The one-way tolerance angle is a field: a one-way collider and a one-way tile gain One-way angle (0 to 90 degrees, default 45), a contact blocks when its normal is within that angle of the blocking side, without a value the limit is bit-identical to before, and the rule holds for Move, Raycast and dynamic bodies in Rapier; tiles with different angles never merge into one rectangle, the scene view draws the angle as a cone in the middle of the thick side, and the inspector shows Blocks from and One-way angle only while One-way is on, through the new schema option shownWith (#159)

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/core/model/tile.ts

@@ -22,6 +22,8 @@ export const TILE_PLAYBACK_KEY = 'playback';
 export const TILE_SOLID_KEY = 'solid';
 /** Whether a solid tile only blocks from above, as a platform one jumps through from below (#155). */
 export const TILE_ONE_WAY_KEY = 'oneWay';
+/** How far a contact may lean from straight up and still land on a one-way tile, in degrees (#159). */
+export const TILE_ONE_WAY_ANGLE_KEY = 'oneWayAngle';
 /** How big the blocking box of a cell is against the cell, 1 = the whole cell (#140). */
 export const TILE_COLLISION_SCALE_KEY = 'collisionScale';
 export const TILE_COLLISION_SCALE_MIN = 0.1;

src/core/model/tilemapCollision.ts

@@ -19,7 +19,8 @@
  * quarters it is drawn from (see `tileShape`).
  *
  * One-way tiles (#155) block only from above. They are worked out on their own, by the same rules –
- * each function takes `oneWay` – so a platform never merges with a wall into one rectangle.
+ * each function takes `oneWay` – so a platform never merges with a wall into one rectangle, nor with
+ * a platform of another angle (#159).
  */
 import type { TileAsset, TilemapAsset } from './Asset';
 import { tileQuadrants } from './autotile';
@@ -28,9 +29,17 @@ import { boundaryOf, type BoundaryLine, clipToRect, convexPieces, signedArea } f
 import type { PropertyBag, Vec2 } from './Properties';
 import { findAssetOf, type Project } from './Project';
 import { findFrame } from './texture';
-import { isTileOneWay, isTileSolid, readTile, tileCollisionScale, tileKind, type TileKind } from './tile';
+import {
+  isTileOneWay,
+  isTileSolid,
+  readTile,
+  TILE_ONE_WAY_ANGLE_KEY,
+  tileCollisionScale,
+  tileKind,
+  type TileKind,
+} from './tile';
 import { cellOrigin, inGrid, neighboursOf, parseCellKey, tilemapTileSize } from './tilemap';
-import type { ColliderShape } from '../properties/collider';
+import { type ColliderShape, oneWayAngle } from '../properties/collider';
 
 /** A rectangle in cells: top-left corner and size. Whole cells at collision scale 1, parts of one otherwise. */
 export interface CellRect {
@@ -172,18 +181,48 @@ function placed(outline: TileOutline, x: number, y: number, size: number): TileO
   return { outline: outline.outline.map(place), pieces: outline.pieces.map((piece) => piece.map(place)) };
 }
 
