refactor: split physics update into multiple functions

1 files changed, 85 insertions, 62 deletions

diff --git a/honey/ecs/physics.lua b/honey/ecs/physics.lua
index eac3846..e2c9b9a 100644
--- a/honey/ecs/physics.lua
+++ b/honey/ecs/physics.lua
@@ -8,6 +8,89 @@ local module = {}
 setmetatable(module, {__index=_G})
 setfenv(1, module)
 
+
+-- create a new mass
+local function createMass(tbl)
+	local mass = ode.MassCreate()
+	local class = tbl.class
+	if not class then
+		-- configure mass manually
+	elseif class == "sphere" then
+		ode.MassSetSphere(
+			mass, 
+			tbl.density, 
+			tbl.radius
+		)
+	elseif class == "capsule" then
+		ode.MassSetCapsule(
+			mass,
+			tbl.density,
+			tbl.direction,
+			tbl.radius,
+			tbl.length
+		)
+	end
+	return mass
+end
+
+
+-- create a new physics body
+local function createPhysicsBody(db, world, id, component)
+	-- initialize the body with garbage collector
+	print("add component body for "..id)
+	local body = ode.BodyCreate(world)
+	component._gc = honey.util.gc_canary(function() 
+		print("releasing component body for " .. id)
+		ode.BodyDestroy(body) 
+		body = nil
+	end)
+
+	-- connect the body with a collision geom
+	local collision = db:getComponent(id, "collision")
+	if collision then
+		print(id, collision.class)
+		ode.GeomSetBody(collision._geom, body)
+	end
+
+	-- set the mass of the body
+	ode.BodySetMass(body, createMass(component.mass))
+
+	-- set the transform of the body
+	local m = db:getComponent(id, "node").matrix
+	ode.BodySetPosition(
+		body,
+		m[1][4], m[2][4], m[3][4]
+	)
+	ode.BodySetRotation(
+		body,
+		m[1][1], m[1][2], m[1][3],
+		m[2][1], m[2][2], m[2][3],
+		m[3][1], m[3][2], m[3][3]
+	)
+
+	-- set the linear velocity
+	local vel = component.velocity or Vec3{0,0,0}
+	ode.BodySetLinearVel(
+		body, vel[1], vel[2], vel[3]
+	)
+	component.velocity = vel
+
+	-- set the angular velocity
+	local avel = component.angularVelocity or Vec3{0,0,0}
+	ode.BodySetAngularVel(
+		body, avel[1], avel[2], avel[3]
+	)
+	component.angularVelocity = avel
+
+	-- optionally set a maximum angular speed
+	if component.maxAngularSpeed then
+		ode.BodySetMaxAngularSpeed(body, component.maxAngularSpeed)
+	end
+
+	-- put the body into the physics component
+	component._body = body
+end
+
 --===== physics =====--
 
 
@@ -29,70 +112,10 @@ system = function(params)
 			end
 			local query = self.db:queryComponent("physics")
 
+			-- check for new physics entities
 			for id, physics in pairs(query) do
 				if not physics._body then
-					print("add physics body for "..id)
-					local body = ode.BodyCreate(self.world)
-					physics._gc = honey.util.gc_canary(function() 
-						print("releasing physics body for " .. id)
-						ode.BodyDestroy(body) 
-						body = nil
-					end)
-
-					local collision = self.db:getComponent(id, "collision")
-					if collision then
-						print(id, collision.class)
-						ode.GeomSetBody(collision._geom, body)
-					end
-
-					local mass = ode.MassCreate()
-					local class = physics.mass.class
-					if not class then
-						-- configure mass manually
-					elseif class == "sphere" then
-						ode.MassSetSphere(
-							mass, 
-							physics.mass.density, 
-							physics.mass.radius
-						)
-					elseif class == "capsule" then
-						ode.MassSetCapsule(
-							mass,
-							physics.mass.density,
-							physics.mass.direction,
-							physics.mass.radius,
-							physics.mass.length
-						)
-					end
-					ode.BodySetMass(body, mass)
-					local m = self.db:getComponent(id, "node").matrix
-					ode.BodySetPosition(
-						body,
-						m[1][4], m[2][4], m[3][4]
-					)
-					ode.BodySetRotation(
-						body,
-						m[1][1], m[1][2], m[1][3],
-						m[2][1], m[2][2], m[2][3],
-						m[3][1], m[3][2], m[3][3]
-					)
-					local vel = physics.velocity or Vec3{0,0,0}
-					ode.BodySetLinearVel(
-						body, vel[1], vel[2], vel[3]
-					)
-					physics.velocity = vel
-
-					local avel = physics.angularVelocity or Vec3{0,0,0}
-					ode.BodySetAngularVel(
-						body, avel[1], avel[2], avel[3]
-					)
-					physics.angularVelocity = avel
-
-					if physics.maxAngularSpeed then
-						ode.BodySetMaxAngularSpeed(body, physics.maxAngularSpeed)
-					end
-
-					physics._body = body
+					createPhysicsBody(self.db, self.world, id, physics)
 				end
 			end