/**
 * @file c_keyframe.c
 *
 * This file implements a skeletal animation system supporting all of scale, rotation and translation on all joints. It
 * uses keyframe data and interpolates intermediate values via cubic Hermite splines.
 */
#include "global.h"
#include "libc64/fixed_point.h"

#define FMOD(x, mod) ((x) - ((s32)((x) * (1.0f / (mod))) * (f32)(mod)))

/**
 * @note Original name: cKF_FrameControl_zeroClera
 */
void FrameCtrl_Reset(FrameControl* frameCtrl) {
    frameCtrl->frameCount = 0.0f;
    frameCtrl->curTime = 0.0f;
    frameCtrl->speed = 0.0f;
    frameCtrl->end = 0.0f;
    frameCtrl->start = 0.0f;
    frameCtrl->animMode = KEYFRAME_ANIM_ONCE;
}

/**
 * @note Original name: cKF_FrameControl_ct
 */
void FrameCtrl_Init(FrameControl* frameCtrl) {
    FrameCtrl_Reset(frameCtrl);
}

/**
 * @note Original name: cKF_FrameControl_setFrame
 */
void FrameCtrl_SetProperties(FrameControl* frameCtrl, f32 startTime, f32 endTime, f32 frameCount, f32 t, f32 speed,
                             s32 animMode) {
    frameCtrl->start = startTime;
    frameCtrl->end = (endTime < 1.0f) ? frameCount : endTime;
    frameCtrl->frameCount = frameCount;
    frameCtrl->speed = speed;
    frameCtrl->curTime = t;
    frameCtrl->animMode = animMode;
}

/**
 * @note Original name: cKF_FrameControl_passCheck
 */
s32 FrameCtrl_PassCheck(FrameControl* frameCtrl, f32 t, f32* remainingTime) {
    f32 curTime;
    f32 speed;

    *remainingTime = 0.0f;
    curTime = frameCtrl->curTime;

    if (t == curTime) {
        return false;
    }

    speed = ((frameCtrl->start < frameCtrl->end) ? frameCtrl->speed : -frameCtrl->speed) * (30.0f / 20.0f);

    if (((speed >= 0.0f) && (curTime < t) && (t <= curTime + speed)) ||
        ((speed < 0.0f) && (t < curTime) && (curTime + speed <= t))) {

        *remainingTime = curTime + speed - t;
        return true;
    }
    return false;
}

/**
 * Updates a FrameControl structure whose mode is KEYFRAME_ANIM_ONCE
 *
 * @note Original name: cKF_FrameControl_stop_proc
 */
s32 FrameCtrl_UpdateOnce(FrameControl* frameCtrl) {
    f32 remainingTime;

    if (frameCtrl->curTime == frameCtrl->end) {
        // If the current time is at the end time, the animation is done.
        return KEYFRAME_DONE_ONCE;
    }
    if (FrameCtrl_PassCheck(frameCtrl, frameCtrl->end, &remainingTime)) {
        frameCtrl->curTime = frameCtrl->end;
        return KEYFRAME_DONE_ONCE;
    }
    if (FrameCtrl_PassCheck(frameCtrl, frameCtrl->start, &remainingTime)) {
        frameCtrl->curTime = frameCtrl->end;
        return KEYFRAME_DONE_ONCE;
    }
    return KEYFRAME_NOT_DONE;
}

/**
 * Updates a FrameControl structure whose mode is KEYFRAME_ANIM_LOOP
 *
 * @note Original name: cKF_FrameControl_repeat_proc
 */
s32 FrameCtrl_UpdateLoop(FrameControl* frameCtrl) {
    f32 remainingTime;

    if (FrameCtrl_PassCheck(frameCtrl, frameCtrl->end, &remainingTime)) {
        frameCtrl->curTime = frameCtrl->start + remainingTime;
        return KEYFRAME_DONE_LOOP;
    }
    if (FrameCtrl_PassCheck(frameCtrl, frameCtrl->start, &remainingTime)) {
        frameCtrl->curTime = frameCtrl->end + remainingTime;
        return KEYFRAME_DONE_LOOP;
    }
    return KEYFRAME_NOT_DONE;
}

/**
 * Check if the animation has finished playing and update the animation frame number.
 *
 * @note Original name: cKF_FrameControl_play
 */
s32 FrameCtrl_Update(FrameControl* frameCtrl) {
    s32 result;
    f32 speed;

    // Check if the animation is done, possibly updating curTime
    if (frameCtrl->animMode == KEYFRAME_ANIM_ONCE) {
        result = FrameCtrl_UpdateOnce(frameCtrl);
    } else {
        result = FrameCtrl_UpdateLoop(frameCtrl);
    }

    if (result == KEYFRAME_NOT_DONE) {
        // Animation is not done, step curTime by (speed * (30.0f / 20.0f)), adjusting the sign if the animation is
        // playing in reverse (end <= start)
        speed = (frameCtrl->start < frameCtrl->end) ? frameCtrl->speed : -frameCtrl->speed;
        frameCtrl->curTime = frameCtrl->curTime + speed * (30.0f / 20.0f);
    }

    // Adjust time for looping
    if (frameCtrl->curTime < 1.0f) {
        // Wrap from the start to the end of the animation
        frameCtrl->curTime = (frameCtrl->curTime - 1.0f) + frameCtrl->frameCount;
    } else if (frameCtrl->frameCount < frameCtrl->curTime) {
        // Wrap from the end to the start of the animation
        frameCtrl->curTime = (frameCtrl->curTime - frameCtrl->frameCount) + 1.0f;
    }

    return result;
}

/**
 * @note Original name unknown
 */
void Keyframe_ResetFlex(KFSkelAnimeFlex* kfSkelAnime) {
    kfSkelAnime->skeleton = NULL;
    kfSkelAnime->animation = NULL;
    kfSkelAnime->jointTable = NULL;
    kfSkelAnime->transformCallbacks = NULL;
    kfSkelAnime->morphTable = NULL;
    kfSkelAnime->morphFrames = 0.0f;
}

/**
 * Initializes a flex-type keyframe skeleton. The initial animation type is KEYFRAME_ANIM_ONCE.
 *
 * @param skeleton Skeleton to animate
 * @param animation Initial animation to use
 * @param jointTable Joint table to store limb transformations. Should have enough space to store a root translation
 *                   plus a limb rotation for all limbs in the skeleton.
 * @param morphTable Joint table to store morph interpolation values. Should have enough space to store a root
 *                   translation plus a limb rotation for all limbs in the skeleton.
 * @param transformCallbacks Array of limb transformation callbacks that will be called when drawing a particular limb.
 *                           The limb data contains the index to select which callback to run.
 *
 * @note Original name unknown
 */
void Keyframe_InitFlex(KFSkelAnimeFlex* kfSkelAnime, KeyFrameFlexSkeleton* skeleton, KeyFrameAnimation* animation,
                       Vec3s* jointTable, Vec3s* morphTable, KeyframeTransformCallback* transformCallbacks) {
    Keyframe_ResetFlex(kfSkelAnime);
    FrameCtrl_Init(&kfSkelAnime->frameCtrl);
    kfSkelAnime->skeleton = Lib_SegmentedToVirtual(skeleton);
    kfSkelAnime->animation = Lib_SegmentedToVirtual(animation);
    kfSkelAnime->jointTable = jointTable;
    kfSkelAnime->morphTable = morphTable;
    kfSkelAnime->transformCallbacks = transformCallbacks;
}

