Animation.hpp File Reference

A deliberately small transform-hierarchy + clip layer that drives CPU deformation. More...

#include <Core/Container.hpp>
#include <Math/Math.hpp>
#include "Mesh.hpp"

Go to the source code of this file.

Classes
struct	FJoint
	One node of a transform hierarchy (a skeleton joint or an articulation node). More...
struct	FSkeleton
	A flat skeleton: the only hierarchy the animation layer retains, owned by the asset. More...
struct	FAnimChannel
	A single animated component of a single joint: sorted keyframe times + packed values. More...
struct	FAnimationClip
	A clip: a set of channels plus its total duration (seconds). More...
struct	FPose
	Reusable per-instance evaluation scratch for one skeleton (allocate once, reuse per frame). More...

Enumerations
enum class	FAnimPath : uint8_t { Translation , Rotation , Scale }
	Which local TRS component an animation channel drives. More...
enum class	FAnimInterp : uint8_t { Step , Linear , CubicSpline }
	Keyframe interpolation mode (mirrors glTF sampler interpolation). More...

Functions
mat4	JointLocalMatrix (float3 const &t, quat const &r, float3 const &s)
	Composes a joint's local TRS into a matrix (T * R * S).
void	ResetToRest (FSkeleton const &skel, FPose &pose)
	Seeds a pose's local TRS from the skeleton rest pose (call before SampleClip).
void	SampleClip (FAnimationClip const &clip, float t, FPose &pose)
	Samples a clip at time t, overwriting the seeded local TRS for every channel's joint.
void	ComputeGlobals (FSkeleton const &skel, FPose &pose)
	Walks the hierarchy, composing local TRS into world matrices in FPose::globals.
void	SampleTrack (Span< const float > times, Span< const float > values, uint32_t comps, FAnimInterp interp, float t, Span< float > out)
	Samples a generic keyframed track of comps-wide values at time t into out.
void	ComputeSkinningMatrices (FSkeleton const &skel, FPose const &pose, Span< mat4 > outPalette)
	Builds the skinning palette globals[j] * inverseBind[j] into outPalette.
void	SkinVertices (Span< const FVertex > bind, Span< const FSkinBinding > binding, Span< const mat4 > palette, Span< FQVertex > out)
	Linear-blend skins bind-pose vertices by the palette, packing results for the dynamic ring.
void	RecomputeNormals (Span< FVertex > verts, Span< const uint32_t > indices)
	Recomputes smooth per-vertex normals from positions over an indexed triangle list.

Detailed Description

A deliberately small transform-hierarchy + clip layer that drives CPU deformation.

The whole system is one idea applied twice: a flat, topologically sorted joint hierarchy whose local TRS we sample from a clip and accumulate into world matrices (FPose::globals). Skinning then multiplies those by per-joint inverse-bind matrices to build a palette and linear-blend-skins bind-pose vertices into the GPUScene dynamic ring (SkinVertices). "Rigid articulation" is the same evaluator with the skinning step omitted: a caller reads FPose::globals directly and feeds them as per-instance transforms (inverse-bind is then unused / identity). There is intentionally no general retained scene graph - the only hierarchy is this asset-local skeleton.

Enumeration Type Documentation

FAnimInterp

enum class FAnimInterp : uint8_t

strong

Keyframe interpolation mode (mirrors glTF sampler interpolation).

Enumerator
Step
Linear
CubicSpline

FAnimPath

enum class FAnimPath : uint8_t

strong

Which local TRS component an animation channel drives.

Enumerator
Translation
Rotation
Scale

Function Documentation

ComputeGlobals()

void ComputeGlobals	(	FSkeleton const &	skel,
		FPose &	pose
	)

Walks the hierarchy, composing local TRS into world matrices in FPose::globals.

ComputeSkinningMatrices()

void ComputeSkinningMatrices	(	FSkeleton const &	skel,
		FPose const &	pose,
		Span< mat4 >	outPalette
	)

Builds the skinning palette globals[j] * inverseBind[j] into outPalette.

Parameters

outPalette

Must hold FSkeleton::Count matrices.

JointLocalMatrix()

mat4 JointLocalMatrix	(	float3 const &	t,
		quat const &	r,
		float3 const &	s
	)

Composes a joint's local TRS into a matrix (T * R * S).

RecomputeNormals()

void RecomputeNormals	(	Span< FVertex >	verts,
		Span< const uint32_t >	indices
	)

Recomputes smooth per-vertex normals from positions over an indexed triangle list.

Area-weighted face-normal accumulation, then normalize. Needed after POSITION-only morph deformation (which moves vertices without supplying normals); run it on the morphed vertices before packing/skinning so shading matches the deformed surface. Tangents are left as-is (re-projected onto the new normal frame by FQVertex::PackTBN).

ResetToRest()

void ResetToRest	(	FSkeleton const &	skel,
		FPose &	pose
	)

Seeds a pose's local TRS from the skeleton rest pose (call before SampleClip).

SampleClip()

void SampleClip	(	FAnimationClip const &	clip,
		float	t,
		FPose &	pose
	)

Samples a clip at time t, overwriting the seeded local TRS for every channel's joint.

Note

Channels with no key for a component leave that component at its rest value, so call ResetToRest first. t is clamped per channel to its key range.

SampleTrack()

void SampleTrack	(	Span< const float >	times,
		Span< const float >	values,
		uint32_t	comps,
		FAnimInterp	interp,
		float	t,
		Span< float >	out
	)

Samples a generic keyframed track of comps-wide values at time t into out.

Same time/value packing and interpolation rules as FAnimChannel (step/linear/cubic, clamped to the key range). Used for morph-target weight tracks (comps == target count).

Parameters

out	Must be exactly comps wide.

SkinVertices()

void SkinVertices	(	Span< const FVertex >	bind,
		Span< const FSkinBinding >	binding,
		Span< const mat4 >	palette,
		Span< FQVertex >	out
	)

Linear-blend skins bind-pose vertices by the palette, packing results for the dynamic ring.

Parameters

bind	Rest-pose, full-precision vertices (positions/normals/tangents in bind space).
binding	Per-vertex joint indices + weights (parallel to bind).
palette	Skinning matrices from ComputeSkinningMatrices.
out	Destination quantized vertices (size == bind.size()); write straight into the span returned by GPUScene::UpdateDynamicGeometry.