no idea

Former-commit-id: 9738d12e5a468b71142745fbf0ce02fcf1ca623c
Former-commit-id: a26b80a1990996d9c05b0909128c210e0f897312

Known problems.md

@@ -8,6 +8,9 @@
 ### Physics ###
 
 
+### System ###
+
+
 
 # Resolved #
 

src/net/torvald/terrarum/Game.kt

@@ -416,12 +416,11 @@ constructor() : BasicGameState() {
     /**
      * Check for duplicates, append actor and sort the list
      */
-    fun addActor(actor: Actor): Boolean {
+    fun addActor(actor: Actor) {
         if (hasActor(actor.referenceID))
             throw RuntimeException("Actor with ID ${actor.referenceID} already exists.")
         actorContainer.add(actor)
         insertionSortLastElem(actorContainer) // we can do this as we are only adding single actor
-        return true
     }
 
     /**
@@ -445,7 +444,7 @@ constructor() : BasicGameState() {
         var index: Int = arr.size - 1
         x = arr[index]
         j = index - 1
-        while (j > 0 && arr[j].referenceID > x.referenceID) {
+        while (j > 0 && arr[j] > x) {
             arr[j + 1] = arr[j]
             j -= 1
         }

src/net/torvald/terrarum/REFERENCING.md

@@ -0,0 +1,6 @@
+|Range|Description|
+|-----|-----------|
+|0..4095|Tiles|
+|4096..32767|Items|
+|32768..0x7FFFFFFF|Actors|
+|0x80000000L..0xFFFFFFFFL|Faction|

src/net/torvald/terrarum/gameactors/Actor.kt

@@ -2,6 +2,7 @@ package net.torvald.terrarum.gameactors
 
 import net.torvald.random.HQRNG
 import net.torvald.terrarum.Terrarum
+import net.torvald.terrarum.itemproperties.ItemPropCodex
 import org.newdawn.slick.GameContainer
 
 /**
@@ -21,11 +22,13 @@ abstract class Actor : Comparable<Actor>, Runnable {
 
     override fun equals(other: Any?) = referenceID == (other as Actor).referenceID
     override fun hashCode() = referenceID
-    override fun toString() = if (actorValue.getAsString(AVKey.NAME).isNullOrEmpty())
+    override fun toString() = "Actor, " + if (actorValue.getAsString(AVKey.NAME).isNullOrEmpty())
         "ID: ${hashCode()}"
     else
         "ID: ${hashCode()} (${actorValue.getAsString(AVKey.NAME)})"
-    override fun compareTo(other: Actor): Int = this.referenceID - other.referenceID
+    override fun compareTo(other: Actor): Int = (this.referenceID - other.referenceID).sign()
+
+    fun Int.sign(): Int = if (this > 0) 1 else if (this < 0) -1 else this
 
     /**
      * Usage:
@@ -33,11 +36,10 @@ abstract class Actor : Comparable<Actor>, Runnable {
      * override var referenceID: Int = generateUniqueReferenceID()
      */
     fun generateUniqueReferenceID(): Int {
-        fun Int.abs() = if (this < 0) -this else this
         var ret: Int
         do {
-            ret = HQRNG().nextInt().abs() // set new ID
+            ret = HQRNG().nextInt().and(0x7FFFFFFF) // set new ID
-        } while (Terrarum.game.hasActor(ret)) // check for collision
+        } while (Terrarum.game.hasActor(ret) || ret < ItemPropCodex.ITEM_UNIQUE_MAX) // check for collision
         return ret
     }
 }

src/net/torvald/terrarum/gameactors/ActorWithBody.kt

@@ -91,7 +91,7 @@ open class ActorWithBody constructor() : Actor(), Visible {
             actorValue[AVKey.BASEMASS] = value
         }
     /** Valid range: [0, 1]  */
-    var elasticity = 0.0
+    var elasticity: Double = 0.0
         set(value) {
             if (value < 0)
                 throw IllegalArgumentException("[ActorWithBody] Invalid elasticity value: $value; valid elasticity value is [0, 1].")
@@ -103,6 +103,18 @@ open class ActorWithBody constructor() : Actor(), Visible {
                 field = value * ELASTICITY_MAX
         }
     @Transient private val ELASTICITY_MAX = 0.993 // No perpetual motion!
+
+    /**
+     * what pretty much every physics engine has, instead of my 'elasticity'
+     *
+     * This is just a simple macro for 'elasticity'.
+     *
+     * Formula: restitution = 1.0 - elasticity
+     */
+    var restitution: Double
+        set(value) { elasticity = 1.0 - value }
+        get() = 1.0 - elasticity
+
     private var density = 1000.0
 
