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Bezier fixes #90

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6f6d7e4
Bezier fixes
ZigyTheBird Jan 2, 2026
37599c6
Update AnimationLoader.java
ZigyTheBird Jan 8, 2026
f1e35bd
Truly fix bezier
ZigyTheBird Feb 17, 2026
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2 changes: 1 addition & 1 deletion core/src/main/java/com/zigythebird/playeranimcore/bones/PlayerAnimBone.java
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Original file line number Diff line number Diff line change
Expand Up @@ -432,7 +432,7 @@ private float beginOrEndTickLerp(float startValue, float endValue, Float transit
if (!keyFrames.isEmpty()) easingType = keyFrames.getLast().easingType();
}
}
if (easingType == EasingType.BEZIER || easingType == EasingType.BEZIER_AFTER || easingType == EasingType.CATMULLROM)
if (easingType == EasingType.BEZIER || easingType == EasingType.CATMULLROM)
easingType = EasingType.EASE_IN_OUT_SINE;
}
if (transitionLength == null) return endValue;
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188 changes: 97 additions & 91 deletions core/src/main/java/com/zigythebird/playeranimcore/easing/BezierEasing.java
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Expand Up @@ -11,125 +11,131 @@
import java.util.ArrayList;
import java.util.List;

abstract class BezierEasing implements EasingTypeTransformer {
public class BezierEasing implements EasingTypeTransformer {
@Override
public Float2FloatFunction buildTransformer(@Nullable Float value) {
return EasingType.easeIn(EasingType::linear);
}

abstract boolean isEasingBefore();

@Override
public float apply(MochaEngine<?> env, AnimationPoint animationPoint, @Nullable Float easingValue, float lerpValue) {
List<List<Expression>> easingArgs = animationPoint.easingArgs();
if (easingArgs.isEmpty())
return MochaMath.lerp(animationPoint.animationStartValue(), animationPoint.animationEndValue(), buildTransformer(easingValue).apply(lerpValue));

float rightValue = isEasingBefore() ? 0 : env.eval(easingArgs.getFirst());
float rightTime = isEasingBefore() ? 0.1f : env.eval(easingArgs.get(1));
float leftValue = isEasingBefore() ? env.eval(easingArgs.getFirst()) : 0;
float leftTime = isEasingBefore() ? env.eval(easingArgs.get(1)) : -0.1f;
float rightValue;
float rightTime;
float leftValue = env.eval(easingArgs.getFirst());
float leftTime = env.eval(easingArgs.get(1));

if (easingArgs.size() > 3) {
rightValue = env.eval(easingArgs.get(2));
rightTime = env.eval(easingArgs.get(3));
}

leftValue = (float) Math.toRadians(leftValue);
rightValue = (float) Math.toRadians(rightValue);

float gapTime = animationPoint.transitionLength()/20;

float time_handle_before = Math.clamp(rightTime, 0, gapTime);
float time_handle_after = Math.clamp(leftTime, -gapTime, 0);

CubicBezierCurve curve = new CubicBezierCurve(
new ModVector2d(0, animationPoint.animationStartValue()),
new ModVector2d(time_handle_before, animationPoint.animationStartValue() + rightValue),
new ModVector2d(time_handle_after + gapTime, animationPoint.animationEndValue() + leftValue),
new ModVector2d(gapTime, animationPoint.animationEndValue()));
float time = gapTime * lerpValue;

List<ModVector2d> points = curve.getPoints(200);
ModVector2d closest = new ModVector2d();
float closest_diff = Float.POSITIVE_INFINITY;
for (ModVector2d point : points) {
float diff = Math.abs(point.x - time);
if (diff < closest_diff) {
closest_diff = diff;
closest.set(point);
}
else {
rightValue = 0;
rightTime = 0.1f;
}
ModVector2d second_closest = new ModVector2d();
closest_diff = Float.POSITIVE_INFINITY;
for (ModVector2d point : points) {
if (point == closest) continue;
float diff = Math.abs(point.x - time);
if (diff < closest_diff) {
closest_diff = diff;
second_closest.set(closest);
second_closest.set(point);
}

float transitionLength = animationPoint.transitionLength()/20f;

float time_handle_before = Math.clamp(rightTime/transitionLength, 0, 1);
float time_handle_after = Math.clamp(leftTime/transitionLength, -1, 0);

