pa28/custom_physics.lua

116 lines
3.9 KiB
Lua
Executable File

local min = math.min
local abs = math.abs
--local deg = math.deg
function pa28.physics(self)
local friction = 0.99
local vel=self.object:get_velocity()
-- bounciness
if self.springiness and self.springiness > 0 then
local vnew = vector.new(vel)
if not self.collided then -- ugly workaround for inconsistent collisions
for _,k in ipairs({'y','z','x'}) do
if vel[k]==0 and abs(self.lastvelocity[k])> 0.1 then
vnew[k]=-self.lastvelocity[k]*self.springiness
end
end
end
if not vector.equals(vel,vnew) then
self.collided = true
else
if self.collided then
vnew = vector.new(self.lastvelocity)
end
self.collided = false
end
self.object:set_velocity(vnew)
end
--buoyancy
local surface = nil
local surfnodename = nil
local spos = airutils.get_stand_pos(self)
spos.y = spos.y+0.01
-- get surface height
local snodepos = airutils.get_node_pos(spos)
local surfnode = airutils.nodeatpos(spos)
while surfnode and (surfnode.drawtype == 'liquid' or surfnode.drawtype == 'flowingliquid') do
surfnodename = surfnode.name
surface = snodepos.y +0.5
if surface > spos.y+self.height then break end
snodepos.y = snodepos.y+1
surfnode = airutils.nodeatpos(snodepos)
end
local new_velocity = nil
self.isinliquid = surfnodename
if surface then -- standing in liquid
self.isinliquid = true
end
local accell = {x=0, y=0, z=0}
self.water_drag = 0.1
if self.isinliquid then
local height = self.height
local submergence = min(surface-spos.y,height)/height
-- local balance = self.buoyancy*self.height
local buoyacc = airutils.gravity*(self.buoyancy-submergence)
--[[airutils.set_acceleration(self.object,
{x=-vel.x*self.water_drag,y=buoyacc-vel.y*abs(vel.y)*0.4,z=-vel.z*self.water_drag})]]--
accell = {x=-vel.x*self.water_drag,y=buoyacc-(vel.y*abs(vel.y)*0.4),z=-vel.z*self.water_drag}
--local v_accell = {x=0,y=buoyacc-(vel.y*abs(vel.y)*0.4),z=0}
--airutils.set_acceleration(self.object,v_accell)
new_velocity = vector.add(vel, vector.multiply(accell, self.dtime))
else
airutils.set_acceleration(self.object,{x=0,y=0,z=0})
self.isinliquid = false
new_velocity = vector.add(vel, {x=0,y=airutils.gravity * self.dtime,z=0})
--self.object:set_velocity(new_velocity)
end
if new_velocity then
new_velocity = vector.add(new_velocity, vector.multiply(self._last_accell, self.dtime))
if new_velocity.x == nil then new_velocity.x = 0 end
if new_velocity.y == nil then new_velocity.y = 0 end
if new_velocity.z == nil then new_velocity.z = 0 end
--[[
new_velocity correction
under some circunstances the velocity exceeds the max value accepted by set_velocity and
the game crashes with an overflow, so limiting the max velocity in each axis prevents the crash
]]--
local max_factor = 55
local vel_adjusted = 40
if new_velocity.x > max_factor then new_velocity.x = vel_adjusted end
if new_velocity.x < -max_factor then new_velocity.x = -vel_adjusted end
if new_velocity.z > max_factor then new_velocity.z = vel_adjusted end
if new_velocity.z < -max_factor then new_velocity.z = -vel_adjusted end
if new_velocity.y > max_factor then new_velocity.y = vel_adjusted end
if new_velocity.y < -max_factor then new_velocity.y = -vel_adjusted end
-- end correction
self.object:set_pos(self.object:get_pos())
-- dumb friction
if self.isonground and not self.isinliquid then
self.object:set_velocity({x=new_velocity.x*friction,
y=new_velocity.y,
z=new_velocity.z*friction})
else
if pa28.mode == 1 then
self.object:set_velocity(new_velocity)
end
end
end
if pa28.mode == 2 then
self.object:set_acceleration({x=0,y=airutils.gravity,z=0})
end
end