     /**
@@ -175,9 +187,11 @@ open class ActorWithBody constructor() : Actor(), Visible {
     @Transient val DYNAMIC = 2
     @Transient val STATIC = 3
 
-    private val SLEEP_THRE = 0.125
+    private val SLEEP_THRE = 1.0 / 16.0
-    private val CCD_THRE = 1.0
+    private val CCD_TICK = 1.0 / 16.0
-    private val CCD_TICK = 0.125
+
+    internal var walledLeft = false
+    internal var walledRight = false
 
     init {
 
@@ -297,6 +311,9 @@ open class ActorWithBody constructor() : Actor(), Visible {
                 clampNextHitbox()
                 clampHitbox()
             }
+
+            walledLeft = isColliding(CONTACT_AREA_LEFT, -1, 0)
+            walledRight = isColliding(CONTACT_AREA_RIGHT, 1, 0)
         }
     }
 
@@ -534,11 +551,34 @@ open class ActorWithBody constructor() : Actor(), Visible {
             val delta: Vector2 = Vector2(hitbox.toVector() - nextHitbox.toVector()) // we need to traverse back, so may as well negate at the first place
             val ccdDelta = delta.setMagnitude(CCD_TICK)
 
-            while (isColliding(CONTACT_AREA_LEFT) || isColliding(CONTACT_AREA_RIGHT)
+            if (ccdDelta.x.abs() >= SLEEP_THRE || ccdDelta.y.abs() >= SLEEP_THRE) { // regular situation
-                   || isColliding(CONTACT_AREA_TOP) || isColliding(CONTACT_AREA_BOTTOM)
+                // CCD to delta while still colliding
-            ) {
+                while (isColliding(CONTACT_AREA_LEFT) || isColliding(CONTACT_AREA_RIGHT)
-                // while still colliding, CCD to the 'delta'
+                       || isColliding(CONTACT_AREA_TOP) || isColliding(CONTACT_AREA_BOTTOM)
-                nextHitbox.translate(ccdDelta)
+                ) {
+                    nextHitbox.translate(ccdDelta)
+                }
+            }
+            else { // stuck while standing still
+                // CCD upward
+                var upwardDelta = 0.0
+                while (isColliding(CONTACT_AREA_LEFT) || isColliding(CONTACT_AREA_RIGHT)
+                       || isColliding(CONTACT_AREA_TOP) || isColliding(CONTACT_AREA_BOTTOM)
+                ) {
+                    nextHitbox.translate(0.0, -CCD_TICK)
+                    upwardDelta += CCD_TICK
+
+                    if (upwardDelta >= TSIZE) break
+
+                    /* TODO CCD in order of:
+
+                    .. 10 11 12 13 14 ..
+                    .. 08 03 04 05 09 ..
+                    .. 06 01 [] 02 07 ..
+
+                    until the stucking is resolved
+                     */
+                }
             }
         }
     }
@@ -546,10 +586,9 @@ open class ActorWithBody constructor() : Actor(), Visible {
     private fun applyNormalForce() {
         if (!isNoCollideWorld) {
             // axis Y
-            if (veloY >= 0) { // check downward
+            if (moveDelta.y >= 0) { // check downward
                 if (isColliding(CONTACT_AREA_BOTTOM) || isColliding(CONTACT_AREA_BOTTOM, 0, 1)) {
                     // the actor is hitting the ground
-                    //veloY = 0.0 // reset veloY, simulating normal force
                     hitAndReflectY()
                     grounded = true
                 }
@@ -557,33 +596,30 @@ open class ActorWithBody constructor() : Actor(), Visible {
                     grounded = false
                 }
             }
-            else if (veloY < 0) { // check upward
+            else if (moveDelta.y < 0) { // check upward
                 grounded = false
                 if (isColliding(CONTACT_AREA_TOP) || isColliding(CONTACT_AREA_TOP, 0, -1)) {
                     // the actor is hitting the ceiling
-                    //veloY = 0.0 // reset veloY, simulating normal force
                     hitAndReflectY()
                 }
                 else { // the actor is not grounded at all
                 }
             }
             // axis X
-            if (veloX >= 0.5) { // check right
+            if (moveDelta.x > 0) { // check right
                 if ((isColliding(CONTACT_AREA_RIGHT) && !isColliding(CONTACT_AREA_LEFT))
                 || (isColliding(CONTACT_AREA_RIGHT, 1, 0) && !isColliding(CONTACT_AREA_LEFT, 0, -1))) {
                     // the actor is hitting the right wall
-                    //veloX = 0.0 // reset veloX, simulating normal force
                     hitAndReflectX()
                 }
                 else {
                 }
             }
-            else if (veloX <= -0.5) { // check left
+            else if (moveDelta.x < 0) { // check left
                 // System.out.println("collidingleft");
                 if ((isColliding(CONTACT_AREA_LEFT) && !isColliding(CONTACT_AREA_RIGHT))
                 || (isColliding(CONTACT_AREA_LEFT, -1, 0) && !isColliding(CONTACT_AREA_RIGHT, 1, 0))) {
                     // the actor is hitting the left wall
-                    //veloX = 0.0 // reset veloX, simulating normal force
                     hitAndReflectX()
                 }
                 else {
@@ -597,18 +633,22 @@ open class ActorWithBody constructor() : Actor(), Visible {
     private fun hitAndReflectX() {
         if ((veloX * elasticity).abs() > SLEEP_THRE) {
             veloX *= -elasticity
+            walkX *= -elasticity
         }
         else {
             veloX = 0.0
+            walkX = 0.0
         }
     }
 
