Ore Detection and Amplification

Property	Details
Core Logic Class	OreLogic.java
Amplification Mixins	RepeatingPlacementMixin, RarityFilterMixin, OreFeatureMixin
Blacklist Tags	#c:ore_amplifier_blacklist, #ore-amplifier:blacklist
Static Blacklist	amethyst_geode, monster_room, monster_room_deep
Stochastic Engine	StochasticUtil (DasikLibrary)
Controlling GameRules	ig:ore_vanilla_global, ig:ore_modded_global, ig:ore_vein_size_multiplier

---

How Ore Detection Works

Ore Amplifier dynamically detects ores during world generation by analyzing feature and block identifiers. The detection pipeline runs in this order:

Step 1: Blacklist Filtering

Before any amplification, the feature identifier is checked against three blacklist sources:

1. Convention Tag: #c:ore_amplifier_blacklist — community-standard tag for cross-mod compatibility
2. Mod Tag: #ore-amplifier:blacklist — mod-specific tag (references the convention tag)
3. Static Blacklist: Hardcoded exclusions:
   • minecraft:amethyst_geode
   • minecraft:monster_room
   • minecraft:monster_room_deep

💡 Early-Init Safety: Tag resolution uses a try-catch(IllegalStateException) guard to handle cases where tags haven't been bound yet during early world generation.

Step 2: Ore Name Heuristics

If not blacklisted, the identifier is checked against name patterns:

Pattern	Example Matches
_ore (suffix)	iron_ore, deepslate_gold_ore, nether_quartz_ore
ore_ (prefix)	ore_iron_upper, ore_diamond_large
ore (exact)	ore
debris (contains)	ancient_debris

If the identifier matches any pattern, it is considered an ore and eligible for amplification.

Identifier Check Pipeline:
  │
  ▼
[Blacklist Tags?] ──Yes──► SKIP (return original count)
  │ No
  ▼
[Static Blacklist?] ──Yes──► SKIP
  │ No
  ▼
[Name Matches Heuristic?] ──No──► SKIP
  │ Yes
  ▼
[AMPLIFY] ──► Proceed to multiplier lookup

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Multiplier Resolution Hierarchy

When an ore is detected, the multiplier is resolved through a 3-tier priority hierarchy:

┌─────────────────────────────────────────────────────┐
│  Tier 1: JSON Config Per-Ore Override               │
│  config/ore-amplifier.json → perOreMultipliers      │
│  (Highest priority — explicit user intent)           │
├─────────────────────────────────────────────────────┤
│         ↓ (if not set / returns -1)                 │
├─────────────────────────────────────────────────────┤
│  Tier 2: Dynamic GameRule Override                  │
│  ig:ore_<namespace>_<path>                          │
│  (e.g., ig:ore_minecraft_iron_ore)                  │
├─────────────────────────────────────────────────────┤
│         ↓ (if default 100%)                         │
├─────────────────────────────────────────────────────┤
│  Tier 3: Namespace Global Fallback                  │
│  minecraft: → ig:ore_vanilla_global (default 200%)  │
│  other:     → ig:ore_modded_global  (default 120%)  │
│  (Lowest priority — catch-all defaults)             │
└─────────────────────────────────────────────────────┘

Resolution Examples

Ore	Tier 1 (JSON)	Tier 2 (GameRule)	Tier 3 (Global)	Effective
minecraft:diamond_ore	500	100	200	500 (Tier 1)
minecraft:iron_ore	—	300	200	300 (Tier 2)
minecraft:coal_ore	—	100	200	200 (Tier 3: vanilla)
techmod:tin_ore	—	100	120	120 (Tier 3: modded)

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Amplification Math

Vein Count Multiplication

The core amplification uses stochastic (probabilistic) rounding to handle non-integer multiplier results:

$$\text{amplifiedCount} = \text{StochasticUtil.getAmplifiedCount}(\text{original}, \text{multiplier%}, \text{random})$$

The stochastic algorithm:

