oot/include/z64curve.h

#ifndef Z64_CURVE_H
#define Z64_CURVE_H

#include "ultra64/ultratypes.h"
#include "z64math.h"

struct PlayState;

typedef struct CurveInterpKnot {
    /* 0x0 */ u16 flags;         // Only the bottom two bits are used, although others are set in objects
    /* 0x2 */ s16 abscissa;      // knot input value
    /* 0x4 */ s16 leftGradient;  // left derivative at the point
    /* 0x6 */ s16 rightGradient; // right derivative at the point
    /* 0x8 */ f32 ordinate;      // output value
} CurveInterpKnot; // size = 0xC

typedef struct CurveAnimationHeader {
    /* 0x0 */ u8* knotCounts;
    /* 0x4 */ CurveInterpKnot* interpolationData;
    /* 0x8 */ s16* constantData;
    /* 0xC */ s16 unk_0C;     // Set but not used, always 1 in objects
    /* 0xE */ s16 frameCount; // Not used, inferred from use in objects
} CurveAnimationHeader; // size = 0x10

typedef struct SkelCurveLimb {
    /* 0x0 */ u8 child;
    /* 0x1 */ u8 sibling;
    /* 0x4 */ Gfx* dList[2];
} SkelCurveLimb; // size = 0xC

typedef struct CurveSkeletonHeader {
    /* 0x0 */ SkelCurveLimb** limbs;
    /* 0x4 */ u8 limbCount;
} CurveSkeletonHeader; // size = 0x8

typedef struct SkelCurve {
    /* 0x00 */ u8 limbCount;
    /* 0x04 */ SkelCurveLimb** skeleton;
    /* 0x08 */ CurveAnimationHeader* animation;
    /* 0x0C */ f32 unk_0C; // set but not used
    /* 0x10 */ f32 endFrame;
    /* 0x14 */ f32 playSpeed;
    /* 0x18 */ f32 curFrame;
    /* 0x1C */ s16 (*jointTable)[9];
} SkelCurve; // size = 0x20

typedef s32 (*OverrideCurveLimbDraw)(struct PlayState* play, SkelCurve* skelCuve, s32 limbIndex, void* thisx);
typedef void (*PostCurveLimbDraw)(struct PlayState* play, SkelCurve* skelCuve, s32 limbIndex, void* thisx);

f32 Curve_Interpolate(f32 x, CurveInterpKnot* knots, s32 knotCount);

void SkelCurve_Clear(SkelCurve* skelCurve);
s32 SkelCurve_Init(struct PlayState* play, SkelCurve* skelCurve, CurveSkeletonHeader* skeletonHeaderSeg,
                   CurveAnimationHeader* animation);
void SkelCurve_Destroy(struct PlayState* play, SkelCurve* skelCurve);
void SkelCurve_SetAnim(SkelCurve* skelCurve, CurveAnimationHeader* animation, f32 arg2, f32 endFrame, f32 curFrame,
                       f32 playSpeed);
s32 SkelCurve_Update(struct PlayState* play, SkelCurve* skelCurve);
void SkelCurve_Draw(Actor* actor, struct PlayState* play, SkelCurve* skelCurve, OverrideCurveLimbDraw overrideLimbDraw,
                    PostCurveLimbDraw postLimbDraw, s32 lod, void* data);

#endif