     private fun hitAndReflectY() {
         if ((veloY * elasticity).abs() > SLEEP_THRE) {
             veloY *= -elasticity
+            walkY *= -elasticity
         }
         else {
             veloY = 0.0
+            walkY *= 0.0
         }
     }
 

src/net/torvald/terrarum/gameactors/DroppedItem.kt

@@ -16,7 +16,7 @@ class DroppedItem constructor(itemID: Int) : ActorWithBody() {
 
         isVisible = true
 
-        mass = if (itemID < 4096)
+        mass = if (itemID < TilePropCodex.TILE_UNIQUE_MAX)
             TilePropCodex.getProp(itemID).density / 1000.0
         else
             ItemPropCodex.getProp(itemID).mass

src/net/torvald/terrarum/gameactors/Player.kt

@@ -73,7 +73,7 @@ class Player : ActorWithBody, Controllable, Pocketed, Factionable, Luminous, Lan
         }
 
     companion object {
-        @Transient internal const val ACCEL_MULT_IN_FLIGHT: Double = 0.31
+        @Transient internal const val ACCEL_MULT_IN_FLIGHT: Double = 0.21 // TODO air control still too 'slippery' with 0.31, lower the value!
         @Transient internal const val WALK_ACCEL_BASE: Double = 0.67
 
         @Transient const val PLAYER_REF_ID: Int = 0x51621D
@@ -130,33 +130,35 @@ class Player : ActorWithBody, Controllable, Pocketed, Factionable, Luminous, Lan
      * @author minjaesong
      */
     private fun walkHorizontal(left: Boolean, absAxisVal: Float) {
-        readonly_totalX = //veloX +
+        if ((!walledLeft && left) || (!walledRight && !left)) {
-                          /*actorValue.getAsDouble(AVKey.ACCEL)!! *
+            readonly_totalX = //veloX +
+                    /*actorValue.getAsDouble(AVKey.ACCEL)!! *
                           actorValue.getAsDouble(AVKey.ACCELMULT)!! *
                           Math.sqrt(scale) *
                           applyAccelRealism(walkPowerCounter) *
                           (if (left) -1 else 1).toFloat() *
                           absAxisVal*/
-                actorValue.getAsDouble(AVKey.ACCEL)!! *
+                    actorValue.getAsDouble(AVKey.ACCEL)!! *
-                actorValue.getAsDouble(AVKey.ACCELMULT)!! *
+                    actorValue.getAsDouble(AVKey.ACCELMULT)!! *
-                Math.sqrt(scale) *
+                    Math.sqrt(scale) *
-                applyVelo(walkCounter) *
+                    applyVelo(walkCounter) *
-                (if (left) -1 else 1).toFloat() *
+                    (if (left) -1 else 1).toFloat() *
-                absAxisVal
+                    absAxisVal
 
