Chess board
chess-board · an adoption of Grid and direction, version 1
Use in your game
Opens the authoring tool with these answers and settings already filled in. You still add your game's own rules and tuning.
What is in the ZIP
The ZIP holds the adoption and its acceptance tests. In the authoring tool, choose Add contract and pick this ZIP. If you keep your design as files, put them in contracts/.
The contract behind it
Covers square grids and the direction words your game uses. It says where numbering starts, which cells touch, and how a position belongs to a cell. It says how rules measure distance, choose between equal cells, list cells in order, and turn. Grid edges, pathfinding, non-square cells, and a third axis stay with your game.
Questions
The supplied answer is marked on each question. Pick other answers to see what changes. Nothing is saved here: the ZIP and the authoring tool use the supplied answers.
Where is this grid's first cell, and which way do its row and column numbers grow?
Why this is asked
Every later rule needs one shared reading of row and column numbers. This contract only carries columns that grow right; state a left-growing grid in your own prose.
When you write a cell with two numbers, does the row or column come first?
Why this is asked
Swapping the two numbers turns rows into columns. A square grid can hide that mistake, so the order must be clear.
Do the first row and column use zero or one?
- Asked when
- Origin and axes is Top left or Bottom left.
Why this is asked
Starting at zero or one changes every written cell address. Naming it prevents an off-by-one shift between the design and the build.
A point lies exactly on the line between two cells. Which cell owns it?
Why this is asked
A boundary point needs one owner. Different rounding rules can place the same point in different cells, especially beside zero.
When your rules say nearest or within some distance, how do they measure between cells?
Why this is asked
Games often use several distance rules. This answer only controls what your written rules mean by nearest or within a distance.
From one cell, which other cells can a thing reach in one step?
Why this is asked
Movement neighbours do not follow automatically from distance or effect range. A game can use different cells for each.
When a rule says two cells are next to each other, do corners count?
Why this is asked
Movement and effects can count neighbours differently. This answer keeps words such as next to from changing meaning between rules.
In what order does an authored layout list its cells?
Why this is asked
Drawing, updates, and save files may use different orders. This answer covers only layouts designers write and read.
A rule rates two cells equally and must pick one. How does it decide?
Why this is asked
Equal choices are common and rarely written down. A fixed answer stops two builds from choosing different cells.
When your rules turn a facing by an amount, which way does the amount go on the grid?
Why this is asked
Axis direction does not decide turn direction. Naming clockwise or counter-clockwise prevents equivalent formulas from reading as opposite rules.
Numbers1 number
Each value is either a number set here or a reference to one of your tuning keys.
Cell size = 0
fixed as writtencell-size
The length of one cell in your position units. For centre-based cells, measure from one centre to the next. Use a positive size when rules read positions. Use zero when they only read whole cells. Changing this number changes which cell holds a position.
Rules1 rule
A rule is a check between the numbers. Validation reports a rule that fails.
cell-size >= 0
Lists1 list
Each list holds the rows this adoption supplies. A list can be empty.
Directions
directions
| Id | Frame | Points | Order |
|---|---|---|---|
forward | piece | — | — |
Test inputsscope and seeds
Some tests need a scope or seeds from the adoption before they can run.
one-step-moves
One step moves
- Scope
- the king's one-cell moves from every central square c3 through f6 on an otherwise empty 8x8 board, before checks and occupied squares remove illegal destinations
- Seeds
["chess-king-centre","chess-king-centre-b"]
Acceptance tests7 tests apply
The contract comes with 22 tests. A test that runs once per row is counted once for each row. Tests that do not apply to these answers are still listed, with the reason.
axes-grow
the numbers grow one way
Applies to chess-board.
In chess-board the two numbers grow right across rows and up columns, one per cell. The layout this is read against is the one this package declares, not the finished picture: a build may draw the grid any way its presentation chapter allows and still has to number it this way.
Test steps and diagnostics
- Given
chess-boardas this package lays it out, with at least two rows and at least two columns- When
- a cell is located in the layout
- the cells one step from it across and down are located
- Then
- the numbers grow right across rows and up columns
- moving one cell that way raises exactly one of the two numbers by one and lowers neither
- moving one cell the opposite way lowers exactly one of them by one
- Diagnostics
chess-board-cell-addresseschess-board-declared-layout
the-first-cell-is-in-one-corner
the grid has a first cell, in one named corner
Applies to chess-board.
chess-board is a bounded rectangle whose first cell — the one whose two numbers are both smallest — is the bottom-left corner of the grid as this package lays it out. A build that numbers from the opposite corner fails this test even when every layout still loads.