/**
 * Destroys a flex-type keyframe skeleton.
 *
 * @note Original name unknown
 */
void Keyframe_DestroyFlex(KFSkelAnimeFlex* kfSkelAnime) {
}

void Keyframe_FlexChangeAnim(KFSkelAnimeFlex* kfSkelAnime, KeyFrameFlexSkeleton* skeleton, KeyFrameAnimation* animation,
                             f32 startTime, f32 endTime, f32 t, f32 speed, f32 morphFrames, s32 animMode);

/**
 * Immediately changes to an animation that plays once from start to end at the default speed.
 *
 * @param animation Animation data to switch to
 *
 * @note Original name unknown
 */
void Keyframe_FlexPlayOnce(KFSkelAnimeFlex* kfSkelAnime, KeyFrameAnimation* animation) {
    Keyframe_FlexChangeAnim(kfSkelAnime, kfSkelAnime->skeleton, animation, 1.0f,
                            ((KeyFrameAnimation*)Lib_SegmentedToVirtual(animation))->frameCount, 1.0f, 1.0f, 0.0f,
                            KEYFRAME_ANIM_ONCE);
}

/**
 * Immediately changes to an animation that plays once from start to end at the specified speed.
 *
 * @param animation Animation data to switch to
 * @param speed Playback speed
 *
 * @note Original name unknown
 */
void Keyframe_FlexPlayOnceSetSpeed(KFSkelAnimeFlex* kfSkelAnime, KeyFrameAnimation* animation, f32 speed) {
    Keyframe_FlexChangeAnim(kfSkelAnime, kfSkelAnime->skeleton, animation, 1.0f,
                            ((KeyFrameAnimation*)Lib_SegmentedToVirtual(animation))->frameCount, 1.0f, speed, 0.0f,
                            KEYFRAME_ANIM_ONCE);
}

/**
 * Smoothly transitions to an animation that plays once from start to end at the default speed, specifying the number of
 * frames for the transition.
 *
 * @param animation Animation data to switch to
 * @param morphFrames Number of frames to take to transition from the previous pose to the new animation. Positive morph
 *                    frames morph from the current pose to the start pose of the new animation, then start the new
 *                    animation. Negative morph frames start the new animation immediately, modified by the pose
 *                    immediately before the animation change.
 *
 * @note Original name unknown
 */
void Keyframe_FlexMorphToPlayOnce(KFSkelAnimeFlex* kfSkelAnime, KeyFrameAnimation* animation, f32 morphFrames) {
    Keyframe_FlexChangeAnim(kfSkelAnime, kfSkelAnime->skeleton, animation, 1.0f,
                            ((KeyFrameAnimation*)Lib_SegmentedToVirtual(animation))->frameCount, 1.0f, 1.0f,
                            morphFrames, KEYFRAME_ANIM_ONCE);
}

/**
 * Immediately changes to an animation that loops over start to end at the default speed.
 *
 * @param animation Animation data to switch to
 *
 * @note Original name unknown
 */
void Keyframe_FlexPlayLoop(KFSkelAnimeFlex* kfSkelAnime, KeyFrameAnimation* animation) {
    Keyframe_FlexChangeAnim(kfSkelAnime, kfSkelAnime->skeleton, animation, 1.0f,
                            ((KeyFrameAnimation*)Lib_SegmentedToVirtual(animation))->frameCount, 1.0f, 1.0f, 0.0f,
                            KEYFRAME_ANIM_LOOP);
}

/**
 * Immediately changes to an animation that loops over start to end at the specified speed.
 *
 * @param animation Animation data to switch to
 * @param speed Playback speed
 *
 * @note Original name unknown
 */
void Keyframe_FlexPlayLoopSetSpeed(KFSkelAnimeFlex* kfSkelAnime, KeyFrameAnimation* animation, f32 speed) {
    Keyframe_FlexChangeAnim(kfSkelAnime, kfSkelAnime->skeleton, animation, 1.0f,
                            ((KeyFrameAnimation*)Lib_SegmentedToVirtual(animation))->frameCount, 1.0f, speed, 0.0f,
                            KEYFRAME_ANIM_LOOP);
}

/**
 * Smoothly transitions to an animation that loops over start to end at the default speed, specifying the number of
 * frames for the transition.
 *
 * @param animation Animation data to switch to
 * @param morphFrames Number of frames to take to transition from the previous pose to the new animation. Positive morph
 *                    frames morph from the current pose to the start pose of the new animation, then start the new
 *                    animation. Negative morph frames start the new animation immediately, modified by the pose
 *                    immediately before the animation change.
 *
 * @note Original name unknown
 */
void Keyframe_FlexMorphToPlayLoop(KFSkelAnimeFlex* kfSkelAnime, KeyFrameAnimation* animation, f32 morphFrames) {
    Keyframe_FlexChangeAnim(kfSkelAnime, kfSkelAnime->skeleton, animation, 1.0f,
                            ((KeyFrameAnimation*)Lib_SegmentedToVirtual(animation))->frameCount, 1.0f, 1.0f,
                            morphFrames, KEYFRAME_ANIM_LOOP);
}

/**
 * General way to set a new animation for flex-type skeletons, allowing choice of playback speed, start/end loop points,
 * start time, play mode, and number of transition frames.
 *
 * Time parameters are valid from 0 to the last frame of the animation.
 *
 * @param skeleton Skeleton that will be animated
 * @param animation Animation data to switch to
 * @param startTime Loop start time
 * @param endTime Loop end time, 0 indicates to use the animation length
 * @param t Playback start time
 * @param speed Playback speed
 * @param morphFrames Number of frames to take to transition from the previous pose to the new animation. Positive morph
 *                    frames morph from the current pose to the start pose of the new animation, then start the new
 *                    animation. Negative morph frames start the new animation immediately, modified by the pose
 *                    immediately before the animation change.
 * @param animMode Animation play mode, see KeyFrameAnimMode enum
 *
 * @see KeyFrameAnimMode
 *
 * @note Original name unknown
 */
void Keyframe_FlexChangeAnim(KFSkelAnimeFlex* kfSkelAnime, KeyFrameFlexSkeleton* skeleton, KeyFrameAnimation* animation,
                             f32 startTime, f32 endTime, f32 t, f32 speed, f32 morphFrames, s32 animMode) {
    kfSkelAnime->morphFrames = morphFrames;

    if (kfSkelAnime->skeleton != skeleton) {
        kfSkelAnime->skeleton = Lib_SegmentedToVirtual(skeleton);
    }
    kfSkelAnime->animation = Lib_SegmentedToVirtual(animation);

    FrameCtrl_SetProperties(&kfSkelAnime->frameCtrl, startTime, endTime, kfSkelAnime->animation->frameCount, t, speed,
                            animMode);
}

/**
 * Switches to a new animation without changing any of the playback parameters.
 *
 * @param animation The animation to switch to
 *
 * @note Original name unknown
 */
void Keyframe_FlexChangeAnimQuick(KFSkelAnimeFlex* kfSkelAnime, KeyFrameAnimation* animation) {
    kfSkelAnime->animation = Lib_SegmentedToVirtual(animation);
    kfSkelAnime->frameCtrl.frameCount = kfSkelAnime->animation->frameCount;
}

