Sur bsky, MagicalScope nous poste d'impressionnants designs d'objets magiques qui sont ensuite vendus à des internautes. Parmi eux, je suis tombé sur une potion-qui-marche particulièrement inspirante. J'ai d'abord eu le réflexe de voir comment je pourrais l'intégrer comme nouveau perso dans la pyramide jusqu' ce que je réalise que mon brave scorpeye pourrait simplement profiter du type de déplacement que suggère cette potion tout en restant lui-même.
Many of the tutorials I had encountered between SEDS and LEDS are now out of the web. Too bad, they were key material I sent readers towards when I did not feel like translating some lengthy explanation about tiled games in general. Since I'm editing some part of the blog as if it was going to be the Chapter 1: Tiled Games of a book, I found myself digging through archive.org to find the original material, print it and review it as much as possible.
The most influential of them all was certainly the MC Kids big post. Where we have Greggman discussing *really* how they made the game back on NES days. It details several clever tricks that help making a quite-sized game on limited resources, some of which make mostly sense if you're on #6502 CPU (like having a set of byte tables rather than structures), but also the key gamedev concept of a "hotspot", a single point that will be used to model the position of the character on slopes.
It is also the most official one, as the post was originally written in 1992 for the Journal of Computer Game Design while the game was from 1992 as well. And since there was an official body publishing it, I can't quite just bring in many pictures of it ... but I guess it's fair to study it, take notes and then post my own notes about what was being said.
The paper goes into significant details of how the levels are encoded (1 byte per 16x16 block, that is used to lookup the 4 tiles composing the block and its type among 100 possible types), how collision with terrain are handled (with direction-conditional testpoints and 5 collision functions per tile type). The author relates the fight to get that extra memory and how you could map the whole level into memory and thus make it easily explorable and transformable thanks to this, but how 8x8 granularity would have explosed the RAM space budget.
It is also completed with retrospective thought of the author about how they'd have inserted "beginning of hill" and "end of hill" types (helpful to save lookups in the slope management) and how they'd have made the "how do I move left[tiletype, xpos]" array providing absolute position rather than relative (+1, 0, -1) positions in a revised version of the engine.
Retrospectively, most of it did not end up in the GEDS engine. With a 66MHz CPU, if you realize that you need one extra memory lookup to get proper slope implementation, you go for that extra lookup. And if you may need more than one, you just write a loop. It's not about being lazy or not, it's about getting the most of what you have. And nowadays, you could "easily" add some "start-of-slope", "end-of-slope" meta tiles by means of auto-tiling rules.
The second note-worthy series are Tony PA tutorials about tiled games development. These were for flash games, with full-running examples at each step and detailed ActionScript code. Smartly enough, Tony starts his tutorials with top-down playfield in which the character can move freely, and then step by step introduces gravity, moving platforms, ladders and finally slopes.
I was enjoyed to start reading it as it featured a picture of Charlie the Duck (which may explain why I was researching about it in 2007 and certainly why I just posted about it, btw :P) and saying "Sure if our hero is a jumper-type of hreo, he could still [proceed forward in a stair-like, slopeless ground], but normal heroes are very happy if they can avoid jumping. It could have been a good resource, but I knew from the time I've spotted a drawing with "impossible slopes" that I couldn't derive from what was presented there.
During this 2026 retro-review, I noted that most of the slope logic seems to imply that only the display of the character is aligned with the slope. The logic entity made of testpoints and hitboxes simply moves along a stair. The two locations are only re-aligned if we jump from a slope. It also bypass the problem of solid-ground-tiles-and-slopes by disabling all horizontal checks while you're on a slope. That explains some of the "forbidden tile combinations", and implies that if you make a slope in a path that is high enough for certain characters in your game but not all, the engine will completely ignore the fact that the monster you're fleeing through that narrow passage should get hit in the face and not be able to follow you. And that has been a critical thing to address for my games even before I started working with the Nintendo DS.
So why would you put slopes in a Mario game ? so that your koopa shell keeps flowing forward and not bounce back in your face. Here's why. (Or simply to make your organic level feel organic and not just look organic).