+/**
+ * Which solid tiles a function looks at: false the ones blocking from everywhere, true every one-way
+ * tile, a number the one-way tiles of that angle (#159) – so tiles of two angles never merge.
+ */
+export type OneWayFilter = boolean | number;
+
+/** The angle a one-way tile lands things within, held to 0 … 90°. */
+export function tileOneWayAngle(tile: TileAsset): number {
+  return oneWayAngle(tile.props[TILE_ONE_WAY_ANGLE_KEY]);
+}
+
+function passesFilter(tile: TileAsset, oneWay: OneWayFilter): boolean {
+  if (!isTileOneWay(tile)) return oneWay === false;
+  return oneWay === true || tileOneWayAngle(tile) === oneWay;
+}
+
+/** The angles of the solid one-way tiles painted on the map, each once, smallest first. */
+export function oneWayAngles(project: Project, asset: TilemapAsset): number[] {
+  const angles = new Set<number>();
+  const seen = new Set<string>();
+  for (const layer of asset.layers)
+    for (const tileId of Object.values(layer.cells)) {
+      if (!tileId || seen.has(tileId)) continue;
+      seen.add(tileId);
+      const tile = findAssetOf(project, tileId, 'tile');
+      if (tile && isTileSolid(tile) && isTileOneWay(tile)) angles.add(tileOneWayAngle(tile));
+    }
+  return [...angles].sort((a, b) => a - b);
+}
+
 function blockingCells(
   project: Project,
   props: PropertyBag,
   asset: TilemapAsset,
-  oneWay: boolean,
+  oneWay: OneWayFilter,
 ): CellBlock[] {
   const tiles = new Map<string, { scale: number; shape: TileShape | null } | null>();
   const tileOf = (id: string) => {
     if (tiles.has(id)) return tiles.get(id)!;
     const tile = findAssetOf(project, id, 'tile');
     const value =
-      tile && isTileSolid(tile) && isTileOneWay(tile) === oneWay
+      tile && isTileSolid(tile) && passesFilter(tile, oneWay)
         ? { scale: tileCollisionScale(tile), shape: tileShape(project, tile) }
         : null;
     tiles.set(id, value);
@@ -239,7 +278,7 @@ export function solidCells(
   project: Project,
   props: PropertyBag,
   asset: TilemapAsset,
-  oneWay = false,
+  oneWay: OneWayFilter = false,
 ): Required<SolidCell>[] {
   return blockingCells(project, props, asset, oneWay)
     .filter((cell) => cell.box !== null)
@@ -256,7 +295,7 @@ export function solidPolygons(
   project: Project,
   props: PropertyBag,
   asset: TilemapAsset,
-  oneWay = false,
+  oneWay: OneWayFilter = false,
 ): CellPolygon[] {
   const polygons: CellPolygon[] = [];
   for (const cell of blockingCells(project, props, asset, oneWay)) {
@@ -370,7 +409,7 @@ export function solidRects(
   project: Project,
   props: PropertyBag,
   asset: TilemapAsset,
-  oneWay = false,
+  oneWay: OneWayFilter = false,
 ): CellRect[] {
   return mergeCells(solidCells(project, props, asset, oneWay));
 }

src/core/properties/PropertySchema.ts

@@ -26,6 +26,7 @@ import {
   TILE_COLLISION_SCALE_MIN,
   TILE_FPS_KEY,
   TILE_KIND_KEY,
+  TILE_ONE_WAY_ANGLE_KEY,
   TILE_ONE_WAY_KEY,
   TILE_PLAYBACK_KEY,
   TILE_SOLID_KEY,
@@ -68,11 +69,35 @@ type Extras<K extends FlatKind> = K extends 'number'
       ? { assetTypes?: readonly AssetType[] }
       : unknown;
 
-/** The definition of a flat kind: its default is a value of that kind, as the table says. */
+/**
+ * The definition of a flat kind: its default is a value of that kind, as the table says.
+ * `shownWith` names a switch on the same bag; the inspector shows the row only while it is on
+ * (see `isRowShown`), everything else – graph, defaults, files – always has it.
+ */
 export type FlatDef<K extends FlatKind = FlatKind> = {
-  [P in K]: { key: string; label: string; kind: P; default: ValueOf<P> } & Extras<P>;
+  [P in K]: { key: string; label: string; kind: P; default: ValueOf<P>; shownWith?: string } & Extras<P>;
 }[K];
 
