneTransforms.Empty();
			}

		}

	}

}