TheGameCreators - CodeBase - Flight simulator code

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Category: Complete Applications

Version: 1.0

Information

Uploaded: 29th Oct 2007 20:30

Modified: 29th Oct 2007 22:14

Author: Muddleglum

Summary

Natural, realistic flight performance, yet easy and intuitive to use.

Full Description

Uses alternate geometry to make a flight simulator that can be used for simple games or developed into something which matches a sophisticated mathematical simulator. <br /> explanations are in the code as remarks. <br /> The demo here requires no extra data, Use as you will.<br /> <br />

DarkBASIC Source Code

` This code was downloaded from The Game Creators

` It is reproduced here with full permission

` http://www.thegamecreators.com

`             Flight angles demo by David Lawrence ( muddleglum in the forums)  September 2007.

`                 email -    muddle (at) orcon.net.nz

`   If you want a scientific simulator you will have to use a different system

` that works out the  effects of rotation and position change seperately.  ... but this method, using

` angular change to represent the forces,  is simple,  convincing to most appearances,

`  and pleasingly natural to control for most uses.

`  The method can be matched to specific  aerodynamic factors,

`  ie.  scaling  of  turn radius to plane size,  scaling of  gravity,

`    specific  inertia ,  drag,   control reaction rate according to speed or plane type,

`    improved rudder yaw action  etc etc.   so that the whole system  is almost

`     indistinguishable from the scientific method.

`   Note that this  is a fixed frame rate method, which make a lot of things simpler, and does not

`   normally cause a visual problem because of the smoothness of the movement.

`  ` The essential flight rotation code is only two lines and without complicated maths -- much of the

`    program is 'setting  up'--- however, the imitation inertia inputs  are an essential

`    part of the natural feel.  You also get a few simple but effective methods for power and views.

`       Please use  a joystick if you have one.  It is much more satisfying.

`     ( Use with a classic DB version later than 1.1  ..  db pro should also work I believe,

`      but my trial version just expired .. maybe minor changes?)

`  -----------------------------------------------------------------------------------

`                                       NOTE  NOTE

` The simulation method contained in this code may be freely copied

`If found useful for commercial purposes acknowledgment would be nice,  or even reward for this author!

`  -------------------------------------------------------------------- ----------------------

`set up a world stuff

set display mode 1024,768,16

hide mouse

sync on

`make a ground texture

cls rgb(80,130,90)

ink rgb(90,110,60),0

for x=0 to 56

dot x,rnd(56):dot x,rnd(56):dot x,rnd(56):dot x,rnd(56)

next x

ink rgb(70,120,70),0

for x=0 to 56

dot x,rnd(56):dot x,rnd(56):dot x,rnd(56):dot x,rnd(56)

next x

ink rgb(95,115,90),0

for x=0 to 56

dot x,rnd(56):dot x,rnd(56):dot x,rnd(56):dot x,rnd(56)

next x

get image 1,0,0,56,56

cls rgb(50,90,90)

sync rate 30

set camera range 1,9000

set camera view 25,55,1000,700

autocam off

make matrix 1,20000,20000,45,45

prepare matrix texture 1,1,2,2

randomize matrix 1,150.0

ink rgb(250,125,20),0

set cursor 10,1: print "F1  cockpit view"

set cursor 540,1: print "F4 follow view level"

set cursor 270,1: print "F2  follow view rolling"

set cursor 850,1:print "F3  fly by view"

set cursor 10, 18:print "A -accelerate ,  S  slow"

set cursor 270,18:print "R  reset position to start"

set cursor 540,18:print " arrow keys for roll/pitch"

set cursor 850,18:print "Q left yaw ,   W right yaw"

set cursor 10,36:print " J -  use joystick control  ... or  .... ... K -  use Arrow key controls(default)"

set cursor 540,36:print  "Elevator is used to pull a sharp banked turn "

ink rgb(250,225,220),0

view=2

auto=0

control=0

`make an 'aircraft'

make object cube 4, 20

scale object 4,130,3,20

make object cone 5,25

scale object 5,8,600,400

pitch object down 5,90

fix object pivot 5

glue object to limb 5,4,0

color object 5,rgb(255,40,40)

set ambient light 30

fog on

fog color rgb(60,140,150)

color backdrop rgb(70,150,170)

fog distance 3500

sync on

direction#=0

climb#=0

speed# = 0

power#=2

position object 4, 3400,250,3200

rotate object 4,0,0,0

mainloop:

