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Improve LodDataBuilder.java

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- Use bitwise modulo
- Don't compute certain things 256 times when they can be computed once.
- Removed expressions that are always false
- Improved comments
This commit is contained in:
Ran
2025-04-11 11:24:16 +10:00
parent e079b28e77
commit 09174c2d2a
1 changed files with 104 additions and 122 deletions
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core/src/main/java/com/seibel/distanthorizons/core/dataObjects/transformers/LodDataBuilder.java
+104 -122
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@@ -65,8 +65,6 @@ public class LodDataBuilder
// only block lighting is needed here, sky lighting is populated at the data source stage
LodUtil.assertTrue(chunkWrapper.isDhBlockLightingCorrect());
int sectionPosX = getXOrZSectionPosFromChunkPos(chunkWrapper.getChunkPos().getX());
int sectionPosZ = getXOrZSectionPosFromChunkPos(chunkWrapper.getChunkPos().getZ());
long pos = DhSectionPos.encode(DhSectionPos.SECTION_BLOCK_DETAIL_LEVEL, sectionPosX, sectionPosZ);
@@ -80,47 +78,31 @@ public class LodDataBuilder
// compute the chunk dataSource offset
// this offset is used to determine where in the dataSource this chunk's data should go
int chunkOffsetX = chunkWrapper.getChunkPos().getX();
if (chunkWrapper.getChunkPos().getX() < 0)
{
// expected offset positions:
// chunkPos -> offset
// 5 -> 1
// 4 -> 0 ---
// 3 -> 3
// 2 -> 2
// 1 -> 1
// 0 -> 0 ===
// -1 -> 3
// -2 -> 2
// -3 -> 1
// -4 -> 0 ---
// -5 -> 3
chunkOffsetX = ((chunkOffsetX) % FullDataSourceV2.NUMB_OF_CHUNKS_WIDE);
if (chunkOffsetX != 0)
{
chunkOffsetX += FullDataSourceV2.NUMB_OF_CHUNKS_WIDE;
}
}
else
{
chunkOffsetX %= FullDataSourceV2.NUMB_OF_CHUNKS_WIDE;
}
chunkOffsetX *= LodUtil.CHUNK_WIDTH;
int chunkOffsetZ = chunkWrapper.getChunkPos().getZ();
if (chunkWrapper.getChunkPos().getZ() < 0)
{
chunkOffsetZ = ((chunkOffsetZ) % FullDataSourceV2.NUMB_OF_CHUNKS_WIDE);
if (chunkOffsetZ != 0)
{
chunkOffsetZ += FullDataSourceV2.NUMB_OF_CHUNKS_WIDE;
}
}
else
{
chunkOffsetZ %= FullDataSourceV2.NUMB_OF_CHUNKS_WIDE;
}
// expected offset positions:
// chunkPos -> offset
// 5 -> 1
// 4 -> 0 ---
// 3 -> 3
// 2 -> 2
// 1 -> 1
// 0 -> 0 ===
// -1 -> 3
// -2 -> 2
// -3 -> 1
// -4 -> 0 ---
// -5 -> 3
// Fast modulo calculation using bitwise AND since NUMB_OF_CHUNKS_WIDE is a power of 2 (4)
// For any number n: n & (2^k - 1) is equivalent to Math.floorMod(n, 2^k)
// Original: Math.floorMod(x, 4) - Handles negative numbers, gives non-negative result in range [0,3]
// Bitwise: x & (4-1) - Also gives non-negative result in range [0,3]
// Example: -5 & 3 = 3, which equals Math.floorMod(-5, 4) = 3
int chunkOffsetX = chunkWrapper.getChunkPos().getX() & (FullDataSourceV2.NUMB_OF_CHUNKS_WIDE - 1);
int chunkOffsetZ = chunkWrapper.getChunkPos().getZ() & (FullDataSourceV2.NUMB_OF_CHUNKS_WIDE - 1);
// Convert from chunk coordinates to block coordinates
chunkOffsetX *= LodUtil.CHUNK_WIDTH;
chunkOffsetZ *= LodUtil.CHUNK_WIDTH;
@@ -138,54 +120,49 @@ public class LodDataBuilder
IBlockStateWrapper previousBlockState = null;
int minBuildHeight = chunkWrapper.getMinNonEmptyHeight();
int exclusiveMaxBuildHeight = chunkWrapper.getExclusiveMaxBuildHeight();
int inclusiveMinBuildHeight = chunkWrapper.getInclusiveMinBuildHeight();
int dataCapacity = chunkWrapper.getHeight() / 4;
for (int relBlockX = 0; relBlockX < LodUtil.CHUNK_WIDTH; relBlockX++)
{
for (int relBlockZ = 0; relBlockZ < LodUtil.CHUNK_WIDTH; relBlockZ++)
{
LongArrayList longs = dataSource.get(
relBlockX + chunkOffsetX,
relBlockZ + chunkOffsetZ);
// Calculate column position
int columnX = relBlockX + chunkOffsetX;
int columnZ = relBlockZ + chunkOffsetZ;
// Get column data
LongArrayList longs = dataSource.get(columnX, columnZ);
if (longs == null)
{
longs = new LongArrayList(chunkWrapper.getHeight() / 4);
longs = new LongArrayList(dataCapacity);
}
else
{
longs.clear();
}
int lastY = chunkWrapper.getExclusiveMaxBuildHeight();
int lastY = exclusiveMaxBuildHeight;
IBiomeWrapper biome = chunkWrapper.getBiome(relBlockX, lastY, relBlockZ);
IBlockStateWrapper blockState = AIR;
int mappedId = dataSource.mapping.addIfNotPresentAndGetId(biome, blockState);
// Determine lighting (we are at the height limit. There are no torches here, and sky is not obscured.) // TODO: Per face lighting someday?