A last one ? Hopefully, the video from Vblank Entertainment about the conversion of Retro City Rampage into ROM City Rampage is still online. It goes into details about what tiles are and how it allows a large world to run on a sub-MegaByte cartridge, what palettes are, why you need to care about not putting too many sprites per line and so on. If you ever need a primer to the "Retro Game Mechanics Explained" series and feel like sitting idle for 10 minutes, this is the best I can think of at the moment.
(The author ended up writing his own NES emulator full with debugging features and his own high-level assembly -- NESHLA hosted on sourceforge -- in the process)
Si ça ne vous impressionne pas, c'est parce que je n'ai pas encore précisé qu'il s'agit d'un shareware réalisé pour MS-DOS. Et par une seule personne s'il vous plaît: Charlie the Duck.
Il me semble bien que j'étais tombé dessus la première fois aux alentours de '97 ou '98, pendant que je cherchais des infos sur les DOS Extenders, les bibliothèques graphiques pour DJGPP du style de Allegro et ce genre de choses. Et il est fort probable que je sois d'abord tombé sur le clone de Mario World du même auteur avant de tomber sur Charlie... mais je n'ai pu trouver aucune infos corroborant cette impression. Mais j'avais été impressionné. Puis un peu déçu: Mike non plus n'avait pas encore trouvé de solution convaincante au problème de la musique de fond pendant que le jeu tourne.
Je sais que je suis retombé sur Charlie et Mike au début de ce blog, ou plus précisément sur le TFE de Mike que j'ai pris à l'époque pour une thèse de doctorat. L'équipe de recherche sur la programmation fonctionnelle du coin voyait d'un bon oeil la création d'une bibliothèque de création de jeux (de plate-forme) pour étoffer son palmarès d'applications et comme le langage s'appelait "Clean" (il est assez proche d'Haskell, au passage), on a eu droit à la Clean Game Library. Le document est sympa et utilise abondamment Charlie pour les illustrations. La bibliothèque est en théorie multi-plate-forme mais a été distribuée pour DirectX. Elle a aussi permis à Mike de faire une suite à son jeu, qui reçoit un accueil mitigé suite à des ajouts/suppressions de mécaniques de jeu.
Je n'ai jamais oublié Charlie, même si avec le temps, je l'ai confondu avec le jeu-référence d'un bouquin qui parlait du mode X (et de la bibliothèque FastGraph ?) Et en re-creusant un peu le sujet pour ce post, je tombe sur un morceau croustillant de Wikipedia:
Game-Maker seems also to have made an impression in the Benelux, with references in various academic papers,[26] coverage in the largest game magazine in the region,[27] and dissection by the local demoscene.[28]
Parce que si [26] est la présentation de Mike à la conférence IFL aux Pays-Bas en '99, si je n'ai jamais entendu parler du magazine [27], la démoscène locale, c'est bibi, et la dissection, ce sont mes posts ^_^Eh oui, les gars: vous êtes en train de lire un site web référencé sur Wikipédia!
While I was checking collisions/interactions were still working fine after introducing the G_FIGHT group, I noted something not so right about the dumblador. Something I don't think I've ever blogged although it was available since the anniversary level: throw a dumblador into pencil spikes and it will snap to the spike it lands on, turning itself into an additional safe platform.
I first tried to tune collision areas, but that did not seem to help. I checked some values in the DDD debugger, but it's a bit of a lottery: you can't really tell in advance whether you'll find yourself in an interesting case. Note to future self: there are save states in desmume! (In such a case, I should have saved the emulator state before throwing the blador, save again when the breakpoint triggers, fast-forward to see whether the condition will happen and only then go back in time to either review the step-by-step behaviour or change a little bit the initial conditions and try another throw).
And there I realised that when the blador ended up misaligned, it was colliding with a spike whose position was a mere multiple of 8 rather than a multiple of 16 ...
Back in SchoolRush times, it was mandatory to be a 16x16 pixels block if you wanted to have special behaviour such as hurting the player. But it changed with the tiled engine revision where each individual 8x8 tile can be of any 64 special type (or any of the other 192 "normal" types).
