Track geometry: GetSectionYawAngle

       Name: GetSectionYawAngle                                      [Show more]
       Type: Subroutine
   Category: Track geometry
    Summary: Calculate the difference in yaw angle between an object and the
             player
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * GetSectionAngles (Part 3 of 3) calls GetSectionYawAngle


 This routine is typically used to calculate the difference in yaw angle
 between a track section and the player.


 Arguments:

   Y                    Index from xVergeRight to store the difference in yaw
                        angle between the object and the player

   (JJ II)              The yaw angle of the object


 Returns:

   xVergeRight          The difference in the yaw angle between the object and
                        the player (if Y points to the right verge)

   xVergeLeft           The difference in the yaw angle between the object and
                        the player (if Y points to the left verge)

   (L K)                The distance between the object and the player's car

   A                    Contains the high byte of (L K)

   M                    The smaller yaw angle of the object, where 0 to 255
                        represents 0 to 45 degrees


.GetSectionYawAngle

 LDA II                 \ Set the following for the Y-th section:
 SEC                    \
 SBC playerYawAngleLo   \   xVergeRight = (JJ II) - playerYawAngle
 STA xVergeRightLo,Y    \
                        \ starting with the low bytes

 LDA JJ                 \ And then the high bytes
 SBC playerYawAngleHi
 STA xVergeRightHi,Y

 JMP GetObjectDistance  \ Set (L K) to the distance between the object and the
                        \ player's car, with A set to L, returning from the
                        \ subroutine using a tail call