byte blockLight = LodUtil.MIN_MC_LIGHT;
byte skyLight = LodUtil.MAX_MC_LIGHT;
byte blockLight;
byte skyLight;
if (lastY < chunkWrapper.getExclusiveMaxBuildHeight())
{
// FIXME: The lastY +1 offset is to reproduce the old behavior. Remove this when we get per-face lighting
blockLight = (byte) chunkWrapper.getDhBlockLight(relBlockX, lastY + 1, relBlockZ);
skyLight = (byte) chunkWrapper.getDhSkyLight(relBlockX, lastY + 1, relBlockZ);
}
else
{
//we are at the height limit. There are no torches here, and sky is not obscured.
blockLight = LodUtil.MIN_MC_LIGHT;
skyLight = LodUtil.MAX_MC_LIGHT;
}
// determine the starting Y Pos
// Get the maximum height from both heightmaps
int y = Math.max(
// max between both heightmaps to account for solid invisible blocks (glass)
// and non-solid opaque blocks (at one point this was stairs, not sure what would fit this now)
chunkWrapper.getLightBlockingHeightMapValue(relBlockX, relBlockZ),
chunkWrapper.getSolidHeightMapValue(relBlockX, relBlockZ)
);
// go up until we reach open air or the world limit
);
// Go up until we reach open air or the world limit
IBlockStateWrapper topBlockState = previousBlockState = chunkWrapper.getBlockState(relBlockX, y, relBlockZ, mcBlockPos, previousBlockState);
while (!topBlockState.isAir() && y < chunkWrapper.getExclusiveMaxBuildHeight())
while (!topBlockState.isAir() && y < exclusiveMaxBuildHeight)
{
try
{
@@ -198,7 +175,7 @@ public class LodDataBuilder
{
if (!getTopErrorLogged)
{
LOGGER.warn("Unexpected issue in LodDataBuilder, future errors won't be logged. Chunk [" + chunkWrapper.getChunkPos() + "] with max height: [" + chunkWrapper.getExclusiveMaxBuildHeight() + "] had issue getting block at pos [" + relBlockX + "," + y + "," + relBlockZ + "] error: " + e.getMessage(), e);
LOGGER.warn("Unexpected issue in LodDataBuilder, future errors won't be logged. Chunk [" + chunkWrapper.getChunkPos() + "] with max height: [" + exclusiveMaxBuildHeight + "] had issue getting block at pos [" + relBlockX + "," + y + "," + relBlockZ + "] error: " + e.getMessage(), e);
getTopErrorLogged = true;
}
@@ -207,7 +184,7 @@ public class LodDataBuilder
}
}
// Process blocks from top to bottom
for (; y >= minBuildHeight; y--)
{
IBiomeWrapper newBiome = chunkWrapper.getBiome(relBlockX, y, relBlockZ);
@@ -215,10 +192,10 @@ public class LodDataBuilder
byte newBlockLight = (byte) chunkWrapper.getDhBlockLight(relBlockX, y + 1, relBlockZ);
byte newSkyLight = (byte) chunkWrapper.getDhSkyLight(relBlockX, y + 1, relBlockZ);
// save the biome/block change
// Save the biome/block change if different from previous
if (!newBiome.equals(biome) || !newBlockState.equals(blockState))
{
longs.add(FullDataPointUtil.encode(mappedId, lastY - y, y + 1 - chunkWrapper.getInclusiveMinBuildHeight(), blockLight, skyLight));
longs.add(FullDataPointUtil.encode(mappedId, lastY - y, y + 1 - inclusiveMinBuildHeight, blockLight, skyLight));
biome = newBiome;
blockState = newBlockState;
@@ -228,17 +205,16 @@ public class LodDataBuilder
lastY = y;
}
}
longs.add(FullDataPointUtil.encode(mappedId, lastY - y, y + 1 - chunkWrapper.getInclusiveMinBuildHeight(), blockLight, skyLight));
dataSource.setSingleColumn(longs,
relBlockX + chunkOffsetX,
relBlockZ + chunkOffsetZ,
EDhApiWorldGenerationStep.LIGHT,
worldCompressionMode);
// Add the final data point
longs.add(FullDataPointUtil.encode(mappedId, lastY - y, y + 1 - inclusiveMinBuildHeight, blockLight, skyLight));
// Set the column in the data source
dataSource.setSingleColumn(longs, columnX, columnZ, EDhApiWorldGenerationStep.LIGHT, worldCompressionMode);
}
}
if (ignoreHiddenBlocks)
if (ignoreHiddenBlocks)
{
cullHiddenBlocks(dataSource, chunkOffsetX, chunkOffsetZ);
}
@@ -275,16 +251,16 @@ public class LodDataBuilder
{
long currentPoint = centerColumn.getLong(centerIndex);
// translucent data points are not eligible to be culled.