So the script for the dumblador now looks like
$THROWN :anim3 {
using gravity(24,1536)
testpoint off (8,18)
test 0 (0,0)-(8,12) ${F_BAD|G_FIGHT|F_WEAPON} //# weapon against other monsters.
test 1 (0,15)-(16,16) ${F_BAD|F_PLATFORM};
area 0 (0,0)-(16,12) ${F_ISINK} //# deleted-by-ink
area 1 (0,0)-(16,8) ${G_FIGHT|F_HURT} // # stand-on-spike
}
$THROWN->$STUNSTAND on hit1 (0 :1 0 :0 Lc $vPlatform(2));
$STUNFALL->$STUNSTAND on hit1 (0 :1 0 :0 Lc $vPlatform(2));
block 21 { is spike "0101030307070f0f" area (7,0)-(8,16) 10010010 # hurts on hit [0] (t) }
Together, they allow to get a functional blador-align-on-spike (aligning is performed by the Lc opcode), but there's still one thing to fix if I don't want to see dumblador waking up and start walking on pencils: duplicate the $STUNSTAND state into something like $SPIKED, while removing the "get feet" area. But well, a remaining glitch makes some more fun for ScreenshotSaturday ;-)
While reviewing the "tiled" chapter produced by my blogpress tools, I remembered that landing on a slope still produces odd effects from time to time. And then came an idea to reproduce these conditions in the unit-test environment.
Just as I was observing that the "dkp54" branch has been around from a long time and so has been the "cflags" branch and that "right, I promised myself I wouldn't merge things unless I've first checked they still pass automated tests."
And unfortunately, right then, the tests were not passing, they were crashing. First with an exception and then with a segmentation fault. The "offending" commit was something from 2025, a few lines that will report (rather than ignore) syntax errors within the GobState parsing.
It took some times to identify where the error was introduced, much less to fix it (hopefully) and so the 'dkp' branch (toolkit update) is now finally merged and the cflags can be just that: a branch propagating the new collision mechanism (and not a adventurous combination of features).
Alors c'était l'occasion de se demander "et si en fait on faisait un groupe pour toutes ces actions qui retirent des points de vie à un des objets ?". Petit à petit, hein, en vérifiant qu'on ne casse rien (et donc, forcément avec une vidéo Screenshot Saturday où tout d'un coup, on passe à travers les branches au lieu de rebondir et à travers les pommes sans qu'elles ne se doutent de rien...)
Un nouveau G_FIGHT donc (j'ai un peu chipoté pour trouver le nom du groupe puis le Fight Club s'est rappelé à mon bon souvenir, tel une évidence inévitable). Peu à peu, les différents scripts-personnages sont convertis en nettoyant les vieilleries comme les scripts avec des valeurs numériques plutôt que des combinaisons de symboles. Puis arrive le moment crucial de réactiver la branche-qui-rebondit, et là, je me rends compte que garder dans G_FIGHT l'action principale F_STOMP, celle que Bilou utilise jouer à Super Mario assommant un goomba, ça ne va pas marcher. ça va imposer aux zones de collision destinées à être de simples plate-formes de faire partie du Fight Club alors qu'elles n'ont même pas de "points de vie". D'autant plus problématiques qu'on a aussi des flags du type F_PLATFORM pour, par exemple, empiler des taille-crayons sans qu'ils n'infligent de dommages.
Heureusement, j'avais prévu de garder une portion des flags "neutres" (CFLAGS_LONE_FLAGS), valables qu'il y ait accord sur les groupes ou non. On pourra donc mettre la branche dans le groupe G_GROUND (qui n'existe pas encore) dont F_PLATFORM ferait partie et lui ajouter un "ah, oui, on prend F_STOMP aussi, même si ça ne fait pas vraiment partie du groupe". Certaines des zones de collisions ont dû être dédoublée (une avec G_FIGHT, l'autre sans), un petit défaut dans la réécriture quand ça arrive et on se retrouve avec des branches qui ne rebondissent plus aussi bien qu'avant ... un petit schéma, un peu de ddd et ça se remet en place. Le code pour tester deux zones de collisions ressemble donc maintenant à
cflags GobArea::test(const GobArea *o, GameObject *g, cflags mask, GobCollision* gc) const {
if (o==this) return 0;
cflags group = mask & CFLAGS_GROUP_MASK;
- if (group && (flags & CFLAGS_GROUP_MASK) != group) return 0;
+ if ((flags & CFLAGS_GROUP_MASK) != group) mask &= ~CFLAGS_IN_GROUP_FLAGS;
if ((mask & flags & CFLAGS_EXPR_MASK)==0) return 0;
// congratulations: you may compare coordinates, now.