Test steps and diagnostics
- Given
chess-boardas this package lays it out- When
- the cell whose two numbers are both the smallest on the grid is located in the layout
- Then
- that cell is the bottom-left corner of the grid as this package lays it out
- no other corner of
chess-boardholds a smaller pair of numbers - the grid is bounded: every cell of it lies inside the declared number of rows and columns
- Diagnostics
chess-board-cell-addresseschess-board-declared-layout
the-grid-has-no-first-cell
the grid runs on in every direction
Does not apply to chess-board: origin and axes is bottom left, not unbounded right and down or unbounded right and up.
coordinate-reading
a written pair names the cell this package means
Applies to chess-board.
In chess-board, the first number is the column, counted across the grid, and the second is the row, counted down it, and the first row and the first column are numbered 1. The test asks for a grid whose rows and columns differ in number on purpose: on a square grid a build that reads the pair backwards passes every test anyone would think to write, and ships transposed.
One surveyed game numbers its authored map files from one and its engine from zero, and records that nowhere but a source comment. The numbers this test is about are the ones this package's own material writes.
Test steps and diagnostics
- Given
chess-boardwith a different number of rows and columns, so that reading a pair the wrong way round cannot land on a real cell by luck, or a stated reason why no such grid exists in this game- When
- the build resolves a cell that this package's own material writes as a pair of numbers
- Then
- the first number is the column, counted across the grid, and the second is the row, counted down it
- the first row and the first column are numbered 1
- the cell the build resolves is the cell this package's material means
- the same pair with its two numbers swapped resolves to a different cell, or to no cell at all
- Diagnostics
chess-board-resolved-cellchess-board-source-reference
every-position-has-one-cell
every position belongs to exactly one cell
Does not apply to chess-board: cell ownership is not applicable, not next cell along or truncate toward zero or cell centres are whole numbers.
boundary-belongs-to-one-cell
a position on a shared line belongs to one cell
Does not apply to chess-board: cell ownership is not applicable, not next cell along or truncate toward zero or cell centres are whole numbers.
distance-is-measured
distance between two cells is measured one way
Does not apply to chess-board: distance metric is not applicable, not no diagonals or diagonals count the same or octile or straight line.
equal-distance-is-decided
two distances count as equal by a declared rule
Does not apply to chess-board: distance metric is not applicable, not straight line or octile.
one-step-moves
one step reaches exactly the neighbouring cells
Applies to chess-board.
From any cell of chess-board, one step reaches exactly the eight cells sharing an edge or a corner with it, with nothing standing in the way. What happens when a step would leave the grid, and whether something in the way blocks it, are settled elsewhere in this package; this test fixes only which cells a step can reach at all.
Test steps and diagnostics
- Diagnostics
chess-board-reachable-in-one-step- first-unexpected-destination
- Holds
of the cells on the grid, the ones a thing can move to from this cell in one step, with nothing standing in the way, are exactly the eight cells sharing an edge or a corner with it — no more and no fewer
- Seeds
["chess-king-centre","chess-king-centre-b"]- Scope
the king's one-cell moves from every central square c3 through f6 on an otherwise empty 8x8 board, before checks and occupied squares remove illegal destinations
next-to-means
next to means the same cells in every rule
Does not apply to chess-board: adjacency for effects is not applicable, not four neighbours or eight neighbours.
authored-order-lists-every-cell
this package's own material lists every cell once
Applies to chess-board.
An authored layout of chess-board lists every cell exactly once, one whole row at a time, counting from the smallest numbers upward, and reading that layout back gives the same cells in the same places.
This does not set save-file order, drawing order, update order, or the order in which rules visit cells. Naming the authored order stops a rule from quietly depending on one of those other orders.