ModVector2d P0 = new ModVector2d(0, animationPoint.animationStartValue());
ModVector2d P1 = new ModVector2d(time_handle_before, animationPoint.animationStartValue() + rightValue);
ModVector2d P2 = new ModVector2d(time_handle_after + 1, animationPoint.animationEndValue() + leftValue);
ModVector2d P3 = new ModVector2d(1, animationPoint.animationEndValue());

// Determine t
float t;
if (lerpValue == P0.x) {
// Handle corner cases explicitly to prevent rounding errors
t = 0;
} else if (lerpValue == P3.x) {
t = 1;
} else {
// Calculate t
float a = -P0.x + 3 * P1.x - 3 * P2.x + P3.x;
float b = 3 * P0.x - 6 * P1.x + 3 * P2.x;
float c = -3 * P0.x + 3 * P1.x;
float d = P0.x - lerpValue;
Float tTemp = SolveCubic(a, b, c, d);
if (tTemp == null) return animationPoint.animationEndValue();
t = tTemp;
}
return MochaMath.lerp(closest.y, second_closest.y, Math.clamp(MochaMath.lerp(closest.x, second_closest.x, time), 0, 1));
}
}

class BezierEasingBefore extends BezierEasing {
@Override
boolean isEasingBefore() {
return true;
// Calculate y from t
return Cubed(1 - t) * P0.y
+ 3 * t * Squared(1 - t) * P1.y
+ 3 * Squared(t) * (1 - t) * P2.y
+ Cubed(t) * P3.y;
}
}

class BezierEasingAfter extends BezierEasing {
@Override
boolean isEasingBefore() {
return false;
}
}

class CubicBezierCurve {
private ModVector2d v0;
private ModVector2d v1;
private ModVector2d v2;
private ModVector2d v3;

public CubicBezierCurve(ModVector2d v0, ModVector2d v1, ModVector2d v2, ModVector2d v3) {
this.v0 = v0;
this.v1 = v1;
this.v2 = v2;
this.v3 = v3;
}
// Solves the equation ax³+bx²+cx+d = 0 for x ϵ ℝ
// and returns the first result in [0, 1] or null.
private static Float SolveCubic(float a, float b, float c, float d) {
if (a == 0) return SolveQuadratic(b, c, d);
if (d == 0) return 0f;

b /= a;
c /= a;
d /= a;
float q = (3 * c - Squared(b)) / 9;
float r = (-27 * d + b * (9 * c - 2 * Squared(b))) / 54;
float disc = Cubed(q) + Squared(r);
float term1 = b / 3;

if (disc > 0) {
float s = (float) (r + Math.sqrt(disc));
s = (s < 0) ? -CubicRoot(-s) : CubicRoot(s);
float t = (float) (r - Math.sqrt(disc));
t = (t < 0) ? -CubicRoot(-t) : CubicRoot(t);

float result = -term1 + s + t;
if (result >= 0 && result <= 1) return result;
} else if (disc == 0) {
float r13 = (r < 0) ? -CubicRoot(-r) : CubicRoot(r);

float result = -term1 + 2 * r13;
if (result >= 0 && result <= 1) return result;

result = -(r13 + term1);
if (result >= 0 && result <= 1) return result;
} else {
q = -q;
float dum1 = q * q * q;
dum1 = (float) Math.acos(r / Math.sqrt(dum1));
float r13 = (float) (2 * Math.sqrt(q));

float result = (float) (-term1 + r13 * Math.cos(dum1 / 3));
if (result >= 0 && result <= 1) return result;

result = (float) (-term1 + r13 * Math.cos((dum1 + 2 * Math.PI) / 3));
if (result >= 0 && result <= 1) return result;