I'm not considering to add some for these projects at this point, despite I now have a few things on codeberg and codeberg sure comes with some CI/CD option, maybe they'll look like the one of gitlab which I've had to deal with today.
Most of gitlab's CI options are tweaked through variables within the .gitlab-ci.yml file of your repository. Most of those variables are free to configure yourself but some directly affect the “Getting source from Git repository” step, especially GIT_SUBMODULE_STRATEGY, GIT_STRATEGY (where you can tell whether you want a full clone or a mere fetch of the branch you're using in your job).
And unfortunately, it's one of those case where git turns out to be complicated, with many trivial things (do you have a "main" branch here?) requiring long commands (git show-ref --quiet main ... you thought that would have been one of the 8+ modes of "git branch" command ? too bad :P) that you may have to post-process. For instance, you can pick only a few commits at the top of some branch, you need not to crawl back to that initial commit.
mkdir mere_window
cd mere_window
git init # a new place to toy with commits
git fetch ~/myFavoriteRepo --depth 10
git checkout FETCH_HEAD # so we're somewhere on the history
whereami 80
See ? 1) not all commits are there, although I asked 'whereami' (alias wh) to show me at least 20 of them, and 2) at the bottom of it, there's one tagged with (grafted). If you had branches merged lately, you might have more. Such grafts still have the same ID as the original commit, but they contain much more things if you show them: the whole content you're missing since repository started is condensed in such grafts. They'll delegate that extra weight to a deeper commit if you decide to fetch again with a higher depth, and turn back to their original size.
But back to gitlab. Its default setting seems to be to fetch with a depth of 20, performing what appears to be dubbed "a shallow fetch". You can spot that with "Fetching changes with git depth set to 20...". Mostly sufficient but if the CI/CD is introduced late in the life of the repository, and if you've been working on long branches for a while, it might not know about the main branch at all. That turned to be a problem for some packaging steps, but hopefully, we have GIT_DEPTH that can tweak things, and setting it to "0" is the way to tell gitlab to drop the --depth argument altogether. There at least, you should have some value of "main", even if it isn't the latest (just the latest known to your branch, I presume).
Gitlab may also play trick on you by keeping the things you already fetched when you start some old test again, just to find that the branch is now listed. You know it does when the job step will mention it "Reinitialized existing Git repository in your_path".
One more trap to avoid: git branch does not list *all* branches. Only those you created locally by checking something out. You'll need an extra -a to also show the remote branches (or -r to see only them).
Si vous avez un peu essayé n'importe laquelle de mes démos "green zone" ces 20 dernières années, ça n'a pas pu vous échapper: le petit ver jaune - ce croisement entre un combattant dans Worms Armageddon et un poison slug de Commander Keen - est pénible.
Jusque là, je ne lui avais jamais fait d'animation "éliminé, le petit ver". On l'assomme, il attend, il repart. Il n'avait qu'un rôle minime dans Apple Assault... et le fait qu'on puisse le réassommer à volonté y permettait de reprendre des points. On le supportait.
Enfin, on le supportait mais de loin, parce que sa manie de repartir à l'attaque sans avertissement, c'est certainement ce qui vous a pompé le plus. Alors le week-end dernier, après avoir déposé les gamins en camp, j'ai allumé la DS et refait 3 petits dessins de ce ver tournoyant dans les airs pour qu'au moins, quand on lui roule dessus avec une pomme, on en soit quitte. ça ajoute de l'interaction et en théorie, ça devrait être rigolo à voir.