` ///////////////////////////////////////////-MAIN LOOP ////////////////////////////////

` if hit ground

if object position y(4) < get ground height(1,object position x(4), object position z(4))

set cursor 250,250

print "THUD!  CRASH!"

position object 4,object position x(4),object position y(4)+20,object position z(4)

pitch object up 4,20

endif

`  view control Inputs

if scancode()=59 then view =2 : ` F1

if scancode()=60 then view =0

if scancode()=62 then view =1

if scancode()=61 then view=3

`  power  input

if inkey$()="a" then power#=power#+.15

if power#>15 then power#=15

if inkey$()="s"

power#=power# -.2

if power#<0 then power#=0

endif

if inkey$()="j" then control =1

if inkey$()="k" then control=0

arrowkeycontrol:

if control =0

if rightkey() = 1 then   rollstep#=rollstep#+.4

if leftkey() = 1  then    rollstep#=rollstep#-.4

rollstep#=rollstep#*.9

roll object right 4,rollstep#:` basic aileron / roll action of plane.

if downkey() = 1 then pitchstep#=pitchstep#+.2

if upkey() = 1 then pitchstep#=pitchstep#-.2

pitchstep#=pitchstep#*.9

pitch object up 4, pitchstep#: `basic pitch action of plane

endif

alternatejoystick:

if control =1

joyr#=joystick x()/180.0

joyp#=joystick y()/180.0

`  apply aileron

rollstep#=rollstep#+(joyr#/8) :` provides an intertia effect

rollstep#=rollstep#*.9  :` provides a damping effect..   a value like .95 or higher  will also allow a

` wandering effect such as you get with some less laterally stable model aircraft.

roll object right 4,rollstep#:` basic aileron / roll action of plane

` apply elevator

pitchstep#=pitchstep#+(joyp#/20)

pitchstep#=pitchstep#*.9

pitch object up 4, pitchstep#

endif

` -----------------------------------------------------------

` the critical code follows  ...

` -----------------------------------------------------

` get a roll angle  related to WORLD horizontal. When the plane is tilted, pitched or turned this provides

`  a  result different from  the plane relative roll angle.  This difference  makes the system work.

alt#=object position y(4)

turn object right 4,90

move object 4,1

sineroll#= object position y(4) -alt#

move object 4, -1

turn object left 4, 90

`then split the tilted lift vector of the wings between the WORLD horizontal and vertical axis using sineroll.

turn object left 4,sineroll#

pitch object up 4, abs(sineroll#)/2

` The above lines are the approximate lift split version, but are better for common use as they

`  include a slight over elevation effect which require less pilot input.

`                                 ----------------------

` The ACCURATE force split is shown just below .... BUT..  it is actually more demandng

` of the pilot , especially without the rest of a full code, and effects of wing/tailplane  incidence at speed.

` The following may still be simple, but it  was a giant and ORIGINAL effort to discover (geometric-graphically?).

`     turn object left 4, sineroll#

`     if sinroll#<0 then cotilt#=(1+sineroll#)*-1 else cotilt#=1-sineroll#

`     pitch object up 4, (abs(sineroll#) - abs(sineroll#*cotilt#))

`  The split code also imitates the  gravity effect when the rolled wing loses vertical lift

` and the plane turns towards the ground.   When correctly scaled to match a 1G turn radius ( which is

` when the height remains constant through the turn)  with a correct forward speed increase for G

` then the turn downwards matches gravity quite accurately.