// Translucent data points are not eligible to be culled.
if (isTranslucent(dataSource, currentPoint))
{
continue;
}
// the top segment should never be culled.
if (centerIndex == 0
|| isTranslucent(dataSource, centerColumn.getLong(centerIndex - 1))
)
if (centerIndex == 0
|| isTranslucent(dataSource, centerColumn.getLong(centerIndex - 1))
)
{
continue;
}
@@ -292,9 +268,9 @@ public class LodDataBuilder
// the bottom segment can sometimes be culled.
// assume it will not be seen from below,
// because this would imply the player is in the void.
if (centerIndex + 1 < centerColumn.size()
&& isTranslucent(dataSource, centerColumn.getLong(centerIndex + 1))
)
if (centerIndex + 1 < centerColumn.size()
&& isTranslucent(dataSource, centerColumn.getLong(centerIndex + 1))
)
{
continue;
}
@@ -327,9 +303,11 @@ public class LodDataBuilder
continue;
}
// current point is fully surrounded. remove it.
// Current point is fully surrounded. remove it.
centerColumn.removeLong(centerIndex);
// make the above data point cover the area that the current point used to occupy.
// Make the above data point cover the area that the current point used to occupy.
// The element that was at `centerIndex - 1` is still at that position even after removal of centerIndex.
long above = centerColumn.getLong(centerIndex - 1);
above = FullDataPointUtil.setBottomY(above, FullDataPointUtil.getBottomY(currentPoint));
above = FullDataPointUtil.setHeight(above, FullDataPointUtil.getHeight(currentPoint) + FullDataPointUtil.getHeight(above));
@@ -338,31 +316,31 @@ public class LodDataBuilder
}
}
}
/**
checks if centerPoint is "covered" by opaque data points in adjacentColumn.
centerPoint counts as covered if, and only if, for all Y levels in its height range,
there exists an opaque data point in adjacentColumn which overlaps with that Y level.
@param source used to lookup blocks (and their opacities) based on their IDs.
@param centerPoint the point being checked to see if it's fully covered.
@param adjacentColumn the data points which might cover centerPoint.
@param adjacentIndex the starting index in adjacentColumn to start scanning at.
indices greater than adjacentIndex have already been checked and confirmed to
not overlap or only overlap partially with centerPoint's Y range.
@return if centerPoint is covered, returns the index of the segment which finishes covering it.
the start of the covering may be a smaller index. in this case, the returned index may be used
as the adjacentIndex provided to this method on the next iteration which yields a new centerPoint.
if centerPoint is NOT covered, returns the bitwise negation of the index of the
segment which did not cover it. this guarantees that the returned value is negative.
the caller should check for negative return values and manually un-negate them to proceed with the loop.
in other words, this function returns the index of the next adjacent data
point to use in the loop, AND a boolean indicating whether or not the
centerPoint is covered; both are packed into the same int, and returned.
*/
checks if centerPoint is "covered" by opaque data points in adjacentColumn.
centerPoint counts as covered if, and only if, for all Y levels in its height range,
there exists an opaque data point in adjacentColumn which overlaps with that Y level.
@param source used to lookup blocks (and their opacities) based on their IDs.
@param centerPoint the point being checked to see if it's fully covered.
@param adjacentColumn the data points which might cover centerPoint.
@param adjacentIndex the starting index in adjacentColumn to start scanning at.
indices greater than adjacentIndex have already been checked and confirmed to
not overlap or only overlap partially with centerPoint's Y range.
