# HS_DollyCam Project Information

This repository contains LSL (Linden Scripting Language) scripts for **HS_DollyCam**, a professional camera control system for Second Life.

The project is highly memory-sensitive. LSL script memory is limited, and large lists, mixed-type lists, and repeated string splitting can create avoidable memory pressure. Prefer targeted parsing and short-lived data where practical.

## Core Components

The system is split across specialized scripts that communicate mostly via `llMessageLinked`.

### 1. `HS_CamController.lsl` (Main Controller)

The central command and state coordinator.

- Handles chat commands and menu commands.
- Coordinates playlist, menu, marker, FOV, and engine scripts.
- Saves presets into Linkset Data.
- Handles marker click events and forwards camera movement requests.
- Maintains FOLLOW and LOCK state in Linkset Data.

Important note: movement math and continuous tour playback are not owned entirely by the Controller anymore. Controller dispatches movement/tour commands to helper scripts and engine scripts.

### 2. `HS_CamPlaylist.lsl` (Playlist Manager)

Primary script for notecard-driven workflows.

- Reads playlist notecards line by line.
- Uses `llGetNotecardLineSync` when the simulator has the notecard cached, with fallback to `llGetNotecardLine` on `NAK`.
- Handles `moveto`, `goto`, `load`, `wait`, `tour ... endtour`, `dollyzoom`, `fov`, `lock`, `follow`, and marker show/hide commands.
- Builds tour payloads and sends them to `HS_CamEngineTour.lsl` via `CE_CMD_TOUR`.
- For notecard tour blocks, the builder stores preset indices, holds, and weights, then loads position/focus only at `endtour`.
- Also supports compact notecard tours (`tour <ms> [mode] <idx...>`) to avoid slow multi-line notecard reads when no holds/weights are needed.
- Compact notecard tours add an internal `startfirst` mode flag so `HS_CamEngineTour.lsl` starts from the first preset without a current-camera-state roundtrip.
- `loadPreset()` intentionally uses targeted field parsing instead of splitting the full preset string into a list.
- Standard notecard command parsing uses token helpers rather than full `llParseString2List(line, [" "], [])`.

The user's primary workflow is Notecard Tours, so optimize this file carefully and prioritize notecard-tour memory use over chat/menu one-liner convenience.

### 3. `HS_CamTourCommands.lsl` (Secondary Tour Command Helper)

Dedicated helper for chat/menu one-shot tour builders.

- Handles `/88 tour ...`, `/88 dollyzoom ...`, and menu-built `TOURRUN` payloads.
- Builds `CE_CMD_TOUR` payloads for secondary workflows without adding memory pressure to `HS_CamPlaylist.lsl`.
- Uses targeted preset parsing for position/focus/FOV fields.
- Keep notecard playlist logic in `HS_CamPlaylist.lsl`; keep chat/menu convenience parsing here.

### 4. `HS_CamEngineTour.lsl` (Continuous Tour Runtime)

Dedicated runtime for continuous multi-waypoint camera tours.

- Receives `CE_CMD_TOUR` payloads from Playlist and TourCommands paths.
- Requests current camera state from Core via `CE_CMD_GET_STATE`.
- Builds runtime lists for active tour playback: position, focus, holds, segment lengths, cumulative lengths, point times, and optional weights.
- Drives the camera by sending `CE_INT_SET_CAM` to `HS_CamEngineCore.lsl`.
- Supports spline/linear movement, easing profiles, FOV ramps, and keep-frame mode.
- Uses throttled camera-frame sending via `tourSendCam()` to reduce repeated `CE_INT_SET_CAM` messages.
- Uses segment caching during timer playback to reduce repeated `llList2Vector` access.
- Parses large `CE_CMD_TOUR` payloads using targeted pipe-field helpers rather than splitting the whole payload list.

Do not move active tour runtime lists into Linkset Data. They are read every timer tick; Linkset Data would reduce script memory but likely hurt runtime performance due to repeated string reads and conversions.

### 5. `HS_CamEngineCore.lsl` (Camera Engine Core)

Low-level camera engine.

- Handles camera permissions, base camera params, MoveTo, Follow, Lock, config, and state queries.
- Receives internal tour camera frames with `CE_INT_SET_CAM`.
- `CE_INT_SET_CAM` is parsed without `llParseString2List` because it is part of the active tour hot path.
- Applies `llSetCameraParams` for active camera movement.
- Holds engine configuration and emits config dumps consumed by Playlist and TourEngine.

Tour-related config keys include:

- `tour_max_points`
- `tour_cam_min_interval`
- `tour_pos_epsilon`
- `tour_focus_epsilon`

### 6. `HS_CamMenu.lsl` (Menu/UI)

Handles dialog menus, page state, menu-driven tour building, nearby target lists, and UI command dispatch.

- Sends menu commands with `MN_CMD`.
- Keeps short UI lists such as nearby avatars/objects and selected tour indices.
- Menu paths are secondary compared with notecard tours.

### 7. `HS_CamMarkers.lsl` (Marker Helper)

Marker support is a comparatively rare workflow.

- Rezzes `HS_CamMarker` objects at preset positions.
- Uses `MARKER_CH = -880088`.
- Uses `llRegionSayTo` for marker setup/cleanup when marker keys are known.
- Keeps a mixed marker list internally. This is known to be less memory-efficient, but marker usage is rare and should not be prioritized unless marker workflows become important.