result = (float) (-term1 + r13 * Math.cos((dum1 + 4 * Math.PI) / 3));
if (result >= 0 && result <= 1) return result;
}

public ModVector2d getPoint(float t) {
return getPoint(t, new ModVector2d());
return null;
}

public ModVector2d getPoint(float t, ModVector2d target) {
if (target == null) {
target = new ModVector2d();
}

float u = 1 - t;
float tt = t * t;
float uu = u * u;
float uuu = uu * u;
float ttt = tt * t;
// Solves the equation ax² + bx + c = 0 for x ϵ ℝ
// and returns the first result in [0, 1] or null.
private static Float SolveQuadratic(float a, float b, float c) {
float result = (float) ((-b + Math.sqrt(Squared(b) - 4 * a * c)) / (2 * a));
if (result >= 0 && result <= 1) return result;

target.x = uuu * v0.x + 3 * uu * t * v1.x + 3 * u * tt * v2.x + ttt * v3.x;
target.y = uuu * v0.y + 3 * uu * t * v1.y + 3 * u * tt * v2.y + ttt * v3.y;
result = (float) ((-b - Math.sqrt(Squared(b) - 4 * a * c)) / (2 * a));
if (result >= 0 && result <= 1) return result;

return target;
return null;
}

public List<ModVector2d> getPoints(int divisions) {
List<ModVector2d> points = new ArrayList<>();
private static float Squared(float f) { return f * f; }

for (int i = 0; i <= divisions; i++) {
points.add(getPoint((float) i / divisions));
}
private static float Cubed(float f) { return f * f * f; }

return points;
}
private static float CubicRoot(float f) { return (float) Math.pow(f, 1.0 / 3.0); }
}
3 changes: 1 addition & 2 deletions core/src/main/java/com/zigythebird/playeranimcore/easing/EasingType.java
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Original file line number Diff line number Diff line change
Expand Up @@ -70,8 +70,7 @@ public enum EasingType implements EasingTypeTransformer {
CATMULLROM(36, "catmullrom", new CatmullRomEasing()),
// 37 - STEP

BEZIER(38, "bezier", new BezierEasingBefore()),
BEZIER_AFTER(39, "bezier_after", new BezierEasingAfter());
BEZIER(38, "bezier", new BezierEasing());

public final byte id;
public final String name;
Expand Down
35 changes: 29 additions & 6 deletions core/src/main/java/com/zigythebird/playeranimcore/loading/AnimationLoader.java
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Original file line number Diff line number Diff line change
Expand Up @@ -43,13 +43,16 @@
import team.unnamed.mocha.parser.ast.Expression;
import team.unnamed.mocha.parser.ast.FloatExpression;
import team.unnamed.mocha.parser.ast.IdentifierExpression;
import team.unnamed.mocha.runtime.IsConstantExpression;

import java.lang.reflect.Type;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import static com.zigythebird.playeranimcore.molang.MolangLoader.MOCHA_ENGINE;

public class AnimationLoader implements JsonDeserializer<Animation> {
@Override
public Animation deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {
Expand Down Expand Up @@ -274,7 +277,7 @@ private static KeyframeStack buildKeyframeStack(List<FloatObjectPair<JsonElement
prevEntry = entry;
}

return new KeyframeStack(addArgsForKeyframes(xFrames), addArgsForKeyframes(yFrames), addArgsForKeyframes(zFrames));
return new KeyframeStack(addArgsForKeyframes(xFrames, type), addArgsForKeyframes(yFrames, type), addArgsForKeyframes(zFrames, type));
}

private static EasingType getEasingForAxis(JsonObject entryObj, Axis axis, EasingType easingType) {
Expand All @@ -291,7 +294,7 @@ private static List<List<Expression>> getEasingArgsForAxis(JsonObject entryObj,
easingArg;
}

