Soccer Field Dimensions

1
Soccer Field Dimensions
(65, 65)
(-65, 65)
130
(65, -65)
(-65, -65)
130
Angles are measured in radians going
anti-clockwise from the positive x axis. Goal
Size (radius) was 7.5m by default, I had to
increase it to 13m to cover the actual goal nets
adequately. All other parameters were left at
their defaults. Parameters are set inside
default.sma inside the engine sub-directory of
Gun-Tactyx
2
Math Requirements

• You must be competent with basic trigonometry and
  geometry.
• You need to be confident converting between Polar
  and Cartesian coordinates.
• Youll need to convert between relative and
  absolute vectors and handle vector arithmetic
  such as normalising vectors, adding vectors and
  doing dot and cross products.
• You also need to remember your SOHCAHTOA rules
  and how to calculate distances between two
  Cartesian points using the Pythagoras formula.

3
Useful Functions 1
floatBoundAngle(floatangle) if(angle gt
0.0) angle mod(angle, 2PI) else
angle 2.0PI - mod(-angle, 2PI) if(angle
gt PI) angle - (2.0PI) return
angle //end BoundAngle
Takes an unbounded angle and returns a bounded
angle between 0 and 2p, without using any loops.
4
Useful Functions 2
ConvertCartesian(floatyaw,floatdist,floatx,fl
oaty) x dist cos(yaw) y dist
sin(yaw) //end ConvertCartesian
Takes a Polar coordinate, such as returned by one
of the sensor functions and converts it to
Cartesian coordinates.
5
Useful Functions 3
ConvertPolar(floatx,floaty,floatyaw,floatdis
t) //new const float PI 3.1415 dist
sqrt(xx yy) if((x lt 0.01)(x gt -0.01))
if(y gt 0) yaw
PI / 2.0 else
yaw PI 3.0 / 2.0 //end if
- check if x is close to zero else
yaw atan(y / x) if(x lt 0.0) yaw
PI else if(y lt 0.0) yaw (2.0
PI) //end else yaw BoundAngle(yaw)
Takes a Cartesion coordinate, such as the goal to
aim for and converts it to polar coordinates to
steer the bot with.
6
Last Years League Winners
Rank Name Win/Loss Win/Loss
1 David 43/47 91.489 2 Roland 30/36 83.333
3 Jeff 23/30 76.667 4 Recruit 26/43 60.
465
Map Field Teams 2 Players 8 Match
Length 30 mins Start Corners 0 and 1, 2 and 3
(opposite sides) Description All on all
tournament, each bot played every other bot 4
times, once from each starting corner (total 48
matches per bot). Drawn game results not shown.
7
Davids bot

• Pros
• Only bot that could accurately kick towards the
  goals (calculated a vector between the ball and
  the goals, then projected a perpendicular vector
  from the bots position to the ball to
  sideswipe the ball in the right direction).
• Often made it to the ball before opponents since
  it took a very direct approach.
• Premier bot, consistently beat every other
  opponent.
• Very simple code, one of the smallest bots in
  terms of source code.
• Cons
• No team play whatsoever, each bot behaved exactly
  the same and ignored team mates.
• Could only kick the ball within 90 degrees of the
  direction it was currently travelling.
• Prone to kicking own goals if the ball was on the
  opposite side of the bot to the direction it
  wanted to kick in.

8
Rolands bot

• Pros
• Best team play, reserved 3 bots as defenders and
  while the rest roamed.
• Defenders were well organised and effective.
• Attackers were reasonable and never kicked own
  goals.
• Cons
• Attacking bots had no memory, when they got too
  close to the ball it would go beneath their field
  of vision and they would forget it was there,
  turning away at the last moment to look for the
  ball else where.

9
Jeffs bot

• Pros
• Sophisticated attack code for circling onto the
  ball and kicking it directly in the desired
  direction.
• Best coding standards, most readable and
  efficient code (all the useful functions copied
  straight from Jeffs code).
• Also showed team behaviour with three bots
  allocated to defensive (but not as effective as
  Rolands).
• Cons
• The circling attack took too long to make contact
  with the ball, opponents would often kick it away
  first.
• Had poor thrashing behaviour, so could get
  tangled up with allied and opposing bots easily
  and never break free.

10
Recruit

• Pros
• Took the most direct path to the ball, usually
  making contact before the opponents and spoiling
  their more sophisticated tactics.
• Would widely disperse around the field and rarely
  get tangled up when colliding for long.
• Despite completely goalless behaviour still beat
  all last years the students bots (in every
  league that was played) with the exception of
  Davids, Rolands and Jeffs bots.
• Cons
• Just wanted to kick the ball, doesnt care where.
  So just as likely to kick own goals as opposing
  goals.

11
General tips

• Take the time to learn the keys, especially the
  time modifiers (-/) on the number pad Watching
  games in x1 speed gets boring really fast and
  its a big waste of time.
• Remember the bots angles are absolute, not
  relative, use the functions in these notes to
  take a relative angle you wish to turn and add it
  to the bots absolute angle. Otherwise your bots
  will spend most of their time spinning in
  circles.
• The 2d view is generally more useful for judging
  the bots behaviours and team play.
• Use the provided gtplaylist and gtstat command
  line tools to set up your own tournaments to play
  at high speed. They are simple to use and let you
  quickly evaluate the performance of your bot
  versus the others. They also allow you to specify
  the start locations of the bots, which saves time
  having to reset when the bots are not assigned
  goals which are opposite one another.