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⌂ ∞ Elite on the BBC Micro and NES

Drawing pixels: draw_blob

[Elite-A, I/O processor]

       Name: draw_blob                                               [Show more]
       Type: Subroutine
   Category: Drawing pixels
    Summary: Implement the draw_blob command (draw a single-height dash on the
             dashboard)

    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * tube_table calls draw_blob




 This routine is run when the parasite sends a draw_blob command. It draws a
 single-height dash on the dashboard.



.draw_blob

 JSR tube_get           \ Get the parameters from the parasite for the command:
 STA X1                 \
 JSR tube_get           \   draw_blob(x, y, colour)
 STA Y1                 \
 JSR tube_get           \ and store them as follows:
 STA COL                \
                        \   * X1 = the dash's x-coordinate
                        \
                        \   * Y1 = the dash's y-coordinate
                        \
                        \   * COL = the dash's colour

                        \ Fall through into CPIX2 to draw a single-height dash
                        \ at the above coordinates and in the specified colour