> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/toxicity188/BetterModel/llms.txt
> Use this file to discover all available pages before exploring further.

# TrackerUpdateAction

> Actions for updating rendered bone display properties

## Overview

The `TrackerUpdateAction` sealed interface represents an action that updates the state of a `RenderedBone`. Actions can modify display properties like brightness, glow, item stack, billboard mode, and more. They are applied to bones matching a specific predicate.

**Package:** `kr.toxicity.model.api.tracker`

**Since:** 1.15.2

## Interface Methods

### test

```java theme={null}
boolean test(@NotNull RenderedBone bone, @NotNull BonePredicate predicate)
```

Applies the action to a bone if it matches the predicate.

**Parameters:**

* `bone` - The target bone
* `predicate` - The predicate to check against

**Returns:** `true` if the bone was updated

### then

```java theme={null}
default @NotNull TrackerUpdateAction then(@NotNull TrackerUpdateAction action)
```

Chains this action with another action.

**Parameters:**

* `action` - The next action

**Returns:** The combined action

### stream

```java theme={null}
default @NotNull Stream<TrackerUpdateAction> stream()
```

Returns a stream of actions (useful for flattening composites).

**Returns:** The stream of actions

## Factory Methods

### brightness

```java theme={null}
static @NotNull Brightness brightness(int block, int sky)
```

Creates an action to update display brightness.

**Parameters:**

* `block` - The block light level (0-15)
* `sky` - The skylight level (0-15)

**Returns:** The brightness action

### glow

```java theme={null}
static @NotNull Glow glow(boolean glow)
```

Creates an action to toggle the glowing effect.

**Parameters:**

* `glow` - `true` to enable glow

**Returns:** The glow action

### glowColor

```java theme={null}
static @NotNull GlowColor glowColor(int glowColor)
```

Creates an action to set the glow color.

**Parameters:**

* `glowColor` - The RGB glow color (hex format)

**Returns:** The glow color action

### viewRange

```java theme={null}
static @NotNull ViewRange viewRange(float viewRange)
```

Creates an action to set the view range.

**Parameters:**

* `viewRange` - The view range in blocks

**Returns:** The view range action

### tint

```java theme={null}
static @NotNull Tint tint(int rgb)
```

Creates an action to apply a tint color.

**Parameters:**

* `rgb` - The RGB tint color (hex format)

**Returns:** The tint action

### previousTint

```java theme={null}
static @NotNull PreviousTint previousTint()
```

Creates an action to revert to the previous tint.

**Returns:** The previous tint action

### enchant

```java theme={null}
static @NotNull Enchant enchant(boolean enchant)
```

Creates an action to toggle the enchanted glint effect.

**Parameters:**

* `enchant` - `true` to enable glint

**Returns:** The enchant action

### togglePart

```java theme={null}
static @NotNull TogglePart togglePart(boolean toggle)
```

Creates an action to toggle the visibility of a part.

**Parameters:**

* `toggle` - `true` to show, `false` to hide

**Returns:** The toggle part action

### itemStack

```java theme={null}
static @NotNull ItemStack itemStack(@NotNull TransformedItemStack itemStack)
```

Creates an action to update the displayed item stack.

**Parameters:**

* `itemStack` - The new item stack

**Returns:** The item stack action

### billboard

```java theme={null}
static @NotNull Billboard billboard(@NotNull PlatformBillboard billboard)
```

Creates an action to set the billboard constraint.

**Parameters:**

* `billboard` - The billboard type (FIXED, VERTICAL, HORIZONTAL, CENTER)

**Returns:** The billboard action

### itemMapping

```java theme={null}
static @NotNull ItemMapping itemMapping()
```

Creates an action to update the item mapping.

**Returns:** The item mapping action

### moveDuration

```java theme={null}
static @NotNull MoveDuration moveDuration(int moveDuration)
```

Creates an action to set the movement interpolation duration.

**Parameters:**

* `moveDuration` - The duration in ticks

**Returns:** The move duration action

### composite

```java theme={null}
static @NotNull TrackerUpdateAction composite(@NotNull TrackerUpdateAction... actions)
```

Combines multiple actions into a single composite action.

**Parameters:**

* `actions` - The actions to combine

**Returns:** The composite action

### perBone

```java theme={null}
static @NotNull PerBone perBone(@NotNull Function<RenderedBone, TrackerUpdateAction> builder)
```

Creates an action that generates a specific action for each bone.

**Parameters:**

* `builder` - The function to generate actions

**Returns:** The per-bone action

### none

```java theme={null}
static @NotNull None none()
```

Returns a no-op action.

