1 files changed, 75 insertions, 0 deletions
diff --git a/honey/ecs-systems.lua b/honey/ecs-systems.lua
new file mode 100644
index 0000000..a511b3d
--- /dev/null
+++ b/honey/ecs-systems.lua
@@ -0,0 +1,75 @@
+local ecs = require 'honey.ecs'
+
+
+local module = {}
+setmetatable(module, {__index=_G})
+setfenv(1, module)
+
+
+
+--===== transform cascading =====--
+
+local function recursiveComputeTransform(entity)
+	if entity._transformComputed then 
+		return entity._transform 
+	end
+	if entity.parent == false then
+		entity._transformComputed = true
+		entity._transform = entity.transform
+		return entity.transform
+	end
+
+	entity._transformComputed = true
+	local parentTransform = recursiveComputeTransform(entity.parent)
+	entity._transform = parentTransform * entity.transform
+	return entity._transform
+end
+
+-- update transforms
+transformCascade = {
+	filter=ecs.Filter.AND{"transform", "parent"},
+	preUpdate=function(entity)
+		entity._transform = nil
+		entity._transformComputed = false
+	end,
+	update=function(entity, dt)
+		recursiveComputeTransform(entity)
+	end,
+	priority=98,
+}
+
+
+--===== rendering =====--
+
+function renderCam(camera, priority)
+	local priority = priority or 99
+	return {
+		filter=ecs.Filter.AND{"mesh", "shader", "transform"},
+		update=function(entity, dt)
+			entity.shader:use()
+			entity.shader:configure{
+				matrix={
+					model=entity._transform,
+					view=camera.view,
+					projection=camera.projection,
+				},
+			}
+			entity.mesh:drawElements()
+		end,
+		priority=priority,
+	}
+end
+
+--===== update functions =====--
+
+update = {
+	filter=ecs.Filter.AND{"update"},
+	update=function(entity, dt)
+		entity.update(entity, dt)
+	end,
+	priority=50,
+}
+
+
+
+return module