/**
 * Compute a value on the cubic Hermite spline x(t) at a time `t` in the unit interval [0, 1]
 *
 * @param t Time parameter at which to sample the curve
 * @param delta Scales the rates of change of the curve endpoints v0 and v1
 * @param x0 Value on the curve at t=0
 * @param x1 Value on the curve at t=1
 * @param v0 Rate of change of the curve at t=0
 * @param v1 Rate of change of the curve at t=1
 *
 * @note Original name: cKF_HermitCalc
 */
f32 Keyframe_Interpolate(f32 t, f32 delta, f32 x0, f32 x1, f32 v0, f32 v1) {
    f32 px1 = 3.0f * SQ(t) - 2.0f * CB(t);
    f32 px0 = 1.0f - px1;
    f32 pv0 = CB(t) - 2.0f * SQ(t) + t;
    f32 pv1 = CB(t) - SQ(t);

    return px0 * x0 + px1 * x1 + (pv0 * v0 + pv1 * v1) * delta;
}

/**
 * Computes an output value at time `t` based on interpolation of the provided keyframes.
 * Interpolation between keyframes is performed via cubic Hermite splines.
 *
 * @param kfStart Index of the first keyframe to consider
 * @param kfNum Number of keyframes following the first keyframe to consider
 * @param keyFrames Array of all keyframes
 * @param t Time at which to sample the interpolated curve
 *
 * @return The interpolated value
 *
 * @note Original name: cKF_KeyCalc
 */
s16 Keyframe_KeyCalc(s16 kfStart, s16 kfNum, KeyFrame* keyFrames, f32 t) {
    KeyFrame* keyFramesOffset = &keyFrames[kfStart];
    f32 delta;
    s16 kf1;
    s16 kf2;

    if (t <= keyFramesOffset->frame) {
        return keyFramesOffset->value;
    }
    if (keyFramesOffset[kfNum - 1].frame <= t) {
        return keyFramesOffset[kfNum - 1].value;
    }

    kf1 = 0;
    kf2 = 1;
    while (true) {
        // Search for the keyframes kf1 and kf2 such that kf1.frame <= t < kf2.frame
        if (t < keyFramesOffset[kf2].frame) {
            delta = keyFramesOffset[kf2].frame - keyFramesOffset[kf1].frame;

            if (!IS_ZERO(delta)) {
                // Between two keyframes, interpolate a value and round to nearest integer
                return nearbyint(Keyframe_Interpolate((t - keyFramesOffset[kf1].frame) / delta, delta * (1.0f / 30),
                                                      keyFramesOffset[kf1].value, keyFramesOffset[kf2].value,
                                                      keyFramesOffset[kf1].velocity, keyFramesOffset[kf2].velocity));
            } else {
                // Close enough to a keyframe, take the specified value with no interpolation
                return keyFramesOffset[kf1].value;
            }
        }
        kf1++;
        kf2++;
    }
}

/**
 * Morph interpolator for rotation.
 *
 * Linearly interpolates between `rot1` and `rot2` with weight `t`, choosing either signed angles or unsigned angles
 * based on whichever choice has the smaller distance between the two.
 *
 * @note Original name: cKF_SkeletonInfo_subRotInterpolation
 */
void Keyframe_MorphInterpolateRotation(f32 t, s16* out, s16 rot1, s16 rot2) {
    u16 urot1 = rot1;
    s32 pad;
    u16 urot2 = rot2;
    f32 rot1f = rot1;
    f32 signedDiff = rot2 - rot1f;
    f32 urot1f = urot1;
    f32 unsignedDiff = urot2 - urot1f;

    if (fabsf(signedDiff) < fabsf(unsignedDiff)) {
        *out = rot1f + signedDiff * t;
    } else {
        *out = urot1f + unsignedDiff * t;
    }
}

/**
 * Morph interpolator for translation and scale.
 *
 * Linearly interpolates between `jointData` and `morphData` with weight `t`, storing the result back into `jointData`.
 *
 * @note Original name: cKF_SkeletonInfo_morphST
 */
void Keyframe_MorphInterpolateLinear(s16* jointData, s16* morphData, f32 t) {
    s32 i;

    for (i = 0; i < 3; i++) {
        if (*jointData != *morphData) {
            f32 f1 = *jointData;
            f32 f2 = *morphData;
            *jointData = f1 + (f2 - f1) * t;
        }
        jointData++;
        morphData++;
    }
}

/**
 * Apply morph interpolation for the provided skeleton. Morph interpolation seeks to provide interpolation between
 * a previous animation and a new animation over a fixed period of time (morphFrames)
 *
 * @note Original name unknown
 */
void Keyframe_FlexMorphInterpolation(KFSkelAnimeFlex* kfSkelAnime) {
    Vec3s* jointTable = kfSkelAnime->jointTable;
    Vec3s* morphTable = kfSkelAnime->morphTable;
    f32 t = 1.0f / fabsf(kfSkelAnime->morphFrames);
    s32 limbIndex;

    for (limbIndex = 0; limbIndex < kfSkelAnime->skeleton->limbCount; limbIndex++) {
        Vec3s frameRot;
        Vec3s morphRot;

        // Interpolate scale
        Keyframe_MorphInterpolateLinear((s16*)jointTable, (s16*)morphTable, t);
        jointTable++;
        morphTable++;

        // Read rotation
        frameRot.x = jointTable->x;
        frameRot.y = jointTable->y;
        frameRot.z = jointTable->z;

        morphRot.x = morphTable->x;
        morphRot.y = morphTable->y;
        morphRot.z = morphTable->z;

        // Interpolate rotation
        if (frameRot.x != morphRot.x || frameRot.y != morphRot.y || frameRot.z != morphRot.z) {
            Vec3s frameRotInv;
            f32 norm1;
            f32 norm2;

            frameRotInv.x = 0x7FFF + frameRot.x;
            frameRotInv.y = 0x7FFF - frameRot.y;
            frameRotInv.z = 0x7FFF + frameRot.z;

            // Compute L1 norms
            norm1 = fabsf((f32)morphRot.x - frameRot.x) + fabsf((f32)morphRot.y - frameRot.y) +
                    fabsf((f32)morphRot.z - frameRot.z);
            norm2 = fabsf((f32)morphRot.x - frameRotInv.x) + fabsf((f32)morphRot.y - frameRotInv.y) +
                    fabsf((f32)morphRot.z - frameRotInv.z);

            if (norm1 < norm2) {
                // frameRot is closer to morphRot than frameRotInv, interpolate between these two
                Keyframe_MorphInterpolateRotation(t, &jointTable->x, frameRot.x, morphRot.x);
                Keyframe_MorphInterpolateRotation(t, &jointTable->y, frameRot.y, morphRot.y);
                Keyframe_MorphInterpolateRotation(t, &jointTable->z, frameRot.z, morphRot.z);
            } else {
                // frameRotInv is closer to morphRot than frameRot, interpolate between these two
                Keyframe_MorphInterpolateRotation(t, &jointTable->x, frameRotInv.x, morphRot.x);
                Keyframe_MorphInterpolateRotation(t, &jointTable->y, frameRotInv.y, morphRot.y);
                Keyframe_MorphInterpolateRotation(t, &jointTable->z, frameRotInv.z, morphRot.z);
            }
        }
        morphTable++;
        jointTable++;

        // Interpolate translation
        Keyframe_MorphInterpolateLinear((s16*)jointTable, (s16*)morphTable, t);
        jointTable++;
        morphTable++;
    }
}