Il m'a fallu un peu de chipotage pour que le sens de rotation soit cohérent avec celui de la pomme, et j'en ai profité pour lui rajouté un état "détection" qui le remballe directement dans l'état "assommé" s'il sent Bilou à proximité. J'aimerais aussi rajouter une autre fioriture, un état "se fait rouler dessus" qui le maintiendrait au sol jusqu'à ce que la pomme soit passée, et ça, ça va sans doute demander un petit contrôleur supplémentaire...
it isn'tnow it is). That would give
$STUNNED->$ROLLEDOVER on hit0 [w0 0 >] (128 :0 A);
$STUNNED->$ROLLEDOVER on hit1 [w0 0 <] (128 ~ :0 A);
$ROLLEDOVER->$LKICKED on event0 [v0 0 <] (400 ~:1);
$ROLLEDOVER->$RKICKED on event0 [v0 0 >] (400 ~:1);
$ROLLEDOVER->$RECOVER on done (0 :1)
$ROLLEDOVER :anim7 {
using tracking(@ over 12);
}
Un dernier détail qu'il faudra régler: de base, si on touchait le ver avec la pomme avant que la pomme ne se soit mise à rouler, la pomme rebondissait dans la direction opposée. Un reste de quand elle était un taille-crayon, j'imagine. Mais maintenant que j'ai modifié le script de la pomme pour qu'elle passe à travers le ver, elle peut aussi passer à travers les autres pommes ... pas terrible. Il faudrait bien que je me donne une variante de F_WEAPON qui indique "ennemi léger" et une autre "ennemi lourd", ou encoder ça dans encore-une-autre-variable-propre des gobs, ce qui serait sûrement plus facile, mais moins cohérent avec le type de programmation proposée ... un peu comme ajouter un "if" bash dans un Makefile, quoi :P
L'occasion de passer au nouveau système de flags de collisions ?
I completely forgot to tell you about that patch from early June that allowed to see clearly the space occupied by larger monsters in LEDS. And I forgot to pull it from "the cube" and to push it on sourceforge, too.
It did not work exactly how I hoped though, so there was still some manual tweaking to get those bouncy branches properly aligned with the tiled tree when I assembled the tree, and I even figured out why. But well, June was fairly crowded IRL.
edit: Ah. Yeah, of course. I'll have to push that new patch, else I'll start hunting for it again when I'll want it running on NDS for more map patching ^^"
Ah, yeah. Early this month, while the heatwave had not burnt our energy and house wasn't yet a post-camp-departure-mess, I had that Silly Idea (tm) that I could enter the
I would have read https://gbadev.net/resources.html#articles, installed the GBA devkit in addition to the NDS devkitpro (reality: done, but where) and I'd have quickly (ahem) converted the Green Zone graphics into 16-colors-per-tile so that they could fit in the smaller video memory of the GBA. Some sprites (funky funghi, Bilou) would have been turned into 16-colors too while some others (appleman, mostly) would have stuck to 256 colors because they're taking more than 16 :P
Only then, I'd have tried to rebuild the Dreams engine for GBA and imported the Dreams animation over the Apple Assault levels, and that would have been the basis for Apple Assault Advance. Luckily enough, the sound engine promoted by devkitpro would have been happy about my brother's good old 6-track variant of String Tracking.
Likely, I'd have needed to find a way to compile the GobScript state machines into plain old data that could stay in ROM so that the smaller-sized (256K?) GBA RAM could have been saved for really-read/write features. Same for the maps, most likely ... They're not that big, so they could have been fit to RAM. Maybe they would have to so that collectible tiles would have worked. (not that there are many such things in Apple Assault).
But that was before blogpress started pressing me to develop it again. I think I'll focus on making first steps with bosses in NDS Dreams engine, instead :P
I also managed to put it on sourceforge download before my own laptop's battery told me to stop and go to bed...
French journalists have a word for that seasonal topic that comes up again in newspapers when every high-end interviewers are on holiday and things are up to interns: "Le marronnier de l'été" ... and it may feel that doing some blog-to-printable/epub conversions pops up every summer here, but hopefully not for the same reason.