-        //applyForce(Vector2(readonly_totalX, 0.0))
+            //applyForce(Vector2(readonly_totalX, 0.0))
-        walkX += readonly_totalX
+            walkX += readonly_totalX
-        walkX = absClamp(walkX, actorValue.getAsDouble(AVKey.SPEED)!! * actorValue.getAsDouble(AVKey.SPEEDMULT)!!)
+            walkX = absClamp(walkX, actorValue.getAsDouble(AVKey.SPEED)!! * actorValue.getAsDouble(AVKey.SPEEDMULT)!!)
 
-        walkCounter += 1
+            walkCounter += 1
 
-        // Heading flag
+            // Heading flag
-        if (left)
+            if (left)
-            walkHeading = LEFT
+                walkHeading = LEFT
-        else
+            else
-            walkHeading = RIGHT
+                walkHeading = RIGHT
 
-        println("$walkCounter: ${readonly_totalX}")
+            // println("$walkCounter: ${readonly_totalX}")
+        }
     }
 
     /**
@@ -243,7 +245,9 @@ class Player : ActorWithBody, Controllable, Pocketed, Factionable, Luminous, Lan
     }
 
     /**
-     * See ./work_files/Jump\ power\ by\ pressing\ time.gcx
+     * See ./work_files/Jump power by pressing time.gcx
+     *
+     * TODO linear function (play Super Mario Bros. and you'll get what I'm talking about)
      */
     private fun jump() {
         if (jumping) {

src/net/torvald/terrarum/gameactors/faction/Faction.kt

@@ -7,17 +7,16 @@ import java.util.HashSet
 /**
  * Created by minjaesong on 16-02-15.
  */
-class Faction(factionName: String) {
+class Faction(name: String) : Comparable<Faction> {
 
-    lateinit var factionName: String
+    var factionName: String = name
     lateinit var factionAmicable: HashSet<String>
     lateinit var factionNeutral: HashSet<String>
     lateinit var factionHostile: HashSet<String>
     lateinit var factionFearful: HashSet<String>
-    var factionID: Long = generateUniqueID()
+    var referenceID: Long = generateUniqueID()
 
     init {
-        this.factionName = factionName
         factionAmicable = HashSet<String>()
         factionNeutral = HashSet<String>()
         factionHostile = HashSet<String>()
@@ -60,8 +59,18 @@ class Faction(factionName: String) {
         factionFearful.remove(faction)
     }
 
-    fun generateUniqueID(): Long {
+    private fun generateUniqueID(): Long {
-        fun Long.abs() = if (this < 0) -this else this
+        var ret: Long
-        return HQRNG().nextLong().abs() // set new ID
+        do {
+            ret = HQRNG().nextLong().or(0x80000000L).and(0xFFFFFFFFL) // guaranteed to be 2147483648..4294967295
+        } while (FactionCodex.hasFaction(ret)) // check for collision
+        return ret
     }
+
+    override fun equals(other: Any?) = referenceID == (other as Faction).referenceID
+    override fun hashCode() = (referenceID - 0x80000000L).toInt()
+    override fun toString() = "Faction, ID: $referenceID ($factionName)"
+    override fun compareTo(other: Faction): Int = (this.referenceID - other.referenceID).toInt().sign()
+
+    fun Int.sign(): Int = if (this > 0) 1 else if (this < 0) -1 else this
 }

