1 files changed, 47 insertions, 0 deletions
diff --git a/honey/ecs/node.lua b/honey/ecs/node.lua
new file mode 100644
index 0000000..39f1898
--- /dev/null
+++ b/honey/ecs/node.lua
@@ -0,0 +1,47 @@
+local module = {}
+setmetatable(module, {__index=_G})
+setfenv(1, module)
+
+--===== transform cascading =====--
+
+system = function(params)
+	return {
+		db = params.db,
+		
+		priority = 2,
+		update = function(self, dt)
+			local nodes = self.db:queryComponent("node")
+	
+			-- prepare nodes
+			for id, node in pairs(nodes) do
+				node._visited = false
+			end
+	
+			-- helper function
+			local function recursiveTransform(node)
+				if node._visited then
+					return node._matrix
+				end
+	
+				if not node.parent then
+					node._matrix = node.matrix
+				else
+					local parentTransform = self.db:getComponent(node.parent, "node")
+					local parentMatrix = recursiveTransform(parentTransform)
+					node._matrix = parentMatrix * node.matrix
+				end
+				node._visited = true
+				return node._matrix
+			end
+	
+			-- compute nodes
+			for id, node in pairs(nodes) do
+				recursiveTransform(node)
+			end
+		end,
+	}
+end
+
+
+
+return module