Hi
I know how to move an object to a point, but how to move in a random direction?
For an example, if I wan’t to create a car object, that rotates and drive in a random direction, how do I set the direction and move the car/object in that direction?
If anyone can link to a (very) simple tutorial - I’ll be happy 
Thanks
Is your car just a drawing or a drawing+physics object? With drawing you have to manage the movement steps youself, with physics object just set linearVelocity property.
It could be a simple line
.@Jorgensen if you know how to move an object to a point(say coordinates Targetx,Targety) you could make that point a random location.
Targetx=math.random(WIDTH)
Targety=math.random(HEIGHT)
If you put this in the setup it will generate a random location. If you put it in the main draw loop then it will generate a new location each cycle so you’ll want to control when you create a new location somehow.
Here’s a simple example of moving a circle to a random point. Depending on what you want to do will determine how much you change this.
displayMode(FULLSCREEN)
function setup()
rx=math.random(WIDTH)
ry=math.random(HEIGHT)
x=rx
y=ry
end
function draw()
background(40, 40, 50)
fill(255)
ellipse(x,y,20)
ellipse(rx,ry,5)
if math.abs(x-rx)<5 and math.abs(y-ry)<5 then
rx=math.random(WIDTH)
ry=math.random(HEIGHT)
else
x=x+((rx-x)/60)
y=y+((ry-y)/60)
end
end
Thanks West - I’ll try that.
Do know how i best rotate my ‘car’ - Can one totate the global coordinates before drawing the car?
Thanks
Here is my code so far
--# Main
-- car 1
-- Use this function to perform your initial setup
function setup()
print("Hello World!")
car_a = car(WIDTH, HEIGHT/2, -1.5, 0)
--noStroke()
end
-- This function gets called once every frame
function draw()
background(81, 188, 57, 255)
car_a:draw()
-- This sets a dark background color
--
-- This sets the line thickness
--strokeWidth(5)
-- Do your drawing here
end
function touched(touch)
if touch.state == BEGAN then
car_a.color_lights_back = color(255, 5, 0, 255)
car_a.breaking = true
--print(touch)
end
if touch.state == ENDED then
car_a.color_lights_back = color(222, 115, 116, 255)
--print(touch)
car_a.breaking = false
end
end
--# car
car = class()
function car:init(_x, _y, _xspeed, _yspeed)
-- you can accept and set parameters here
self.breaking = false
self.x = _x
self.y = _y
self.xspeed = _xspeed
self.yspeed = _yspeed
self.color_body = color(100,100,100)
self.color_lights_front = color(255, 255, 255, 255)
self.color_lights_back = color(221, 127, 127, 255)
self.dimensions_width = 5
self.dimensions_length = 7
end
function car:draw()
-- Codea does not automatically call this method
self:body()
self:lights_front()
self:lights_back()
self:move()
end
function car:touched(touch)
-- Codea does not automatically call this method
end
function car:body()
fill(self.color_body)
y = self.y
x = self.x
rect(x, y, self.dimensions_length, self.dimensions_width)
end
function car:lights_front()
fill(self.color_lights_front)
y = self.y
x = self.x
rect(x-3, y, 3, self.dimensions_width)
end
function car:lights_back()
fill(self.color_lights_back)
y = self.y
x = self.x
rect(x+self.dimensions_length -1, y, 3, self.dimensions_width)
end
function car:move()
if self.breaking == true and self.xspeed <=0 then
self.xspeed = self.xspeed + 0.02
--else self.xspeed = -1
end
if self.breaking == false and self.xspeed > -1.5 then
self.xspeed = self.xspeed - 0.02
end
self.x = self.x + self.xspeed
end
Hmm this don’t look good 
Hi Dave
Thanks for you input. I’ll try it out - but Can’t one use vectors for moving?
