86 lines
2.5 KiB
Lua
Executable File
86 lines
2.5 KiB
Lua
Executable File
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local min = math.min
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local abs = math.abs
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--local deg = math.deg
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function airutils.physics(self)
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local friction = 0.99
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local vel=self.object:get_velocity()
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-- dumb friction
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if self.isonground and not self.isinliquid then
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vel = {x=vel.x*friction,
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y=vel.y,
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z=vel.z*friction}
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self.object:set_velocity(vel)
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end
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--buoyancy
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local surface = nil
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local surfnodename = nil
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local spos = airutils.get_stand_pos(self)
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spos.y = spos.y+0.01
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-- get surface height
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local snodepos = airutils.get_node_pos(spos)
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local surfnode = airutils.nodeatpos(spos)
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while surfnode and (surfnode.drawtype == 'liquid' or surfnode.drawtype == 'flowingliquid') do
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surfnodename = surfnode.name
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surface = snodepos.y +0.5
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if surface > spos.y+self.height then break end
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snodepos.y = snodepos.y+1
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surfnode = airutils.nodeatpos(snodepos)
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end
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local new_velocity = nil
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self.isinliquid = surfnodename
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if surface then -- standing in liquid
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self.isinliquid = true
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end
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local accell = {x=0, y=0, z=0}
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self.water_drag = 0.1
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if self.isinliquid then
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local height = self.height
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local submergence = min(surface-spos.y,height)/height
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-- local balance = self.buoyancy*self.height
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local buoyacc = airutils.gravity*(self.buoyancy-submergence)
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--[[airutils.set_acceleration(self.object,
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{x=-vel.x*self.water_drag,y=buoyacc-vel.y*abs(vel.y)*0.4,z=-vel.z*self.water_drag})]]--
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accell = {x=-vel.x*self.water_drag,y=buoyacc-(vel.y*abs(vel.y)*0.4),z=-vel.z*self.water_drag}
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--local v_accell = {x=0,y=buoyacc-(vel.y*abs(vel.y)*0.4),z=0}
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--airutils.set_acceleration(self.object,v_accell)
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new_velocity = vector.add(vel, vector.multiply(accell, self.dtime))
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else
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airutils.set_acceleration(self.object,{x=0,y=0,z=0})
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self.isinliquid = false
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new_velocity = vector.add(vel, {x=0,y=airutils.gravity * self.dtime,z=0})
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--self.object:set_velocity(new_velocity)
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end
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-- bounciness
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if self.springiness and self.springiness > 0 then
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local vnew = vector.new(vel)
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if not self.collided then -- ugly workaround for inconsistent collisions
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for _,k in ipairs({'y','z','x'}) do
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if vel[k]==0 and abs(self.lastvelocity[k])> 0.1 then
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vnew[k]=-self.lastvelocity[k]*self.springiness
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end
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end
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end
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if not vector.equals(vel,vnew) then
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self.collided = true
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else
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if self.collided then
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vnew = vector.new(self.lastvelocity)
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end
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self.collided = false
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end
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self.object:set_velocity(vnew)
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end
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self.object:set_acceleration({x=0,y=airutils.gravity,z=0})
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end
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