Math Utilities

Amber provides utilities for mathematical operations, probability calculations, and random number generation. These utilities help simplify common math tasks and provide consistent behavior across platforms.

Deprecated

The Chance class is deprecated and will be removed in Amber 10.0.

Use com.iamkaf.amber.api.functions.v1.MathFunctions instead. See Functions API → MathFunctions for the new API.

Chance

The Chance class provides methods for probability calculations and random events.

Basic Probability

Calculate random events with specific probabilities:

import com.iamkaf.amber.api.math.Chance;

public class RandomEvents {
    // 25% chance of critical hit
    public static boolean tryCriticalHit() {
        return Chance.of(0.25f);
    }
    
    // 5% chance of rare drop
    public static boolean tryRareDrop() {
        return Chance.of(0.05f);
    }
    
    // 75% chance of common event
    public static boolean tryCommonEvent() {
        return Chance.of(0.75f);
    }
    
    // 100% chance (always true)
    public static boolean tryGuaranteedEvent() {
        return Chance.of(1.0f);
    }
    
    // 0% chance (always false)
    public static boolean tryImpossibleEvent() {
        return Chance.of(0.0f);
    }
}

Random Rewards

Process random rewards based on probability:

public class RewardSystem {
    public static void processRandomRewards(Player player) {
        if (Chance.of(0.1f)) { // 10% chance
            // Rare reward
            player.getInventory().add(new ItemStack(Items.DIAMOND));
            FeedbackHelper.message(player, Component.literal("Rare reward!"));
        } else if (Chance.of(0.5f)) { // 50% chance
            // Common reward
            player.getInventory().add(new ItemStack(Items.GOLD_INGOT));
            FeedbackHelper.message(player, Component.literal("Common reward!"));
        }
        // 40% chance of no reward
    }
    
    public static void processMultipleRewards(Player player) {
        // Multiple independent chances
        if (Chance.of(0.3f)) { // 30% chance for item 1
            player.getInventory().add(new ItemStack(Items.IRON_INGOT));
        }
        
        if (Chance.of(0.2f)) { // 20% chance for item 2
            player.getInventory().add(new ItemStack(Items.GOLD_INGOT));
        }
        
        if (Chance.of(0.1f)) { // 10% chance for item 3
            player.getInventory().add(new ItemStack(Items.DIAMOND));
        }
    }
    
    public static ItemStack processRandomEnchantment() {
        Random random = new Random();
        
        // Choose enchantment type
        if (Chance.of(0.5f)) { // 50% chance for protection
            return new ItemStack(Items.ENCHANTED_BOOK);
        } else if (Chance.of(0.3f)) { // 30% chance for sharpness
            return new ItemStack(Items.ENCHANTED_BOOK);
        } else { // 20% chance for efficiency
            return new ItemStack(Items.ENCHANTED_BOOK);
        }
    }
}

Environmental Randomness

Apply randomness to environmental events:

public class EnvironmentalRandomness {
    public static boolean shouldSpawnMob(Level level) {
        // Higher chance at night, lower during day
        boolean isNight = level.isNight();
        float chance = isNight ? 0.3f : 0.1f;
        return Chance.of(chance);
    }
    
    public static boolean shouldGrowPlant(Level level, BlockPos pos) {
        // Base growth chance
        float baseChance = 0.1f;
        
        // Increase chance if raining
        if (level.isRaining()) {
            baseChance += 0.1f;
        }
        
        // Increase chance if day time
        if (level.isDay()) {
            baseChance += 0.05f;
        }
        
        // Check for bonemeal nearby
        for (int x = -2; x <= 2; x++) {
            for (int z = -2; z <= 2; z++) {
                BlockPos checkPos = pos.offset(x, 0, z);
                if (level.getBlockState(checkPos).is(Blocks.WHITE_CONCRETE_POWDER)) {
                    baseChance += 0.2f;
                    break;
                }
            }
        }
        
        // Clamp to maximum of 0.8 (80%)
        baseChance = Math.min(baseChance, 0.8f);
        
        return Chance.of(baseChance);
    }
    
    public static boolean shouldTriggerLightning(Level level) {
        // Only during thunderstorms
        if (!level.isThundering()) {
            return false;
        }
        
        // Base chance during thunderstorm
        float baseChance = 0.02f; // 2%
        
        // Increase chance in specific biomes
        BlockPos pos = BlockPos.containing(level.getSharedSpawnPos());
        Biome biome = level.getBiome(pos).value();
        
        if (biome.getBiomeCategory() == Biome.BiomeCategory.LUKEWARM_OCEAN ||
            biome.getBiomeCategory() == Biome.BiomeCategory.COLD_OCEAN) {
            baseChance += 0.03f; // +3% in oceans
        }
        
        return Chance.of(baseChance);
    }
}

Advanced Math Operations

Weighted Random Selection

Create weighted random selection systems:

public class WeightedRandom {
    // Select item from weighted list
    public static <T> T selectWeighted(Map<T, Float> weights) {
        float totalWeight = weights.values().stream().reduce(0f, Float::sum);
        float random = new Random().nextFloat() * totalWeight;
        
        float currentWeight = 0;
        for (Map.Entry<T, Float> entry : weights.entrySet()) {
            currentWeight += entry.getValue();
            if (random <= currentWeight) {
                return entry.getKey();
            }
        }
        