Put three ‘~’ before and after your code (—), it will lool good
.@Jorgensen the following modifications to your code will rotate your car body by 30 degrees. You’ll need something similar for the other parts of the car. Lookup the help to get an overview of the commands used
function car:body()
fill(self.color_body)
y = self.y
x = self.x
pushMatrix()
translate(x,y)
rotate(30)
translate(-x,-y)
rect(x, y, self.dimensions_length, self.dimensions_width)
popMatrix()
end
… @Jorgensen Maybe this will give you some ideas.
displayMode(FULLSCREEN)
function setup()
car=image(20,10) -- car image area
-- head lights
c=color(255, 255, 255, 255)
for x=1,5 do
for y=1,3 do
car:set(x,y,c)
car:set(x,y+7,c)
end
end
-- car body
c=color(250, 162, 13, 255)
for x=6,20 do
for y=1,10 do
car:set(x,y,c)
end
end
-- tail lights
c=color(255, 0, 0, 255)
for x=17,20 do
for y=1,3 do
car:set(x,y,c)
car:set(x,y+7,c)
end
end
cx=200
cy=400
rx=cx
ry=cy
end
function draw()
background(40, 40, 50)
calcNext()
fill(255)
ellipse(rx,ry,5)
pushMatrix()
translate(cx,cy)
rotate(270-direction)
sprite(car,0,0)
popMatrix()
end
function calcNext() -- next random position
if math.abs(cx-rx)<5 and math.abs(cy-ry)<5 then
rx=math.random(WIDTH)
ry=math.random(HEIGHT)
dx=cx-rx
dy=cy-ry
speed=2/math.sqrt(dx*dx+dy*dy)
sx=dx*speed
sy=dy*speed
carDirection()
end
cx = cx - sx
cy = cy - sy
end
function carDirection() -- direction facing forward
direction=math.deg(math.atan2(rx-cx,ry-cy))
end
Below is my little contribution to things moving randomly:
--
-- Random Thing
--
supportedOrientations(LANDSCAPE_ANY)
function setup()
myThing = Thing(WIDTH / 2, HEIGHT / 2, 0)
img = image(WIDTH, HEIGHT) -- For breadcrumb trail
spriteMode(CORNER)
end
function draw()
background(64)
sprite(img, 1, 1)
myThing:draw()
-- Update breadcrumb trail
setContext(img)
fill(127, 127, 0)
ellipse(myThing.x, myThing.y, 5)
setContext()
end
Thing = class()
-- Initialise the Thing
function Thing:init(x, y, angle)
self.x = x
self.y = y
self.angle = angle
self.speed = 100
self.spin = 360
self.colour = color(255, 255, 0)
self:think(self.turn)
end
-- Tell the Thing to think a second about its next action
function Thing:think(nextAction)
if self.state == "thinking" then return end
self.state = "thinking"
self.stopThinking = ElapsedTime + 1
self.nextAction = nextAction
end
-- Tell the Thing to turn
function Thing:turn()
self.state = "turning"
local turn = math.random(15, 105) * (math.random(2) * 2 - 3)
if turn * self.spin < 0 then
self.spin = -self.spin
end
self.remainingTurn = turn
end
-- Tell the Thing to move
function Thing:move()
self.state = "moving"
local dx = self.x - WIDTH / 2
local dy = self.y - HEIGHT / 2
local strayDistance = math.sqrt(dx * dx + dy * dy)
local maxRun = math.max(10, math.exp(-strayDistance / WIDTH * 5) *
200)
maxRun = math.min(200, maxRun)
self.remainingDistance = math.random(10, maxRun)
end
-- Update and draw the Thing
function Thing:draw()
-- Update the Thing given its state
if self.state == "thinking" then
if ElapsedTime > self.stopThinking then
self.state = nil
self.nextAction(self)
end
elseif self.state == "moving" then
local distance = self.speed * DeltaTime
self.x = self.x + math.cos(math.rad(self.angle)) *
distance
self.y = self.y + math.sin(math.rad(self.angle)) *
distance
self.remainingDistance = self.remainingDistance -
distance
if self.remainingDistance < 0 then
self:think(self.turn) -- Think about turning
end
elseif self.state == "turning" then
local turn = self.spin * DeltaTime
self.angle = (self.angle + turn) % 360
self.remainingTurn = self.remainingTurn - turn
if self.spin * self.remainingTurn < 0 then
self:think(self.move) -- Think about moving
end
end
-- If doing nothing, a random thought may occur...
if self.state == nil and math.random(60) == 1 then
self:think(self.turn)
end
-- Draw the Thing
pushMatrix()
pushStyle()
resetMatrix()
translate(self.x, self.y)
rotate(self.angle)
noStroke()
fill(self.colour)
ellipseMode(CENTER)
ellipse(0, 0, 50, 20)
fill(0)
ellipse(18, 3, 4)
ellipse(18, -3, 4)
popStyle()
popMatrix()
end