The motion started with the late-night idea that "tiled" engine discussions could be a chapter 1 if the blog ever had to be converted into a book, but also that editions could use their own tag, like "ch1" for that chapter 1. On the next day, I was dusting off repositories and working directories for the next "blogpress" round, motivated by the fact that I'll have up to early August before the next automated snapshot/takeout.
I wrote a small introduction to that chapter (french only, atm) and then grew surprised by how little preparation there was on that "tiled" tag. Reader would just be thrown stuff at their eyes, and they'd better understand things. Sure, I introduced it rather late, not as I was writing those posts... I discovered a bit sadly that most of the tutorial I had used by the time are now offline (and even their archive.org copy are firewalled T_T by "my" most powerful computer).
I edited some of the early posts in "tiled" following the idea that "Many posts contain parts that would be useful for a chapter (say, one about tiled game engines) but also parts that don't quite fit. So how about having <span> or <div> tags assigning those items a "no-ch1" (or no-ch5 when I'll be at chapter 5) and let the simple.css make them display: none ?"
Finally, 4 days ago, I managed to get all the issues fixed in my scripts and re-generate a good-looking page that I can use in calibre to export an epub file. And because each issue involved a good deal of html snippets and that I'd rather have a clipboard to compare them when that happens, I decided to use codeberg's issue tracking system for that.
 script output, as uploaded on codeberg |
 what it looks like on the blog |
 what it looks like copy-pasted in office |
 what I had from older (2025) script output |
A sad discovery while working at all this was that the 72x72 thumbs are no longer automatically provided by the takeout. They might have annoyed me when doing the last conversion back in 2025, but no more than I month later I had figured out that they could be a "magical portal" to posts and uploaded them to neocities.
And now I have another project for those thumbs. I had included the "milestone" tag together with "tiled" to get a bit of reminder of what had already happened and what not between two "tiled" posts, but many of the milestones are too large and distracting compared to what I want. The first paragraph (?), the date, title and the thumbnail would likely be sufficient. Hopefully, I can recontruct some thumbs URIs from regular picture URIs, but I'll need to resort on my drive-archived blogthumbs.zip for the missing ones...
There's one line of all that that I'd like to bring here. It's the incarnation of "make the possible easy" part of Perl:
$post=~s/src=\"([^"]+)"/src="$larger{$pix{$1}}$escaped{$1}" alt="$1 ; $pix{$1}"/sg;
In that single line, we iterate through (thanks, g modifier) all the image URLs of a single post and patch them using the hash tables that we constructed by parsing "temporary" files that other scripts produced. No need for split-patch-join sort of loop.
edit: Some commands used to generate the latest version:
THUMBS=../thumbs/thumbz.html perl ../git/list-atoms.pl ../bilou/feed.atom <(cat ../pictures3.lst ../morepix.lst ../pictures2.lst) tiled '(milestone)' > tm3t.htmlgrep '<!-- all images' -A9999 tm3t.html | grep ^i | fe - "cp % /d/local/pages/geds/attach_files/ -v"BLOG=https://sylvainhb.blogspot.com perl ../git/thumbify.pl <(perl ../git/summarize-atoms.pl ../bilou/feed.atom) > thumbz.htmlblogthumbs.zip I got from that-time-where-thumbs-appeared-in-exported-data.
ls i* | sed -e 's/\(i[0-9][0-9]*\)-\([^0]\)-\(.*\)/mv \1-\2-\3 \1-0-\3/' | grep -v '^i' > renamethumbs.sh
edit+: fine-tuning keeps going on mastodon
Bon, oui, le GB studio, c'est rigolo comme concept. Et ça fait pas mal de titres tout à fait sympa comme ce dinosaure de luxe. Mais y convertir du Bilou, je vois mal le truc ... même Badman aurait du mal. .. mais, petit délire de Mars ... j'ai déjà un jeu qui avait été pensé pour le monochrome dès le début: Caliméro!
On ne va pas se mentir, par contre, ça n'avait pas vraiment été pensé pour les 160 pixels de large du DMG. Le personnage ne ferait pas loin de la moitié de l'écran!