**Returns:** The none action

## Action Types

### Brightness

```java theme={null}
record Brightness(int block, int sky)
```

Updates the display brightness (light levels).

### Glow

```java theme={null}
enum Glow { TRUE, FALSE }
```

Toggles the glowing effect.

### GlowColor

```java theme={null}
record GlowColor(int glowColor)
```

Sets the glow color (RGB hex).

### ViewRange

```java theme={null}
record ViewRange(float viewRange)
```

Sets the view range in blocks.

### Enchant

```java theme={null}
enum Enchant { TRUE, FALSE }
```

Toggles the enchantment glint effect.

### Tint

```java theme={null}
record Tint(int rgb)
```

Applies a color tint (RGB hex).

### PreviousTint

```java theme={null}
enum PreviousTint { INSTANCE }
```

Reverts to the previous tint.

### TogglePart

```java theme={null}
enum TogglePart { TRUE, FALSE }
```

Toggles part visibility (show/hide).

### ItemStack

```java theme={null}
record ItemStack(@NotNull TransformedItemStack itemStack)
```

Updates the displayed item stack.

### Billboard

```java theme={null}
record Billboard(@NotNull PlatformBillboard billboard)
```

Sets the billboard constraint mode.

### ItemMapping

```java theme={null}
enum ItemMapping { INSTANCE }
```

Updates the item mapping.

### MoveDuration

```java theme={null}
record MoveDuration(int moveDuration)
```

Sets movement interpolation duration.

### Composite

```java theme={null}
record Composite(@NotNull @Unmodifiable List<TrackerUpdateAction> actions)
```

Combines multiple actions.

### PerBone

```java theme={null}
record PerBone(@NotNull Function<RenderedBone, TrackerUpdateAction> builder)
```

Generates dynamic actions per bone.

### None

```java theme={null}
enum None { INSTANCE }
```

No-op action.

## Usage Examples

### Basic Updates

```java theme={null}
import kr.toxicity.model.api.tracker.Tracker;
import kr.toxicity.model.api.tracker.TrackerUpdateAction;

Tracker tracker = ...;

// Set brightness to full
tracker.update(TrackerUpdateAction.brightness(15, 15));

// Enable glow effect
tracker.update(TrackerUpdateAction.glow(true));

// Set glow color to red
tracker.update(TrackerUpdateAction.glowColor(0xFF0000));

// Apply red tint
tracker.update(TrackerUpdateAction.tint(0xFF0000));

// Remove tint
tracker.update(TrackerUpdateAction.previousTint());

// Enable enchant glint
tracker.update(TrackerUpdateAction.enchant(true));

// Hide part
tracker.update(TrackerUpdateAction.togglePart(false));
```

### Filtered Updates

```java theme={null}
import kr.toxicity.model.api.util.function.BonePredicate;

// Update specific bones
tracker.update(
    TrackerUpdateAction.glow(true),
    BonePredicate.name("weapon")
);

// Update bones with tag
tracker.update(
    TrackerUpdateAction.brightness(15, 15),
    BonePredicate.tag("glowing_part")
);

// Update using custom predicate
tracker.update(
    TrackerUpdateAction.tint(0x00FF00),
    bone -> bone.name().toString().contains("armor")
);
```

### Composite Actions

```java theme={null}
// Combine multiple actions
TrackerUpdateAction action = TrackerUpdateAction.composite(
    TrackerUpdateAction.glow(true),
    TrackerUpdateAction.glowColor(0xFF0000),
    TrackerUpdateAction.brightness(15, 15)
);

tracker.update(action);

// Chain actions using then()
TrackerUpdateAction chained = TrackerUpdateAction.glow(true)
    .then(TrackerUpdateAction.glowColor(0xFF0000))
    .then(TrackerUpdateAction.brightness(15, 15));

tracker.update(chained);
```

### Per-Bone Dynamic Actions

```java theme={null}
// Different action for each bone
TrackerUpdateAction perBone = TrackerUpdateAction.perBone(bone -> {
    String name = bone.name().toString();
    
    if (name.contains("weapon")) {
        return TrackerUpdateAction.glow(true);
    } else if (name.contains("armor")) {
        return TrackerUpdateAction.tint(0x0000FF);
    } else {
        return TrackerUpdateAction.none();
    }
});

tracker.update(perBone);
```

### Billboard Modes

```java theme={null}
import kr.toxicity.model.api.platform.PlatformBillboard;

// Make bone always face player
tracker.update(
    TrackerUpdateAction.billboard(PlatformBillboard.CENTER),
    BonePredicate.name("nameplate")
);

// Vertical billboard (rotates on Y axis only)
tracker.update(
    TrackerUpdateAction.billboard(PlatformBillboard.VERTICAL),
    BonePredicate.name("healthbar")
);
```

