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Conduit

Prefab geometry

The geometry primitives Prefab elements use to describe shape: BlockVolumeShape chooses solid / walls-only / shell; IntVec3 is a triple of IntExpr for parametric coordinates; IntExpr parses literals, parameter refs (@xMin), and parameter + offset (@xMin + 1); OrientationUtil converts between cardinal directions and integer yaw for the yawDegrees field on screens and labels.

When to use it

Section titled “When to use it”
  • You’re authoring a prefab and want to know which shape variants exist.
  • You’re writing tooling that emits prefab JSON and need the coordinate grammar.
  • You’re rotating screens or labels by yaw and want the conversion helpers.

API

Section titled “API”
package me.zlex.conduit.prefab;


public enum BlockVolumeShape {
    CUBOID,   // every block inside the AABB
    WALLS,    // four side walls across all y
    SHELL;    // all six faces — walls + floor + ceiling


    public static final Codec<BlockVolumeShape> CODEC;
}


public record IntVec3(IntExpr x, IntExpr y, IntExpr z) {
    public BlockPos resolve(PrefabBindings bindings);
    public BlockPos resolveAt(PrefabBindings bindings, BlockPos origin);
    public static final Codec<IntVec3> CODEC;
}


public sealed interface IntExpr {
    int eval(PrefabBindings bindings);


    record Literal(int value) implements IntExpr {}
    record ParamRef(String name) implements IntExpr {}
    record Offset(String name, int delta) implements IntExpr {}


    static IntExpr parse(String text);
    Codec<IntExpr> CODEC;       // accepts JSON number or string
}


public final class OrientationUtil {
    public static int directionToYaw(Direction d);
    public static Vec3 yawToNormal(int yawDegrees);
    public static int snapYaw(int yawDegrees, int step);
    public static int normalise(int yawDegrees);
}

Example

Section titled “Example”

Authoring side (JSON):

{
  "elements": [
    { "type": "block-volume", "shape": "shell", "block": "minecraft:barrier",
      "from": ["@xMin", "@yFloor", "@zMin"],
      "to":   ["@xMax", "@yCeiling", "@zMax"] },


    { "type": "block-volume", "shape": "walls", "block": "minecraft:glass",
      "from": ["@xMin + 1", "@yFloor + 1", "@zMin + 1"],
      "to":   ["@xMax - 1", "@yCeiling - 1", "@zMax - 1"] }
  ]
}

Consumer side (Java):

import me.zlex.conduit.prefab.OrientationUtil;
import net.minecraft.core.Direction;
import net.minecraft.world.phys.Vec3;


public final class WallMount {


    public static Vec3 normalFromDirection(Direction face) {
        int yaw = OrientationUtil.directionToYaw(face);
        return OrientationUtil.yawToNormal(yaw);
    }


    public static int rotateClockwise15(int currentYaw) {
        return OrientationUtil.snapYaw(currentYaw + 15, 15);
    }
}

Notes

Section titled “Notes”
  • IntExpr is deliberately tiny — three forms only. Anything more elaborate, add a named parameter instead of growing the expression language.
  • Yaw convention: 0° is +Z (south), 90° is +X (east). UP/DOWN map to 0 — there’s no vertical-axis rotation in the data model.
  • BlockVolumeShape.SHELL is the “hollow cube” primitive used by /set <block> in the editor.
Section titled “Related”