@return if centerPoint is covered, returns the index of the segment which finishes covering it.
the start of the covering may be a smaller index. in this case, the returned index may be used
as the adjacentIndex provided to this method on the next iteration which yields a new centerPoint.
if centerPoint is NOT covered, returns the bitwise negation of the index of the
segment which did not cover it. this guarantees that the returned value is negative.
the caller should check for negative return values and manually un-negate them to proceed with the loop.
in other words, this function returns the index of the next adjacent data
point to use in the loop, AND a boolean indicating whether or not the
centerPoint is covered; both are packed into the same int, and returned.
*/
private static int checkOcclusion(FullDataSourceV2 source, long centerPoint, LongArrayList adjacentColumn, int adjacentIndex)
{
int bottomOfCenter = FullDataPointUtil.getBottomY(centerPoint);
@@ -387,12 +365,12 @@ public class LodDataBuilder
throw new LodUtil.AssertFailureException("Adjacent column ends before center column does.");
}
private static boolean isTranslucent(FullDataSourceV2 source, long point) {
return source.mapping.getBlockStateWrapper(FullDataPointUtil.getId(point)).getOpacity() < LodUtil.BLOCK_FULLY_OPAQUE;
}
/** @throws ClassCastException if an API user returns the wrong object type(s) */
public static FullDataSourceV2 createFromApiChunkData(DhApiChunk apiChunk, boolean runAdditionalValidation) throws ClassCastException, DataCorruptedException, IllegalArgumentException
@@ -402,9 +380,13 @@ public class LodDataBuilder
int sectionPosZ = getXOrZSectionPosFromChunkPos(apiChunk.chunkPosZ);
long pos = DhSectionPos.encode(DhSectionPos.SECTION_BLOCK_DETAIL_LEVEL, sectionPosX, sectionPosZ);
// chunk relative block position in the data source
int relSourceBlockX = Math.floorMod(apiChunk.chunkPosX, 4) * LodUtil.CHUNK_WIDTH;
int relSourceBlockZ = Math.floorMod(apiChunk.chunkPosZ, 4) * LodUtil.CHUNK_WIDTH;
// Fast modulo calculation using bitwise AND since NUMB_OF_CHUNKS_WIDE is a power of 2 (4)
// For any number n: n & (2^k - 1) is equivalent to Math.floorMod(n, 2^k)
// Original: Math.floorMod(x, 4) - Handles negative numbers, gives non-negative result in range [0,3]
// Bitwise: x & (4-1) - Also gives non-negative result in range [0,3]
// Example: -5 & 3 = 3, which equals Math.floorMod(-5, 4) = 3
int relSourceBlockX = (apiChunk.chunkPosX & (FullDataSourceV2.NUMB_OF_CHUNKS_WIDE - 1)) * LodUtil.CHUNK_WIDTH;
int relSourceBlockZ = (apiChunk.chunkPosZ & (FullDataSourceV2.NUMB_OF_CHUNKS_WIDE - 1)) * LodUtil.CHUNK_WIDTH;
FullDataSourceV2 dataSource = FullDataSourceV2.createEmpty(pos);
for (int relBlockZ = 0; relBlockZ < LodUtil.CHUNK_WIDTH; relBlockZ++)
@@ -423,8 +405,8 @@ public class LodDataBuilder
// TODO add the ability for API users to define a different compression mode
// or add a "unkown" compression mode
dataSource.setSingleColumn(
packedDataPoints,
relBlockX + relSourceBlockX, relBlockZ + relSourceBlockZ,
packedDataPoints,
relBlockX + relSourceBlockX, relBlockZ + relSourceBlockZ,
EDhApiWorldGenerationStep.LIGHT, EDhApiWorldCompressionMode.MERGE_SAME_BLOCKS);
dataSource.isEmpty = false;
}
@@ -440,7 +422,7 @@ public class LodDataBuilder
/** @see FullDataPointUtil */
public static LongArrayList convertApiDataPointListToPackedLongArray(
@Nullable List<DhApiTerrainDataPoint> columnDataPoints, FullDataSourceV2 dataSource,
@Nullable List<DhApiTerrainDataPoint> columnDataPoints, FullDataSourceV2 dataSource,
int bottomYBlockPos) throws DataCorruptedException
{
// this null check does 2 nice things at the same time:
@@ -533,13 +515,13 @@ public class LodDataBuilder
}
// is there a gap between the last datapoint?
if (topYPos != lastBottomYPos
&& lastBottomYPos != Integer.MIN_VALUE)
&& lastBottomYPos != Integer.MIN_VALUE)
{
throw new IllegalArgumentException("DhApiTerrainDataPoint ["+i+"] has a gap between it and index ["+(i-1)+"]. Empty spaces should be filled by air, otherwise DH's downsampling won't calculate lighting correctly.");
}
lastBottomYPos = bottomYPos;
lastBottomYPos = bottomYPos;
}
}