feat: landing slide prediction (theoretical + real) #1

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wait4mi commented 2026-05-12 09:56:35 +00:00

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Ajoute la prediction de glissage a l'atterrissage au mod ElytraTrajectory.

Phase glide (modifiee)

• Plus d'arret sec sur collision laterale : la velocite est projetee sur la surface (wall-slide), ce qui permet de glisser en diagonale le long d'un mur.
• Budget de 4 redirections max pour eviter les boucles dans les coins.
• Sur impact face = UP (sol) : bascule en phase slide.

Phase slide (nouvelle)

• Formule vanilla : v *= friction * 0.91 par tick.
• friction lue dynamiquement sur le bloc sous le joueur (Block.getFriction()).
• Aucun input joueur suppose (modele conservateur).
• Arret a |v| < 0.005 b/tick ou 80 ticks max.

Distances attendues : ~3 blocs sur stone, ~20+ sur blue_ice.

Slide reel post-atterrissage

• LandingTracker detecte la transition isFallFlying() -> false.
• Capture position() + getDeltaMovement() reels, recalcule le slide via predictSlideOnly().
• Affichage pendant 60 ticks (3 s) en remplacement de la prediction theorique.

Rendu

• Glide : cyan -> magenta (inchange)
• Slide : jaune -> orange
• Point d'arret : + rouge au sol

CI

• Trigger etendu a feature/** pour valider le build sur branche avant merge.

Test plan

• CI verte sur cette branche
• In-game : atterrissage sur stone (slide court ~3 blocs)
• In-game : atterrissage sur blue_ice (slide long ~20 blocs)
• In-game : approche diagonale d'un mur (trajectoire suit le mur)
• In-game : pique + redressement (comparer prediction theorique vs slide reel)
• In-game : marqueur + rouge present au point d'arret final

## Resume Ajoute la prediction de **glissage a l'atterrissage** au mod ElytraTrajectory. ### Phase glide (modifiee) - Plus d'arret sec sur collision laterale : la velocite est projetee sur la surface (wall-slide), ce qui permet de glisser en diagonale le long d'un mur. - Budget de 4 redirections max pour eviter les boucles dans les coins. - Sur impact face = UP (sol) : bascule en phase slide. ### Phase slide (nouvelle) - Formule vanilla : `v *= friction * 0.91` par tick. - `friction` lue dynamiquement sur le bloc sous le joueur (`Block.getFriction()`). - Aucun input joueur suppose (modele conservateur). - Arret a `|v| < 0.005 b/tick` ou 80 ticks max. Distances attendues : ~3 blocs sur stone, ~20+ sur blue_ice. ### Slide reel post-atterrissage - `LandingTracker` detecte la transition `isFallFlying() -> false`. - Capture `position()` + `getDeltaMovement()` reels, recalcule le slide via `predictSlideOnly()`. - Affichage pendant 60 ticks (3 s) en remplacement de la prediction theorique. ### Rendu - Glide : cyan -> magenta (inchange) - Slide : jaune -> orange - Point d'arret : `+` rouge au sol ### CI - Trigger etendu a `feature/**` pour valider le build sur branche avant merge. ## Test plan - [ ] CI verte sur cette branche - [ ] In-game : atterrissage sur stone (slide court ~3 blocs) - [ ] In-game : atterrissage sur blue_ice (slide long ~20 blocs) - [ ] In-game : approche diagonale d'un mur (trajectoire suit le mur) - [ ] In-game : pique + redressement (comparer prediction theorique vs slide reel) - [ ] In-game : marqueur `+` rouge present au point d'arret final

wait4mi added 1 commit 2026-05-12 09:56:35 +00:00

feat: add landing slide prediction (theoretical + real) ... 815e8d4b68

Refactors TrajectoryPredictor to keep simulating past the first
collision instead of stopping there:

- Glide phase now slides along walls/ceilings (projects velocity onto
  the surface) so a diagonal approach keeps moving instead of dead-
  stopping, with a redirect budget to avoid infinite loops in corners.
- When the simulation lands on top of a block (face = UP), a second
  "slide" phase is run with the residual horizontal velocity and the
  block-below friction (vanilla formula: v *= friction * 0.91 per
  tick, no player input assumed).

predict() now returns a Prediction(glidePath, slidePath, stopPoint,
landed) struct.

The renderer draws both phases plus a red "+" marker at the predicted
stop point: cyan->magenta for glide (unchanged), yellow->orange for
slide.

LandingTracker watches the fall-flying transition each client tick.
On touchdown it captures the player's real position+velocity and
recomputes the slide prediction (via predictSlideOnly), shown for ~3 s
in place of the theoretical one — lets the user see the actual landing
point with the real velocity rather than the pre-landing estimate.

Build CI also runs on feature/** branches so we can validate before
merging to main.

wait4mi added 1 commit 2026-05-12 10:03:43 +00:00

fix(slide): apply friction after move, not before (vanilla order) ... 355f9f45ab

The slide phase was decaying velocity *before* the first move, which
made the predicted distance roughly half the vanilla value (on stone:
~2.4 blocks predicted vs ~4.4 actual). Vanilla LivingEntity#travel for
ground motion uses the current velocity to move, then sets the next
tick's velocity to v * friction * 0.91 — drag is applied after move,
not before. Match that ordering.

Also:
- Match vanilla's friction probe offset (0.500001 below feet, like
  getBlockPosBelowThatAffectsMyMovement) instead of 0.2.
- Raise MAX_SLIDE_TICKS to 200 and lower the stop threshold to
  0.003 b/tick so long slides on blue_ice / packed_ice aren't
  truncated by the safety cap.

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• src/main/java/fr/ekaii/elytratrajectory/TrajectoryRenderer.java

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Merge commit title Merge pull request 'feat: landing slide prediction (theoretical + real)' (#1) from feature/landing-slide into main

Merge commit body Reviewed-on: https://forgejo.ekaii.fr/wait4mi/elytra-trajectory/pulls/1

Merge pull request 'feat: landing slide prediction (theoretical + real)' (#1) from feature/landing-slide into main Reviewed-on: https://forgejo.ekaii.fr/wait4mi/elytra-trajectory/pulls/1 Copy merge commit message

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