/**
 * Advances the current animation and updates all frame tables for flex-type keyframe skeletons.
 *
 * @return s32
 *  KEYFRAME_NOT_DONE  : If the animation is still playing
 *  KEYFRAME_DONE_ONCE : If the animation was set to play once and has finished playing
 *  KEYFRAME_DONE_LOOP : If the animation was set to play in a loop and has finished a loop
 *
 * @note Original name unknown
 */
s32 Keyframe_UpdateFlex(KFSkelAnimeFlex* kfSkelAnime) {
    s32 limbIndex;
    s32 pad[2];
    u16* bitFlags;
    s16* outputValues;
    s32 kfn = 0;
    s32 fixedValueIndex = 0;
    s32 kfStart = 0;
    s16* fixedValues;
    KeyFrame* keyFrames;
    s16* kfNums;
    u32 bit;
    s32 i;
    s32 j;

    // If there are morph frames to process, use the morph table
    if (kfSkelAnime->morphFrames != 0.0f) {
        outputValues = (s16*)kfSkelAnime->morphTable;
    } else {
        outputValues = (s16*)kfSkelAnime->jointTable;
    }

    // Array of preset values to pull from
    fixedValues = Lib_SegmentedToVirtual(kfSkelAnime->animation->fixedValues);

    // Array of number of keyframes belonging to each limb
    kfNums = Lib_SegmentedToVirtual(kfSkelAnime->animation->kfNums);

    // Array of keyframes, ordered by frame number
    keyFrames = Lib_SegmentedToVirtual(kfSkelAnime->animation->keyFrames);

    // The bitFlags array indicates whether a transformation on an axis should interpolate a value (if the bit is set)
    // or pull from an array of constant values (if the bit is unset) if the transformation on an axis does not change
    // during the animtion. For the flex-type keyframe skeletons the flags for each limb are contained in 16 bits.
    // The bitFlags layout for the flex-type keyframe skeletons is the same for all limbs:
    //  [8] : Scale x
    //  [7] : Scale y
    //  [6] : Scale z
    //  [5] : Rotate x
    //  [4] : Rotate y
    //  [3] : Rotate z
    //  [2] : Translate x
    //  [1] : Translate y
    //  [0] : Translate z
    bitFlags = Lib_SegmentedToVirtual(kfSkelAnime->animation->bitFlags.flex);

    // For each limb
    for (limbIndex = 0; limbIndex < kfSkelAnime->skeleton->limbCount; limbIndex++) {
        bit = 1 << (3 * 3 - 1);

        // 3 iter (scale, rotate, translate)
        for (i = 0; i < 3; i++) {
            // 3 iter (x, y, z)
            for (j = 0; j < 3; j++) {
                if (bitFlags[limbIndex] & bit) {
                    // If the bit is set, interpolate with keyframes
                    *outputValues = Keyframe_KeyCalc(kfStart, kfNums[kfn], keyFrames, kfSkelAnime->frameCtrl.curTime);
                    kfStart += kfNums[kfn];
                    kfn++;
                } else {
                    // If the bit is not set, pull from preset values
                    *outputValues = fixedValues[fixedValueIndex];
                    fixedValueIndex++;
                }
                bit >>= 1;

                if (i == 1) {
                    // For rotations, translate angle value from tenths of a degree to binang
                    *outputValues = DEG_TO_BINANG(FMOD(*outputValues * 0.1f, 360));
                }
                outputValues++;
            }
        }
    }

    if (IS_ZERO(kfSkelAnime->morphFrames)) {
        // No morph, just play the animation
        return FrameCtrl_Update(&kfSkelAnime->frameCtrl);
    } else if (kfSkelAnime->morphFrames > 0.0f) {
        // Morph to first frame before playing the animation proper
        Keyframe_FlexMorphInterpolation(kfSkelAnime);
        kfSkelAnime->morphFrames -= 1.0f;
        if (kfSkelAnime->morphFrames <= 0.0f) {
            kfSkelAnime->morphFrames = 0.0f;
        }
        return KEYFRAME_NOT_DONE;
    } else {
        // Play the animation immediately, morphing as it plays
        Keyframe_FlexMorphInterpolation(kfSkelAnime);
        kfSkelAnime->morphFrames += 1.0f;
        if (kfSkelAnime->morphFrames >= 0.0f) {
            kfSkelAnime->morphFrames = 0.0f;
        }
        return FrameCtrl_Update(&kfSkelAnime->frameCtrl);
    }
}

/**
 * Draws the limb specified by `limbIndex` of type `KeyFrameFlexLimb` belonging to a flex-type keyframe skeleton to the
 * display buffer specified by the limb's drawFlags.
 *
 * @param limbIndex Pointer to the index of the limb to draw
 * @param overrideKeyframeDraw Callback for before submitting the limb to be drawn. The matrix state will not include
 *                             the transformation for the current limb.
 * @param postKeyframeDraw Callback for after submitting the limb to be drawn. The matrix state will include
 *                         the transformation for the current limb.
 * @param arg An arbitrary argument to pass to the callbacks.
 * @param mtxStack Matrix stack for limb transformations. Should have enough room for one matrix per limb.
 *
 * @note Original name unknown
 */
void Keyframe_DrawFlexLimb(PlayState* play, KFSkelAnimeFlex* kfSkelAnime, s32* limbIndex,
                           OverrideKeyframeDrawScaled overrideKeyframeDraw, PostKeyframeDrawScaled postKeyframeDraw,
                           void* arg, Mtx** mtxStack) {
    KeyFrameFlexLimb* limb = Lib_SegmentedToVirtual(kfSkelAnime->skeleton->limbs);
    s32 i;
    Gfx* newDList;
    Gfx* limbDList;
    u8 drawFlags;
    Vec3f scale;
    Vec3s rot;
    Vec3f pos;
    Vec3s* jointData;

    OPEN_DISPS(play->state.gfxCtx);

    limb += *limbIndex;
    jointData = &kfSkelAnime->jointTable[*limbIndex * 3];

    scale.x = jointData->x * 0.01f;
    scale.y = jointData->y * 0.01f;
    scale.z = jointData->z * 0.01f;

    jointData++;

    rot.x = jointData->x;
    rot.y = jointData->y;
    rot.z = jointData->z;

    jointData++;

    pos.x = jointData->x;
    pos.y = jointData->y;
    pos.z = jointData->z;

    Matrix_Push();

    newDList = limbDList = limb->dList;
    drawFlags = limb->drawFlags;

    if (overrideKeyframeDraw == NULL ||
        (overrideKeyframeDraw != NULL &&
         overrideKeyframeDraw(play, kfSkelAnime, *limbIndex, &newDList, &drawFlags, arg, &scale, &rot, &pos))) {
        if ((kfSkelAnime->transformCallbacks == NULL) || (limb->callbackIndex == KF_CALLBACK_INDEX_NONE) ||
            (kfSkelAnime->transformCallbacks[limb->callbackIndex] == NULL) ||
            kfSkelAnime->transformCallbacks[limb->callbackIndex](play, kfSkelAnime, *limbIndex, &newDList, &drawFlags,
                                                                 arg)) {

