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⌂ ∞ ▽ Elite on the BBC Micro and NES

Drawing circles: LL164

[BBC Master version]

       Name: LL164                                                   [Show more]
       Type: Subroutine
   Category: Drawing circles
    Summary: Make the hyperspace sound and draw the hyperspace tunnel

    Context: See this subroutine in context in the source code
 Variations: See code variations for this subroutine in the different versions
 References: This subroutine is called as follows:
             * MJP calls LL164
             * TT18 calls LL164




 See the IRQ1 routine for details on the multi-coloured effect that's used.



.LL164

 LDY #sohyp             \ Call the NOISE routine with Y = 10 to make the first
 JSR NOISE              \ sound of the hyperspace drive being engaged

 LDY #sohyp2            \ Call the NOISE routine with Y = 11 to make the second
 JSR NOISE              \ sound of the hyperspace drive being engaged

 LDA #4                 \ Set the step size for the hyperspace rings to 4, so
                        \ there are more sections in the rings and they are
                        \ quite round (compared to the step size of 8 used in
                        \ the much more polygonal launch rings)

 STA HFX                \ Set HFX to 4, which switches the screen mode to a full
                        \ mode 2 screen, therefore making the hyperspace rings
                        \ multi-coloured and all zig-zaggy (see the IRQ1 routine
                        \ for details)

 JSR HFS2               \ Call HFS2 to draw the hyperspace tunnel rings

 STZ HFX                \ Set HFX back to 0, so we switch back to the normal
                        \ split-screen mode

 RTS                    \ Return from the subroutine