Chase the Shape

A geometric shape travels back and forth across the wall. Players press every hold that belongs to the shape to complete it before it moves on. Each hit gets a short cue; a completed shape gets a success cue.

Up to four children play at once, each in their own zone with their own shape. Everything a zone does is tagged with its zone index, so SuperCollider can place each child’s sounds on their side of the room and keep the four games audibly apart.

The engine owns the shape, its movement and the hit rule. In particular, a hold that was already being touched when the shape arrived does not count — the engine enforces that, and only reports hits that counted.

Mode id: chase · Status: draft · Since: 0.2.0 · Spec: Prototype Use Cases, p. 1

Loading

Load this mode with /mode/load and type tags sisifs:

NetAddr("127.0.0.1", 57120).sendMsg('/mode/load', "chase", 1, "line", 3, 0.5, "chimes");

Init parameters

Sent in this exact order, immediately after the mode id.

#	Name	Type	Range / default	Description
1	`zoneCount`	`i`	1 – 4 default `1`	Simultaneous play zones, one child each. Each zone runs its own shape.
2	`shape`	`s`	`line`, `square`, `triangle`, `cross`, `zigzag` default `line`	Shape type. Every zone uses the same shape.
3	`shapeSize`	`i`	2 – 6 default `3`	Size of the shape in holds along its longest side.
4	`speed`	`f`	0.1 – 2.0 holds per second default `0.5`	Movement speed. SuperCollider uses it to set the tempo of the moving shape’s own sound, so it travels audibly at the pace it travels visibly.
5	`soundSet`	`s`	`chimes`, `marimba`, `retro` default `chimes`	Palette for hit and success cues.

Runtime parameters

Changed while the mode runs, with /mode/param name value. Always a float, always clamped, never an error if the name is unknown.

Name	Range / default	Description
`speed`	0.1 – 2.0 holds per second default `0.5`	Change movement speed mid-game, e.g. to make it harder.

NetAddr("127.0.0.1", 57120).sendMsg('/mode/param', "speed", 0.5);

Configured in the engine

Settings from the use case that never cross the wire. The engine applies them; SuperCollider does not need them, so they are not in the protocol.

Setting
Hold colours	Colour of shape holds, activated holds and the success animation.
Success animation style	Purely visual.
Movement path	The shape stays inside its zone, travelling back and forth; the engine plans the path.

Messages

/mode/chase/spawn/mode/chase/move/mode/chase/hit/mode/chase/complete

/mode/chase/spawn

engine → sc event since 0.2.0

A new shape has appeared in a zone.

i zone

i holdCount

s shape

iis

zone i int32 zone index · 0 – zoneCount−1: Which zone, 0 leftmost.
holdCount i int32 1 – 36: How many holds make up this shape — the hits needed to complete it.
shape s string "line" | "square" | "triangle" | "cross" | "zigzag": The shape type, echoed so each shape can have its own sound.

packet /mode/chase/spawn 0 3 line

SuperCollider NetAddr("127.0.0.1", 57120).sendMsg('/mode/chase/spawn', 0, 3, "line");

engine (C#) osc.Send(Osc.ModeChaseSpawn, 0, 3, "line");

/mode/chase/move

engine → sc stream 10 Hz since 0.2.0

Where each zone's shape currently is.

i zone

f x

f y

iff

zone i int32 zone index · 0 – zoneCount−1: Which zone.
x f float32 0.0 – 1.0normalized: Horizontal centre of the shape across the whole wall, 0.0 left edge.
y f float32 0.0 – 1.0normalized: Vertical centre of the shape, 0.0 bottom.

packet /mode/chase/move 0 0.18 0.42

SuperCollider NetAddr("127.0.0.1", 57120).sendMsg('/mode/chase/move', 0, 0.18, 0.42);

engine (C#) osc.Send(Osc.ModeChaseMove, 0, 0.18f, 0.42f);

One message per zone per frame, so four zones is 40 messages a second — well inside what sclang handles. Absolute positions: a dropped frame corrects itself on the next.

/mode/chase/hit

engine → sc event since 0.2.0

A hold in the shape was pressed in time.

i zone

i holdId

i activated

i holdCount

iiii

zone i int32 zone index · 0 – zoneCount−1: Which zone.
holdId i int32 hold index · 0 – holdCount−1: The hold that was activated.
activated i int32 1 – 36: Holds activated in this shape so far, including this one.
holdCount i int32 1 – 36: Holds in the shape. activated == holdCount means complete.

packet /mode/chase/hit 0 43 2 3

SuperCollider NetAddr("127.0.0.1", 57120).sendMsg('/mode/chase/hit', 0, 43, 2, 3);

engine (C#) osc.Send(Osc.ModeChaseHit, 0, 43, 2, 3);

Only hits that count are sent: a hold already held when the shape arrived is not a hit until it is released and pressed again. SuperCollider rises in pitch with activated / holdCount, so progress is audible.

/mode/chase/complete

engine → sc event since 0.2.0

Every hold in a zone's shape has been activated.

i zone

i completed

f duration

iif

zone i int32 zone index · 0 – zoneCount−1: Which zone.
completed i int32 1 – 9999: Shapes this zone has completed this game, including this one.
duration f float32 seconds: Time from spawn to completion.

packet /mode/chase/complete 0 4 6.8

SuperCollider NetAddr("127.0.0.1", 57120).sendMsg('/mode/chase/complete', 0, 4, 6.8);

engine (C#) osc.Send(Osc.ModeChaseComplete, 0, 4, 6.8f);

Plays the success cue. The engine then sends /mode/chase/spawn for the zone's next shape when it is ready.