            Matrix_TranslateRotateZYX(&pos, &rot);

            if (scale.x != 1.0f || scale.y != 1.0f || scale.z != 1.0f) {
                Matrix_Scale(scale.x, scale.y, scale.z, MTXMODE_APPLY);
            }

            if (newDList != NULL) {
                Matrix_ToMtx(*mtxStack);

                if (drawFlags & KEYFRAME_DRAW_XLU) {
                    gSPMatrix(POLY_XLU_DISP++, *mtxStack, G_MTX_NOPUSH | G_MTX_LOAD | G_MTX_MODELVIEW);
                    gSPDisplayList(POLY_XLU_DISP++, newDList);
                } else {
                    gSPMatrix(POLY_OPA_DISP++, *mtxStack, G_MTX_NOPUSH | G_MTX_LOAD | G_MTX_MODELVIEW);
                    gSPDisplayList(POLY_OPA_DISP++, newDList);
                }

                (*mtxStack)++;
            } else if (limbDList != NULL) {
                gSPMatrix(POLY_OPA_DISP++, *mtxStack, G_MTX_NOPUSH | G_MTX_LOAD | G_MTX_MODELVIEW);
                Matrix_ToMtx(*mtxStack);

                (*mtxStack)++;
            }
        }
    }

    if (postKeyframeDraw != NULL) {
        postKeyframeDraw(play, kfSkelAnime, *limbIndex, &newDList, &drawFlags, arg, &scale, &rot, &pos);
    }

    (*limbIndex)++;

    for (i = 0; i < limb->numChildren; i++) {
        Keyframe_DrawFlexLimb(play, kfSkelAnime, limbIndex, overrideKeyframeDraw, postKeyframeDraw, arg, mtxStack);
    }

    Matrix_Pop();
    CLOSE_DISPS(play->state.gfxCtx);
}

/**
 * Draws a flex-type keyframe skeleton in its current pose.
 *
 * @param mtxStack Matrix stack for limb transformations. Should have enough room for one matrix per limb.
 * @param overrideKeyframeDraw Callback for before submitting the limb to be drawn. The matrix state will not include
 *                             the transformation for the current limb.
 * @param postKeyframeDraw Callback for after submitting the limb to be drawn. The matrix state will include
 *                         the transformation for the current limb.
 * @param arg An arbitrary argument to pass to the callbacks.
 *
 * @note Original name unknown
 */
void Keyframe_DrawFlex(PlayState* play, KFSkelAnimeFlex* kfSkelAnime, Mtx* mtxStack,
                       OverrideKeyframeDrawScaled overrideKeyframeDraw, PostKeyframeDrawScaled postKeyframeDraw,
                       void* arg) {
    s32 limbIndex;

    if (mtxStack == NULL) {
        return;
    }

    OPEN_DISPS(play->state.gfxCtx);

    gSPSegment(POLY_OPA_DISP++, 0x0D, mtxStack);
    gSPSegment(POLY_XLU_DISP++, 0x0D, mtxStack);

    limbIndex = 0;
    Keyframe_DrawFlexLimb(play, kfSkelAnime, &limbIndex, overrideKeyframeDraw, postKeyframeDraw, arg, &mtxStack);

    CLOSE_DISPS(play->state.gfxCtx);
}

/**
 * @note Original name: cKF_SkeletonInfo_R_zeroClear
 */
void Keyframe_ResetStandard(KFSkelAnime* kfSkelAnime) {
    kfSkelAnime->skeleton = NULL;
    kfSkelAnime->animation = NULL;
    kfSkelAnime->jointTable = NULL;
    kfSkelAnime->morphTable = NULL;
    kfSkelAnime->rotOffsetsTable = NULL;
    kfSkelAnime->morphFrames = 0.0f;
}

/**
 * Initializes a standard-type keyframe skeleton. The initial animation type is KEYFRAME_ANIM_ONCE.
 *
 * @param skeleton Skeleton to animate
 * @param animation Initial animation to use
 * @param jointTable Joint table to store limb transformations. Should have enough space to store a root translation
 *                   plus a limb rotation for all limbs in the skeleton.
 * @param morphTable Joint table to store morph interpolation values. Should have enough space to store a root
 *                   translation plus a limb rotation for all limbs in the skeleton.
 *
 * @note Original name: cKF_SkeletonInfo_R_ct
 */
void Keyframe_InitStandard(KFSkelAnime* kfSkelAnime, KeyFrameSkeleton* skeleton, KeyFrameAnimation* animation,
                           Vec3s* jointTable, Vec3s* morphTable) {
    Keyframe_ResetStandard(kfSkelAnime);
    FrameCtrl_Init(&kfSkelAnime->frameCtrl);
    kfSkelAnime->skeleton = Lib_SegmentedToVirtual(skeleton);
    kfSkelAnime->animation = Lib_SegmentedToVirtual(animation);
    kfSkelAnime->jointTable = jointTable;
    kfSkelAnime->morphTable = morphTable;
}

/**
 * Destroys a standard-type keyframe skeleton.
 *
 * @note Original name: cKF_SkeletonInfo_R_dt
 */
void Keyframe_DestroyStandard(KFSkelAnime* kfSkelAnime) {
}

void Keyframe_StandardChangeAnim(KFSkelAnime* kfSkelAnime, KeyFrameSkeleton* skeleton, KeyFrameAnimation* animation,
                                 f32 startTime, f32 endTime, f32 t, f32 speed, f32 morphFrames, s32 animMode,
                                 Vec3s* rotOffsetsTable);

/**
 * Immediately changes to an animation that plays once from start to end at the default speed.
 *
 * @param animation Animation data to switch to
 * @param rotOffsetsTable Table of length `skeleton->limbCount` containing rotations to add to every pose of the
 *                        animation.
 *
 * @note Original name: cKF_SkeletonInfo_R_init_standard_stop
 */
void Keyframe_StandardPlayOnce(KFSkelAnime* kfSkelAnime, KeyFrameAnimation* animation, Vec3s* rotOffsetsTable) {
    Keyframe_StandardChangeAnim(kfSkelAnime, kfSkelAnime->skeleton, animation, 1.0f,
                                ((KeyFrameAnimation*)Lib_SegmentedToVirtual(animation))->frameCount, 1.0f, 1.0f, 0.0f,
                                KEYFRAME_ANIM_ONCE, rotOffsetsTable);
}

/**
 * Immediately changes to an animation that plays once from start to end at the specified speed.
 *
 * @param animation Animation data to switch to
 * @param rotOffsetsTable Table of length `skeleton->limbCount` containing rotations to add to every pose of the
 *                        animation.
 * @param speed Playback speed
 *
 * @note Original name: cKF_SkeletonInfo_R_init_standard_stop_speedset
 */
void Keyframe_StandardPlayOnceSetSpeed(KFSkelAnime* kfSkelAnime, KeyFrameAnimation* animation, Vec3s* rotOffsetsTable,
                                       f32 speed) {
    Keyframe_StandardChangeAnim(kfSkelAnime, kfSkelAnime->skeleton, animation, 1.0f,
                                ((KeyFrameAnimation*)Lib_SegmentedToVirtual(animation))->frameCount, 1.0f, speed, 0.0f,
                                KEYFRAME_ANIM_ONCE, rotOffsetsTable);
}

