This README is the one indexed from the repository at its latest ref, not from the tag for this version.

SUCC-CR — Source Engine Unofficial Character Controller (Crystal / Lapis Port)

SUCC-CR (succ-cr) is a native Crystal port of SUCC (Source Engine Unofficial Character Controller) built with the Lapis GDExtension framework for Godot 4.

Original Author & Repository Credit:
This addon is a Crystal port of SUCC, originally created in GDScript by bearlikelion (Mark Arneman) & Nerdiful. All movement math, Quake/GoldSrc/Source physics parameters, presets, and controller architecture are credited to the original author.

---

Features

• Authentic Quake & Source Movement Physics (PM_Accelerate, PM_AirAccelerate, PM_Friction, PM_ClipVelocity)
  • Ground acceleration, friction with stop_speed (sv_stopspeed), and slope velocity projection
  • Air strafing (sv_airaccelerate + max_air_speed wish-speed cap)
  • Bunny hopping (bhop_buffered_jump hold-to-bhop or manual frame-perfect bhop)
  • Ramp surfing on steep angled surfaces (45.57°–80°)
  • Per-axis velocity clamping (sv_maxvelocity)
• Stair Stepping & View Smoothing
  • Three-phase test_move sweep (up $\rightarrow$ forward $\rightarrow$ down) with raycast surface normal verification
  • Air-stepping onto ledges when falling
  • Downward stair snapping when walking down steps
  • Smooth camera vertical step interpolation (WalkMove style)
• Crouching & Hull Management
  • Standing (BoxShape3D or CylinderShape3D) and crouching collision hulls automatically built and updated in-editor (@[Tool])
  • Source-style mid-air crouch (feet pull up while head stays in place)
  • Overhead shape-cast clearance check before uncrouching (intersect_shape_into)
  • Smooth cubic ease-out (SMOOTH) or instant (SNAP) crouch view transition
• Camera Rig (SUCCCamera)
  • First-person and third-person (SpringArm3D) camera modes
  • Quake/GoldSrc asymmetric triangle-wave view bob (V_CalcBob)
  • Quake lateral strafe camera roll (V_CalcRoll)
  • Source-style mouse sensitivity (degrees_per_unit = 0.022, m_yaw)
  • Physics tick camera interpolation for high-refresh-rate monitors
• 5 Ready-to-Use Engine Presets
  • Default (SUCC) (res://addons/succ_cr/resources/default_config.tres)
  • Quake (1996) (res://addons/succ_cr/resources/quake.tres)
  • Quake 2 (1997) (res://addons/succ_cr/resources/quake2.tres)
  • GoldSrc / Half-Life (1998) (res://addons/succ_cr/resources/goldsrc.tres)
  • Source / Half-Life 2 (2004) (res://addons/succ_cr/resources/source.tres)
• Multiplayer Pawn (SUCCPawn)
  • Lightweight networked player representation for MultiplayerSynchronizer state interpolation

---

Installation

Via Lapis CLI

In any Lapis-powered Godot 4 project:

lapis install addon github:sol-vin/succ-cr

Or add succ_cr to your shard.yml dependencies and copy addons/succ_cr into your project's addons/ folder:

dependencies:
  succ_cr:
    github: sol-vin/succ-cr
    version: ~> 0.1.0

Then require it in your src/main.cr:

require "succ_cr"

---

Quick Start

1. Drop in the Character Scene

Instance res://addons/succ_cr/scenes/succ_character.tscn into your 3D level, or construct the node hierarchy manually:

SUCC (CharacterBody3D)
└── SUCCCamera (SpringArm3D)
    └── Camera3D

SUCC automatically generates its standing and crouching CollisionShape3D nodes at runtime and in the Godot Editor.

2. Configure Input Map Actions

Ensure the following actions exist in Project > Project Settings > Input Map (or customize the action names in the SUCC Inspector under Input Actions):

Action Property	Default Input Map Name	Suggested Binding
action_move_forward	forward	W
action_move_backward	back	S
action_move_left	left	A
action_move_right	right	D
action_jump	jump	Space
action_crouch	crouch	Ctrl
action_sprint	sprint	Shift
action_camera_mode	camera_mode	V

---

Engine Presets

Swap movement feel at edit-time via the config property in the Inspector or at runtime in Crystal:

# Using pre-built .tres resources
player.config = SUCCConfig.new(Godot.load("res://addons/succ_cr/resources/quake.tres").pointer)

# Or using Crystal preset constructors
player.config = SUCCConfig.default_preset
player.config = SUCCConfig.quake_preset
player.config = SUCCConfig.quake2_preset
player.config = SUCCConfig.goldsrc_preset
player.config = SUCCConfig.source_preset

Preset	Max Speed	Gravity	Jump Height	Friction	Air Accel	Auto Bhop	Crouch Mode
Default (SUCC)	8.128 m/s (320u)	20.32 m/s² (800u)	1.128 m (44.4u)	4.0	10.0	true	SMOOTH
Quake (1996)	8.128 m/s (320u)	20.32 m/s² (800u)	1.158 m (45.6u)	6.0	10.0	false	Disabled (SNAP)
Quake 2 (1997)	7.620 m/s (300u)	20.32 m/s² (800u)	1.158 m (45.6u)	6.0	1.0	false	SNAP
GoldSrc (1998)	8.128 m/s (320u)	20.32 m/s² (800u)	1.128 m (44.4u)	4.0	10.0	false	SNAP
Source (2004)	4.826 m/s (190u, Sprint 320u)	15.24 m/s² (600u)	0.533 m (21.0u)	4.0	10.0	false	SMOOTH

Unit Conversion Helpers

Source and Quake use inches (1 meter = 39.37 units):

meters = SUCCConfig.source_units(320.0_f32) # => 8.128_f32
meters = SUCCConfig.quake_units(800.0_f32)  # => 20.32_f32
units  = SUCCConfig.to_source_units(1.829_f32) # => 72.0_f32

---

Signals & States

Signals on SUCC

• movement_state_changed(old_state : SUCC::MovementState, new_state : SUCC::MovementState)
• game_state_changed(old_state : SUCC::GameState, new_state : SUCC::GameState)
• jumped()
• landed(impact_speed : Float64)
• camera_mode_changed(mode : SUCC::CameraMode)

Enums on SUCC

• SUCC::MovementState: IDLE, WALKING, SPRINTING, CROUCHING, FALLING, SURFING
• SUCC::GameState: PLAYING, PAUSED, MENU, CUTSCENE
• SUCC::CameraMode: FIRST_PERSON, THIRD_PERSON
• SUCC::FloorType: NONE, GROUND, RAMP

---

Development & Testing

# Run Crystal unit specs
crystal spec

# Build the GDExtension shared library
lapis build

---

Credits & License

• Original GDScript Addon (SUCC): Created by bearlikelion (Mark Arneman) & Nerdiful (MIT License).
• Crystal / Lapis Port (succ-cr): Ported by Ian Rash (Sol-Vin) (MIT License).

See LICENSE for full license text.