Fix multiversion LOD biome tint sampling position

src/main/java/me/cortex/voxy/client/core/model/ModelFactory.java

@@ -64,6 +64,16 @@
 // this _quarters_ the memory requirements for the texture atlas!!! WHICH IS HUGE saving
 public class ModelFactory {
     public static final int MODEL_TEXTURE_SIZE = 16;
+
+    // Position-aware biome tint compatibility mode.
+    // Biome-tinted LOD models share one fixed 512-entry RGB333 palette.
+    // RenderDataFactory writes the palette index produced from BlockColors
+    // at the actual LOD sample world position into the quad biome-id bits.
+    public static final boolean USE_POSITION_TINT_PALETTE = true;
+    public static final int POSITION_TINT_PALETTE_SIZE = 512;
+    public static final int POSITION_TINT_PALETTE_INDEX = 0;
+    public static final int POSITION_TINT_FALLBACK_INDEX = POSITION_TINT_PALETTE_SIZE - 1;
+
     public static final int LAYERS = Integer.numberOfTrailingZeros(MODEL_TEXTURE_SIZE);
 
     //TODO: replace the fluid BlockState with a client model id integer of the fluidState, requires looking up
@@ -131,6 +141,8 @@ public ModelEntry(ColourDepthTextureData[] textures, int fluidBlockStateId, int
 
     private final ConcurrentLinkedDeque<ResultUploader> uploadResults = new ConcurrentLinkedDeque<>();
 
+    private boolean positionTintPaletteUploaded = false;
+
     private Object2IntMap<BlockState> customBlockStateIdMapping;
 
     //TODO: NOTE!!! is it worth even uploading as a 16x16 texture, since automatic lod selection... doing 8x8 textures might be perfectly ok!!!
@@ -649,6 +661,12 @@ private ModelBakeResultUpload processTextureBakeResult(int blockId, BlockState b
             MemoryUtil.memPutInt(uploadPtr, -1);//Set the default to nothing so that its faster on the gpu
         } else if (!isBiomeColourDependent) {
             MemoryUtil.memPutInt(uploadPtr, entry.tintingColour);
+        } else if (USE_POSITION_TINT_PALETTE) {
+            // Position-aware tinting mode: use the quad biome-id bits as an RGB333 palette index.
+            // All tinted models point at the same shared palette; RenderDataFactory computes
+            // the per-quad palette index from the actual LOD sample world position.
+            MemoryUtil.memPutInt(uploadPtr, POSITION_TINT_PALETTE_INDEX);
+            this.queuePositionTintPaletteUpload(uploadResult);
         } else {
             //Populate the list of biomes for the model state
             int biomeIndex = this.modelsRequiringBiomeColours.size() * this.biomes.size();
@@ -730,6 +748,63 @@ public int getMinBuildHeight() {
         return Math.clamp(state.getLightEmission(),0,15);
     }
 
+    private void queuePositionTintPaletteUpload(ModelBakeResultUpload uploadResult) {
+        if (this.positionTintPaletteUploaded) {
+            return;
+        }
+        this.positionTintPaletteUploaded = true;
+        uploadResult.biomeUploadIndex = POSITION_TINT_PALETTE_INDEX;
+        long clrUploadPtr = (uploadResult.biomeUpload = new MemoryBuffer(4L * POSITION_TINT_PALETTE_SIZE)).address;
+        writePositionTintPalette(clrUploadPtr);
+    }
+
+    private static void writePositionTintPalette(long ptr) {
+        for (int i = 0; i < POSITION_TINT_PALETTE_SIZE; i++) {
+            MemoryUtil.memPutInt(ptr + i * 4L, positionTintPaletteColour(i) | 0xFF000000);
+        }
+    }
+
+    private static int positionTintPaletteColour(int index) {
+        int r = (index >> 6) & 7;
+        int g = (index >> 3) & 7;
+        int b = index & 7;
+        return ((r * 255 / 7) << 16) | ((g * 255 / 7) << 8) | (b * 255 / 7);
+    }
+
+    public int getPositionTintPaletteIndex(int blockId, BlockPos pos) {
+        if (!USE_POSITION_TINT_PALETTE) {
+            return -1;
+        }
+        var level = Minecraft.getInstance().level;
+        if (level == null) {
+            return POSITION_TINT_FALLBACK_INDEX;
+        }
+        BlockState state = this.mapper.getBlockStateFromBlockId(blockId);
+        int color;
+        try {
+            color = Minecraft.getInstance().getBlockColors().getColor(state, level, pos, 0);
+            if (color == -1) {
+                color = Minecraft.getInstance().getBlockColors().getColor(state, level, pos, 1);
+            }
+        } catch (Throwable throwable) {
+            return POSITION_TINT_FALLBACK_INDEX;
+        }
+        if (color == -1) {
+            return POSITION_TINT_FALLBACK_INDEX;
+        }
+        return quantizePositionTintColour(color);
+    }
+
+    private static int quantizePositionTintColour(int color) {
+        int r = (color >> 16) & 255;
+        int g = (color >> 8) & 255;
+        int b = color & 255;
+        int r3 = (r * 7 + 127) / 255;
+        int g3 = (g * 7 + 127) / 255;
+        int b3 = (b * 7 + 127) / 255;
+        return (r3 << 6) | (g3 << 3) | b3;
+    }
+
     private static final class BiomeUploadResult implements ResultUploader {
         private final MemoryBuffer biomeColourBuffer;
         private final MemoryBuffer modelBiomeIndexPairs;
@@ -781,6 +856,10 @@ private BiomeUploadResult addBiome0(int id, Biome biome) {
             return null;
         }
 