/**
 * Smoothly transitions to an animation that plays once from start to end at the default speed.
 *
 * @param animation Animation data to switch to
 * @param rotOffsetsTable Table of length `skeleton->limbCount` containing rotations to add to every pose of the
 *                        animation.
 * @param morphFrames Number of frames to take to transition from the previous pose to the new animation. Positive morph
 *                    frames morph from the current pose to the start pose of the new animation, then start the new
 *                    animation. Negative morph frames start the new animation immediately, modified by the pose
 *                    immediately before the animation change.
 *
 * @note Original name: cKF_SkeletonInfo_R_init_standard_stop_morph
 */
void Keyframe_StandardMorphToPlayOnce(KFSkelAnime* kfSkelAnime, KeyFrameAnimation* animation, Vec3s* rotOffsetsTable,
                                      f32 morphFrames) {
    Keyframe_StandardChangeAnim(kfSkelAnime, kfSkelAnime->skeleton, animation, 1.0f,
                                ((KeyFrameAnimation*)Lib_SegmentedToVirtual(animation))->frameCount, 1.0f, 1.0f,
                                morphFrames, KEYFRAME_ANIM_ONCE, rotOffsetsTable);
}

/**
 * Immediately changes to an animation that loops at the default.
 *
 * @param animation Animation data to switch to
 * @param rotOffsetsTable Table of length `skeleton->limbCount` containing rotations to add to every pose of the
 *                        animation.
 *
 * @note Original name: cKF_SkeletonInfo_R_init_standard_repeat
 */
void Keyframe_StandardPlayLoop(KFSkelAnime* kfSkelAnime, KeyFrameAnimation* animation, Vec3s* rotOffsetsTable) {
    Keyframe_StandardChangeAnim(kfSkelAnime, kfSkelAnime->skeleton, animation, 1.0f,
                                ((KeyFrameAnimation*)Lib_SegmentedToVirtual(animation))->frameCount, 1.0f, 1.0f, 0.0f,
                                KEYFRAME_ANIM_LOOP, rotOffsetsTable);
}

/**
 * Immediately changes to an animation that loops over start to end at the specified speed.
 *
 * @param animation Animation data to switch to
 * @param rotOffsetsTable Table of length `skeleton->limbCount` containing rotations to add to every pose of the
 *                        animation.
 * @param speed Playback speed
 *
 * @note Original name: cKF_SkeletonInfo_R_init_standard_repeat_speedset
 */
void Keyframe_StandardPlayLoopSetSpeed(KFSkelAnime* kfSkelAnime, KeyFrameAnimation* animation, Vec3s* rotOffsetsTable,
                                       f32 speed) {
    Keyframe_StandardChangeAnim(kfSkelAnime, kfSkelAnime->skeleton, animation, 1.0f,
                                ((KeyFrameAnimation*)Lib_SegmentedToVirtual(animation))->frameCount, 1.0f, speed, 0.0f,
                                KEYFRAME_ANIM_LOOP, rotOffsetsTable);
}

/**
 * Smoothly transitions to an animation that loops over start to end at the default speed, specifying the number of
 * frames for the transition.
 *
 * @param animation Animation data to switch to
 * @param rotOffsetsTable Table of length `skeleton->limbCount` containing rotations to add to every pose of the
 *                        animation.
 * @param morphFrames Number of frames to take to transition from the previous pose to the new animation. Positive morph
 *                    frames morph from the current pose to the start pose of the new animation, then start the new
 *                    animation. Negative morph frames start the new animation immediately, modified by the pose
 *                    immediately before the animation change.
 *
 * @note Original name: cKF_SkeletonInfo_R_init_standard_repeat_morph
 */
void Keyframe_StandardMorphToPlayLoop(KFSkelAnime* kfSkelAnime, KeyFrameAnimation* animation, Vec3s* rotOffsetsTable,
                                      f32 morphFrames) {
    Keyframe_StandardChangeAnim(kfSkelAnime, kfSkelAnime->skeleton, animation, 1.0f,
                                ((KeyFrameAnimation*)Lib_SegmentedToVirtual(animation))->frameCount, 1.0f, 1.0f,
                                morphFrames, KEYFRAME_ANIM_LOOP, rotOffsetsTable);
}

/**
 * General way to set a new animation for standard-type skeletons, allowing choice of playback speed, start/end loop
 * points, start time, play mode, and number of transition frames.
 *
 * Time parameters are valid from 0 to the last frame of the animation.
 *
 * @param skeleton Skeleton that will be animated
 * @param animation Animation data to switch to
 * @param startTime Loop start time
 * @param endTime Loop end time, 0 indicates to use the animation length
 * @param t Playback start time
 * @param speed Playback speed
 * @param morphFrames Number of frames to take to transition from the previous pose to the new animation. Positive morph
 *                    frames morph from the current pose to the start pose of the new animation, then start the new
 *                    animation. Negative morph frames start the new animation immediately, modified by the pose
 *                    immediately before the animation change.
 * @param animMode Animation play mode, see KeyFrameAnimMode enum
 * @param rotOffsetsTable Table of length `skeleton->limbCount` containing rotations to add to every pose of the
 *                        animation.
 *
 * @see KeyFrameAnimMode
 *
 * @note Original name: cKF_SkeletonInfo_R_init
 */
void Keyframe_StandardChangeAnim(KFSkelAnime* kfSkelAnime, KeyFrameSkeleton* skeleton, KeyFrameAnimation* animation,
                                 f32 startTime, f32 endTime, f32 t, f32 speed, f32 morphFrames, s32 animMode,
                                 Vec3s* rotOffsetsTable) {
    kfSkelAnime->morphFrames = morphFrames;
    kfSkelAnime->skeleton = Lib_SegmentedToVirtual(skeleton);
    kfSkelAnime->animation = Lib_SegmentedToVirtual(animation);

    FrameCtrl_SetProperties(&kfSkelAnime->frameCtrl, startTime, endTime, kfSkelAnime->animation->frameCount, t, speed,
                            animMode);
    kfSkelAnime->rotOffsetsTable = rotOffsetsTable;
}

/**
 * Switches to a new animation without changing any of the playback parameters.
 *
 * @param animation The animation to switch to
 *
 * @note Original name: cKF_SkeletonInfo_R_setAnim
 */
void Keyframe_StandardChangeAnimQuick(KFSkelAnime* kfSkelAnime, KeyFrameAnimation* animation) {
    kfSkelAnime->animation = Lib_SegmentedToVirtual(animation);
    kfSkelAnime->frameCtrl.frameCount = kfSkelAnime->animation->frameCount;
}

/**
 * Apply morph interpolation for the provided skeleton. Morph interpolation seeks to provide interpolation between
 * a previous animation and a new animation over a fixed period of time (morphFrames)
 *
 * @note Original name: cKF_SkeletonInfo_R_morphJoint
 */
void Keyframe_StandardMorphInterpolation(KFSkelAnime* kfSkelAnime) {
    Vec3s* jointTable = kfSkelAnime->jointTable;
    Vec3s* morphTable = kfSkelAnime->morphTable;
    f32 t = 1.0f / fabsf(kfSkelAnime->morphFrames);
    s32 limbIndex;

    // Interpolate root translation
    Keyframe_MorphInterpolateLinear((s16*)jointTable, (s16*)morphTable, t);
    jointTable++;
    morphTable++;

    for (limbIndex = 0; limbIndex < kfSkelAnime->skeleton->limbCount; limbIndex++) {
        Vec3s frameRot;
        Vec3s morphRot;

        frameRot.x = jointTable->x;
        frameRot.y = jointTable->y;
        frameRot.z = jointTable->z;

        morphRot.x = morphTable->x;
        morphRot.y = morphTable->y;
        morphRot.z = morphTable->z;

        // Interpolate rotation
        if (frameRot.x != morphRot.x || frameRot.y != morphRot.y || frameRot.z != morphRot.z) {
            Vec3s frameRotInv;
            f32 norm1;
            f32 norm2;

            frameRotInv.x = 0x7FFF + frameRot.x;
            frameRotInv.y = 0x7FFF - frameRot.y;
            frameRotInv.z = 0x7FFF + frameRot.z;