+/** Whether the inspector shows the row, given the values of the bag it is on. */
+export function isRowShown(def: PropertyDef, values: PropertyBag): boolean {
+  return !('shownWith' in def) || def.shownWith === undefined || values[def.shownWith] === true;
+}
+
+/** How far a contact normal may lean from a one-way side and still land on it, in degrees (#155, #159). */
+export const ONE_WAY_ANGLE_DEFAULT = 45;
+export const ONE_WAY_ANGLE_MAX = 90;
+
+const ONE_WAY_ANGLE_ROW: FlatDef<'number'> = {
+  key: 'oneWayAngle',
+  label: 'One-way angle',
+  kind: 'number',
+  default: ONE_WAY_ANGLE_DEFAULT,
+  min: 0,
+  max: ONE_WAY_ANGLE_MAX,
+  step: 5,
+  shownWith: 'oneWay',
+};
+
 /** The inspector is generated from these entries, so a new property is one line in a schema below. */
 export type PropertyDef =
   | FlatDef
@@ -265,6 +290,7 @@ const ASSET_SCHEMAS: Record<AssetType, PropertySchema> = {
     { key: TILE_SOLID_KEY, label: 'Solid', kind: 'boolean', default: false },
     // A solid tile that only blocks from above, like a platform one jumps through (#155).
     { key: TILE_ONE_WAY_KEY, label: 'One-way (from above)', kind: 'boolean', default: false },
+    { ...ONE_WAY_ANGLE_ROW, key: TILE_ONE_WAY_ANGLE_KEY, shownWith: TILE_ONE_WAY_KEY },
     // Below 1 a cell blocks less than its square, above 1 more – but only on the sides without a
     // blocking neighbour, so a wall of such cells stays closed (#140).
     {
@@ -389,7 +415,10 @@ const ASSET_SCHEMAS: Record<AssetType, PropertySchema> = {
         { value: 'left', label: 'Left' },
         { value: 'right', label: 'Right' },
       ],
+      shownWith: 'oneWay',
     },
+    // How far a contact may lean from that side and still land (#159).
+    ONE_WAY_ANGLE_ROW,
   ],
   rigidbody: [
     {

src/core/properties/collider.ts

@@ -15,7 +15,7 @@ import {
   preferredOnTie,
   type Rounded,
 } from './convex';
-import { defaultsFor } from './PropertySchema';
+import { defaultsFor, ONE_WAY_ANGLE_DEFAULT, ONE_WAY_ANGLE_MAX } from './PropertySchema';
 
 const DEFAULTS = defaultsFor('collider');
 
@@ -112,27 +112,42 @@ const ONE_WAY_SIDES: Record<string, Vec2> = {
 };
 
 /**
- * A contact normal at most this far from a one-way collider's side (45°) is a landing on it; any
- * other contact passes through (#155).
+ * The world direction a one-way shape blocks from, and `cone`, the cosine of its angle: a contact
+ * whose normal lies within that angle of the direction is a landing, any other passes through.
  */
-const ONE_WAY_CONE = Math.cos(Math.PI / 4) - 1e-9;
+export interface OneWaySide extends Vec2 {
+  cone: number;
+}
+
+/** The angle held to 0 … 90°, anything unreadable the default. */
+export function oneWayAngle(value: PropertyValue | undefined): number {
+  const angle = Number(value ?? ONE_WAY_ANGLE_DEFAULT);
+  if (typeof value === 'boolean' || !Number.isFinite(angle)) return ONE_WAY_ANGLE_DEFAULT;
+  return Math.min(ONE_WAY_ANGLE_MAX, Math.max(0, angle));
+}
+
+/** The cone of an angle in degrees, a hair wide so a normal exactly on its edge still lands. */
+export function oneWayCone(angle: number): number {
+  return Math.cos((angle * Math.PI) / 180) - 1e-9;
+}
 
 /**
  * The world direction a one-way collider blocks from – its top face for the default "up", turned
- * and mirrored with it – or null for a collider that blocks from everywhere.
+ * and mirrored with it – with its cone, or null for a collider that blocks from everywhere.
  */
-export function oneWayFacing(props: PropertyBag, m: Mat): Vec2 | null {
+export function oneWayFacing(props: PropertyBag, m: Mat): OneWaySide | null {
   if (!(props.oneWay ?? DEFAULTS.oneWay)) return null;
   const side = ONE_WAY_SIDES[textOf(props.oneWayDirection ?? DEFAULTS.oneWayDirection)] ?? ONE_WAY_SIDES.up!;
   const x = m.a * side.x + m.c * side.y;
   const y = m.b * side.x + m.d * side.y;
   const length = Math.hypot(x, y);
-  return length > 0 ? { x: x / length, y: y / length } : null;
+  const cone = oneWayCone(oneWayAngle(props.oneWayAngle));
+  return length > 0 ? { x: x / length, y: y / length, cone } : null;
 }
 
