Friday, April 29, 2016

My bookshelves.

I realize recently that I'm weird programmer. If you would look on my bookshelves you will find there:
  • manga, 
  • fantasy books,
  • movies art books,
  • games art books,
  • books about drawing, 
  • books about anatomy,
  • books about animations,
  • D&D manuals.
What you won't find there is any programming book. My only book kind of in this topic is Showstopper about development of windows NT on my kindle. Which is in the fact not programming book but more story of people who created it and I'm still in middle of reading it :) 

The other book I reading is  "The Animator's Survival Kit: A Manual of Methods, Principles and Formulas for Classical, Computer, Games, Stop Motion and Internet Animators." which is for me really interesting. So far I finding there a lot of interesting advice which some even apply to programming.

And this is weird because as programmer I probably should read some books in my field of work. But I don't fell any push into this direction. I don't wan't to read book about programming language because what for? I tried long time ago and they are boring like hell :/ If I need to learn syntax I can just look into online tutorials.

All new stuff about C++ I learning when I searching online for solutions of problems or discuss with others. Sometimes I spend more time on trying understand small piece of example code than on fixing the initial issue. This happening mostly because I go from one page to another and finding more and more interesting stuff.

I would really love to read programming book which is not about language or algorithms but more about programming itself. I imagine such a book would contain stories of development, tips and tricks how to be better programmer. You know this kind of book which you start reading and before you noticing its ends.

Do you know book like that ? If you know I would really like to know its title.

Greg

Sunday, April 24, 2016

Plans, real life and monkey job.

Funny thing about planning is that sometimes its not working out the way you want. This was case this week I planned to work on animations and ended doing small upgrade for resource system. The best thing is that I don't even feel bad about stuff ending this way :D 

How I ended doing that is other story. Because I have policy of moving everything what I can to resource system which I have (this make stuff more consistent) I moved my rendering script to it. Everything would be good if not the fact that render script is initialized on main thread and my resource system never was prepared for request from other thread than game thread. So it was time to do improvement to allow for this :D

This was even more important because there were sometimes crashes at startup of game. I split my task on 3 sub task:

  1. Access to resource data require locking of resource (i.e. meshRes->lock()->getMaterial();)
  2. Separation of resource from data so you could have resource handle and it was still loading 
  3. Moving prepared stuff on multithreading.
First two task were robust :/ required iterating over all my resource types and changing it's interface. This was boring like hell but well programming is not only about interesting stuff.

My mind was blank when I was doing this so I had time to think and came to conclusion:
Some people saying that programming is about creating stuff. But reality is different. We as programmer spend most of our time improving existing stuff, changing them, fixing and redesigning. When we do all of this we make small piece of code which do something new and we once again starting whole thing again. This is also true in personal projects.
Few hour later changes were ready and I could start preparing functions which worked on one thread but were already separated in a way part of it could be moved to other thread. This was more interesting task which resulted in changes for some of resources. Generally my resource system look like this:

class ResourceXYZ
{
     ResourceId  m_id;
     DataType*  m_privateData;
};

Till now private data was part which control whole resource but now in some cases I want to hold some data in resource so even when private data change it will still be the same. I.e. LevelID (Yes level is also resource).

Another hour later I was ready. I know that my game worked because I were changes step by step with running game to be sure it at least work. Next step was mutli-threaded code which went smoothly.

Thanks to lock system I would add simple wait for loading of resource if it was still loading. There were small issue with dependencies of compiling GPU programs (they expected other resources to be already loaded) but well thanks to my split on soft and hard references fixing it was also easy.

And so my code working now and my previous 700 ms loading on debug configuration resulted in 600 ms loading now :) There are still few things I want to make:

  • File asynchronous loading with forward loading for better performance.
  • Reloading of resources
  • Cleanup iteration over whole system
But well you cannot have everything in life but some day I will make this all work :) For now I will return to animation topic to push everything forward :)

Greg

Thursday, April 14, 2016

After break

I took some break from writing on this blog but I had busy last few months. In this time I done a lot of changes in engine one of biggest "finished" one are changes in file system. But this time I don't to talk about what I done but more about what will come and what I working on right now.

And I do some stuff with which I'm not feel most comfortable: Animation system. So I decided to seek some advice and explain what I do, why and how I would like to improve it. So be free to comment and critique.

I don't fell that system I have right now is what I really want to have.

This is this weird felling when you fell that system that you created is working but you fell that it's limiting you. Because of this felling recently more often I turn of computer and sit down with pen and notebook and think what I really want to do with this system. So far my conclusion is because I'm iterative develop White Rabbit Engine technology I didn't notice till now that what was I searching for was different thing from what I have now. 

What I have now is "decent" system for playing animation using blends trees. And what I was searching for are behavior trees. I already have some idea how to make this system part of existing code. This will require some changes because I want blend trees to be just input nodes for behaviors nodes. Everything so whole system was consistent on all levels.

New movement system
Right now there is simple system which apply on character: orientation from pad/keyboard relative to camera direction and then play walk/run animation. This work but don't look nice when you try to change direction.

Because of that currently I started experimenting with simple system which based on direction vector try to choose the animation which will allow to get root bone position to destiny point. How it will work I don't know this is more R&D. So far I'm still not convinced by result. I will also probably postpone this "task" to first do proper behavior tree which will allow me on easier experimenting.

I am doing animations so if it possible I want to optimize whole workflow as much as I can.

This is for more simpler problem than it may sound. Currently I can create "Animation Database" (AnimDB) resource which contain link to animations resource and blends trees inside. 

Sound good but it's not because I cannot reuse the same blend tree between different AnimDB. This was one of this problem I didn't thought so much when I was doing initial system and if I decide to do different animations for each race in Little Big Adventure: Remake it would require from me supporting multiple copies of the same tree which would be really inefficient. So I need to fix :)

Animations in White Rabbit Engine are used to locomotion of character.

Right now this happening by calculating root bone relative movement and applying this to kinematic physics in each frame. This works nice but you need to be really careful how you do animations because slight foot movement may result in sliding effects of foots.

What I would like to experiment with is possibility to lock one of bones in world space and retrieving root offset from this.This would look like we have animation with marked when left or right foot touch ground and when it do it I lock position of marked bone in world space (b.w.s.) and store local animation position (b.l.a.p) of it. Bone is locked as long as distance between stored (b.l.a.p) and current (b.l.a.p) won't be bigger then some delta. I would use this lock to apply corrections to root offset so even if foot slightly move in animation in engine it would still look good

Conclusion

As you can see I think about a lot of stuff and try to improve a lot of different issues. Right now we redoing assets for Little Big Adventure: Remake. Thanks to that we don't need to put extra effort into changing content. But once I will define whole workflow there will be only place for small improvement. 

There will be no second chance so it would be nice to do it right so I'm going back to my pen and notebook to figure out in my head how I want this whole stuff to work. When whole idea will be in my head coding should be the easiest part.