Test steps and diagnostics
- Scope
an authored layout of
chess-board, with every cell distinguishable from every other, read from the first cell to the last as designers write it- Holds
the material lists every cell of
chess-boardexactly once, one whole row at a time, counting from the smallest numbers upward, and a board written out and read back arrives cell for cell the same- Diagnostics
chess-board-authored-order-sequence- first-cell-out-of-order
- cells-listed-twice-or-never
block-layout-is-declared
the blocks this material is written in are declared
Does not apply to chess-board: enumeration order is rows then columns, not block tiled.
tie-break-settles
a tie between two cells settles the same way every time
Does not apply to chess-board: tie break between cells is player chooses, not lower column wins or lower row wins or direction order or named priority list.
tie-break-follows-arrival
a tie between two cells goes to whichever came first
Does not apply to chess-board: tie break between cells is player chooses, not arrival order.
tie-break-is-arbitrary
a tie between two cells comes out the same way in a replay
Does not apply to chess-board: tie break between cells is player chooses, not deliberately arbitrary.
tie-break-is-drawn
a tie between two cells is drawn from a declared stream
Does not apply to chess-board: tie break between cells is player chooses, not random from a declared seed.
tie-break-asks-the-player
a tie between two cells is put to the player
Applies to chess-board.
chess-board does not settle a tie between two equally ranked candidates by itself: the player is asked. Where a rule cannot ask — an automatic step, a replay, a resolution with nobody watching — it does not guess. It does not run, and nothing changes.
Test steps and diagnostics
- Given
a rule of this game that must pick one cell, and two candidates the rule ranks equally
- When
- the rule runs and the player can be asked
- the rule runs where the player cannot be asked
- Then
- in the first case the player is asked which candidate they mean, and the game picks neither on its own
- in the second case the rule does not run and nothing about the game state changes
- no candidate is ever picked because of the order things were created in, the order they are drawn in, or where the pointer is
- Diagnostics
chess-board-tie-break-prompt-logchess-board-state-before-after
no-tie-ever-arises
no rule ever faces a tie between two cells
Does not apply to chess-board: tie break between cells is player chooses, not not applicable.
a-positive-turn-goes
a positive turn goes one way
Does not apply to chess-board: turn direction is not applicable, not clockwise or counter clockwise.
grid-direction-points
Row.id points Bind points phrase
Does not apply to chess-board: no row in directions matches frame grid.
direction-walk-order
Row.id takes place Row.order in the direction walk
Does not apply to chess-board: tie break between cells is player chooses, not direction order.
piece-direction-follows-facing · forward
forward is read from the facing of whatever uses it
Applies to the forward row.
In chess-board, the word forward is read from the facing of whatever uses it, so it points somewhere else after that thing turns, and it can mean two different directions for two things standing on the same cell. That is the whole difference from a word fixed to the grid, and it is worth stating in a package that uses both kinds.
Test steps and diagnostics
- Given
a thing standing on a cell of
chess-board, with a facing and a cell on every side of it- When
- a rule of this game moves it, points it, or reads a cell
forwardof it - the thing turns, and the same rule runs again
- a rule of this game moves it, points it, or reads a cell
- Then
- the direction the word
forwardnames is read from that thing's own facing, not from the grid - after the turn,
forwardnames a different direction on the grid, turned by exactly as much as the facing was - two things with different facings, standing on the same cell, resolve
forwarddifferently
- the direction the word
- Diagnostics
chess-board-direction-resolutionchess-board-facing-before-after
JSONthe adoption as one file
The adoption file as supplied. Answers you try on this page are not written into it; to change an adoption, open it in the authoring tool.
{
"contract": "grid-and-direction",
"version": 1,
"origin": "https://opengdd.org/contracts/grid-and-direction-1",
"summary": "Covers square grids and the direction words your game uses. It says where numbering starts, which cells touch, and how a position belongs to a cell. It says how rules measure distance, choose between equal cells, list cells in order, and turn. Grid edges, pathfinding, non-square cells, and a third axis stay with your game.",
"mechanism": [
"The mechanism is one grid of equal square cells. A row runs across it, and a column runs down it. When a game names a cell with two whole numbers, coordinate-order says which one comes first; a layout may name cells by their contents instead. The grid may be a bounded rectangle with a first cell in one corner, or run on in every direction with signed numbers and no first cell; the first question says which.",
"The grid's own frame. Every answer below is read against the grid as this package declares it: the layout your content writes out, or your own chapter's sentence about which way the numbers grow. Up, down, left and right mean those directions on the declared grid. On a bounded grid where content writes the grid out row by row, the first written row is nearest the declared origin corner: the top row for top-left, and the bottom row for bottom-left. These directions never follow the finished picture, which a build may draw any way its presentation chapter allows. A Delegated view can never change a Fixed answer.",
"Where a game also has positions — things resting between cells rather than on them — zero is the same place for cells and for positions, and where a cell-ownership option makes the cell at zero a different width, that option says so. Two neighbouring cells share a line, and cell-ownership says which cell the line belongs to. Every conversion below divides by the cell size and, where the grid counts from 1, adds 1. Each cell-ownership option that uses positions states how position zero and shared lines are treated.",
"Several nearby decisions are deliberately not here — the grid's edge, sharing a cell, corner-cutting, pathfinding, a third axis, cells that are not squares, whether a sweep sees its own changes. The note at the end says where each lives."
