implement skeleton of physics system

1 files changed, 94 insertions, 45 deletions

diff --git a/main.lua b/main.lua
index 9f26eb3..2c92223 100644
--- a/main.lua
+++ b/main.lua
@@ -4,54 +4,20 @@ local glfw = honey.glfw
 local gl = honey.gl
 local Vec3 = honey.Vec3
 local Mat4 = honey.Mat4
+local Quaternion = honey.Quaternion
 local ecs = honey.ecs
 local systems = honey.standardSystems
 local ode = honey.ode
+local nvg = honey.nvg
 
 
 -- initialize honey
 local window = honey.init()
 
--- setup physics
-local world = ode.WorldCreate()
-local space = ode.HashSpaceCreate(ode.Space0)
-ode.WorldSetGravity(world, 0, -10, 0)
-ode.WorldSetCFM(world, 1e-5)
-ode.CreatePlane(space, 0, 1, 0, 0)
-local contactgroup = ode.JointGroupCreate(16)
-local body = ode.BodyCreate(world)
-local geom = ode.CreateSphere(space, 0.5)
-local mass = ode.MassCreate()
-ode.MassSetSphere(mass, 1, 0.5)
-ode.BodySetMass(body, mass)
-ode.GeomSetBody(geom, body)
-ode.BodySetPosition(body, 0, 3, 0)
-
-function physicsStep()
-	ode.SpaceCollide(space, function(o1, o2)
-		local b1 = ode.GeomGetBody(o1)
-		local b2 = ode.GeomGetBody(o2)
-		local contact = ode.CreateContact{
-			surface = {
-				mode = ode.ContactBounce + ode.ContactSoftCFM,
-				mu = ode.Infinity,
-				bounce = 1.0,
-				bounce_vel = 0.1,
-				soft_cfm = 0.001,
-			},
-		}
-		local collisions = ode.Collide(o1, o2, 1)
-		if #collisions > 0 then
-			print("collision detected!")
-			ode.ContactSetGeom(contact, collisions[1])
-			local joint = ode.JointCreateContact(world, contactgroup, contact)
-			ode.JointAttach(joint, b1, b2)
-		end
-	end)
-	ode.WorldQuickStep(world, 0.01)
-	ode.JointGroupEmpty(contactgroup)
-end
-
+-- setup vector graphics
+local vg = nvg.CreateContext()
+local november = nvg.CreateFont(vg, "November", "assets/november.regular.ttf")
+local vw, vh = 640, 480
 
 -- create camera matrices
 local camera = {
@@ -65,6 +31,63 @@ level:addSystem(systems.transformCascade)
 level:addSystem(systems.renderCam(camera))
 level:addSystem(systems.update)
 
+-- physics system
+local world = ode.WorldCreate()
+local space = ode.HashSpaceCreate(ode.Space0)
+level:addSystem{
+	setup=function(self)
+		self.time = 0
+		self.world=world
+		self.space=space
+		ode.WorldSetGravity(self.world, 0, -10, 0)
+		ode.WorldSetCFM(self.world, 1e-5)
+		self.contactgroup = ode.JointGroupCreate(32)
+		self.__gc = honey.util.gc_canary(function()
+			ode.WorldDestroy(self.world)
+			ode.SpaceDestroy(self.space)
+		end)
+	end,
+	filter = ecs.Filter.AND{"transform", "collisionShape", "physicsBody"},
+	preUpdate = function(self)
+		self.dt = nil
+		if self.time > 0.01 then
+			self.time = self.time - 0.01
+			ode.SpaceCollide(self.space, function(o1, o2)
+				local b1 = ode.GeomGetBody(o1)
+				local b2 = ode.GeomGetBody(o2)
+				local contact = ode.CreateContact{
+					surface = {
+						mode = ode.ContactBounce + ode.ContactSoftCFM,
+						mu = ode.Infinity,
+						bounce = 0.99,
+						bounce_vel = 0.1,
+						soft_cfm = 0.001,
+					},
+				}
+				local collisions = ode.Collide(o1, o2, 1)
+				if #collisions > 0 then
+					print("collision detected!")
+					ode.ContactSetGeom(contact, collisions[1])
+					local joint = ode.JointCreateContact(self.world, self.contactgroup, contact)
+					ode.JointAttach(joint, b1, b2)
+				end
+			end)
+			ode.WorldQuickStep(self.world, 0.01)
+			ode.JointGroupEmpty(self.contactgroup)
+		end
+	end,
+	update = function(self, entity, dt) 
+		if not self.dt then
+			self.dt = dt
+			self.time = self.time + dt
+		end
+
+		local x, y, z = ode.BodyGetPosition(entity.physicsBody)
+		local a, b, c, d = ode.BodyGetQuaternion(entity.physicsBody)
+		entity.transform:identity():translate(Vec3{x, y, z}):mul(Quaternion{a, b, c, d}:toMat4())
+	end,
+}
+
 -- create shader
 local shader = honey.Shader{
 	vertexFile = "vertex.glsl",
@@ -127,13 +150,20 @@ local ball = {
 	parent=false,
 	mesh=icosa,
 	shader=shader,
-	update=function(self, dt)
-		local x, y, z = ode.BodyGetPosition(body)
-		self.transform:identity():translate(Vec3{x, y, z})
-	end,
+	collisionShape=ode.CreateSphere(space, 0.5),
+	physicsBody=ode.BodyCreate(world),
 }
 level:addEntity(ball)
 
+local mass = ode.MassCreate()
+ode.MassSetSphere(mass, 1, 0.5)
+ode.BodySetMass(ball.physicsBody, mass)
+ode.GeomSetBody(ball.collisionShape, ball.physicsBody)
+ode.BodySetPosition(ball.physicsBody, 0, 3, 0)
+ode.BodySetLinearVel(ball.physicsBody, 1, 0, 0)
+
+ode.CreatePlane(space, 0, 1, 0, -2)
+
 -- close window on ESCAPE key
 window:setKeyCallback(function(_, key)
 	if key == glfw.KEY_ESCAPE then
@@ -145,14 +175,33 @@ end)
 window:setFramebufferSizeCallback(function(_, width, height)
 	gl.Viewport(0, 0, width, height)
 	camera.projection:perspectiveResize(width/height)
+	vw, vh = width, height
 end)
 
+-- averager (for fps)
+function averager(memory)
+	local buf = {}
+	local avg = 0
+	for i=1,memory do table.insert(buf, 0) end
+	return function(value)
+		table.insert(buf, value)
+		local val = table.remove(buf, 1)
+		avg = avg + value - val
+		return avg / memory
+	end
+end
+local fpsAverage = averager(200)
+
 -- main loop
 honey.loop(window, function(dt)
 	gl.ClearColor(0.2, 0.4, 1.0, 1.0)
 	gl.Clear(gl.COLOR_BUFFER_BIT + gl.DEPTH_BUFFER_BIT)
 	level:update(dt)
-	physicsStep()
+	nvg.BeginFrame(vg, vw, vh, 1.0)
+	nvg.StrokeColor(vg, nvg.RGBf(1, 1, 1))
+	nvg.FontFace(vg, "November")
+	nvg.Text(vg, 50, 50, "fps: "..tostring(math.floor(fpsAverage(1/dt))))
+	nvg.EndFrame(vg)
 end)
 
 -- clean up