From a2ae7aae8357c8c2684d85fd58b0c5a0563ebab9 Mon Sep 17 00:00:00 2001
From: sanine-a <sanine.not@pm.me>
Date: Tue, 9 May 2023 11:31:17 -0500
Subject: refactor: split ecs systems into multiple files

---
 honey/ecs/physics.lua | 158 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 158 insertions(+)
 create mode 100644 honey/ecs/physics.lua

(limited to 'honey/ecs/physics.lua')

diff --git a/honey/ecs/physics.lua b/honey/ecs/physics.lua
new file mode 100644
index 0000000..eac3846
--- /dev/null
+++ b/honey/ecs/physics.lua
@@ -0,0 +1,158 @@
+local glm = require 'honey.glm'
+local Vec3       = glm.Vec3
+local Mat4       = glm.Mat4
+local Quaternion = glm.Quaternion
+local ode = honey.ode
+
+local module = {}
+setmetatable(module, {__index=_G})
+setfenv(1, module)
+
+--===== physics =====--
+
+
+system = function(params)
+	local interval = params.interval or 0.016
+	local groupSize = params.groupSize or 20
+	local refs = {}
+	return {
+		db=params.db,
+		space=params.space,
+		world=params.world,
+		contactGroup=ode.JointGroupCreate(groupSize),
+		time=interval,
+
+		priority=1,
+		update=function(self, dt)
+			for i, ref in ipairs(refs) do
+				print(i, ref.tbl, ref.physics)
+			end
+			local query = self.db:queryComponent("physics")
+
+			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
+				end
+			end
+
+			self.time = self.time + dt
+			-- only run the update every [interval] seconds
+			if self.time > interval then
+				self.time = self.time - interval
+
+				-- check for near collisions between geoms
+				ode.SpaceCollide(self.space, function(a, b)
+					-- check for actual collisions
+					local collisions = ode.Collide(a, b, 1)
+					if #collisions > 0 then
+						-- set up the joint params
+						local contact = ode.CreateContact{ surface={
+							mode = ode.ContactBounce + ode.ContactSoftCFM,
+							mu = ode.Infinity,
+							bounce = 0.90,
+							bounce_vel = 0.1,
+							soft_cfm = 0.001,
+						}}
+						ode.ContactSetGeom(contact, collisions[1])
+						-- create the joint
+						local joint = ode.JointCreateContact(
+							self.world,
+							self.contactGroup,
+							contact
+						)
+						-- attach the two bodies
+						local bodyA = ode.GeomGetBody(a)
+						local bodyB = ode.GeomGetBody(b)
+						ode.JointAttach(joint, bodyA, bodyB)
+					end
+				end)
+				-- update the world
+				ode.WorldQuickStep(self.world, interval)
+				-- remove all contact joints
+				ode.JointGroupEmpty(self.contactGroup)
+
+				-- update entity nodes
+				for id, physics in pairs(query) do
+					local x,y,z = ode.BodyGetPosition(physics._body)
+					local d,a,b,c = ode.BodyGetQuaternion(physics._body)
+					local node = self.db:getComponent(id, "node")
+					local q = Quaternion{a,b,c,d}
+					node.matrix
+						:identity()
+						:translate(Vec3{x,y,z})
+						:mul(Quaternion{a,b,c,d}:toMat4())
+
+					local vel = physics.velocity
+					vel[1], vel[2], vel[3] = ode.BodyGetLinearVel(physics._body)
+					local avel = physics.angularVelocity
+					avel[1], avel[2], avel[3] = ode.BodyGetAngularVel(physics._body)
+				end
+			end
+		end,
+	}
+end
+
+
+
+return module
-- 
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