Simplifying Attaching and Detaching

Continued from the previous entry.

After all of the previous work on attaching and detaching and getting it pretty close to working, I found that there were still a few issues, like the cuffs not attaching properly to Guybrush's wrists in the set wed. Additionally, after a code review by Akz, he suggested that the code could be made simpler and that instead of trying to match the internal matrices in the retail version, I should just aim to match the output. Of note was that I needed to insert a large number of transposes to make the intermediate values work.

As such, I scrapped the previous code and instead tried to fix the problem of attaching and detaching with all of the new information that I'd learned over the course of debugging this problem. This new version of the attach and detach code is much less intrusive and achieves the same result with far fewer calculations. This code was re-submitted as PR #948. So, how does the pole in the set pph look now?

The set pph after getting off the raft

Looks pretty close, the pole is in the right position, but let's compare it with the original:

Difference between retail and ResidualVM

It's a little hard to see, but there's still a different in the orientation of the pole. I'm not exactly sure where this comes from, but I suspect that it has to do with the joint rotation of Guybrush's hand. Still, the result is much better than it was before.

The next outstanding rotation issue that needed to be looked into was Issue #958. I thought that I had fixed this bug, but it appears to still be broken. The best item for displaying the issue is the itty-bitty brass screw, which is rotating on the wrong axis.

Retail

ResidualVM

As you can see, the screw starts in the wrong orientation and is upside down! Additionally, the rotation of some items in the inventory are incorrect with rotation being applied to the wrong axis. As it turns out, the orientation was incorrect because the rotation was applied backwards. Inverting the rotation Quaternion result of GetRotationQuat made this problem go away, but the resulting angle was wrong for the attached actor. This was because GetRotationQuat was being used as part of the attach and detach sequence. Iverting those usages as well found that the result now matched what we had before, except that the screw was rotated correctly.

The pole in the set pph is effected by the rotation of the hand joint in Guybrush's hand. As it turns out, the code that I had written for the attach and detach had neglected the position of the attached joint. Incorporating this rotation and translation slightly improved the position and rotation of the pole in the set mot.

At this point, I was hoping that all of the issues were resolved enough to move on, but two major issues remain:

1. The boats in the lava puzzle were placed incorrectly, appearing (well, not actually appearing) under the lava instead of on top.
2. When Guybrush rotates on the raft after boarding, he spins on a wrong axis.

In the next post, we'll tackle these issues!