private static List<Keyframe> addArgsForKeyframes(List<Keyframe> frames) {
private static List<Keyframe> addArgsForKeyframes(List<Keyframe> frames, TransformType type) {
if (frames.getFirst().startValue().getFirst() instanceof AccessExpression accessExpression
&& "disabled".equals(accessExpression.property()) && accessExpression.object() instanceof IdentifierExpression identifierExpression
&& "pal".equals(identifierExpression.name()))
Expand All @@ -317,24 +320,44 @@ private static List<Keyframe> addArgsForKeyframes(List<Keyframe> frames) {
)));
}
else if (frame.easingType() == EasingType.BEZIER) {
List<Expression> leftValue = frame.easingArgs().getFirst();
List<Expression> rightValue = frame.easingArgs().get(2);
List<Expression> rightTime = frame.easingArgs().get(3);
frame.easingArgs().remove(2);
frame.easingArgs().remove(2);
if (type == TransformType.ROTATION) {
rightValue = toRadiansForBezier(rightValue);
leftValue = toRadiansForBezier(leftValue);
}
frames.set(i, new Keyframe(frame.length(), frame.startValue(), frame.endValue(), frame.easingType(),
ObjectArrayList.of(leftValue, frame.easingArgs().get(1))));
if (frame.easingArgs().size() > 4) {
frames.get(i).easingArgs().add(frame.easingArgs().get(4));
frames.get(i).easingArgs().add(frame.easingArgs().get(5));
}
if (frames.size() > i + 1) {
Keyframe nextKeyframe = frames.get(i + 1);
if (nextKeyframe.easingType() == EasingType.BEZIER) {
if (nextKeyframe.easingType() != EasingType.BEZIER) {
frames.set(i + 1, new Keyframe(nextKeyframe.length(), nextKeyframe.startValue(), nextKeyframe.endValue(),
EasingType.BEZIER, ObjectArrayList.of(PlayerAnimatorLoader.ZERO, PlayerAnimatorLoader.ZERO, rightValue, rightTime))); //TODO Maybe move the ZERO field to UniversalAnimLoader
}
else {
nextKeyframe.easingArgs().add(rightValue);
nextKeyframe.easingArgs().add(rightTime);
}
else frames.set(i + 1, new Keyframe(nextKeyframe.length(), nextKeyframe.startValue(), nextKeyframe.endValue(), EasingType.BEZIER_AFTER, ObjectArrayList.of(rightValue, rightTime)));
}
}
}

return frames;
}

private static List<Expression> toRadiansForBezier(List<Expression> expressions) {
if (expressions.size() == 1 && IsConstantExpression.test(expressions.getFirst())) {
return Collections.singletonList(FloatExpression.of(Math.toRadians(MOCHA_ENGINE.eval(expressions))));
}
PlayerAnimLib.LOGGER.warn("Invalid easing arguments for bezier: {}\nFor rotations bezier args can only be floats.", expressions);
return expressions;
}

public static float calculateAnimationLength(Map<String, BoneAnimation> boneAnimations) {
float length = 0;

Expand Down
53 changes: 53 additions & 0 deletions ...mon/src/main/resources/assets/player_animation_library/player_animations/bezier_test.json
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Original file line number Diff line number Diff line change
@@ -0,0 +1,53 @@
{
"format_version": "1.8.0",
"geckolib_format_version": 2,
"model": {},
"parents": {},
"animations": {
"bezier_test": {
"loopTick": 0.0,
"loop": true,
"animation_length": 2.0,
"player_animation_library": {
"name": "Тест экспорта бедрока",
"author": "MineEmotes",
"description": "",
"bages": []
},
"bones": {
"leftArm": {
"rotation": {
"0.0": {
"vector": [
0.0,
"pal.disabled",
"pal.disabled"
],
"easingX": "bezier",
"easingArgsX": [
-88.22536,
-0.66596,
-260.45306,
0.98345
]
},
"2.0": {
"vector": [
0.0,
"pal.disabled",
"pal.disabled"
],
"easingX": "bezier",
"easingArgsX": [
246.38388,
-1.02578,
80.31529,
0.66608
]
}
}
}
}
}
}
}