1. Calculate the raw scaled value: $\text{rawValue} = \text{original} \times \frac{\text{multiplier}}{100}$
2. Take the integer floor: $\text{intPart} = \lfloor \text{rawValue} \rfloor$
3. Calculate fractional remainder: $\text{frac} = \text{rawValue} - \text{intPart}$
4. With probability $\text{frac}$, add 1: $\text{result} = \text{intPart} + (\text{random.nextFloat()} < \text{frac}\ ?\ 1 : 0)$

Stochastic Rounding Examples

Original Count	Multiplier	Raw Value	Result	Probability
5 veins	200% (2.0×)	10.0	10	100% deterministic
10 veins	120% (1.2×)	12.0	12	100% deterministic
1 vein	200% (2.0×)	2.0	2	100% deterministic
1 vein	120% (1.2×)	1.2	1 (80%) or 2 (20%)	Probabilistic
3 veins	150% (1.5×)	4.5	4 (50%) or 5 (50%)	Probabilistic

💡 Why Stochastic? When a multiplier produces a fractional result (e.g., 1 vein × 1.2 = 1.2), the game can't place 0.2 of a vein. Stochastic rounding preserves the statistical average over many chunks while giving natural-feeling results.

Vein Size Multiplication

Separate from vein count, the vein size (blocks per vein) can be amplified via ig:ore_vein_size_multiplier:

$$\text{amplifiedSize} = \left\lfloor \text{originalSize} \times \frac{\text{multiplier}}{100.0} \right\rceil$$

Original Size	Multiplier	Amplified Size
8 blocks (diamond)	100%	8 blocks (no change)
8 blocks (diamond)	200%	16 blocks
8 blocks (diamond)	500%	40 blocks
33 blocks (iron)	150%	50 blocks

⚠️ Vein size amplification only activates when ig:ore_vein_size_multiplier > 100. At the default value of 100%, no vein size changes occur.

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Rarity Filter Amplification

Some ores use a chance-based placement filter (e.g., emerald ore has chance: 6, meaning only 1 in 6 attempts succeeds). The RarityFilterMixin amplifies this probability:

$$p_{\text{base}} = \frac{1.0}{\text{chance}}$$

$$p_{\text{amplified}} = \text{StochasticUtil.getAmplifiedProbability}(p_{\text{base}}, \text{multiplier}, \text{random})$$

This means at 200% multiplier, a 1-in-6 chance effectively becomes a 2-in-6 chance (1 in 3).

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Interaction with Fortune Enchantment

Ore Amplifier and Fortune enchantment operate on different layers and stack multiplicatively:

Layer	What It Affects	When It Applies
Ore Amplifier	Number of ore veins generated per chunk + blocks per vein	During world generation (chunk creation)
Fortune	Number of items dropped per block mined	During block breaking

Example with 200% Ore Amplifier + Fortune III:

• Normal: 4 diamond veins × 8 blocks × ~2.2 drops = ~70 diamonds per chunk
• Amplified: 8 diamond veins × 8 blocks × ~2.2 drops = ~141 diamonds per chunk

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Safety Protection: Runaway Crash Diagnostic

If the amplified vein count exceeds 100,000 for any single feature, the mod triggers a ReportedException with a detailed crash report. This prevents:

• Server freezes from extreme multiplier combinations
• Memory exhaustion during chunk generation
• Cascading worldgen failures

The crash report includes the feature identifier, original count, multiplier, and calculated result to help diagnose the issue.

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Blacklist Customization (Datapacks)

Modpack creators can exclude custom features from amplification by adding entries to the convention blacklist tag. See Developer Setup and Building for a complete datapack guide.

Quick Example

Create data/c/tags/worldgen/placed_feature/ore_amplifier_blacklist.json:

{
  "replace": false,
  "values": [
    "mymod:custom_crystal_vein",
    "mymod:rare_gem_placement"
  ]
}

For the full configuration reference, see GameRules and Configuration.