fluid physics: reduce allocations

src/main/java/de/bixilon/minosoft/data/registries/fluid/Fluid.kt

@@ -24,6 +24,7 @@ import de.bixilon.minosoft.data.world.chunk.chunk.Chunk
 import de.bixilon.minosoft.data.world.positions.BlockPosition
 import de.bixilon.minosoft.gui.rendering.models.fluid.FluidModel
 import de.bixilon.minosoft.gui.rendering.util.vec.vec3.Vec3dUtil.EMPTY
+import de.bixilon.minosoft.gui.rendering.util.vec.vec3.Vec3dUtil.EMPTY_INSTANCE
 import de.bixilon.minosoft.physics.entities.living.LivingEntityPhysics
 import de.bixilon.minosoft.physics.input.MovementInput
 import de.bixilon.minosoft.protocol.network.session.play.PlaySession
@@ -72,7 +73,7 @@ abstract class Fluid(override val identifier: ResourceLocation) : RegistryItem()
 
         // ToDo: Falling fluid
 
-        if (velocity == Vec3d.EMPTY) {
+        if (velocity == Vec3d.EMPTY_INSTANCE) {
             return velocity
         }
 

src/main/java/de/bixilon/minosoft/data/world/iterator/BlockPair.kt

@@ -18,7 +18,7 @@ import de.bixilon.minosoft.data.world.chunk.chunk.Chunk
 import de.bixilon.minosoft.data.world.positions.BlockPosition
 
 data class BlockPair(
-    val position: BlockPosition,
-    val state: BlockState,
-    val chunk: Chunk,
+    var position: BlockPosition,
+    var state: BlockState,
+    var chunk: Chunk,
 )

src/main/java/de/bixilon/minosoft/data/world/iterator/WorldIterator.kt

@@ -31,6 +31,7 @@ class WorldIterator(
     private val world: World,
     private var chunk: Chunk? = null,
 ) : Iterator<BlockPair> {
+    private var pair: BlockPair? = null
     private var next: BlockPair? = null
     private var revision = -1
 
@@ -61,7 +62,15 @@ class WorldIterator(
             }
 
             val state = chunk[position.inChunkPosition] ?: continue
-            this.next = BlockPair(position, state, chunk)
+
+            val pair = pair ?: BlockPair(position, state, chunk)
+            this.pair = pair
+
+            pair.position = position
+            pair.state = state
+            pair.chunk = chunk
+            this.next = pair
+
             return true
         }
 

src/main/java/de/bixilon/minosoft/gui/rendering/util/vec/vec3/Vec3dUtil.kt

@@ -29,6 +29,9 @@ import kotlin.math.abs
 
 object Vec3dUtil {
     const val MARGIN = 0.003
+    private val empty = Vec3d()
+
+    val Vec3d.Companion.EMPTY_INSTANCE get() = empty
 
     val Vec3d.Companion.MIN: Vec3d
         get() = Vec3d(Double.MIN_VALUE, Double.MIN_VALUE, Double.MIN_VALUE)