Refactored mesh handling, imported AABB tree implementation from I-MIC FPS

lib/cyberarm_engine/trees/aabb_node.rb

@@ -0,0 +1,126 @@
+# frozen_string_literal: true
+
+module CyberarmEngine
+  class AABBTree
+    class AABBNode
+      attr_accessor :bounding_box, :parent, :object
+      attr_reader :a, :b
+
+      def initialize(parent:, object:, bounding_box:)
+        @parent = parent
+        @object = object
+        @bounding_box = bounding_box
+
+        @a = nil
+        @b = nil
+      end
+
+      def a=(leaf)
+        @a = leaf
+        @a.parent = self
+      end
+
+      def b=(leaf)
+        @b = leaf
+        @b.parent = self
+      end
+
+      def leaf?
+        @object
+      end
+
+      def insert_subtree(leaf)
+        if leaf?
+          new_node = AABBNode.new(parent: nil, object: nil, bounding_box: @bounding_box.union(leaf.bounding_box))
+
+          new_node.a = self
+          new_node.b = leaf
+
+          new_node
+        else
+          cost_a = @a.bounding_box.volume + @b.bounding_box.union(leaf.bounding_box).volume
+          cost_b = @b.bounding_box.volume + @a.bounding_box.union(leaf.bounding_box).volume
+
+          if cost_a == cost_b
+            cost_a = @a.proximity(leaf)
+            cost_b = @b.proximity(leaf)
+          end
+
+          if cost_b < cost_a
+            self.b = @b.insert_subtree(leaf)
+          else
+            self.a = @a.insert_subtree(leaf)
+          end
+
+          @bounding_box = @bounding_box.union(leaf.bounding_box)
+
+          self
+        end
+      end
+
+      def search_subtree(collider, items = [])
+        if @bounding_box.intersect?(collider)
+          if leaf?
+            items << self
+          else
+            @a.search_subtree(collider, items)
+            @b.search_subtree(collider, items)
+          end
+        end
+
+        items
+      end
+
+      def remove_subtree(leaf)
+        if leaf
+          self
+        elsif leaf.parent == self
+          other_child = other(leaf)
+          other_child.parent = @parent
+          other_child
+        else
+          leaf.parent.disown_child(leaf)
+          self
+        end
+      end
+
+      def other(leaf)
+        @a == leaf ? @b : @a
+      end
+
+      def disown_child(leaf)
+        value = other(leaf)
+        raise "Can not replace child of a leaf!" if @parent.leaf?
+        raise "Node is not a child of parent!" unless leaf.child_of?(@parent)
+
+        if @parent.a == self
+          @parent.a = value
+        else
+          @parent.b = value
+        end
+
+        @parent.update_bounding_box
+      end
+
+      def child_of?(leaf)
+        self == leaf.a || self == leaf.b
+      end
+
+      def proximity(leaf)
+        (@bounding_box - leaf.bounding_box).sum.abs
+      end
+
+      def update_bounding_box
+        node = self
+
+        unless node.leaf?
+          node.bounding_box = node.a.bounding_box.union(node.b.bounding_box)
+
+          while (node = node.parent)
+            node.bounding_box = node.a.bounding_box.union(node.b.bounding_box)
+          end
+        end
+      end
+    end
+  end
+end

lib/cyberarm_engine/trees/aabb_tree.rb

@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+
+module CyberarmEngine
+  class AABBTree
+    include AABBTreeDebug
+
+    attr_reader :root, :objects, :branches, :leaves
+
+    def initialize
+      @objects = {}
+      @root = nil
+      @branches = 0
+      @leaves   = 0
+    end
+
+    def insert(object, bounding_box)
+      raise "BoundingBox can't be nil!" unless bounding_box
+      raise "Object can't be nil!" unless object
+      # raise "Object already in tree!" if @objects[object] # FIXME
+
+      leaf = AABBNode.new(parent: nil, object: object, bounding_box: bounding_box.dup)
+      @objects[object] = leaf
+
+      insert_leaf(leaf)
+    end
+
+    def insert_leaf(leaf)
+      @root = @root ? @root.insert_subtree(leaf) : leaf
+    end
+
+    def update(object, bounding_box)
+      leaf = remove(object)
+      leaf.bounding_box = bounding_box
+      insert_leaf(leaf)
+    end
+
+    # Returns a list of all objects that collided with collider
+    def search(collider, return_nodes = false)
+      items = []
+      if @root
+        items = @root.search_subtree(collider)
+        items.map!(&:object) unless return_nodes
+      end
+
+      items
+    end
+
+    def remove(object)
+      leaf  = @objects.delete(object)
+      @root = @root.remove_subtree(leaf) if leaf
+
+      leaf
+    end
+  end
+end

lib/cyberarm_engine/trees/aabb_tree_debug.rb

@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+module CyberarmEngine
+  # Gets included into AABBTree
+  module AABBTreeDebug
+    def inspect
+      @branches = 0
+      @leaves = 0
+      if @root
+        node = @root
+
+        debug_search(node.a)
+        debug_search(node.b)
+      end
+
+      puts "<#{self.class}:#{object_id}> has #{@branches} branches and #{@leaves} leaves"
+    end
+
+    def debug_search(node)
+      if node.leaf?
+        @leaves += 1
+      else
+        @branches += 1
+        debug_search(node.a)
+        debug_search(node.b)
+      end
+    end
+  end
+end