Consistent use of line thickness

[g3force]

It was brought up on Discord, that there is some confusion in regards of the line thickness:

• How are distances between lines measured?
• How is the line thickness taken into account when checking if object are inside an area?
• When did the ball cross a line?

Current state:

• ssl-rules
  • 2.1.3: > Lines belong to the areas of which they are boundaries.
• ssl-vision
  • Distances between lines are measured from the line center
  • Line thickness is configurable and sent out in the Geometry message
  • Line thickness is only taken into account during calibration
• ssl-game-controller
  • line thickness is not used and not needed
• TIGERs autoRef
  • The line thickness is not used
• ER-Force autoRef
  • The line thickness is most likely not used

Some relevant quotes from the rules:

• "The ball is inside the field."
• "allowed to be inside the whole center circle"
• "the ball is inside a team’s defense area"
• "while being partially or fully inside the opponent defense area"
• "The robot is at least partially inside the field margin."

The line is usually 1cm thick. The precision of ssl-vision is also about 1cm. So in practice, it should not make a significant difference to take the thickness into account or not.