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⌂ ∞ Elite on the BBC Micro and NES

Drawing the screen: SetSpaceViewInNMI

[NES version, Bank 0]

       Name: SetSpaceViewInNMI                                       [Show more]
       Type: Subroutine
   Category: Drawing the screen
    Summary: Change the current space view and configure the NMI to send both
             bitplanes to the PPU during VBlank

    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * LOOK1 calls SetSpaceViewInNMI




 Arguments:

   X                    The space view to set:

                          * 0 = front

                          * 1 = rear

                          * 2 = left

                          * 3 = right

                          * 4 = generating a new space view



.SetSpaceViewInNMI

 STX VIEW               ; Set the current space view to X

 LDA #$00               ; Clear the screen and set the view type in QQ11 to $00
 JSR TT66               ; (Space view with no fonts loaded)

 JSR CopyNameBuffer0To1 ; Copy the contents of nametable buffer 0 to nametable
                        ; buffer

 LDA #80                ; Tell the PPU to send nametable entries up to tile
 STA lastNameTile       ; 80 * 8 = 640 (i.e. to the end of tile row 19) in both
 STA lastNameTile+1     ; bitplanes

 JSR SetupViewInNMI_b3  ; Setup the view and configure the NMI to send both
                        ; bitplanes to the PPU during VBlank

                        ; Fall through into ResetStardust to hide the sprites
                        ; for the stardust