 /** Whether a contact with that normal (towards the mover) lands on the side a one-way shape blocks from. */
-export function landsOn(normal: Vec2, facing: Vec2): boolean {
-  return dot(normal, facing) >= ONE_WAY_CONE;
+export function landsOn(normal: Vec2, facing: OneWaySide): boolean {
+  return dot(normal, facing) >= facing.cone;
 }
 
 /** The shape with every point moved by `move` and turned by `turn` more – a body carrying it moved rigidly. */

src/editor/inspector/assetSection.ts

@@ -19,7 +19,12 @@ import { findAsset, type Project } from '../../core/model/Project';
 import type { PropertyBag, PropertyValue } from '../../core/model/Properties';
 import { isGlobal, readScope, scopeOf } from '../../core/model/Scope';
 import { type StructFieldKind, VARIABLE_KINDS } from '../../core/properties/kinds';
-import { type PropertyDef, schemaForAsset, type StructFieldDef } from '../../core/properties/PropertySchema';
+import {
+  isRowShown,
+  type PropertyDef,
+  schemaForAsset,
+  type StructFieldDef,
+} from '../../core/properties/PropertySchema';
 import { markedAssetSchema } from '../../core/properties/deviation';
 import { isModified, resolveAssetProps } from '../../core/properties/resolve';
 import { Dropdown, HStack, Label, Menu, Theme } from '../../ui';
@@ -35,15 +40,17 @@ import { assetValue } from './valueSpecs';
 const newField = (key: string, kind: StructFieldKind): StructFieldDef => ({ key, kind });
 
 /**
- * Structure-defining facts of an asset selection: the schema keys and kinds, plus the fields of a
- * struct – those are rows of their own, so adding one has to rebuild the section.
+ * Structure-defining facts of an asset selection: the schema keys and kinds of the rows shown, plus
+ * the fields of a struct – those are rows of their own, so adding one has to rebuild the section.
  */
 export function assetSignature(project: Project, assetId: string): string {
   const asset = findAsset(project, assetId);
   if (!asset) return 'missing';
   // A machine's own rows are none, so its scope has to be named here or switching it rebuilds nothing.
   const machine = asset.type === 'statemachine' ? `|${scopeOf(asset)}` : '';
-  return schemaForAsset(project, asset).map(defSignature).join(',') + machine;
+  const values = resolveAssetProps(project, asset);
+  const rows = schemaForAsset(project, asset).filter((def) => isRowShown(def, values));
+  return rows.map(defSignature).join(',') + machine;
 }
 
 export function defSignature(def: PropertyDef): string {
@@ -101,7 +108,7 @@ export function refreshAssetSection(host: InspectorHost, assetId: string): boole
 function buildProps(host: InspectorHost, asset: Asset, schema: readonly PropertyDef[]): void {
   const project = () => host.state.project;
   const values = resolveAssetProps(project(), asset);
-  for (const def of schema) {
+  for (const def of schema.filter((d) => isRowShown(d, values))) {
     const row = createFieldRow(
       host,
       def,

src/editor/inspector/objectSection.ts

@@ -31,6 +31,7 @@ import type { SceneObject } from '../../core/model/SceneObject';
 import {
   COMMON_PROPS,
   isCommonProp,
+  isRowShown,
   isTransformProp,
   type PropertyDef,
   schemaFor,
@@ -65,7 +66,7 @@ export function objectRows(project: Project, asset: Asset, object: SceneObject):
     : schemaForObject(project, asset, object).filter((def) => !isCommonProp(def.key));
 }
 
-/** Structure-defining facts of an object selection: parent, template link, schema and painting. */
+/** Structure-defining facts of an object selection: parent, template link, the rows shown and painting. */
 export function objectSignature(
   state: EditorState,
   holderId: string,
@@ -84,7 +85,8 @@ export function objectSignature(
     : isLiveInstance(project, holder, object)
       ? 'instance'
       : '';
-  const rows = schemaForObject(project, asset, object);
+  const values = resolveSceneObjectProps(project, asset, object);
+  const rows = schemaForObject(project, asset, object).filter((def) => isRowShown(def, values));
   // A tilemap warns when it is placed more than once, so the number of placements shapes it too.
   const placed = asset.type === 'tilemap' ? `|placed:${findUsages(project, asset.id).length}` : '';
   return `${object.parentId}|${kind}${placed}|` + rows.map(defSignature).join(',');
@@ -202,7 +204,7 @@ export function buildObjectSection(host: InspectorHost, holderId: string, object
 