        // Fallback (shouldn't happen if weights are valid)
        return weights.keySet().iterator().next();
    }
    
    // Example usage for drops
    public static ItemStack getRandomDrop() {
        Map<Item, Float> dropWeights = Map.of(
            Items.DIAMOND, 0.1f,    // 10% chance
            Items.GOLD_INGOT, 0.3f, // 30% chance
            Items.IRON_INGOT, 0.6f  // 60% chance
        );
        
        Item selectedItem = selectWeighted(dropWeights);
        return new ItemStack(selectedItem);
    }
    
    // Select with guaranteed minimum
    public static <T> T selectWeightedWithMinimum(Map<T, Float> weights, T minimum, float minimumChance) {
        if (Chance.of(minimumChance)) {
            return minimum;
        }
        
        return selectWeighted(weights);
    }
}

Interpolation

Create interpolation utilities:

public class Interpolation {
    // Linear interpolation
    public static float lerp(float start, float end, float t) {
        return start + (end - start) * t;
    }
    
    // Linear interpolation with clamping
    public static float lerpClamped(float start, float end, float t) {
        t = Math.max(0, Math.min(1, t));
        return lerp(start, end, t);
    }
    
    // Smooth interpolation (ease-in-out)
    public static float smoothLerp(float start, float end, float t) {
        t = Math.max(0, Math.min(1, t));
        return lerp(start, end, t * t * (3 - 2 * t));
    }
    
    // Vector interpolation
    public static Vec3 lerp(Vec3 start, Vec3 end, float t) {
        return new Vec3(
            lerp(start.x, end.x, t),
            lerp(start.y, end.y, t),
            lerp(start.z, end.z, t)
        );
    }
    
    // Color interpolation
    public static int lerpColor(int startColor, int endColor, float t) {
        int startA = (startColor >> 24) & 0xFF;
        int startR = (startColor >> 16) & 0xFF;
        int startG = (startColor >> 8) & 0xFF;
        int startB = startColor & 0xFF;
        
        int endA = (endColor >> 24) & 0xFF;
        int endR = (endColor >> 16) & 0xFF;
        int endG = (endColor >> 8) & 0xFF;
        int endB = endColor & 0xFF;
        
        int a = (int) lerp(startA, endA, t);
        int r = (int) lerp(startR, endR, t);
        int g = (int) lerp(startG, endG, t);
        int b = (int) lerp(startB, endB, t);
        
        return (a << 24) | (r << 16) | (g << 8) | b;
    }
    
    // Example usage for animation
    public static void animateValue(float from, float to, int durationTicks, Consumer<Float> setter) {
        // This would be used in a tick-based animation system
        for (int tick = 0; tick <= durationTicks; tick++) {
            float t = (float) tick / durationTicks;
            float value = smoothLerp(from, to, t);
            
            // Schedule setting the value at the appropriate tick
            // Implementation depends on your mod's tick system
        }
    }
}

Math Utilities

Create general math utilities:

public class MathUtils {
    // Clamp value between min and max
    public static float clamp(float value, float min, float max) {
        return Math.max(min, Math.min(max, value));
    }
    
    // Map value from one range to another
    public static float map(float value, float fromMin, float fromMax, float toMin, float toMax) {
        return toMin + (value - fromMin) * (toMax - toMin) / (fromMax - fromMin);
    }
    
    // Normalize angle to 0-360 degrees
    public static float normalizeAngle(float angle) {
        angle = angle % 360;
        if (angle < 0) {
            angle += 360;
        }
        return angle;
    }
    
    // Calculate distance between two points
    public static double distance(double x1, double y1, double x2, double y2) {
        return Math.sqrt(Math.pow(x2 - x1, 2) + Math.pow(y2 - y1, 2));
    }
    
    // Calculate distance between two 3D points
    public static double distance(double x1, double y1, double z1, double x2, double y2, double z2) {
        return Math.sqrt(Math.pow(x2 - x1, 2) + Math.pow(y2 - y1, 2) + Math.pow(z2 - z1, 2));
    }
    
    // Check if value is within range
    public static boolean isInRange(float value, float min, float max) {
        return value >= min && value <= max;
    }
    
    // Round to nearest multiple
    public static float roundToMultiple(float value, float multiple) {
        return Math.round(value / multiple) * multiple;
    }
    
    // Convert degrees to radians
    public static float degToRad(float degrees) {
        return (float) (degrees * Math.PI / 180);
    }
    