Une fois remis à une une échelle un peu plus raisonnable, avec un perso en 24x24, ou quelque-chose comme ça, on commencerait à pouvoir jouer. Pas que le jeu deviendrait automatiquement un hit, hein, mais voilà.
Même quelques boss ;)
Et on pourrait essayer de finir en beauté avec une petite image de Bilou en 4 niveaux de gris, avant et après retouche par votre serviteur de janvier 2025... qui ne tient absolument pas compte des contraintes du genre "3 couleurs + transparence par pavé de 8x8", ni du nombre max de sprites par lignes, ni du nombre max de tiles de la GB ni rien. Un pur délire de Gimp, quoi.
Toujours en mode "post-desktop". Toujours avec mes carnets qui me servent entre-autres à suivre la progression (lente mais présente) du projet "dreamland". Tout le jeu, avec ce genre de carnet, c'est d'arriver à conserver facilement accessible les choses qui sont encore pertinentes. Souvent, ça passe par un coin de feuille sur lequel je vais me faire une espèce de petit index illustré des pages sur lesquelles j'ai encore des cases de "todo" à cocher ... régulièrement quand la dernière page de ce genre a perdu son statut de "priorité absolue".
D'autres points avaient été relevés lors du feuilletage et vont se retrouver grisés: ils ne sont pas utiles pour proposer une "première démo" de Dreamland. C'est le cas pour les ajouts juteux autour du poing-écrabouilleur de la pyramide. Oui, ce serait plus sympa qu'il fasse de la poussière, qu'il fasse trembler l'écran etc. mais on peut très bien tester le jeu sans rien de tout ça.
Et comme vous pouvez le voir, c'est beaucoup autour de l'eau que j'ai pris du retard.
L'idée est d'essayer de mieux grappiller les moments disponibles et ne pas retomber sur "ah oui, il faudrait faire ça ... ah mais non, il faudrait d'abord que je mette à jour Bilou.cmd et je n'ai que la DS" quand j'ai une petite demie-heure qui se dégage.
Et forcément, c'est dans ces moments-là qu'arrive une idée du genre "mais oui! faire des ricochets sur l'eau avec les pommes!" ou "les chauve-souris cessent de vous pourchasser si elles rencontrent de l'eau (façon essaim d'abeilles Disney ;-)
Funky Funghi, un des plus anciens personnages de la Green Zone sur DS, vient de se ramasser une pomme. Jusqu'il y a peu, la pomme serait juste passée à travers, mais alors que ce blog va sur ses 20 ans d'existence, j'ai rajouté les quelques lignes de code script qui manquaient pour que l'interaction proposée début 2022 devienne une réalité: on va pouvoir dégager les champignons du chemin à coup de jets de pommes.
Bon, j'avoue que comparé aux "prunes rebondissantes" de Rayman, on est sur quelque-chose de nettement plus détendu: Funghi ne risque pas d'aller rebondir contre un mur et de revenir vous écrabouiller. Il ne reçoit que la moitié de la vitesse de la pomme et ralentit de moitié à chaque rebond. Juste ce qu'il faut pour passer d'une souche à "entre les deux souches" en une pomme. Mais ça devrait être marrant quand-même vu qu'il y a moyen de ramasser à nouveau la pomme et de la lancer une fois de plus. D'autant plus que maintenant, il va aussi être possible de rebondir sur le chapeau de Funky Funghi! (c'est peut-être encore un peu fort, d'ailleurs).