   // Asset properties (or behavior variables) with overrides; the switches are shown above.
   const values = resolveSceneObjectProps(host.state.project, asset, object);
-  const own = objectRows(host.state.project, asset, object);
+  const own = objectRows(host.state.project, asset, object).filter((def) => isRowShown(def, values));
   if (own.length > 0 || asset.type === 'behavior')
     addTitle(host, asset.type === 'behavior' ? 'VARIABLES' : 'PROPERTIES');
   if (own.length === 0 && asset.type === 'behavior') addNote(host, 'The behavior declares no variables.');

src/editor/viewport/SceneViewport.ts

@@ -61,7 +61,7 @@ import {
 import { gripAt, withCornerAfter, withCornerMoved, withoutCorner } from '../polygonEdit';
 import { collectHolderItems, type DrawItem } from '../../viewport/items';
 import type { LayerFocus } from '../../viewport/tilemap';
-import { dashedLine, drawSourceIcon, markBlockingSide, placeNode } from '../../viewport/symbols';
+import { CONE_LENGTH, dashedLine, drawSourceIcon, markBlockingSide, placeNode } from '../../viewport/symbols';
 import { screenToWorld, type View, worldToScreen } from '../../viewport/view';
 import { type CastRay, RAY_SHOWN, type World } from '../../runtime/World';
 import { FreeViewport } from './FreeViewport';
@@ -879,7 +879,8 @@ export class SceneViewport extends FreeViewport {
     stroke(boundary.solid, width);
     fill(oneWay.solids, oneWay.outlines, 0.06);
     stroke(boundary.oneWay, width / 2);
-    // A platform's top is what blocks, so that is what stands out.
+    // A platform's top is what blocks, so that is what stands out, with the cone it lands within.
+    const length = CONE_LENGTH / (scale * scaleOf(item.m));
     for (const rect of oneWay.solids) {
       const a = cellOrigin(item.props, rect.x, rect.y);
       const b = cellOrigin(item.props, rect.x + rect.w, rect.y + rect.h);
@@ -889,6 +890,7 @@ export class SceneViewport extends FreeViewport {
         { x: 0, y: -1 },
         width * 2,
         color,
+        { angle: rect.angle, length },
       );
     }
   }

src/runtime/physics/PhysicsSystem.ts

@@ -16,6 +16,7 @@ import {
   contactBetween,
   isTrigger,
   landsOn,
+  type OneWaySide,
   movedShape,
   piecesOf,
   shapeArea,
@@ -100,7 +101,7 @@ interface Body {
 interface Part {
   entity: Entity;
   shape: ColliderShape;
-  facing: Vec2 | null;
+  facing: OneWaySide | null;
   owner: Body;
 }
 
@@ -497,7 +498,7 @@ export class PhysicsSystem implements System, CollisionSource {
         local.map(({ entity, pieces, facing }) => [
           entity.id,
           pieces.map(pieceKey),
-          facing && [round(facing.x), round(facing.y)],
+          facing && [round(facing.x), round(facing.y), facing.cone],
           entity.type === 'collider' ? [isTrigger(entity.props), colliderMaterial(entity.props)] : 0,
         ]),
       ) + JSON.stringify(want.settings?.mass ?? 0);
@@ -599,10 +600,11 @@ export class PhysicsSystem implements System, CollisionSource {
   /**
    * Whether each dynamic body near a one-way collider passes through it in the coming step (#155).
    * It lands when it is on the blocking side (or sunk in no deeper than a landing sinks), the contact
-   * faces that side within 45° and it is not moving away from it; a body that landed is held as long
-   * as the two overlap, however deep a fast fall took it in one step. Otherwise it passes – from
-   * below, from the side, from inside – and so does a body told to ignore one-way colliders. One that
-   * is to pass is woken: a resting body sleeps, and a new answer alone would not move it.
+   * faces that side within the collider's angle (#159) and it is not moving away from it; a body
+   * that landed is held as long as the two overlap, however deep a fast fall took it in one step.
+   * Otherwise it passes – from below, from the side, from inside – and so does a body told to ignore
+   * one-way colliders. One that is to pass is woken: a resting body sleeps, and a new answer alone
+   * would not move it.
    */
   private decideOneWay(world: World): void {
     const platforms: [number, Part][] = [];
@@ -657,13 +659,13 @@ export class PhysicsSystem implements System, CollisionSource {
     return movedShape(part.shape, move, turn);
   }
 
