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Overview

Surface conditions determine when surface rules should apply. Lithostitched adds custom condition types that extend Minecraft’s built-in conditions with biome matching, slope detection, and logical operators.

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Custom Condition Types

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Biome Condition

Tests if the current position is in a specific biome or biome tag. Java Interface: 
public record BiomeCondition(HolderSet<Biome> biomes) implements SurfaceRules.ConditionSource {
    @Override
    public SurfaceRules.Condition apply(SurfaceRules.Context context) {
        return () -> this.biomes.contains(context.biome());
    }
}
Source: BiomeCondition.java:12-30 JSON Format: Single Biome: 
{
  "type": "lithostitched:biome",
  "biomes": "minecraft:desert"
}
Multiple Biomes: 
{
  "type": "lithostitched:biome",
  "biomes": [
    "minecraft:desert",
    "minecraft:badlands",
    "mymod:red_desert"
  ]
}
Biome Tag: 
{
  "type": "lithostitched:biome",
  "biomes": "#minecraft:is_badlands"
}
Usage Example: 
{
  "type": "minecraft:condition",
  "if_true": {
    "type": "lithostitched:biome",
    "biomes": "#mymod:has_red_sand"
  },
  "then_run": {
    "type": "minecraft:block",
    "result_state": { "Name": "minecraft:red_sand" }
  }
}

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Slope Condition

Detects steep terrain by measuring height differences between neighboring positions. Java Interface: 
public record SlopeCondition(InclusiveRange<Integer> threshold) implements SurfaceRules.ConditionSource {
    private static class Condition extends SurfaceRules.LazyXZCondition {
        @Override
        public boolean compute() {
            // Measure height difference between N/S/E/W neighbors
            int maxHeight = max(northHeight, southHeight, eastHeight, westHeight);
            int minHeight = min(northHeight, southHeight, eastHeight, westHeight);
            return threshold.isValueInRange(maxHeight - minHeight);
        }
    }
}
Source: SlopeCondition.java:14-67 JSON Format: Default Threshold (4 blocks or more): 
{
  "type": "lithostitched:slope"
}
Custom Threshold: 
{
  "type": "lithostitched:slope",
  "height_difference": {
    "min_inclusive": 6,
    "max_inclusive": 2147483647
  }
}
Specific Range: 
{
  "type": "lithostitched:slope",
  "height_difference": {
    "min_inclusive": 3,
    "max_inclusive": 8
  }
}
Usage Example: 
{
  "type": "minecraft:condition",
  "if_true": {
    "type": "lithostitched:slope",
    "height_difference": { "min_inclusive": 5, "max_inclusive": 2147483647 }
  },
  "then_run": {
    "type": "minecraft:block",
    "result_state": { "Name": "minecraft:stone" }
  }
}
Use slope conditions to expose stone on cliffs, prevent grass on steep terrain, or create realistic erosion patterns.

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All Of Condition

Requires all sub-conditions to be true (logical AND). Java Interface: 
public record AllOfCondition(List<SurfaceRules.ConditionSource> conditions) implements SurfaceRules.ConditionSource {
    private record Condition(List<SurfaceRules.Condition> conditions) implements SurfaceRules.Condition {
        @Override
        public boolean test() {
            for (SurfaceRules.Condition condition : conditions) {
                if (!condition.test()) return false;
            }
            return true;
        }
    }
}
Source: AllOfCondition.java:9-34 JSON Format: 
{
  "type": "lithostitched:all_of",
  "conditions": [
    {
      "type": "lithostitched:biome",
      "biomes": "#minecraft:is_badlands"
    },
    {
      "type": "minecraft:above_preliminary_surface"
    },
    {
      "type": "minecraft:steep"
    }
  ]
}
Usage Example: 
{
  "type": "minecraft:condition",
  "if_true": {
    "type": "lithostitched:all_of",
    "conditions": [
      {
        "type": "lithostitched:biome",
        "biomes": "mymod:snowy_peaks"
      },
      {
        "type": "lithostitched:slope",
        "height_difference": { "min_inclusive": 3, "max_inclusive": 2147483647 }
      },
      {
        "type": "minecraft:y_above",
        "anchor": { "absolute": 120 },
        "surface_depth_multiplier": 0,
        "add_stone_depth": false
      }
    ]
  },
  "then_run": {
    "type": "minecraft:block",
    "result_state": { "Name": "minecraft:packed_ice" }
  }
}