],
"questions": {
"origin-and-axes": {
"asks": "Where is this grid's first cell, and which way do its row and column numbers grow?",
"rationale": "Every later rule needs one shared reading of row and column numbers. This contract only carries columns that grow right; state a left-growing grid in your own prose.",
"options": {
"top-left": {
"meaning": "The first cell is the top-left corner. Column numbers grow right, and row numbers grow down."
},
"bottom-left": {
"meaning": "The first cell is the bottom-left corner. Column numbers grow right, and row numbers grow up."
},
"unbounded-right-and-down": {
"meaning": "There is no first cell or corner. The grid continues through negative and positive numbers. Columns grow right, and rows grow down from the cell your game calls zero."
},
"unbounded-right-and-up": {
"meaning": "There is no first cell or corner. The grid continues through negative and positive numbers. Columns grow right, and rows grow up from the cell your game calls zero."
}
}
},
"coordinate-order": {
"asks": "When you write a cell with two numbers, does the row or column come first?",
"rationale": "Swapping the two numbers turns rows into columns. A square grid can hide that mistake, so the order must be clear.",
"options": {
"column-first": {
"meaning": "The column comes first. The pair (3, 5) means column 3, row 5."
},
"row-first": {
"meaning": "The row comes first. The pair (3, 5) means row 3, column 5."
},
"not-applicable": {
"meaning": "The game never names a cell with a pair of numbers. It uses a layout, cell contents, or another name instead."
}
}
},
"counting-starts-at": {
"asks": "Do the first row and column use zero or one?",
"rationale": "Starting at zero or one changes every written cell address. Naming it prevents an off-by-one shift between the design and the build.",
"when": {
"flag": {
"origin-and-axes": [
"top-left",
"bottom-left"
]
}
},
"options": {
"zero": {
"meaning": "The first row and column are numbered zero. A ten-cell row runs from zero through nine."
},
"one": {
"meaning": "The first row and column are numbered one. A ten-cell row runs from one through ten."
}
}
},
"cell-ownership": {
"asks": "A point lies exactly on the line between two cells. Which cell owns it?",
"rationale": "A boundary point needs one owner. Different rounding rules can place the same point in different cells, especially beside zero.",
"options": {
"next-cell-along": {
"meaning": "The cell with the larger number owns the line. The line where cell five ends and cell six begins belongs to cell six, on either side of zero.",
"semantics": "Divide the position by cell-size and round down, then add one when counting-starts-at is one. A boundary position belongs to the cell with the larger coordinate."
},
"truncate-toward-zero": {
"meaning": "The cell farther from zero owns the line. The zero cell reaches one cell-size to each side, so it is twice as wide as the others.",
"semantics": "Divide the position by cell-size and truncate toward zero, then add one when counting-starts-at is one. Coordinate zero spans one cell-size on each side."
},
"cell-centres-are-whole-numbers": {
"meaning": "Whole numbers mark cell centres. A point halfway between two centres belongs to the cell with the larger number.",
"semantics": "Cell coordinates name centres. Divide the position by cell-size and round to the nearest whole coordinate, taking an exact half toward the larger coordinate, then add one when counting-starts-at is one."
},
"not-applicable": {
"meaning": "Your rules only use whole cells, never positions between them. No boundary choice is needed."
}
}
},
"distance-metric": {
"asks": "When your rules say nearest or within some distance, how do they measure between cells?",
"rationale": "Games often use several distance rules. This answer only controls what your written rules mean by nearest or within a distance.",
"options": {
"no-diagonals": {
"meaning": "Add the steps across and down the grid (Manhattan). A cell two across and one up is three steps away."