-  private facingNow(part: Part): Vec2 {
+  private facingNow(part: Part): OneWaySide {
     const facing = part.facing!;
     if (!part.owner.body.isDynamic()) return facing;
     const turn = part.owner.body.rotation() - part.owner.placed.angle;
     const cos = Math.cos(turn);
     const sin = Math.sin(turn);
-    return { x: facing.x * cos - facing.y * sin, y: facing.x * sin + facing.y * cos };
+    return { x: facing.x * cos - facing.y * sin, y: facing.x * sin + facing.y * cos, cone: facing.cone };
   }
 
   /**

src/runtime/systems/solids.ts

@@ -7,6 +7,7 @@ import {
   cellPolygonShape,
   type CellRect,
   cellRectShape,
+  oneWayAngles,
   solidPolygons,
   solidRects,
 } from '../../core/model/tilemapCollision';
@@ -19,7 +20,9 @@ import {
   isTrigger,
   landsOn,
   movedShape,
+  oneWayCone,
   oneWayFacing,
+  type OneWaySide,
   overlapDepth,
   shapeExtent,
   shapesOverlap,
@@ -83,11 +86,11 @@ export const NOT_BLOCKED: MoveResult = Object.freeze({
 
 /**
  * A shape of a collider or tilemap, and for a one-way one the world direction it blocks from (#155):
- * only a contact whose normal lies within 45° of it stops anything.
+ * only a contact whose normal lies within its angle of it stops anything (#159).
  */
 export interface SolidShape {
   shape: ColliderShape;
-  facing: Vec2 | null;
+  facing: OneWaySide | null;
 }
 
 /** A shape in the mover's way and the collider or tilemap it belongs to. */
@@ -167,10 +170,13 @@ export class Solids {
         ? {
             rects: solidRects(project, props, asset),
             polygons: solidPolygons(project, props, asset),
-            oneWayRects: solidRects(project, props, asset, true),
-            oneWayPolygons: solidPolygons(project, props, asset, true),
+            oneWay: oneWayAngles(project, asset).map((angle) => ({
+              angle,
+              rects: solidRects(project, props, asset, angle),
+              polygons: solidPolygons(project, props, asset, angle),
+            })),
           }
-        : { rects: [], polygons: [], oneWayRects: [], oneWayPolygons: [] };
+        : { rects: [], polygons: [], oneWay: [] };
       this.blocks.set(tilemap, blocks);
     }
     return blocks;
@@ -179,19 +185,25 @@ export class Solids {
   /**
    * The shapes a body occupies in the world: one for a collider; for a tilemap one box per merged
    * rectangle and one polygon per outlined cell (#141), the one-way cells blocking from the map's
-   * top (#155). A tilemap placed before the first tick is worked out on the spot.
+   * top (#155) within their tile's angle (#159). A tilemap placed before the first tick is worked out
+   * on the spot.
    */
   solidShapesOf(world: World, body: Entity): SolidShape[] {
     const m = worldMatrixOf(body);
     if (body.type !== 'tilemap')
       return [{ shape: colliderShape(body.props, m), facing: oneWayFacing(body.props, m) }];
-    const { rects, polygons, oneWayRects, oneWayPolygons } = this.blocksOf(world, body);
+    const { rects, polygons, oneWay } = this.blocksOf(world, body);
     const up = oneWayFacing({ oneWay: true }, m);
-    const shapes = (cells: CellRect[], outlines: CellPolygon[], facing: Vec2 | null) => [
+    const shapes = (cells: CellRect[], outlines: CellPolygon[], facing: OneWaySide | null) => [
       ...cells.map((rect) => ({ shape: cellRectShape(body.props, rect, m), facing })),
       ...outlines.map((polygon) => ({ shape: cellPolygonShape(body.props, polygon, m), facing })),
     ];
-    return [...shapes(rects, polygons, null), ...shapes(oneWayRects, oneWayPolygons, up)];
+    return [
+      ...shapes(rects, polygons, null),
+      ...oneWay.flatMap((group) =>
+        shapes(group.rects, group.polygons, up && { ...up, cone: oneWayCone(group.angle) }),
+      ),
+    ];
   }
 