    // Convert radians to degrees
    public static float radToDeg(float radians) {
        return (float) (radians * 180 / Math.PI);
    }
    
    // Example usage
    public static void exampleUsage() {
        // Clamp value
        float clamped = clamp(150, 0, 100); // Returns 100
        
        // Map value
        float mapped = map(50, 0, 100, 0, 1); // Returns 0.5
        
        // Normalize angle
        float normalized = normalizeAngle(450); // Returns 90
        
        // Check range
        boolean inRange = isInRange(50, 0, 100); // Returns true
        
        // Round to multiple
        float rounded = roundToMultiple(23, 5); // Returns 25
    }
}

Random Number Generation

Advanced Random Systems

Create more sophisticated random number systems:

public class RandomSystems {
    // Random with seed
    public static class SeededRandom {
        private final Random random;
        
        public SeededRandom(long seed) {
            this.random = new Random(seed);
        }
        
        public float nextFloat(float min, float max) {
            return min + random.nextFloat() * (max - min);
        }
        
        public int nextInt(int min, int max) {
            return random.nextInt(max - min + 1) + min;
        }
        
        public boolean nextBoolean(float chance) {
            return random.nextFloat() < chance;
        }
        
        public Vec3 nextVec3(Vec3 center, double radius) {
            double angle = random.nextDouble() * 2 * Math.PI;
            double distance = random.nextDouble() * radius;
            
            return center.add(
                Math.cos(angle) * distance,
                0,
                Math.sin(angle) * distance
            );
        }
    }
    
    // Gaussian random
    public static double nextGaussian(Random random, double mean, double stddev) {
        return random.nextGaussian() * stddev + mean;
    }
    
    // Perlin noise approximation
    public static float noise(int x, int y, int seed) {
        int n = x + y * 57 + seed * 131;
        n = (n << 13) ^ n;
        return (1.0f - ((n * (n * n * 15731 + 789221) + 1376312589) & 0x7fffffff) / 1073741824.0f);
    }
    
    // Example usage
    public static void exampleUsage() {
        SeededRandom seeded = new SeededRandom(12345);
        
        // Generate random position
        Vec3 center = new Vec3(0, 64, 0);
        Vec3 randomPos = seeded.nextVec3(center, 10);
        
        // Generate random value with Gaussian distribution
        Random random = new Random();
        double gaussian = nextGaussian(random, 50, 10); // Mean 50, stddev 10
        
        // Generate noise value
        float noiseValue = noise(10, 20, 54321);
    }
}

Best Practices

1. Seed Management

Use consistent seeds for predictable results:

public class SeedManagement {
    private static final long STRUCTURE_SEED = 12345L;
    private static final long LOOT_SEED = 67890L;
    
    public static void generateStructure(Level level, BlockPos pos) {
        SeededRandom random = new RandomSystems.SeededRandom(
            STRUCTURE_SEED + pos.asLong()
        );
        
        // Use random for consistent structure generation
    }
    
    public static void generateLoot(Level level, BlockPos pos) {
        SeededRandom random = new RandomSystems.SeededRandom(
            LOOT_SEED + pos.asLong()
        );
        
        // Use random for consistent loot generation
    }
}

2. Performance

Consider performance for frequent random operations:

public class PerformanceRandom {
    // Reuse Random instance
    private static final Random SHARED_RANDOM = new Random();
    
    // Fast random for non-critical uses
    public static boolean fastChance(float percent) {
        return SHARED_RANDOM.nextFloat() < percent;
    }
    
    // Thread-safe random
    private static final ThreadLocalRandom THREAD_LOCAL_RANDOM = ThreadLocalRandom.current();
    
    public static boolean threadSafeChance(float percent) {
        return THREAD_LOCAL_RANDOM.nextFloat() < percent;
    }
}

3. Validation

Validate probability values:

public class Validation {
    public static boolean isValidProbability(float probability) {
        return probability >= 0.0f && probability <= 1.0f;
    }
    
    public static float clampProbability(float probability) {
        return Math.max(0.0f, Math.min(1.0f, probability));
    }
    
    public static boolean safeChance(float probability) {
        return Chance.of(clampProbability(probability));
    }
}

4. Testing

Create testable random systems:

public class TestableRandom {
    private final Random random;
    private final List<Float> recordedChances = new ArrayList<>();
    
    public TestableRandom(long seed) {
        this.random = new Random(seed);
    }
    
    public boolean chance(float probability) {
        recordedChances.add(probability);
        return random.nextFloat() < probability;
    }
    
    // For testing - verify that specific chances were tested
    public boolean wasChanceTested(float probability) {
        return recordedChances.contains(probability);
    }
    
    // For testing - get all tested chances
    public List<Float> getTestedChances() {
        return new ArrayList<>(recordedChances);
    }
}

These math utilities provide helpful shortcuts for common mathematical operations while maintaining cross-platform compatibility.