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Any Of Condition

Requires at least one sub-condition to be true (logical OR). Java Interface: 
public record AnyOfCondition(List<SurfaceRules.ConditionSource> conditions) implements SurfaceRules.ConditionSource {
    private record Condition(List<SurfaceRules.Condition> conditions) implements SurfaceRules.Condition {
        @Override
        public boolean test() {
            for (SurfaceRules.Condition condition : conditions) {
                if (condition.test()) return true;
            }
            return false;
        }
    }
}
Source: AnyOfCondition.java:9-34 JSON Format: 
{
  "type": "lithostitched:any_of",
  "conditions": [
    {
      "type": "lithostitched:biome",
      "biomes": "minecraft:desert"
    },
    {
      "type": "lithostitched:biome",
      "biomes": "minecraft:badlands"
    },
    {
      "type": "minecraft:temperature"
    }
  ]
}
Usage Example: 
{
  "type": "minecraft:condition",
  "if_true": {
    "type": "lithostitched:any_of",
    "conditions": [
      {
        "type": "lithostitched:biome",
        "biomes": "#mymod:volcanic_biomes"
      },
      {
        "type": "lithostitched:slope",
        "height_difference": { "min_inclusive": 10, "max_inclusive": 2147483647 }
      }
    ]
  },
  "then_run": {
    "type": "minecraft:block",
    "result_state": { "Name": "minecraft:basalt" }
  }
}

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Complex Condition Examples

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Cliff Detection

Combine slope and biome conditions: 
{
  "type": "lithostitched:all_of",
  "conditions": [
    {
      "type": "lithostitched:slope",
      "height_difference": { "min_inclusive": 6, "max_inclusive": 2147483647 }
    },
    {
      "type": "minecraft:above_preliminary_surface"
    },
    {
      "type": "lithostitched:biome",
      "biomes": "#mymod:has_cliffs"
    }
  ]
}

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Multi-Biome Group

Use any_of for biome variants: 
{
  "type": "lithostitched:any_of",
  "conditions": [
    {
      "type": "lithostitched:biome",
      "biomes": "minecraft:desert"
    },
    {
      "type": "lithostitched:biome",
      "biomes": "minecraft:badlands"
    },
    {
      "type": "lithostitched:biome",
      "biomes": "#mymod:custom_deserts"
    }
  ]
}

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Gentle Slopes Only

Invert slope condition with not: 
{
  "type": "minecraft:not",
  "invert": {
    "type": "lithostitched:slope",
    "height_difference": { "min_inclusive": 4, "max_inclusive": 2147483647 }
  }
}

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Elevation and Biome

{
  "type": "lithostitched:all_of",
  "conditions": [
    {
      "type": "lithostitched:biome",
      "biomes": "mymod:alpine_meadow"
    },
    {
      "type": "minecraft:y_above",
      "anchor": { "absolute": 100 },
      "surface_depth_multiplier": 0,
      "add_stone_depth": false
    },
    {
      "type": "minecraft:not",
      "invert": {
        "type": "lithostitched:slope",
        "height_difference": { "min_inclusive": 5, "max_inclusive": 2147483647 }
      }
    }
  ]
}

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Condition Chaining

Build complex logic by nesting conditions: 
{
  "type": "minecraft:condition",
  "if_true": {
    "type": "lithostitched:all_of",
    "conditions": [
      {
        "type": "lithostitched:any_of",
        "conditions": [
          {
            "type": "lithostitched:biome",
            "biomes": "#mymod:hot_biomes"
          },
          {
            "type": "minecraft:temperature"
          }
        ]
      },
      {
        "type": "lithostitched:slope",
        "height_difference": { "min_inclusive": 3, "max_inclusive": 8 }
      },
      {
        "type": "minecraft:above_preliminary_surface"
      }
    ]
  },
  "then_run": {
    "type": "minecraft:block",
    "result_state": { "Name": "minecraft:red_sandstone" }
  }
}

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Performance Considerations

Slope conditions use heightmap lookups which are more expensive than simple checks. Use them strategically and combine with faster conditions using all_of to short-circuit evaluation.
Optimized Order: 
{
  "type": "lithostitched:all_of",
  "conditions": [
    {
      "type": "lithostitched:biome",
      "biomes": "mymod:rare_biome"
    },
    {
      "type": "minecraft:above_preliminary_surface"
    },
    {
      "type": "lithostitched:slope"
    }
  ]
}
Fast conditions (biome, y-level) come before expensive ones (slope).

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Registry Information

Conditions are registered through Minecraft’s condition source system and integrated via mixins. Custom Condition Types:
  • lithostitched:biome - Biome matching
  • lithostitched:slope - Height difference detection
  • lithostitched:all_of - Logical AND
  • lithostitched:any_of - Logical OR

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See Also

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