Drawing circles: CIRCLE, Removed

       Name: CIRCLE, Removed                                         [Show more]
       Type: Subroutine
   Category: Drawing circles
    Summary: Draw a circle for the planet
  Deep dive: Drawing circles
    Context: See this subroutine in context in the source code
 References: No direct references to this subroutine in this source file


 Draw a circle with the centre at (K3, K4) and radius K. Used to draw the
 planet's main outline.


 Arguments:

   K                    The planet's radius

   K3(1 0)              Pixel x-coordinate of the centre of the planet

   K4(1 0)              Pixel y-coordinate of the centre of the planet


                        \ --- Mod: Code removed for Elite-A: ------------------>

\.CIRCLE
\
\LDA #0                 \ Set LSX2 = 0 to indicate that the ball line heap is
\STA LSX2               \ not empty, as we are about to fill it
\
\LDX K                  \ Set X = K = radius
\
\LDA #8                 \ Set A = 8
\
\CPX #8                 \ If the radius < 8, skip to PL89
\BCC PL89
\
\LSR A                  \ Halve A so A = 4
\
\CPX #60                \ If the radius < 60, skip to PL89
\BCC PL89
\
\LSR A                  \ Halve A so A = 2
\
\.PL89
\
\STA STP                \ Set STP = A. STP is the step size for the circle, so
\                       \ the above sets a smaller step size for bigger circles
\
\                       \ Fall through into CIRCLE2 to draw the circle with the
\                       \ correct step size

                        \ --- End of removed code ----------------------------->