### 8. `HS_CamFov.lsl`

Handles Field of View adjustments and FOV-related state synchronization.

## Communication Protocol

Primary communication uses `llMessageLinked`.

Important constants:

- `MC_CMD = 5100`: Marker helper command channel, e.g. `SHOW|N`, `HIDE`.
- `MC_EVT_CLICK = 5101`: Marker click event from Markers to Controller.
- `MN_CMD = 7000`: Menu command channel.
- `PH_CMD_PLAY = 6100`: Controller/Menu to Playlist play command.
- `PH_CMD_STOP = 6101`: Stop playlist command.
- `PH_CMD_CHAT_TOUR = 6102`: Chat one-liner tour forwarded to TourCommands.
- `PH_CMD_TOURRUN = 6103`: Menu-built tour forwarded to TourCommands.
- `PH_CMD_CHAT_DZ = 6104`: Chat DollyZoom forwarded to TourCommands.
- `CE_CMD_MOVE = 1010`: Engine move command.
- `CE_CMD_TOUR = 1011`: Continuous tour command handled by TourEngine.
- `CE_CMD_STOP = 1012`: Stop engine movement.
- `CE_CMD_LOCK = 1020`: Lock command.
- `CE_CMD_FOLLOW = 1030`: Follow command.
- `CE_CMD_FOV = 1040`: FOV command.
- `CE_CMD_GET_STATE = 1060`: Request current camera state.
- `CE_INT_SET_CAM = 3000`: TourEngine to Core camera frame, payload `<pos>|<focus>`.
- `CE_INT_TOUR_BEGIN = 3001`: TourEngine begins external drive.
- `CE_INT_TOUR_END = 3002`: TourEngine ends external drive.
- `CE_INT_TOUR_STOP = 3003`: Stop external tour drive.
- `MARKER_CH = -880088`: Region channel for marker communication.

## Preset Storage

Presets are stored in Linkset Data using keys like `P1`, `P2`, etc.

Preset format:

```text
px|py|pz|fx|fy|fz|rx|ry|rz|rs|fovRad
```

Many consumers only need the first six fields:

- position: fields `0..2`
- focus: fields `3..5`
- optional FOV: field `10`

When reading presets in memory-sensitive code, avoid full `llParseString2List(data, ["|"], [])` if only these fields are needed.

## Performance And Memory Guidelines

### Prefer targeted parsing in hot paths

Avoid full `llParseString2List` when:

- parsing `CE_INT_SET_CAM`
- parsing preset data
- parsing large `CE_CMD_TOUR` payloads
- parsing normal notecard playlist lines

Use targeted helpers such as:

- `lineToken()` in `HS_CamPlaylist.lsl`
- pipe-field helpers in `HS_CamEngineTour.lsl`
- direct separator lookup for two-field payloads in `HS_CamEngineCore.lsl`

### Keep active runtime data in script memory

Active tour playback reads position/focus/segment lists every timer tick. Keep those lists in `HS_CamEngineTour.lsl`; do not replace them with Linkset Data reads.

Linkset Data is appropriate for persistent presets and shared state, not per-frame runtime data.

### Minimize mixed-type and large temporary lists

Avoid mixed-type list builders for large payloads where a direct string build is clear and safe.

For notecard tour blocks:

- Store preset indices while parsing.
- Load preset position/focus at `endtour`.
- Build the final `CE_CMD_TOUR` payload directly.

### Be careful with timer hot paths

Timer-driven code should avoid:

- full string splitting
- repeated Linkset Data reads
- repeated object detail calls unless needed
- unnecessary `llMessageLinked` calls

Tour playback currently reduces load with:

- `tour_cam_min_interval`
- `tour_pos_epsilon`
- `tour_focus_epsilon`
- segment caching in TourEngine

### Use `llRegionSayTo` when target keys are known

For marker communication, prefer `llRegionSayTo` over `llRegionSay` when the marker key is known. This reduces unnecessary listener wakeups in the region.

## Configuration

Engine configuration lives in `HS_CamEngine.properties`.

Useful current keys:

```text
move_step=0.025
follow_step=0.05
default_move_ms=3000
default_focus_dist=10.0
move_pos_lag=0.5
move_focus_lag=0.5
follow_pos_lag=0.5
follow_focus_lag=0.5
pos_threshold=0.02
focus_threshold=0.02
tour_cam_min_interval=0.033
tour_pos_epsilon=0.005
tour_focus_epsilon=0.005
follow_predict=0.10
tour_max_points=20
```

`tour_cam_min_interval=0.033` caps internal tour camera updates around 30 Hz while still allowing path computation at `move_step`.

## Validation Notes

There is no official local Second Life LSL compiler in this repository. The authoritative compile check is still in-world via the Second Life Viewer or Firestorm.

Local checks that are useful before in-world compile:

- brace-balance checks
- conflict marker search
- targeted `rg` scans for unwanted `llParseString2List` reintroductions in hot paths
- optional `lslint` if installed, with the understanding that it is not the official Linden compiler

## Current Optimization Priorities

Highest priority:

- Notecard tour memory behavior.
- TourEngine timer hot path.
- Core `CE_INT_SET_CAM` hot path.
- Large `CE_CMD_TOUR` startup parsing.

Lower priority:

- Marker memory layout, because marker use is rare.
- Chat one-liner tour convenience paths.
- Menu-only tour building paths, unless they become a primary workflow.