HitscanEffect Class Reference

Hitscan energy beam using fBm (fractional Brownian motion) path deviation. More...

#include <HitscanEffect.hpp>

Collaboration diagram for HitscanEffect:

Classes
struct	Branch
	A single forked branch diverging from the main arc. More...
struct	ReturnStroke
	A scheduled return stroke that re-randomises the arc path. More...
struct	BezierBeam
	State for a single active Bezier-spine beam. More...

Public Member Functions
void	update (float dt, glm::vec3 camForward)
	Update all active beams, rebuilding arc vertex data each frame.
void	spawn (glm::vec3 origin, glm::vec3 hitPos, WeaponType wt, glm::vec3 camForward)
	Fire a beam.
const ArcVertex *	arcData () const
	Get pointer to the arc vertex array for GPU upload.
uint32_t	arcCount () const
	Get the number of arc vertices currently generated.
uint32_t	activeBeamCount () const
	Get the number of active beams.
const HitscanBeam *	beamData () const
uint32_t	beamCount () const

Private Member Functions
void	appendArcStrip (const std::vector< glm::vec3 > &pts, float radius, glm::vec4 color, glm::vec3 camForward)
	Append a camera-facing triangle-strip ribbon to arcVerts_.

Static Private Member Functions
static glm::vec3	evalBezier (glm::vec3 p0, glm::vec3 p1, glm::vec3 p2, glm::vec3 p3, float t)
	Evaluate a cubic Bezier curve at parameter t.
static glm::vec3	evalBezierTangent (glm::vec3 p0, glm::vec3 p1, glm::vec3 p2, glm::vec3 p3, float t)
	Evaluate the tangent of a cubic Bezier curve at parameter t.
static void	randomizeCP (glm::vec3 origin, glm::vec3 hitPos, glm::vec3 camForward, glm::vec3 &cp1, glm::vec3 &cp2)
	Randomize Bezier control points for a new arc shape.
static void	rerandomizeBranches (BezierBeam &beam, glm::vec3 camForward)
	Re-randomize all branch parameters on a beam for flicker.

Private Attributes
BezierBeam	beams_ [k_maxBeams] {}
std::vector< ArcVertex >	arcVerts_

Static Private Attributes
static constexpr int	k_maxBeams = 4
static constexpr int	k_bezierSegs = 32
	Samples along main arc.
static constexpr int	k_branchSegs = 7
	Samples along each branch.
static constexpr int	k_maxBranches = 5
static constexpr float	k_beamLifetime = 0.22f
static constexpr float	k_interpDuration = 0.08f
	Bezier morph time (s).

Detailed Description

Hitscan energy beam using fBm (fractional Brownian motion) path deviation.

Signal chain per frame: t [0,1] along Bezier spine -> optional domain warp -> 4-octave fBm (lacunarity~3, persistence~0.4) -> multiply by sin(t*pi) envelope (pinned at both endpoints) -> scale by baseAmplitude (16 % of beam length) -> apply perpendicular to Bezier tangent

Rendering: three concentric triangle-strip layers per arc (outer bloom halo, inner glow channel, white-hot core) rendered with additive blending, giving an HDR-like look without a post-process pass.

Temporal behaviour:

• Smooth Bezier morph when a new shot is fired (80 ms interpolation).
• Continuous fBm animation (each octave runs at 2x the speed of the one below).
• 2-3 return strokes scheduled at 60/120/180 ms after the initial shot; each re-randomises the arc path and branches, simulating multi-strike behaviour.
• Branches re-randomise every 45 ms for rapid flicker.

Member Function Documentation

activeBeamCount()

uint32_t HitscanEffect::activeBeamCount ( ) const

nodiscard

Get the number of active beams.

Returns

Count of beams with active == true.

appendArcStrip()

void HitscanEffect::appendArcStrip ( const std::vector< glm::vec3 > & pts, float radius, glm::vec4 color, glm::vec3 camForward )

private

Append a camera-facing triangle-strip ribbon to arcVerts_.

