csp-lua-sdk

Assetto Corsa CSP Lua SDK

Instructions

Step 1: Identify Script Type

Determine the type of script you are working with (App, Car, Track, etc.).

Refer to Workspace Rules for directory structure requirements.

Step 2: Consult API Definitions

Use the raw API definition files for accurate IntelliSense and function signatures. These are located in references/api/.

Apps: references/api/ac_apps.lib.lua
Car Physics: references/api/ac_car_cphys.lib.lua
Car Display: references/api/ac_car_scriptable_display.lib.lua
Online: references/api/ac_online_script.lib.lua
Track: references/api/ac_track_script.lib.lua
General Tools: references/api/ac_tools.lib.lua

Step 3: Implement Logic

Use Quick Reference for common snippets.
Use Reference Manual for deep dives into specific subsystems.

Examples

Example 1: Creating a Simple Lag-Filtered Car Display

User says: "Make a speedometer that doesn't jitter." Code:

-- Filtered car state
local speed = math.applyLag(prev, ac.getCar(0).speedKmh, 0.8, dt)
display.text{ text = string.format("%.0f", speed), pos = vec2(10, 10) }

Example 2: Simple Online Event

User says: "How do I send data between clients?" Code:

-- Define event
local ev = ac.OnlineEvent({v = ac.StructItem.float()}, function(s, m) ac.log(m.v) end)
-- Broadcast
ev({v = 42})

Example 3: Drawing Text

User says: "Draw text on the screen." Code:

display.text{ text = "LEVEL", pos = vec2(10, 10), letter = vec2(20, 30) }

Troubleshooting

Error: "Function not found" or "nil value"

Cause: Using functions from a different script type (e.g., using ac.getCar() in a pure Lua app without allow_access) or using internal APIs. Solution:

Check references/Workspace_Rules.md to ensure you are in the correct file type.
Verify the function exists in the references/api/*.lib.lua file for your script type.
Do not use internal APIs (starting with _).

Error: "Performance drop / Stuttering"

Cause: Creating garbage or expensive calls in update(). Solution:

Move vec2/rgb creation outside of loops if possible.
Use math.applyLag instead of complex smoothing tables.
Use ---@ext optimizations where applicable.