### Item Stack Updates

```java theme={null}
import kr.toxicity.model.api.util.TransformedItemStack;

// Change displayed item
TransformedItemStack newItem = TransformedItemStack.of(
    Material.DIAMOND_SWORD,
    1
);

tracker.update(
    TrackerUpdateAction.itemStack(newItem),
    BonePredicate.name("weapon_bone")
);
```

### Movement Interpolation

```java theme={null}
// Smooth movement (10 ticks interpolation)
tracker.update(TrackerUpdateAction.moveDuration(10));

// Instant movement (no interpolation)
tracker.update(TrackerUpdateAction.moveDuration(0));

// Slower movement (20 ticks)
tracker.update(TrackerUpdateAction.moveDuration(20));
```

### Visibility Control

```java theme={null}
// Hide specific parts
tracker.update(
    TrackerUpdateAction.togglePart(false),
    BonePredicate.name("helmet")
);

// Show all parts
tracker.update(
    TrackerUpdateAction.togglePart(true),
    BonePredicate.TRUE
);
```

### View Range Control

```java theme={null}
// Increase view range for important model
tracker.update(TrackerUpdateAction.viewRange(128.0F));

// Decrease view range for detail model
tracker.update(TrackerUpdateAction.viewRange(32.0F));
```

## Advanced Examples

### Damage Effect

```java theme={null}
public void applyDamageEffect(Tracker tracker) {
    // Red tint + glow effect
    TrackerUpdateAction damageEffect = TrackerUpdateAction.composite(
        TrackerUpdateAction.tint(0xFF0000),
        TrackerUpdateAction.glow(true),
        TrackerUpdateAction.glowColor(0xFF0000)
    );
    
    tracker.update(damageEffect);
    
    // Revert after 10 ticks
    scheduler.runLater(() -> {
        TrackerUpdateAction revert = TrackerUpdateAction.composite(
            TrackerUpdateAction.previousTint(),
            TrackerUpdateAction.glow(false)
        );
        tracker.update(revert);
    }, 10);
}
```

### Glowing Outline

```java theme={null}
public void addGlowingOutline(Tracker tracker, int color) {
    tracker.update(TrackerUpdateAction.composite(
        TrackerUpdateAction.glow(true),
        TrackerUpdateAction.glowColor(color)
    ));
}

public void removeGlowingOutline(Tracker tracker) {
    tracker.update(TrackerUpdateAction.glow(false));
}

// Usage
addGlowingOutline(tracker, 0x00FF00); // Green outline
```

### Equipment Display

```java theme={null}
public void updateEquipment(Tracker tracker, ItemStack helmet, ItemStack chestplate) {
    // Update helmet
    if (helmet != null) {
        tracker.update(
            TrackerUpdateAction.itemStack(TransformedItemStack.of(helmet)),
            BonePredicate.name("helmet_bone")
        );
        tracker.update(TrackerUpdateAction.togglePart(true), BonePredicate.name("helmet_bone"));
    } else {
        tracker.update(TrackerUpdateAction.togglePart(false), BonePredicate.name("helmet_bone"));
    }
    
    // Update chestplate
    if (chestplate != null) {
        tracker.update(
            TrackerUpdateAction.itemStack(TransformedItemStack.of(chestplate)),
            BonePredicate.name("chestplate_bone")
        );
        tracker.update(TrackerUpdateAction.togglePart(true), BonePredicate.name("chestplate_bone"));
    } else {
        tracker.update(TrackerUpdateAction.togglePart(false), BonePredicate.name("chestplate_bone"));
    }
}
```

### Night Vision Effect

```java theme={null}
public void applyNightVision(Tracker tracker, boolean enable) {
    if (enable) {
        // Make model fully bright in darkness
        tracker.update(TrackerUpdateAction.brightness(15, 15));
    } else {
        // Use ambient lighting
        tracker.update(TrackerUpdateAction.brightness(0, 0));
    }
}
```

## Best Practices

1. **Combine Actions**: Use `composite()` or `then()` to apply multiple changes atomically
2. **Use Predicates**: Filter bones efficiently with `BonePredicate` instead of updating all bones
3. **Revert Changes**: Store previous states when making temporary changes
4. **Performance**: Batch updates together rather than calling `update()` multiple times
5. **None Action**: Use `none()` for conditional logic instead of null checks

## See Also

* [Tracker](tracker) - Base tracker class that uses update actions
* [EntityTracker](entity-tracker) - Entity tracker implementation
* [DummyTracker](dummy-tracker) - Dummy tracker implementation