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Elite on the BBC Micro and NES

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

[6502 Second Processor version]

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
.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 .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