Main loop: Main flight loop (Part 10 of 16)

       Name: Main flight loop (Part 10 of 16)                        [Show more]
       Type: Subroutine
   Category: Main loop
    Summary: For each nearby ship: Remove if scooped, or process collisions
  Deep dive: Program flow of the main game loop
    Context: See this subroutine in context in the source code
 References: No direct references to this subroutine in this source file


 The main flight loop covers most of the flight-specific aspects of Elite. This
 section covers the following:

   * Continue looping through all the ships in the local bubble, and for each
     one:

     * Remove scooped item after both successful and failed scooping attempts

     * Process collisions


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

\.MA59
\
\                       \ If we get here then scooping failed
\
\ JSR EXNO3             \ Make the sound of the cargo canister being destroyed
\                       \ and fall through into MA60 to remove the canister
\                       \ from our local bubble
\
\.MA60
\
\                       \ If we get here then scooping was successful
\
\ ASL INWK+31           \ Set bit 7 of the scooped or destroyed item, to denote
\ SEC                   \ that it has been killed and should be removed from
\ ROR INWK+31           \ the local bubble
\
\.MA61
\
\ BNE MA26              \ Jump to MA26 to skip over the collision routines and
\                       \ to move on to missile targeting (this BNE is
\                       \ effectively a JMP as A will never be zero)
\
\.MA67
\
\                       \ If we get here then we have collided with something,
\                       \ but not fatally
\
\ LDA #1                \ Set the speed in DELTA to 1 (i.e. a sudden stop)
\ STA DELTA
\
\ LDA #5                \ Set the amount of damage in A to 5 (a small dent) and
\ BNE MA63              \ jump down to MA63 to process the damage (this BNE is
\                       \ effectively a JMP as A will never be zero)
\
\.MA58
\
\                       \ If we get here, we have collided with something in a
\                       \ potentially fatal way
\
\ ASL INWK+31           \ Set bit 7 of the ship we just collided with, to
\ SEC                   \ denote that it has been killed and should be removed
\ ROR INWK+31           \ from the local bubble
\
\ LDA INWK+35           \ Load A with the energy level of the ship we just hit
\
\ SEC                   \ Set the amount of damage in A to 128 + A / 2, so
\ ROR A                 \ this is quite a big dent, and colliding with higher
\                       \ energy ships will cause more damage

                        \ --- And replaced by: -------------------------------->

 LDA auto               \ If the docking computer is on, then auto will be &FF,
 AND #%00000100         \ so this will set A = 1, a tiny amount of damage
 EOR #%00000101         \
                        \ If the docking computer is off, then auto will be 0,
                        \ so this will set A = 5, a small amount of damage

 BNE MA63               \ Jump to MA63 to process the damage in A (this BNE is
                        \ effectively a JMP as A will never be zero)

.MA58

                        \ If we get here, we have collided with something in a
                        \ potentially fatal way

 LDA #64                \ Call n_hit to apply a hit of strength 64 to the ship
 JSR n_hit              \ we just collided with

 JSR anger_8c           \ Call anger_8c to make the ship angry

.n_crunch

                        \ If we get here, we have collided with something, so we
                        \ need to take a hit to our shields

 LDA #128               \ Set A = 128 to indicate a fairly large amount of
                        \ damage

                        \ --- End of replacement ------------------------------>

.MA63

 JSR OOPS               \ The amount of damage is in A, so call OOPS to reduce
                        \ our shields, and if the shields are gone, there's a
                        \ chance of cargo loss or even death

 JSR EXNO3              \ Make the sound of colliding with the other ship and
                        \ fall through into MA26 to try targeting a missile