Homing Missile Library

The project is under the GNU GENERAL PUBLIC LICENSE Version 3

Building project from source

1. Download the latest release from here:

   example ==> https://github.com/yoyoberenguer/Homing-missile/releases/tag/v1.0.2

2. Decompress the archive and enter the project directory

   c:\>cd Homing-missile-1.0.2
   
   Refers to section Building Cython & C
   C:\>python setup.py build_ext --inplace --force
   

Run the demo

In Homing-missile-1.0.2

C:\>cd HomingMissile 
C:\>python homingmissile.py

Key	Assignement
ARROW KEYS	(LEFT, RIGHT, UP and DOWN) for spaceship direction
SPACEBAR	Fire missiles
PAUSE/BREAK	Pause the demo for 2 secs
ESC	to quit
Mouse	Move target

Preview

Missile attributes

The XML file Weapon.xml contains 4 different missile type:

• STINGER
• BUMBLEBEE
• WASP
• HORNET

Missile properties/attributes can be edited and changed in the XML. 
You can change the missile velocity, reloading time, amount of damage, turn radius per frame etc 
e.g 
velocity='-15' | damage='1050' | max_rotation='10' 

You can also change the missile trail sprite animation to your liking, e.g 
missile_trail_fx="MISSILE_TRAIL_DICT2", you can passed a different sprite animation (check the file
`textures.py` for more details on how to create a sprite animation) 

Sound effect can also be changed with the variable `propulsion_sound_fx`

<?xml version="1.0"?>
<class>
    <category name = "MISSILE">
        <modes>
            <mode name = "GUIDED">
                <weapon name="STINGER"
                  type="Missile"
                  image="STINGER_IMAGE"
                  sprite_orientation="90"
                  sprite_rotozoom ="STINGER_ROTATE_BUFFER"
                  propulsion_sound_fx="STINGER_EXHAUST_SOUND"
                  missile_trail_fx="MISSILE_TRAIL_DICT2"
                  missile_trail_fx_blend = "pygame.BLEND_RGB_ADD"
                  animation='None'
                  range='SCREENRECT.h'
                  bingo_range = '(100, 120)'
                  velocity='-15'
                  damage='1050'
                  timestamp='0'
                  reloading_time='2'
                  detonation_dist='None'
                  max_rotation='10'>

Missiles classes

The file Weapon.pyx contains all the missile class such as

• HomingMissile

  PURE PURSUIT ALGORITHM
  Guided ballistic missile :
  This missile adjust its direction by adding small degrees values (turn radius) until
  reaching the optimal angle difference (0 degrees).
  The missile is in on collision course when the angle between the missile heading and the
  target heading difference is approximately null.        
  

• InterceptMissile

  LEAD COLLISION (proportional navigation) more effective, follow an optimal path
  Intercept theorem (Thales basic proportionality theorem)
  https://www.youtube.com/watch?v=T2fPKUfmnKo
  https://codereview.stackexchange.com/questions/86421/line-segment-to-circle-collision-algorithm
  

• AdaptiveMissile

  Homing missile (guided missile) with automatic gradual acceleration/deceleration.
  This projectile is capable of very sharp angle.
  It can accelerate in straight trajectory and decelerate in the turns to increase manoeuvrability
  

This file contains also the following methods

• fast_lead_collision (Written in Cython and provide a very fast calculation for missile intercept, returns a vector)
• lead_collision (written in Cython, this method returns a structure containing both, vectors and collision point)

Code

Check HomingMissile.py to see how to use the missile library.

1 - load the XML data for each missile e.g

# Load the missile from xml file
STINGER_XML   = dict(xml_get_weapon('Weapon.xml', 'STINGER'))
BUMBLEBEE_XML = dict(xml_get_weapon('Weapon.xml', 'BUMBLEBEE'))
WASP_XML      = dict(xml_get_weapon('Weapon.xml', 'WASP'))
HORNET_XML    = dict(xml_get_weapon('Weapon.xml', 'HORNET'))

2 - Parse the XML values into a python dict

# Parse the values into dictionaries
STINGER_FEATURES   = xml_parsing(STINGER_XML)
BUMBLEBEE_FEATURES = xml_parsing(BUMBLEBEE_XML)
WASP_FEATURES      = xml_parsing(WASP_XML)
HORNET_FEATURES    = xml_parsing(HORNET_XML)

Below an example with the class HomingMissile using the missile STINGER (STINGER_FEATURES)

Shoot_angle define the firing angle, 90 degrees here means that the missile will be fire ahead of the aircraft, -90 will lauch the missile from behind the aircraft.

offset (int:x, int:y) define the missile offset position from the aircraft center.