   shapesOf(world: World, body: Entity): ColliderShape[] {
@@ -401,8 +413,8 @@ function unitOf(v: Vec2): Vec2 {
 interface TilemapBlocks {
   rects: CellRect[];
   polygons: CellPolygon[];
-  oneWayRects: CellRect[];
-  oneWayPolygons: CellPolygon[];
+  /** The one-way cells, one group per angle their tiles land things within. */
+  oneWay: { angle: number; rects: CellRect[]; polygons: CellPolygon[] }[];
 }
 
 export function shapeOf(collider: Entity): ColliderShape {

src/viewport/items.ts

@@ -7,7 +7,13 @@ import type { PropertyBag } from '../core/model/Properties';
 import type { ParticlesAsset } from '../core/model/Asset';
 import { readTile, tileFps, type TileInfo, type TilePlayback, tilePlayback } from '../core/model/tile';
 import { isLayerVisible, layerTiles, type TileDraw } from '../core/model/tilemap';
-import { type CellPolygon, type CellRect, solidPolygons, solidRects } from '../core/model/tilemapCollision';
+import {
+  type CellPolygon,
+  type CellRect,
+  oneWayAngles,
+  solidPolygons,
+  solidRects,
+} from '../core/model/tilemapCollision';
 import { findAsset, findAssetOf, type ObjectHolder, type Project } from '../core/model/Project';
 import { fontFileOf } from '../core/model/font';
 import { resolveTexture, type TextureRef } from '../core/model/texture';
@@ -70,8 +76,11 @@ export interface TilemapDraw {
   solids: CellRect[];
   /** The cells that block with an outline (#141), outlined the same way. */
   outlines: CellPolygon[];
-  /** The same for one-way tiles (#155), which block only from above. */
-  oneWay: { solids: CellRect[]; outlines: CellPolygon[] };
+  /**
+   * The same for one-way tiles (#155), which block only from above; each rectangle with the angle
+   * its tiles land things within (#159), since tiles of two angles never merge.
+   */
+  oneWay: { solids: (CellRect & { angle: number })[]; outlines: CellPolygon[] };
 }
 
 /**
@@ -99,14 +108,17 @@ function resolveTilemap(project: Project, assetId: string, props: PropertyBag):
       });
     }
   }
+  const angles = oneWayAngles(project, asset);
   return {
     layers,
     tiles: used,
     solids: solidRects(project, props, asset),
     outlines: solidPolygons(project, props, asset),
     oneWay: {
-      solids: solidRects(project, props, asset, true),
-      outlines: solidPolygons(project, props, asset, true),
+      solids: angles.flatMap((angle) =>
+        solidRects(project, props, asset, angle).map((rect) => ({ ...rect, angle })),
+      ),
+      outlines: angles.flatMap((angle) => solidPolygons(project, props, asset, angle)),
     },
   };
 }