src/net/torvald/terrarum/gameactors/faction/FactionCodex.kt

@@ -0,0 +1,66 @@
+package net.torvald.terrarum.gameactors.faction
+
+import net.torvald.terrarum.Terrarum
+import java.util.*
+
+/**
+ * Created by minjaesong on 16-05-09.
+ */
+object FactionCodex {
+    val factionContainer = ArrayList<Faction>()
+
+    fun hasFaction(ID: Long): Boolean =
+            if (factionContainer.size == 0)
+                false
+            else
+                factionContainer.binarySearch(ID) >= 0
+
+    fun addFaction(faction: Faction) {
+        if (hasFaction(faction.referenceID))
+            throw RuntimeException("Faction with ID ${faction.referenceID} already exists.")
+        factionContainer.add(faction)
+        insertionSortLastElem(factionContainer) // we can do this as we are only adding single actor
+    }
+
+    fun getFactionByID(ID: Long): Faction {
+        if (factionContainer.size == 0) throw IllegalArgumentException("Faction with ID $ID does not exist.")
+
+        val index = factionContainer.binarySearch(ID)
+        if (index < 0)
+            throw IllegalArgumentException("Faction with ID $ID does not exist.")
+        else
+            return factionContainer[index]
+    }
+
+    private fun insertionSortLastElem(arr: ArrayList<Faction>) {
+        var x: Faction
+        var j: Int
+        var index: Int = arr.size - 1
+        x = arr[index]
+        j = index - 1
+        while (j > 0 && arr[j] > x) {
+            arr[j + 1] = arr[j]
+            j -= 1
+        }
+        arr[j + 1] = x
+    }
+
+    private fun ArrayList<Faction>.binarySearch(ID: Long): Int {
+        // code from collections/Collections.kt
+        var low = 0
+        var high = factionContainer.size - 1
+
+        while (low <= high) {
+            val mid = (low + high).ushr(1) // safe from overflows
+            val midVal = get(mid)
+
+            if (ID > midVal.referenceID)
+                low = mid + 1
+            else if (ID < midVal.referenceID)
+                high = mid - 1
+            else
+                return mid // key found
+        }
+        return -(low + 1)  // key not found
+    }
+}

src/net/torvald/terrarum/gameactors/faction/FactionFactory.kt

@@ -20,7 +20,6 @@ object FactionFactory {
         val jsonObj = JsonFetcher.readJson(JSONPATH + filename)
         val factionObj = Faction(jsonObj.get("factionname").asString)
 
-
         jsonObj.get("factionamicable").asJsonArray.forEach { s -> factionObj.addFactionAmicable(s.asString) }
         jsonObj.get("factionneutral").asJsonArray.forEach { s -> factionObj.addFactionNeutral(s.asString) }
         jsonObj.get("factionhostile").asJsonArray.forEach { s -> factionObj.addFactionHostile(s.asString) }

src/net/torvald/terrarum/gamemap/MapLayer.kt

@@ -50,7 +50,7 @@ class MapLayer(var width: Int, var height: Int) : Iterable<Byte> {
     private fun uint8ToInt32(x: Byte): Int = java.lang.Byte.toUnsignedInt(x)
 
     companion object {
-        @Transient val RANGE = 256
+        @Transient const val RANGE = 256
     }
 }
 

src/net/torvald/terrarum/gamemap/PairedMapLayer.kt

@@ -81,6 +81,6 @@ class PairedMapLayer(width: Int, var height: Int) : Iterable<Byte> {
 
     companion object {
 
-        @Transient val RANGE = 16
+        @Transient const val RANGE = 16
     }
 }

src/net/torvald/terrarum/mapdrawer/MapCamera.kt

@@ -95,6 +95,7 @@ object MapCamera {
             , TileNameCode.SANDSTONE_RED
             , TileNameCode.SANDSTONE_WHITE
             , TileNameCode.SANDSTONE_GREEN
+            , TileNameCode.DAYLIGHT_CAPACITOR
     )
 
     /**

src/net/torvald/terrarum/realestate/RealEstateUtility.kt

@@ -1,6 +1,7 @@
 package net.torvald.terrarum.realestate
 
 import net.torvald.terrarum.Terrarum
+import net.torvald.terrarum.gameactors.faction.FactionCodex
 
 /**
  * Created by minjaesong on 16-03-27.
@@ -11,4 +12,13 @@ object RealEstateUtility {
 
     fun resolveAbsoluteTileNumber(t: Long): Pair<Int, Int> =
             Pair((t % Terrarum.game.map.width).toInt(), (t / Terrarum.game.map.width).toInt())
+
+    /**
+     * Get owner ID as an Actor/Faction
+     */
+    fun resolveOwner(id: Long): Any =
+            if (id < 0x80000000L)
+                Terrarum.game.getActorByID(id.toInt())
+            else
+                FactionCodex.getFactionByID(id)
 }

src/net/torvald/terrarum/tileproperties/TilePropCodex.kt

@@ -13,7 +13,7 @@ import java.io.IOException
 class TilePropCodex {
 
     init {
-        tileProps = Array<TileProp>(MapLayer.RANGE * PairedMapLayer.RANGE + 1,
+        tileProps = Array<TileProp>(TILE_UNIQUE_MAX + 1,
                 {i -> TileProp() }
         )
 