At (0, 0) the missile is lauched from the centre of the aircraft while (-30, 0) means that the missile will be fired from the left wing and (+30, 0) from the right wing.

ignition True delay the particle system

if keys[pygame.K_SPACE]:

   if GL.PLAYER.rect.colliderect(SCREENRECT):

       player = GL.PLAYER
       if not player.is_missile_reloading(
               STINGER_FEATURES['reloading_time'] * 1000 / GL.TIME_PASSED_SECONDS):

           extra = ExtraAttributes(
               {'target': target,
                'shoot_angle': 90,
                'ignition': False,
                'offset': (-30, 0)})

           s = HomingMissile(
               gl_=GL,
               group_=(GL.ALL, GL.PLAYER_PROJECTILE),
               weapon_features_=WASP_FEATURES,
               extra_attributes=extra,
               timing_=800,
               )

and below for the class InterceptMissile using the missile BUMBLEBEE (BUMBLEBEE_FEATURES)

extra = ExtraAttributes(
   {'target': target,
    'shoot_angle': 90,
    'ignition': False,
    'offset': (30, 0)})

s = InterceptMissile(
   gl_=GL,
   group_=(GL.ALL, GL.PLAYER_PROJECTILE),
   weapon_features_=BUMBLEBEE_FEATURES,
   extra_attributes=extra,
   timing_=800,
)

Goodies

The file SpriteSheet.pyx contains two super fast algorithms for dealing with spritesheets

- sprite_sheet_per_pixel  
  (for 32-bit spritesheet with per-pixel transparency)
  
- sprite_sheet_fs8 
  (for 24-bit 32-bit without alpha layer)

Building Cython & C

When do you need to compile the cython code ?

The first time compilation and each time you are modifying any of the pyx files such as Sprites.pyx, Sprites.pxd, *.pyx and *.pxd init.pxd or any external C code if applicable

1. open a terminal window
2. Go in the main project directory HomingMissile where (setup.py & requirements.txt are located)
3. run : C:\>python setup.py build_ext --inplace --force

If you have to compile the code with a specific python version, make sure to reference the right python version in (python38 setup.py build_ext --inplace)

If the compilation fail, refers to the requirement section and make sure Cython and a C-compiler are correctly install on your system.

• A compiler such visual studio, MSVC, CGYWIN setup correctly on your system.
  • a C compiler for windows (Visual Studio, MinGW etc) install on your system and linked to your Windows environment. Note that some adjustment might be needed once a compiler is install on your system, refer to external documentation or tutorial in order to setup this process.e.g :

https://devblogs.microsoft.com/python/unable-to-find-vcvarsall-bat/

If the project build successfully, the compilation will end up with the following lines

Generating code
Finished generating code

If you have any compilation error(s) refer to the section Building cython code, make sure your system has the following program & libraries installed. Check also that the code is not running in a different thread.

• Python version >3
• pygame >=2.0.0
• numpy >= 1.18
• cython >=0.29.21 (C extension for python)
• PygameShader >=1.0.8
• A C compiler for windows (Visual Studio, MinGW etc)

OPENMP for Linux and Windows

If you need to build the package with multiprocessing, you can change the flag OPENMP
in the setup.py file such as :

To build the package with multiprocessing (OPENMP=True)

in the setup.py file

# True enable the multiprocessing
OPENMP = True
OPENMP_PROC = "-fopenmp" 
LANGUAGE = "c"
ext_link_args = ""

Then compile the code (e.g :)

C:\...HomingMissile\python setup.py build_ext --inplace

Dependencies :

numpy >= 1.18
pygame >=2.0.0
cython >=0.29.21
PygameShader>=1.0.8
   

Your contribution

Please report any bugs to

https://github.com/yoyoberenguer/Homing-missile/issues

---

Credit

Yoann Berenguer

License :

GNU GENERAL PUBLIC LICENSE Version 3

Copyright (c) 2019 Yoann Berenguer

Copyright (C) 2007 Free Software Foundation, Inc. https://fsf.org/ Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.