src/viewport/symbols.ts

@@ -9,7 +9,13 @@ import {
   RIGIDBODY_SYMBOL,
   textAnchor,
 } from '../core/properties/bounds';
-import { type ColliderShape, colliderShape, isTrigger, oneWayFacing } from '../core/properties/collider';
+import {
+  type ColliderShape,
+  colliderShape,
+  isTrigger,
+  oneWayAngle,
+  oneWayFacing,
+} from '../core/properties/collider';
 import { SHEET_EDGE } from '../core/shader/nodes';
 import type { NineSlice } from '../core/model/texture';
 import type { Vec2 } from '../core/model/Properties';
@@ -193,7 +199,11 @@ export function drawItem(
             : Theme.colors.collider;
       node.fill({ color, alpha: 0.12 }).stroke({ width: 2 / scale, color });
       const facing = oneWayFacing(item.props, IDENTITY);
-      if (facing) markBlockingSide(node, shapeBounds(shape), facing, 5 / scale, color);
+      if (facing)
+        markBlockingSide(node, shapeBounds(shape), facing, 5 / scale, color, {
+          angle: oneWayAngle(item.props.oneWayAngle),
+          length: CONE_LENGTH / scale,
+        });
       node.hitArea = colliderOutlineHitArea(shape, COLLIDER_GRAB_BAND / scale);
       return;
     }
@@ -218,6 +228,9 @@ export function drawSourceIcon(node: Graphics): void {
   }
 }
 
+/** How far the landing cone of a one-way side reaches, in screen pixels (#159). */
+export const CONE_LENGTH = 24;
+
 const DIAGONALS = [
   [Math.SQRT1_2, Math.SQRT1_2],
   [-Math.SQRT1_2, Math.SQRT1_2],
@@ -260,7 +273,9 @@ function shapeBounds(shape: ColliderShape): Bounds {
 
 /**
  * A one-way collider or tile (#155): a thick line along the side of its bounds it blocks from – the
- * top of a platform. `facing` is one of the four axis directions in the same units.
+ * top of a platform. `facing` is one of the four axis directions in the same units. With `cone`,
+ * a fan of `length` stands on the middle of that line, `angle` degrees to either side of `facing`:
+ * the directions a contact may come from and still land (#159).
  */
 export function markBlockingSide(
   node: Graphics,
@@ -268,12 +283,43 @@ export function markBlockingSide(
   facing: Vec2,
   width: number,
   color: number,
+  cone?: { angle: number; length: number },
 ): void {
-  if (facing.y < -0.5) node.moveTo(b.left, b.top).lineTo(b.right, b.top);
-  else if (facing.y > 0.5) node.moveTo(b.left, b.bottom).lineTo(b.right, b.bottom);
-  else if (facing.x < 0) node.moveTo(b.left, b.top).lineTo(b.left, b.bottom);
-  else node.moveTo(b.right, b.top).lineTo(b.right, b.bottom);
-  node.stroke({ width, color });
+  let from: Vec2;
+  let to: Vec2;
+  if (facing.y < -0.5)
+    [from, to] = [
+      { x: b.left, y: b.top },
+      { x: b.right, y: b.top },
+    ];
+  else if (facing.y > 0.5)
+    [from, to] = [
+      { x: b.left, y: b.bottom },
+      { x: b.right, y: b.bottom },
+    ];
+  else if (facing.x < 0)
+    [from, to] = [
+      { x: b.left, y: b.top },
+      { x: b.left, y: b.bottom },
+    ];
+  else
+    [from, to] = [
+      { x: b.right, y: b.top },
+      { x: b.right, y: b.bottom },
+    ];
+  node.moveTo(from.x, from.y).lineTo(to.x, to.y).stroke({ width, color });
+  if (!cone) return;
+  const tip = { x: (from.x + to.x) / 2, y: (from.y + to.y) / 2 };
+  const middle = Math.atan2(facing.y, facing.x);
+  const spread = (cone.angle * Math.PI) / 180;
+  const edge = (turn: number) => ({
+    x: tip.x + Math.cos(middle + turn) * cone.length,
+    y: tip.y + Math.sin(middle + turn) * cone.length,
+  });
+  const start = edge(-spread);
+  node.moveTo(tip.x, tip.y).lineTo(start.x, start.y);
+  if (spread > 0) node.arc(tip.x, tip.y, cone.length, middle - spread, middle + spread).closePath();
+  node.fill({ color, alpha: 0.15 }).stroke({ width: width / 3, color });
 }
 
 /** Adds the outline of a collider shape in its own units (see `colliderShape` with `IDENTITY`). */