I've ported some of Marco Monster's code now, but cant get it to work.
Heres my version of the code:
Code: Select all
function love.load()
cartype = {
b = 1,
c = 1,
wheelBase = 1 + 1,
h = 1,
mass = 1000,
inertia = 1500,
width = 1.5,
length = 3.0,
wheellength = 0.7,
wheelwidth = 0.3
}
car = {
cartype = cartype,
position = {x = 400,y = 400},
velocity = {x = 0,y = 0},
angle = 0,
avelocity = 0,
steerangle = 0,
throttle = 0,
brake = 0
}
end
function math.sign(x)
if x<0 then
return -1
elseif x>0 then
return 1
else
return 0
end
end
function do_physics(dt)
local drag,rest,caR,caF,maxGrip = 5.0,30.0,-5.20,-5.0,2.0
local sn = math.sin(car.angle)
local cs = math.cos(car.angle)
velocity = {}
velocity.x = cs * car.velocity.y + sn * car.velocity.x;
velocity.y = -sn * car.velocity.y + cs * car.velocity.x;
yawspeed = car.cartype.wheelBase * 0.5 * car.avelocity
if velocity.x == 0 then
rot_angle = 0
else
rot_angle = math.atan2(yawspeed,velocity.x)
end
if velocity.x == 0 then
sideslip = 0
else
sideslip = math.atan2( velocity.y, velocity.x);
end
slipanglefront = sideslip + rot_angle - car.steerangle
slipanglerear = sideslip - rot_angle
weight = car.cartype.mass * 9.8 * 0.5
flatf = {}
flatf.x = 0;
flatf.y = caF * slipanglefront;
flatf.y = math.min(maxGrip, flatf.y);
flatf.y = math.max(-maxGrip, flatf.y);
flatf.y = flatf.y * weight;
flatr = {}
flatr.x = 0;
flatr.y = caR * slipanglerear;
flatr.y = math.min(maxGrip, flatr.y);
flatr.y = math.max(-maxGrip, flatr.y);
flatr.y = flatr.y * weight;
ftraction = {}
ftraction.x = 100*(car.throttle - car.brake*math.sign(velocity.x));
ftraction.y = 0;
resistance = {}
resistance.x = -(rest*velocity.x+drag*velocity.x*math.abs(velocity.x))
resistance.y = -(rest*velocity.y+drag*velocity.y*math.abs(velocity.y))
force = {}
force.x = ftraction.x + math.sin(car.steerangle) * flatf.x + flatr.x + resistance.x;
force.y = ftraction.y + math.cos(car.steerangle) * flatf.y + flatr.y + resistance.y;
torque = car.cartype.b * flatf.y - car.cartype.c * flatr.y;
acceleration = {}
acceleration.x = force.x/car.cartype.mass;
acceleration.y = force.y/car.cartype.mass;
angular_acceleration = torque / car.cartype.inertia;
acceleration_wc = {}
acceleration_wc.x = cs * acceleration.y + sn * acceleration.x;
acceleration_wc.y = -sn * acceleration.y + cs * acceleration.x;
car.velocity.x = car.velocity.x + dt * acceleration_wc.x;
car.velocity.y = car.velocity.y + dt * acceleration_wc.y;
car.position.x = car.position.x + dt * car.velocity.x;
car.position.y = car.position.y + dt * car.velocity.y;
car.avelocity = car.avelocity + dt * angular_acceleration;
car.angle = car.angle + dt * car.avelocity ;
end
function love.update(dt)
if love.keyboard.isDown("w") then car.throttle = car.throttle + 100 end
if love.keyboard.isDown("a") then
car.steerangle = car.steerangle - math.rad(15)
end
if love.keyboard.isDown("d") then
car.steerangle = car.steerangle + math.rad(15)
end
do_physics(dt)
end
function love.draw()
gr.circle("fill",car.position.x, car.position.y,3)
end
Might be something to do with deg to rads or vice-versa?