La solution à laquelle je suis arrivé à coup de débuggeur d'expression est un rien intimidante ... entre autres parce qu'elle dérive de la collision destinée à faire rebondir Bilou, et que pour Bilou, je voulais que l'angle change selon qu'on arrivait plutôt sur le bord ou sur le centre de Funghi, comme s'il était vraiment un bumper de flipper. Pour ça, on va préparer deux valeurs et les combiner avec | dans le byte haut et le byte bas d'un entier 16-bit avant d'écrire le tout dans la 10e variable de Funghi avec :a. C'était rigolo avec l'appleman, mais ça devenait compliqué d'y ajouter le transfer d'énergie ... donc au final, pour l'appleman, Funghi agira toujours comme un mur qui absorbe 50% de sa vitesse horizontale et n'a aucun n'effet à la verticale. Et sur l'énergie absorbée, la vitesse acquise par Funghi est moitié moins importante que celle qu'avait l'appleman ce qui nous permet de calculer qu'un Funghi pèse à peu près 2 Applemen ;P
state0->state0 on found$apple [C_THROW we 0 >= w0 0 < & &]
(w0 2/ ~ $ff00 & w1 256 / $ff & | :a w0 4/ v0 + :0)
state0->state0 on found$apple [C_THROW we 0 < w0 0 > & &]
(w0 2/ ~ $ff00 & w1 256 / $ff & | :a w0 4/ v0 + :0)w0) is transferred to Funghi, and the other half is bounced back. But since Funghi is bigger, the half it takes only result in 1/4th of the speed. Not pushing him very far, I'm afraid. And well, that's only the part w0 4 / v0 + :0. All the things that happen before are reusing the "protocol" defined for throwing things where the thrower decides of the direction of the thrown object I already used for dumblador. The X speed and the Y speed will be set in the 10th register of funghi with :a and later used by the appleman with
$RTHROWN->$LTHROWN on hit0 [C_THROW wa 0 < &] (wa $ff00 & :0 wa 256 * :1)Mais dans le code de l'appleman, j'ai quand-même gardé un code générique qui se contente d'appliquer le vecteur-vitesse qu'il trouve dans la 10eme variable de ce qu'il a heurté. ça pourra me permettre par la suite de faire en sorte que les branches rebondissantes puissent elles aussi renvoyer les applemen ^_^. Petite subtilité: la transition hit de l'appleman est testée avant la transition found de Funghi mais c'est found qui fournit le vecteur vitesse que hit va utiliser. c'est pour ça qu'il y a un test qui s'assure que wa < 0, pour que lors de la première frame de collision, l'appleman conserve sa trajectoire pendant que Funghi calcule l'impact. A la 2eme frame, wa est défini et la trajectoire de l'appleman pourra changer.
Et pour la collision Bilou/Funghi, c'est la distance entre le centre des hitbox (we) qui va déterminer l'angle de l'impulsion que Funghi va nous imposer, entre (-3,0), (-2,-1), (-1, -2), (0, -3)
state0->state0 on found$bilou [C_THROW we 0 >= &] (we 4/ 256* we 4/ 3 - $ff & | :a)we is one of the collision-specific parameter (rather than an internal variable of the collided object) containing the center-to-center distance between Bilou and Funghi, ranging from -24 to +24. At the very edge of Funghi, you'll get bounce horizontally by (+-3, 0), and at the center of his hat, you'll be bounced by (0, -3). In between, you could get (+-2, -1) near the edge and (+-1, -2) near the hat. And yup, it's got the overall expr_1 256* expr_2 $ff & | shape again to put both together in a single variable.
Il me restait un truc à régler: Funghi donne l'impression d'être en béton et que rien ne peut lui arriver même quand on rebondit dessus ou qu'on lui lance une pomme. J'aurais bien essayé de réutiliser l'animation "rebondit au sol" dans un sens ou dans l'autre, mais Funghi est toujours un "SimpleGob" premère génération, et je ne leur ai manifestement jamais ajouté le support des transanims.
Je profite donc de la p'tite canicule du week-end pour redécouper un peu Funghi dans le Sprite Editor, refaire ses animations dans AnimEDS et rajouter un "fait rebondir un truc qui arrive du haut" ainsi qu'un "fait rebondir un truc qui arrive sur le côté". Ce n'est pas spectaculaire, mais ça donne plutôt bien quand-même.
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somewhere, on planet Earth, there's a weird guy named Sylvain (aka. PypeBros) who loves to write programs and draw comics with a blue ball named "bilou". That's me.
If you have a blog that talks about similar stuff, just leave me a comment.
3 packages available for download, deprecated CVS and mercurial
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