Thursday, January 11, 2018

Engine Refactory

The Big Refactory has started (I could pretend it is a new-year resolution). And it even went pretty far, like abstracting away the animated objects list so that only the code for animated objects need to know details of the animation scheduler.

I was about to try changing the VRAM allocation system so that only classes deriving from using Resources could request items, and I got stuck in the animation editor.

Unlike SEDs and -to some extent- LEDs, AniMEDs still use a lot of global variables. Things like the sprite set or the animation being editted are used almost directly in many places, instead of being captured as "structural singletons". And at some places, it also means that we were calling Ressource Manager directly at top-level code, and that contradicts what a common base class can do.

There is one other peculiar thing about the animation editor: the set of pixels used in the game isn't uploaded to the video memory. Instead, we keep it in main memory, and only some bits of it go tothe VRAM through a Sprite sheet that map some sprite memory.  These sprite sheets are linked to a specific widget, such as the timeline or the frame preview. I must not try to make them part of a "model": they truly belong to the implementation of the widgets.

And yeah, although I have a digital sketchpad and an e-boox, I still enjoy some good paper and fine (erasable) pens for such things.

Thursday, January 04, 2018

Presenting monsters


This is something I really loved in DKC closing cutscene and which I'll now seriously start working on for School Rush: seeing the nicknames of all the baddies in the game with the baddies themselves. Later on, when I wanted to bring Badman II to an end, I tried to do something similar: which apparently worked quite well it was acclaimed by Aderack in his wiki and essays.

And as if I'd need one more proof, my brother just convinced Lazycow that such a show was all he needed to make the. end-of-game cut scene of Power Glove feel satisfying for the players reaching that point.


J'étais complètement fan de la séquence de fin de Donkey Kong Country, avec sa présentation des ennemis un peu humoriste qui dévoile leurs noms et permet de se souvenir de tout ce qu'on a traversé. J'avais fait quelque-chose d'un peu similaire pour la fin de Badman II, ce qui a plu, visiblement (au moins à Aderack ;)

Et comme s'il en fallait plus pour m'encourager à remettre le couvert dans School Rush, voilà que mon frère me raconte que LazyCowse demandait que faire pour le final de son PowerGlove et mon frère de lui dire que "bin si, les joueurs aiment bien qu'on leur remontre la galerie des monstres/boss avec les noms de tout le monde (surtout quand les noms sont un peu rigolos). Et sisi, y'a pas forcément besoin de beaucoup plus.

Donc ne vous inquiétez pas, je vais quand-même garder un petit quelque-chose d'original : le croquis ci-dessus est une ancienne idée. Mais j'ai encore quelques petits détails à régler pour que ce soit réussi. 

Of course, these are just some preliminary sketches, and there has been some evolutions. But I know you'll allow me to keep those details a secret, and not spoiling your future satisfaction myself.

Wednesday, January 03, 2018

A dos de blador.

Mes taille-crayons, une fois en mouvement, font d'assez mauvaises plates-formes, en vérité. Celà vient de leur animation. D'abord (comme la plupart des animations de marche), elle va retarder certains mouvements pour consommer d'un coup 2 pixels de déplacement après être restée immobile pendant 4 images si la vitesse de consigne est d'1/2 pixel-par-60eme de seconde. Ensuite, parce que contrairement à Bilou, le déplacement de dumblador s'interrompt pour une courte pause avant de reprendre: non seulement ce taille est trop "dumb" pour mettre un pied devant l'autre, mais en plus, il lui faut un moment pour se souvenir de ce qu'il convient de faire pour finir le mouvement qu'il a entammé. Autant dire qu'il vaudrait sans doute mieux pour une "pile de dumbladors" de tomber d'un étage quand un des tailles-crayon se remet en mouvement plutôt que de jouer à rajouter des "selles invisibles" pour offrir quelque-chose de plus souple.

Non. Je préfère tenter maintenant de faire tenir Bilou sur un taille-crayon à l'arrêt. Et là aussi, j'ai du travail: il faudra veiller à

  • forcer une mise à l'arrêt complet au contact, puisque le contrôleur "stopper" sera court-circuité,
  • "détacher" Bilou de son support lorsqu'il saute,
  • compléter le contrôleur "onpath" pour qu'il provoque le détachement lorsque Bilou n'est plus par-dessus le chemin.
This has been a "known issue" since April 2014, and it still wouldn't be easy to fix it today: you can walk on a Dumblador (after stunning it) as if it was a platform, but as it wakes up, weird things occur that make Bilou slightly slip forward and eventually fall of the blador. Initially, it was also affecting stacked dumbladors, so I added a rule to "break" the stack as a blador wakes up.

The core of the problem comes from the fact that a carried GOB will adapt to the "moving platform"'s speed in order to give the illusion of friction, but when it comes to dumbladors, the speed and the effective motion quite disagree. First because - as with any WALKing GOB - the horizontal speed isn't constant, and second because I introduced a small pause between two steps for the blador, to reinforce the feeling of "dumbness". As a reminder, the GPath abstraction is as follow:

  • GameObjects have an 'onpath' pointer, which complements the 'attach' pointer (to a gob).
  • GobArea now implements the (horizontal) GPath API, returning always the same y coordinate, and checking that you're in the desired xrange.
  • 'Ap' in a gobexpression will attach the object to a "path" rather than to an object, the area that triggered the collision will be used to define the new path.
I gave path-capable engine a try back in february 2013, but that was nothing I could test. The idea was to support both NSMB-like angled mushrooms and (softly) swinging ropes. The current code with dynamic GPath comes from June 2013 and has still to be complemented with a controller that uses it.

It's all described and motivated in http://sylvainhb.blogspot.be/2013/06/walking-on-platforms.html