`                                   ---------------------------

` then continue with some simple  rudder yaw input -------- good for aiming at things  ( a true yaw does not

` necessarily alter the plane flight direction as this does).

if inkey$()="w" then rudder#=rudder#+.1

if inkey$()="q" then rudder#=rudder#-.1

rudder#=rudder#*.9

turn object right 4,rudder#

` -------------If you want to add simple gravity and gliding effects ---------------

`get world related pitch.

move object 4,1

truepitch#= alt# -object position y(4)

move object 4, -1

gravity#=truepitch#*2 :` gravity can  be  accurately calculated against world scale and frame rate if desired.

` ie.. the speed increase exactly vertical ( without drag) should be an additional 32 ft every sec.

` You can simply add this each time  and though it is fractionally  different from the 'official'

` calculation over the first frames  it is absolutely accurate therafter.

`add  a cheap glide effect!

if speed#<2.5 and truepitch#<.3 then pitch object down 4,.15

` the nose down attitude will mean gravity#  provides a basic glide speed#  even with power at zero.

`                             -----------------------------------

` To do gliding 'properly' you need

` 1. a  'pitching up' that results from tailplane incidence and speed .. different degree for different designs.

` 2. a 'pitching down'  that results from how far the planes center of gravity is ahead ( usually) of the `

`     centre of lift of the wings.  This pitching is 0 when pitch is vertical.  max when horizontal.

`     ie it matches the  cosine of the pitch angle.  Obtain with a 'move' similar to the pitch angle above.

`            (This  cosine is relative to the world again, since the drop from the wing being tilted /rolled

`              is handled previously)

` 3. an accurate speed increase for gravity.

` 4. an accurate drag coeficient.

`   The whole is a delicate and interactive balance.   You can see its  operation with a simple real

` model plane  or nose weighted paper dart by dropping  and throwing it in different ways.

`  ( which is how  I confirmed this theory.   Then saw similar formula on the internet. )

`  One thing I want to perfect later is  the transition when elevator is used to hold the wing

`   at a steeper angle (and greater drag)  as the speed drops close to the wings stall speed and

`  the inertia and/or  propeller may still maintains  a 'flare' for a short time.

`                            ------------------------------------

rem  ....     some basic speed  control

coefdrag#=.05

drag#=coefdrag#*speed#*speed# : ` airdrag increases with square of airspeed and limits the maximum

speed#=speed#+gravity# + power#-drag#

if speed#<1 then speed#= 1  : ` because this  demo  has no stall routine etc.!

move object 4,speed#

` ................... camera  views ....................

views:

if view =0

position camera object position x(4),object position y(4),object position z(4)

set camera to object orientation 4

pitch camera down 8

move camera -70

endif

if view=1

position camera object position x(4),object position y(4),object position z(4)

set camera to object orientation 4

pitch camera down 8

move camera -70

point camera object position x(4),object position y(4),object position z(4)

endif

if view=2

position camera object position x(4),object position y(4),object position z(4)

set camera to object orientation 4

endif

if view =3:` fly by view

if count<1

position camera object position x(4),object position y(4),object position z(4)

set camera to object orientation 4

move camera   100+(speed#*50)

if camera position y() < 120 then  position camera  camera position x(),130, camera position z()

count= 120

endif

dec count

point camera object position x(4),object position y(4),object position z(4)

endif

` reset to start position

if inkey$()="r"

speed# = 0

power#=2

position object 4, 3400,250,3200

rotate object 4,0,0,0

endif

set cursor 400,90

print "Power  "; int(power#*10)

set cursor 400,110

print "Speed  "; int(speed#)

sync

loop

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Author Name:	Muddleglum
CodeBase Entries:	2

CodeBase - Flight simulator code

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DarkBASIC Source Code

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