Build 0.20.7.0

Barotrauma/BarotraumaShared/SharedSource/Items/Components/Quality.cs

@@ -1,6 +1,7 @@
 using Microsoft.Xna.Framework;
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Xml.Linq;
 
 namespace Barotrauma.Items.Components
@@ -9,14 +10,6 @@ namespace Barotrauma.Items.Components
     {
         public const int MaxQuality = 3;
 
-        public static readonly float[] QualityCommonnesses = new float[]
-        {
-            0.8f,
-            0.15f,
-            0.045f,
-            0.005f,
-        };
-
         public enum StatType
         {
             Condition,
@@ -81,5 +74,29 @@ namespace Barotrauma.Items.Components
             if (!statValues.ContainsKey(statType)) { return 0.0f; }
             return statValues[statType] * qualityLevel;
         }
+
+        /// <summary>
+        /// Get a random quality for an item spawning in some sub, taking into account the type of the submarine and the difficulty of the current level 
+        /// (high-quality items become more common as difficulty increases)
+        /// </summary>
+        public static int GetSpawnedItemQuality(Submarine submarine, Level level, Rand.RandSync randSync = Rand.RandSync.ServerAndClient)
+        {               
+            if (submarine?.Info == null || level == null || submarine.Info.Type == SubmarineType.Player) { return 0; }
+
+            float difficultyFactor = MathHelper.Clamp(level.Difficulty, 0.0f, 1.0f);
+            return ToolBox.SelectWeightedRandom(Enumerable.Range(0, MaxQuality + 1), q => GetCommonness(q, difficultyFactor), randSync);
+
+            static float GetCommonness(int quality, float difficultyFactor)
+            {
+                return quality switch
+                {
+                    0 => 1,
+                    1 => MathHelper.Lerp(0.0f, 1f, difficultyFactor),
+                    2 => MathHelper.Lerp(0.0f, 1f, Math.Max(difficultyFactor-0.15f, 0f)), //15 difficulty transition to next biome - unlock Excellent loot
+                    3 => MathHelper.Lerp(0.0f, 1f, Math.Max(difficultyFactor-0.35f, 0f)), //35 difficulty transition to next biome - unlock Masterwork loot
+                    _ => 0.0f,
+                };
+            }
+        }
     }
 }