@@ -44,6 +44,8 @@ class TilePropCodex {
 
         val CSV_PATH = "./src/net/torvald/terrarum/tileproperties/tileprop.csv"
 
+        const val TILE_UNIQUE_MAX = MapLayer.RANGE * PairedMapLayer.RANGE
+
         fun getProp(index: Int, damage: Int): TileProp {
             try {
                 tileProps[idDamageToIndex(index, damage)].id

src/net/torvald/terrarum/tileproperties/tileprop.csv

@@ -45,7 +45,7 @@
  "11";  "1";"TILE_TORCH_FROST"         ;  "8396808";       "0"; "N/A";    "0";    "0";   "0";  "81916159";  "11";   "1";   "0";"16"
  "12";  "0";"TILE_TORCH"               ;  "8396808";       "0"; "N/A";    "0";    "0";   "0";         "0";  "11";   "0";   "0";"16"
  "12";  "1";"TILE_TORCH_FROST"         ;  "8396808";       "0"; "N/A";    "0";    "0";   "0";         "0";  "11";   "1";   "0";"16"
- "13";  "0";"TILE_ILLUMINATOR_WHITE"   ;  "8396808";       "0"; "N/A";    "0";    "1";   "1"; "246656235";  "13";   "0";   "0";"16"
+ "13";  "0";"TILE_ILLUMINATOR_WHITE"   ;  "8396808";       "0"; "N/A";    "0";    "1";   "1"; "248768744";  "13";   "0";   "0";"16"
  "13";  "1";"TILE_ILLUMINATOR_YELLOW"  ;  "8396808";       "0"; "N/A";    "0";    "1";   "1"; "246656000";  "13";   "1";   "0";"16"
  "13";  "2";"TILE_ILLUMINATOR_ORANGE"  ;  "8396808";       "0"; "N/A";    "0";    "1";   "1"; "246602752";  "13";   "2";   "0";"16"
  "13";  "3";"TILE_ILLUMINATOR_RED"     ;  "8396808";       "0"; "N/A";    "0";    "1";   "1"; "246415360";  "13";   "3";   "0";"16"
@@ -119,23 +119,30 @@
 "255"; "14";"TILE_WATER"               ; "27282445";     "100";"1000";    "1";    "0";   "0";         "0"; "N/A"; "N/A";   "0";"16"
 "255"; "15";"TILE_WATER"               ; "27282445";     "100";"1000";    "1";    "0";   "0";         "0"; "N/A"; "N/A";   "0";"16"
 "256";  "0";"TILE_NULL"                ;        "0";      "-1";"2600";    "0";    "0";   "0";         "0"; "N/A"; "N/A";   "0";"16"
+## Notes ##
+
 # Friction: 0: frictionless, <16: slippery, 16: regular, >16: sticky
 # Opacity/Lumcolor: 40-step RGB
 # Solid: whether the tile has full collision
 # movr: Movement resistance, (walkspeedmax) / (1 + (n/16)), 16 halves movement speed
 # dsty: density. As we are putting water an 1000, it is identical to specific gravity. [g/l]
 
-# Sunstone: Artificial sunlight, change colour over time in sync with sunlight
-# Sunlight capacitor: daylight at 11h of 22h day
 
+## Illuminants ##
+
+# Illuminant white: RGB(237,250,232), simulation of mercury-vapour lamp (If you want high CRI lamp, collect a daylight!)
 # Defalut torch : L 70 a 51 b 59; real candlelight colour taken from properly configured camera.
+# Sunstone: Artificial sunlight, change colour over time in sync with sunlight. Set by game's code.
+# Sunlight capacitor: daylight at 11h of 22h day. Set by game's code.
+
+
+## Tiles ##
 
 # 16 colour palette : Old Apple Macintosh 16-colour palette
-
 # Magical ice: theoretical __metallic__ ice that might form under super-high pressure (> 5 TPa). Its density is a wild guess.
 
-# Off illuminator: NO OPACITY! this is intended!
 
-#   References:
+## References ##
+
 #     * Density of various woods : http://www.engineeringtoolbox.com/wood-density-d_40.html
 #     * Density of various phases of ice : http://www1.lsbu.ac.uk/water/ice_phases.html