},
"diagonals-count-the-same": {
"meaning": "Count the larger of the across and down steps (Chebyshev). A cell two across and one up is two steps away."
},
"octile": {
"meaning": "Straight steps cost one, and diagonal steps cost the square root of two (octile). The distance is the cheapest mix of those steps. Your game's comparison rule decides when two distances count as equal.",
"semantics": "For absolute coordinate differences dx and dy, multiply the smaller difference by the square root of two minus one (about 0.414), then add the result to the larger difference. Equal means equal at whatever precision this game compares its distances with. For straight-line and octile distance, the adoption must state that comparison rule in the distance test's verification scope."
},
"straight-line": {
"meaning": "Measure a straight line between the cell centres (Euclidean). Use position units when positions exist; otherwise use cells. Your game's comparison rule decides when two distances count as equal.",
"semantics": "Equal means equal at whatever precision this game compares its distances with. For straight-line and octile distance, the adoption must state that comparison rule in the distance test's verification scope."
},
"not-applicable": {
"meaning": "No rule measures distance between cells. Rules may still use neighbours, named shapes, or links."
}
}
},
"adjacency-for-movement": {
"asks": "From one cell, which other cells can a thing reach in one step?",
"rationale": "Movement neighbours do not follow automatically from distance or effect range. A game can use different cells for each.",
"options": {
"four-neighbours": {
"meaning": "Only the four cells sharing an edge are one step away. A diagonal cell cannot be reached in one step."
},
"eight-neighbours": {
"meaning": "All eight surrounding cells are one step away. A thing may move across an edge or diagonally across a corner."
},
"not-applicable": {
"meaning": "Nothing moves one cell at a time. Things are placed directly or move freely while the grid only reads their final cell."
}
}
},
"adjacency-for-effects": {
"asks": "When a rule says two cells are next to each other, do corners count?",
"rationale": "Movement and effects can count neighbours differently. This answer keeps words such as next to from changing meaning between rules.",
"options": {
"four-neighbours": {
"meaning": "Only cells sharing an edge count as neighbours. Two cells touching only at a corner are not next to each other."
},
"eight-neighbours": {
"meaning": "All eight surrounding cells count as neighbours. Cells touching only at a corner are still next to each other."
},
"not-applicable": {
"meaning": "No rule uses next to by itself. Each rule names the cells it means, or no rule asks whether cells are neighbours."
}
}
},
"enumeration-order": {
"asks": "In what order does an authored layout list its cells?",
"rationale": "Drawing, updates, and save files may use different orders. This answer covers only layouts designers write and read.",
"options": {
"rows-then-columns": {
"meaning": "List every cell in one row before starting the next row. Start with the smallest row and column numbers. A text map with one line per row already uses this order."
},
"columns-then-rows": {
"meaning": "List every cell in one column before starting the next column. Start with the smallest row and column numbers."
},
"block-tiled": {
"meaning": "List cells inside blocks such as chunks, regions, or screens. Your game's prose states block size, block order, and the order inside each block."
},
"not-applicable": {
"meaning": "No authored layout lists the grid's cells. No order is needed for the material designers write and read."
}
}
},
"tie-break-between-cells": {
"asks": "A rule rates two cells equally and must pick one. How does it decide?",
"rationale": "Equal choices are common and rarely written down. A fixed answer stops two builds from choosing different cells.",
"options": {
"lower-column-wins": {
"meaning": "The cell with the smaller column number wins. Between a cell in column 2 and a cell in column 4, the column-2 cell wins and the column-4 cell loses. If columns match, the smaller row number wins."
},
"lower-row-wins": {
"meaning": "The cell with the smaller row number wins. Between a cell in row 2 and a cell in row 4, the row-2 cell wins and the row-4 cell loses. If rows match, the smaller column number wins."
},
"direction-order": {
"meaning": "Walk the grid-fixed direction words in their chosen order. The first direction that points to a tied neighbour wins. Use another answer when tied cells are not neighbours."
},
"arrival-order": {
"meaning": "The candidate that arrived first wins. Your game names whether arrival means creation, placement, storage, or entering play. The same run repeats the choice, but save and reload follow your persistence rules. The validator cannot check this; a reviewer does."