+        // In position-tint-palette mode, biome-coloured model LUTs are fixed RGB333 palettes.
+        // New biome registrations do not require rebuilding/reuploading those model colour LUTs.
+        if (USE_POSITION_TINT_PALETTE) return null;
+
         if (this.modelsRequiringBiomeColours.isEmpty()) return null;
 
         var result = new BiomeUploadResult(this.biomes.size(), this.modelsRequiringBiomeColours.size());

src/main/java/me/cortex/voxy/client/core/rendering/building/RenderDataFactory.java

@@ -11,6 +11,7 @@
 import me.cortex.voxy.common.world.WorldSection;
 import me.cortex.voxy.common.world.other.Mapper;
 import me.cortex.voxy.commonImpl.VoxyCommon;
+import net.minecraft.core.BlockPos;
 import org.lwjgl.system.MemoryUtil;
 
 import java.util.Arrays;
@@ -201,9 +202,18 @@ private static long getQuadTyping(long metadata) {//2 bits
         return 0b111L&(0b000_000_010_100L>>(ModelQueries._isTranslucent(metadata)*6+ModelQueries._isDoubleSided(metadata)*3));
     }
 
-    private static long packPartialQuadData(int modelId, long state, long metadata) {
+    private long packPartialQuadData(int modelId, long state, long metadata, WorldSection section, int localIndex) {
         //This uses hardcoded data to shuffle things
         long lightAndBiome =  (state&((0x1FFL<<47)|(0xFFL<<56)))>>>1;
+
+        if (ModelFactory.USE_POSITION_TINT_PALETTE && ModelQueries.isBiomeColoured(metadata)) {
+            int paletteIndex = this.modelMan.getPositionTintPaletteIndex(Mapper.getBlockId(state), getWorldSamplePos(section, localIndex));
+            if (paletteIndex >= 0) {
+                lightAndBiome &= ~(0x1FFL << 46);
+                lightAndBiome |= (Integer.toUnsignedLong(paletteIndex) & 0x1FFL) << 46;
+            }
+        }
+
         lightAndBiome &= ~(ModelQueries._notIsBiomeColoured(metadata) * (0x1FFL << 46));//46 not 47 because is already shifted by 1 THIS WASTED 4 HOURS ;-; aaaaaAAAAAA
         lightAndBiome &= ~(ModelQueries._isFullyOpaque(metadata)*(0xFFL << 55));//If its fully opaque it always uses neighbor light?
 
@@ -213,7 +223,20 @@ private static long packPartialQuadData(int modelId, long state, long metadata)
         return quadData;
     }
 
-    private int prepareSectionData(final long[] rawSectionData) {
+    private static BlockPos getWorldSamplePos(WorldSection section, int localIndex) {
+        int localX = localIndex & 31;
+        int localZ = (localIndex >> 5) & 31;
+        int localY = (localIndex >> 10) & 31;
+        int scale = 1 << section.lvl;
+        int offset = scale >> 1;
+        return new BlockPos(
+                ((section.x << 5) + localX) * scale + offset,
+                ((section.y << 5) + localY) * scale + offset,
+                ((section.z << 5) + localZ) * scale + offset
+        );
+    }
+
+    private int prepareSectionData(final long[] rawSectionData, WorldSection section) {
         final var sectionData = this.sectionData;
         final var rawModelIds = this.modelMan._unsafeRawAccess();
         long opaque = 0;
@@ -242,7 +265,7 @@ private int prepareSectionData(final long[] rawSectionData) {
 
                         long modelMetadata = this.modelMan.getModelMetadataFromClientId(modelId);
 
-                        sectionData[i * 2] = packPartialQuadData(modelId, block, modelMetadata);
+                        sectionData[i * 2] = packPartialQuadData(modelId, block, modelMetadata, section, i);
                         sectionData[i * 2 + 1] = modelMetadata;
 
                         notEmpty |= 1L << j;
@@ -1727,7 +1750,7 @@ public BuiltSection generateMesh(WorldSection section) {
         Arrays.fill(this.fluidMasks, 0);
 
         //Prepare everything
-        int neighborMskAndFlags = this.prepareSectionData(section._unsafeGetRawDataArray());
+        int neighborMskAndFlags = this.prepareSectionData(section._unsafeGetRawDataArray(), section);
         if ((neighborMskAndFlags&(1<<31))!=0) {//We failed to get everything so throw exception
             throw new IdNotYetComputedException(neighborMskAndFlags&((1<<20)-1), true);
         }