            // Compute L1 norms
            norm1 = fabsf((f32)morphRot.x - frameRot.x) + fabsf((f32)morphRot.y - frameRot.y) +
                    fabsf((f32)morphRot.z - frameRot.z);
            norm2 = fabsf((f32)morphRot.x - frameRotInv.x) + fabsf((f32)morphRot.y - frameRotInv.y) +
                    fabsf((f32)morphRot.z - frameRotInv.z);

            if (norm1 < norm2) {
                // frameRot is closer to morphRot than frameRotInv, interpolate between these two
                Keyframe_MorphInterpolateRotation(t, &jointTable->x, frameRot.x, morphRot.x);
                Keyframe_MorphInterpolateRotation(t, &jointTable->y, frameRot.y, morphRot.y);
                Keyframe_MorphInterpolateRotation(t, &jointTable->z, frameRot.z, morphRot.z);
            } else {
                // frameRotInv is closer to morphRot than frameRot, interpolate between these two
                Keyframe_MorphInterpolateRotation(t, &jointTable->x, frameRotInv.x, morphRot.x);
                Keyframe_MorphInterpolateRotation(t, &jointTable->y, frameRotInv.y, morphRot.y);
                Keyframe_MorphInterpolateRotation(t, &jointTable->z, frameRotInv.z, morphRot.z);
            }
        }
        morphTable++;
        jointTable++;
    }
}

/**
 * Advances the current animation and updates all frame tables for standard-type keyframe skeletons.
 *
 * @return s32
 *  KEYFRAME_NOT_DONE  : If the animation is still playing
 *  KEYFRAME_DONE_ONCE : If the animation was set to play once and has finished playing
 *  KEYFRAME_DONE_LOOP : If the animation was set to play in a loop and has finished a loop
 *
 * @note Original name: cKF_SkeletonInfo_R_play
 */
s32 Keyframe_UpdateStandard(KFSkelAnime* kfSkelAnime) {
    s32 limbIndex;
    u32 bit;
    u8* bitFlags;
    s32 i;
    s32 kfn = 0;
    s32 fixedValueIndex = 0;
    s32 kfStart = 0;
    s16* fixedValues;
    KeyFrame* keyFrames;
    s16* kfNums;
    s16* outputValues;

    // Choose which array to update, if currently morphing update the morph table else update the joint table
    if (kfSkelAnime->morphFrames != 0.0f) {
        outputValues = (s16*)kfSkelAnime->morphTable;
    } else {
        outputValues = (s16*)kfSkelAnime->jointTable;
    }

    fixedValues = Lib_SegmentedToVirtual(kfSkelAnime->animation->fixedValues);
    kfNums = Lib_SegmentedToVirtual(kfSkelAnime->animation->kfNums);
    keyFrames = Lib_SegmentedToVirtual(kfSkelAnime->animation->keyFrames);

    // The bitFlags array indicates whether a transformation on an axis should interpolate a value (if the bit is set)
    // or pull from an array of constant values (if the bit is unset) if the transformation on an axis does not change
    // during the animtion. For the standard-type keyframe skeletons the flags for each limb are contained in 8 bits.
    // The bitFlags layout for the standard-type keyframe skeletons is different for the root limb, which may have a
    // translation:
    // [5] = tx
    // [4] = ty
    // [3] = tz
    // [2] = rx
    // [1] = ry
    // [0] = rz
    // Otherwise, the layout only contains rotations:
    // [2] = rx
    // [1] = ry
    // [0] = rz
    bitFlags = Lib_SegmentedToVirtual(kfSkelAnime->animation->bitFlags.standard);

    // Interpolate translation for the root limb

    bit = 1 << (3 * 2 - 1);

    // 3 iter (x, y, z)
    for (i = 0; i < 3; i++) {
        if (bitFlags[0] & bit) {
            *outputValues = Keyframe_KeyCalc(kfStart, kfNums[kfn], keyFrames, kfSkelAnime->frameCtrl.curTime);
            kfStart += kfNums[kfn++];
        } else {
            *outputValues = fixedValues[fixedValueIndex++];
        }
        bit >>= 1;
        outputValues++;
    }

    // Update rotation for all limbs

    for (limbIndex = 0; limbIndex < kfSkelAnime->skeleton->limbCount; limbIndex++) {
        bit = 1 << (3 - 1);

        // 3 iter (x, y, z)
        for (i = 0; i < 3; i++) {
            s32 pad;

            if (bitFlags[limbIndex] & bit) {
                *outputValues = Keyframe_KeyCalc(kfStart, kfNums[kfn], keyFrames, kfSkelAnime->frameCtrl.curTime);
                kfStart += kfNums[kfn++];
            } else {
                *outputValues = fixedValues[fixedValueIndex++];
            }
            bit >>= 1;

            // Translate angle value from tenths of a degree to binang
            *outputValues = DEG_TO_BINANG(FMOD(*outputValues * 0.1f, 360));
            outputValues++;
        }
    }

    if (kfSkelAnime->rotOffsetsTable != NULL) {
        Vec3s* table;

        if (kfSkelAnime->morphFrames != 0.0f) {
            table = kfSkelAnime->morphTable;
        } else {
            table = kfSkelAnime->jointTable;
        }
        table++; // Skip root translation

        // Add all offsets to rotations
        for (limbIndex = 0; limbIndex < kfSkelAnime->skeleton->limbCount; limbIndex++, table++) {
            table->x = table->x + kfSkelAnime->rotOffsetsTable[limbIndex].x;
            table->y = table->y + kfSkelAnime->rotOffsetsTable[limbIndex].y;
            table->z = table->z + kfSkelAnime->rotOffsetsTable[limbIndex].z;
        }
    }

    if (IS_ZERO(kfSkelAnime->morphFrames)) {
        // No morph, just play the animation
        return FrameCtrl_Update(&kfSkelAnime->frameCtrl);
    } else if (kfSkelAnime->morphFrames > 0.0f) {
        // Morph to first frame before playing the animation proper
        Keyframe_StandardMorphInterpolation(kfSkelAnime);
        kfSkelAnime->morphFrames -= 1.0f;
        if (kfSkelAnime->morphFrames <= 0.0f) {
            kfSkelAnime->morphFrames = 0.0f;
        }
        return KEYFRAME_NOT_DONE;
    } else {
        // Play the animation immediately, morphing as it plays
        Keyframe_StandardMorphInterpolation(kfSkelAnime);
        kfSkelAnime->morphFrames += 1.0f;
        if (kfSkelAnime->morphFrames >= 0.0f) {
            kfSkelAnime->morphFrames = 0.0f;
        }
        return FrameCtrl_Update(&kfSkelAnime->frameCtrl);
    }
}