},
"named-priority-list": {
"meaning": "The candidate kind listed first in your game's priority order wins. Cell position never decides."
},
"deliberately-arbitrary": {
"meaning": "Either candidate may win, and players must not depend on which one. Replaying the same run repeats the choice, but loading a save may not."
},
"random-from-a-declared-seed": {
"meaning": "Draw one candidate from a random stream declared by your game. The same run and replay draw the same candidate. The validator cannot check this; a reviewer does."
},
"player-chooses": {
"meaning": "The player chooses the candidate. If the game cannot ask, the rule does nothing instead of guessing. The validator cannot check this; a reviewer does."
},
"not-applicable": {
"meaning": "No rule ever chooses one of two equal candidates. The situation cannot happen, or the rule affects every tied candidate."
}
}
},
"turn-direction": {
"asks": "When your rules turn a facing by an amount, which way does the amount go on the grid?",
"rationale": "Axis direction does not decide turn direction. Naming clockwise or counter-clockwise prevents equivalent formulas from reading as opposite rules.",
"options": {
"clockwise": {
"meaning": "A positive turn goes clockwise on the grid. A rotated view may show it differently, but the grid rule stays the same."
},
"counter-clockwise": {
"meaning": "A positive turn goes counter-clockwise on the grid. A rotated view may show it differently, but the grid rule stays the same."
},
"not-applicable": {
"meaning": "No rule turns a facing by an amount. A piece may still snap directly toward movement or a target."
}
}
}
},
"declares": {
"values": {
"cell-size": {
"description": "The length of one cell in your position units. For centre-based cells, measure from one centre to the next. Use a positive size when rules read positions. Use zero when they only read whole cells. Changing this number changes which cell holds a position."
}
},
"rows": {
"directions": {
"description": "List every direction word your game uses. Each row says whether it follows the grid or a piece. A grid direction also says where it points. An empty list means the game names no directions. If ties use this order, list every grid-fixed neighbour that can tie. The validator cannot check this; a reviewer does.",
"record": {
"id": {
"type": "string",
"required": true,
"pattern": "kebab-case",
"unique": true,
"description": "The direction word your game uses, such as north, forward, or starboard. Write it in lowercase with hyphens between words."
},
"frame": {
"type": "string",
"required": true,
"options": [
"grid",
"piece"
],
"description": "Whether the direction follows the grid or a piece. A grid direction always points the same way: north stays north. A piece direction changes when that piece turns: forward, left, and behind turn with it."
},
"points": {
"type": "string",
"when": {
"row": {
"frame": [
"grid"
]
}
},
"options": [
"up",
"down",
"left",
"right",
"up-left",
"up-right",
"down-left",
"down-right"
],
"description": "Where this grid-fixed direction points on the grid. Omit it for a direction that follows a piece. This does not decide whether movement is allowed that way."
},
"order": {
"type": "integer",
"when": {
"flag": {
"tie-break-between-cells": [
"direction-order"
]
},
"row": {
"frame": [
"grid"
]
}
},
"unique": true,
"description": "This direction's place in the tie-breaking walk. One is tried first. Give each grid-fixed direction a different number. Use it only when ties follow direction order."
}
}
}
}
},
"rules": {
"cell-size-not-negative": "cell-size >= 0"
},
"pack": "sha256:b17529b6bce460ee83f7c460f2e73c39d5c32051637613867e42ef85b6e0996a",
"answers": {
"origin-and-axes": "bottom-left",
"coordinate-order": "column-first",
"counting-starts-at": "one",
"cell-ownership": "not-applicable",
"distance-metric": "not-applicable",
"adjacency-for-movement": "eight-neighbours",
"adjacency-for-effects": "not-applicable",
"enumeration-order": "rows-then-columns",
"tie-break-between-cells": "player-chooses",
"turn-direction": "not-applicable"
},
"values": {
"cell-size": 0
},
"rows": {
"directions": [
{
"id": "forward",
"frame": "piece"
}
]
},
"verification": {
"one-step-moves": {
"seeds": [
"chess-king-centre",
"chess-king-centre-b"
],
"scope": "the king's one-cell moves from every central square c3 through f6 on an otherwise empty 8x8 board, before checks and occupied squares remove illegal destinations"
}
}
}