Parameters

pts	Sampled points along the arc segment.
radius	Half-width of the ribbon strip.
color	RGBA color for all vertices in this strip.
camForward	Camera forward vector for billboard orientation.

Here is the caller graph for this function:

arcCount()

uint32_t HitscanEffect::arcCount ( ) const

inlinenodiscard

Get the number of arc vertices currently generated.

Returns

Vertex count.

arcData()

const ArcVertex * HitscanEffect::arcData ( ) const

inlinenodiscard

Get pointer to the arc vertex array for GPU upload.

Returns

Pointer to the first ArcVertex, or nullptr if empty.

beamCount()

uint32_t HitscanEffect::beamCount ( ) const

inlinenodiscard

beamData()

const HitscanBeam * HitscanEffect::beamData ( ) const

inlinenodiscard

evalBezier()

glm::vec3 HitscanEffect::evalBezier ( glm::vec3 p0, glm::vec3 p1, glm::vec3 p2, glm::vec3 p3, float t )

staticprivate

Evaluate a cubic Bezier curve at parameter t.

Here is the caller graph for this function:

evalBezierTangent()

glm::vec3 HitscanEffect::evalBezierTangent ( glm::vec3 p0, glm::vec3 p1, glm::vec3 p2, glm::vec3 p3, float t )

staticprivate

Evaluate the tangent of a cubic Bezier curve at parameter t.

Here is the caller graph for this function:

randomizeCP()

void HitscanEffect::randomizeCP ( glm::vec3 origin, glm::vec3 hitPos, glm::vec3 camForward, glm::vec3 & cp1, glm::vec3 & cp2 )

staticprivate

Randomize Bezier control points for a new arc shape.

Here is the call graph for this function:

Here is the caller graph for this function:

rerandomizeBranches()

void HitscanEffect::rerandomizeBranches ( BezierBeam & beam, glm::vec3 camForward )

staticprivate

Re-randomize all branch parameters on a beam for flicker.

Here is the call graph for this function:

Here is the caller graph for this function:

spawn()

void HitscanEffect::spawn	(	glm::vec3	origin,
		glm::vec3	hitPos,
		WeaponType	wt,
		glm::vec3	camForward )

Fire a beam.

Consecutive shots on the same slot produce a smooth morph.

Parameters

origin	World-space beam start position.
hitPos	World-space beam end position.
wt	Weapon type (reserved for future per-weapon tuning).
camForward	Camera forward vector for control-point placement.

Here is the call graph for this function:

update()

void HitscanEffect::update	(	float	dt,
		glm::vec3	camForward )

Update all active beams, rebuilding arc vertex data each frame.

Parameters

dt	Frame delta time in seconds.
camForward	Camera forward vector for billboard orientation.

Here is the call graph for this function:

Member Data Documentation

arcVerts_

std::vector<ArcVertex> HitscanEffect::arcVerts_

private

beams_

BezierBeam HitscanEffect::beams_[k_maxBeams] {}

private

k_beamLifetime

float HitscanEffect::k_beamLifetime = 0.22f

staticconstexprprivate

k_bezierSegs

int HitscanEffect::k_bezierSegs = 32

staticconstexprprivate

Samples along main arc.

k_branchSegs

int HitscanEffect::k_branchSegs = 7

staticconstexprprivate

Samples along each branch.

k_interpDuration

float HitscanEffect::k_interpDuration = 0.08f

staticconstexprprivate

Bezier morph time (s).

k_maxBeams

int HitscanEffect::k_maxBeams = 4

staticconstexprprivate

k_maxBranches

int HitscanEffect::k_maxBranches = 5

staticconstexprprivate

---

The documentation for this class was generated from the following files:

• src/client/particles/effects/HitscanEffect.hpp
• src/client/particles/effects/HitscanEffect.cpp