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Send three real heightmaps instead of one repeated three times

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writeHeightmaps computed "highest non-air" once and wrote the same 37 longs
under all three ids, on the stated assumption that our terrain has no leaves or
transparency. That stopped being true the moment the generator grew trees and
flowers.

Vanilla's three client heightmaps stop at different blocks: WORLD_SURFACE at the
first thing that is not air, MOTION_BLOCKING at the first that blocks motion or
holds fluid, MOTION_BLOCKING_NO_LEAVES at the first such thing that is not a
LeavesBlock -- an instanceof, not the minecraft:leaves tag. The client places
rain and snow particles off MOTION_BLOCKING and lands a fishing bobber on it, so
a tree canopy reported as solid ground rains under itself.

Neither blocksMotion() nor the leaves test is derivable from blocks.json: the
first reads cached VoxelShape collision geometry and the forceSolidOn/Off
properties, the second is a Java class check. So the Java dumper grows three
flag bits and the whole thing is renamed for what it now is -- block state
properties, not just lighting. tools/VanillaBlockStateDump.java writes
internal/world/block_properties.bin at format 2; the light bytes are unchanged
byte for byte and only the previously unused high flag bits moved.

Verified the dumper round trip while doing it: recompiling the old
VanillaLightDump against the jar reproduces the committed binary exactly, so the
data really does come from the runtime registry and not from a stale checkout.
CLAUDE.md now carries the command to rebuild it.
This commit is contained in:
Master290 2026-07-27 03:27:09 +03:00
parent 57214fbd76
commit 7880531bdb
8 changed files with 280 additions and 48 deletions
Download patch file Download diff file Expand all files Collapse all files

46
tools/VanillaLightDump.java → tools/VanillaBlockStateDump.java
View file

@ -10,14 +10,26 @@ import net.minecraft.SharedConstants;
import net.minecraft.core.Direction;
import net.minecraft.server.Bootstrap;
import net.minecraft.world.level.block.Block;
import net.minecraft.world.level.block.LeavesBlock;
import net.minecraft.world.level.block.state.BlockState;
import net.minecraft.world.phys.AABB;
import net.minecraft.world.phys.shapes.VoxelShape;
// Dumps protocol-775 lighting properties directly from vanilla runtime state.
// Compile/run against the unpacked 26.1.2 server classpath and redirect stdout
// to internal/world/light_properties.bin.
public final class VanillaLightDump {
// Dumps the per-block-state properties the chunk pipeline needs, straight from
// vanilla runtime state. generated/reports/blocks.json carries none of them:
// they only exist once the block-state registry is built.
//
// Compile and run against the unpacked 26.1.2 server classpath and redirect
// stdout to internal/world/block_properties.bin:
//
// CP="versions/26.1.2/server-26.1.2.jar;$(find libraries -name '*.jar' | tr '\n' ';')"
// javac -nowarn -cp "$CP" -d <out> tools/VanillaBlockStateDump.java
// java -cp "<out>;$CP" VanillaBlockStateDump > internal/world/block_properties.bin
//
// Was VanillaLightDump: it dumped only lighting until the heightmaps needed
// blocksMotion and the leaves test, neither of which is derivable from any
// report or tag file.
public final class VanillaBlockStateDump {
private record MaskKey(byte[] data) {
@Override public boolean equals(Object other) {
return other instanceof MaskKey key && Arrays.equals(data, key.data);
@ -25,6 +37,18 @@ public final class VanillaLightDump {
@Override public int hashCode() { return Arrays.hashCode(data); }
}
// Format version. Bump whenever the byte layout or the meaning of a flag
// bit changes; the Go decoder rejects anything it does not know.
private static final int FORMAT_VERSION = 2;
// Flag bits. 1..4 drive lighting, 8..32 drive the heightmaps.
private static final int FLAG_PROPAGATES_SKYLIGHT = 1;
private static final int FLAG_CAN_OCCLUDE = 2;
private static final int FLAG_SHAPE_FOR_OCCLUSION = 4;
private static final int FLAG_BLOCKS_MOTION = 8;
private static final int FLAG_FLUID = 16;
private static final int FLAG_LEAVES = 32;
public static void main(String[] args) throws Exception {
SharedConstants.tryDetectVersion();
Bootstrap.bootStrap();
@ -42,9 +66,15 @@ public final class VanillaLightDump {
dampening[id] = (byte) state.getLightDampening();
emission[id] = (byte) state.getLightEmission();
int stateFlags = 0;
if (state.propagatesSkylightDown()) stateFlags |= 1;
if (state.canOcclude()) stateFlags |= 2;
if (state.useShapeForLightOcclusion()) stateFlags |= 4;
if (state.propagatesSkylightDown()) stateFlags |= FLAG_PROPAGATES_SKYLIGHT;
if (state.canOcclude()) stateFlags |= FLAG_CAN_OCCLUDE;
if (state.useShapeForLightOcclusion()) stateFlags |= FLAG_SHAPE_FOR_OCCLUSION;
// Heightmap.Types: MOTION_BLOCKING is blocksMotion || fluid, and
// MOTION_BLOCKING_NO_LEAVES additionally excludes LeavesBlock --
// an instanceof, not the minecraft:leaves tag, so the two differ.
if (state.blocksMotion()) stateFlags |= FLAG_BLOCKS_MOTION;
if (!state.getFluidState().isEmpty()) stateFlags |= FLAG_FLUID;
if (state.getBlock() instanceof LeavesBlock) stateFlags |= FLAG_LEAVES;
flags[id] = (byte) stateFlags;
byte[] masks = faceMasks(state);
@ -60,7 +90,7 @@ public final class VanillaLightDump {
DataOutputStream out = new DataOutputStream(new BufferedOutputStream(System.out));
out.writeInt(0x52494f4c); // RIOL
out.writeInt(1);
out.writeInt(FORMAT_VERSION);
out.writeInt(count);
out.writeInt(shapes.size());
for (int id = 0; id < count; id++) {