/**
 * Draws the limb specified by `limbIndex` of type `KeyFrameStandardLimb` belonging to a standard-type keyframe skeleton
 * to the display buffer specified by the limb's drawFlags.
 *
 * @param limbIndex Pointer to the index of the limb to draw
 * @param overrideKeyframeDraw Callback for before submitting the limb to be drawn. The matrix state will not include
 *                             the transformation for the current limb.
 * @param postKeyframeDraw Callback for after submitting the limb to be drawn. The matrix state will include
 *                         the transformation for the current limb.
 * @param arg An arbitrary argument to pass to the callbacks.
 * @param mtxStack Matrix stack for limb transformations. Should have enough room for one matrix per limb.
 *
 * @note Original name: cKF_Si3_draw_SV_R_child
 */
void Keyframe_DrawStandardLimb(PlayState* play, KFSkelAnime* kfSkelAnime, s32* limbIndex,
                               OverrideKeyframeDraw overrideKeyframeDraw, PostKeyframeDraw postKeyframeDraw, void* arg,
                               Mtx** mtxStack) {
    KeyFrameStandardLimb* limb =
        *limbIndex + (KeyFrameStandardLimb*)Lib_SegmentedToVirtual(kfSkelAnime->skeleton->limbs);
    s32 i;
    Gfx* newDList;
    Gfx* limbDList;
    u8 drawFlags;
    Vec3s rot;
    Vec3s* jointData = &kfSkelAnime->jointTable[*limbIndex];
    Vec3f pos;

    if (*limbIndex != 0) {
        pos.x = limb->jointPos.x;
        pos.y = limb->jointPos.y;
        pos.z = limb->jointPos.z;
    } else {
        pos.x = jointData->x;
        pos.y = jointData->y;
        pos.z = jointData->z;
    }

    jointData++;

    rot.x = jointData->x;
    rot.y = jointData->y;
    rot.z = jointData->z;

    OPEN_DISPS(play->state.gfxCtx);

    Matrix_Push();

    newDList = limbDList = limb->dList;
    drawFlags = limb->drawFlags;

    if (overrideKeyframeDraw == NULL ||
        (overrideKeyframeDraw != NULL &&
         overrideKeyframeDraw(play, kfSkelAnime, *limbIndex, &newDList, &drawFlags, arg, &rot, &pos))) {

        Matrix_TranslateRotateZYX(&pos, &rot);

        if (newDList != NULL) {
            Matrix_ToMtx(*mtxStack);

            if (drawFlags & KEYFRAME_DRAW_XLU) {
                gSPMatrix(POLY_XLU_DISP++, *mtxStack, G_MTX_NOPUSH | G_MTX_LOAD | G_MTX_MODELVIEW);
                gSPDisplayList(POLY_XLU_DISP++, newDList);
            } else {
                gSPMatrix(POLY_OPA_DISP++, *mtxStack, G_MTX_NOPUSH | G_MTX_LOAD | G_MTX_MODELVIEW);
                gSPDisplayList(POLY_OPA_DISP++, newDList);
            }
            (*mtxStack)++;
        } else if (limbDList != NULL) {
            Matrix_ToMtx(*mtxStack);

            gSPMatrix(POLY_OPA_DISP++, *mtxStack, G_MTX_NOPUSH | G_MTX_LOAD | G_MTX_MODELVIEW);
            (*mtxStack)++;
        }
    }

    if (postKeyframeDraw != NULL) {
        postKeyframeDraw(play, kfSkelAnime, *limbIndex, &newDList, &drawFlags, arg, &rot, &pos);
    }

    (*limbIndex)++;

    for (i = 0; i < limb->numChildren; i++) {
        Keyframe_DrawStandardLimb(play, kfSkelAnime, limbIndex, overrideKeyframeDraw, postKeyframeDraw, arg, mtxStack);
    }

    Matrix_Pop();

    CLOSE_DISPS(play->state.gfxCtx);
}

/**
 * Draws a standard-type keyframe skeleton in its current pose.
 *
 * @param mtxStack Matrix stack for limb transformations. Should have enough room for one matrix per limb.
 * @param overrideKeyframeDraw Callback for before submitting the limb to be drawn. The matrix state will not include
 *                             the transformation for the current limb.
 * @param postKeyframeDraw Callback for after submitting the limb to be drawn. The matrix state will include
 *                         the transformation for the current limb.
 * @param arg An arbitrary argument to pass to the callbacks.
 *
 * @note Original name: cKF_Si3_draw_R_SV
 */
void Keyframe_DrawStandard(PlayState* play, KFSkelAnime* kfSkelAnime, Mtx* mtxStack,
                           OverrideKeyframeDraw overrideKeyframeDraw, PostKeyframeDraw postKeyframeDraw, void* arg) {
    s32 limbIndex;

    if (mtxStack == NULL) {
        return;
    }

    OPEN_DISPS(play->state.gfxCtx);

    gSPSegment(POLY_OPA_DISP++, 0x0D, mtxStack);
    gSPSegment(POLY_XLU_DISP++, 0x0D, mtxStack);

    limbIndex = 0;
    Keyframe_DrawStandardLimb(play, kfSkelAnime, &limbIndex, overrideKeyframeDraw, postKeyframeDraw, arg, &mtxStack);

    CLOSE_DISPS(play->state.gfxCtx);
}

/**
 * Extracts the x,y,z scales for the limb `targetLimbIndex` for the current pose from a flex-type keyframe skeleton.
 *
 * The output scale values are quantized, that is they have been multiplied by 100 and rounded to an integer. To get
 * the scale values in coordinate units, multiply the result by 0.01.
 *
 * @param targetLimbIndex The limb index for which to extract the scale for
 * @param scale Vec3s of the x,y,z scale for the chosen limb
 *
 * @note Original name unknown
 */
void Keyframe_FlexGetScale(KFSkelAnimeFlex* kfSkelAnime, s32 targetLimbIndex, Vec3s* scale) {
    s16* kfNums;
    s32 i;
    s32 kfn = 0;
    s32 fixedValueIndex = 0;
    s32 kfStart = 0;
    s32 j;
    u16* bitFlags;
    s16* scaleArray = (s16*)scale;
    s16* fixedValues;
    KeyFrame* keyFrames;
    s32 limbIndex;

    fixedValues = Lib_SegmentedToVirtual(kfSkelAnime->animation->fixedValues);
    kfNums = Lib_SegmentedToVirtual(kfSkelAnime->animation->kfNums);
    keyFrames = Lib_SegmentedToVirtual(kfSkelAnime->animation->keyFrames);
    bitFlags = Lib_SegmentedToVirtual(kfSkelAnime->animation->bitFlags.flex);

    for (limbIndex = 0; limbIndex < kfSkelAnime->skeleton->limbCount; limbIndex++) {
        u32 bit = 1 << (3 * 3 - 1);

        // 3 iter (scale, rotation, translation)
        for (i = 0; i < 3; i++) {
            if ((limbIndex == targetLimbIndex) && (i == 0)) {
                // Is the target limb and is scale data, compute and write out scale values for each axis
                // 3 iter (x, y, z)
                for (j = 0; j < 3; j++) {
                    if (bitFlags[limbIndex] & bit) {
                        *scaleArray = Keyframe_KeyCalc(kfStart, kfNums[kfn], keyFrames, kfSkelAnime->frameCtrl.curTime);
                        kfStart += kfNums[kfn];
                        kfn++;
                    } else {
                        *scaleArray = fixedValues[fixedValueIndex];
                        fixedValueIndex++;
                    }
                    bit >>= 1;
                    scaleArray++;
                }
            } else {
                // Not the target limb or scale data, step over values
                // 3 iter (x, y, z)
                for (j = 0; j < 3; j++) {
                    if (bitFlags[limbIndex] & bit) {
                        kfStart += kfNums[kfn];
                        kfn++;
                    } else {
                        fixedValueIndex++;
                    }
                    bit >>= 1;
                }
            }
        }
    }
}