Added sprite and background disable control bits

macros/GTE.Macs.s

@@ -138,6 +138,12 @@ _GTESetAddress       MAC
 _GTEUpdateOverlay    MAC
                      UserTool  $2F00+GTEToolNum
                      <<<
+_GTEEnableSprites    MAC
+                     UserTool  $3000+GTEToolNum
+                     <<<
+_GTEEnableBackground MAC
+                     UserTool  $3100+GTEToolNum
+                     <<<
 
 ; EngineMode definitions
 ; Script definition

src/CoreImpl.s

@@ -218,8 +218,9 @@ EngineReset
                   stz       TileMapHeight
                   stz       TileMapPtr
                   stz       TileMapPtr+2
-                  stz       FringeMapPtr
+;                  stz       FringeMapPtr
-                  stz       FringeMapPtr+2
+;                  stz       FringeMapPtr+2
+                  stz       GTEControlBits
 
                   stz       BG1TileMapWidth
                   stz       BG1TileMapHeight

src/Defs.s

@@ -76,7 +76,8 @@ OldBG1TileOriginY      equ   68
 TileMapWidth           equ   70          ; Pointer to memory holding the tile map for the primary background
 TileMapHeight          equ   72
 TileMapPtr             equ   74
-FringeMapPtr           equ   78
+; FringeMapPtr           equ   78
+GTEControlBits         equ   78          ; Enable / disable things
 
 BG1TileMapWidth        equ   82
 BG1TileMapHeight       equ   84
@@ -215,6 +216,10 @@ PAD_BUTTON_B           equ   $0100
 PAD_BUTTON_A           equ   $0200
 PAD_KEY_DOWN           equ   $0400
 
+; GTE Control Bits
+CTRL_SPRITE_DISABLE    equ   $0001
+CTRL_BKGND_DISABLE     equ   $0002
+
 ; Tile constants
 TILE_DAMAGED_BIT       equ   $8000                  ; Mark a tile as damaged (internal only)
 TILE_PRIORITY_BIT      equ   $4000                  ; Put tile on top of sprite (unimplemented)

src/Render.s

@@ -205,6 +205,10 @@ _RenderNES
 ; This is handled by the callback in two phases.  We pass pointers to the internal function the callback needs
 ; access to.  If there is no function defined, do nothing
 
+            lda   GTEControlBits
+            bit   #CTRL_SPRITE_DISABLE
+            bne   :no_render
+
             lda   ExtSpriteRenderer
             ora   ExtSpriteRenderer+2
             beq   :no_render

src/Tool.s

@@ -102,6 +102,9 @@ _CallTable
                 adrl  _TSSetAddress-1
                 adrl  _TSUpdateOverlay-1
 
+                adrl  _TSEnableSprites-1
+                adrl  _TSEnableBackground-1
+
 _CTEnd
 _GTEAddSprite        MAC
                      UserTool  $1000+GTEToolNum
@@ -1029,6 +1032,42 @@ _TSCompileSpriteStamp
 
                 _TSExit  #0;#4
 
+; EnableSprites(bool)
+_TSEnableSprites
+:enable         equ     FirstParam
+                _TSEntry
+
+                lda     :enable
+                beq     :turn_off
+                lda     #CTRL_SPRITE_DISABLE
+                trb     GTEControlBits
+                bra     :done
+
+:turn_off
+                lda     #CTRL_SPRITE_DISABLE
+                tsb     GTEControlBits
+
+:done
+                _TSExit  #0;#2
+
+; EnableBackground(bool)
+_TSEnableBackground
+:enable         equ     FirstParam
+                _TSEntry
+
+                lda     :enable,s
+                beq     :turn_off
+                lda     #CTRL_BKGND_DISABLE
+                trb     GTEControlBits
+                bra     :done
+
+:turn_off
+                lda     #CTRL_BKGND_DISABLE
+                tsb     GTEControlBits
+
+:done
+                _TSExit  #0;#2
+
 ; Insert the GTE code
 
                 put     Math.s

src/blitter/Blitter.s

@@ -18,6 +18,14 @@ _BltRange
                 bcc   *+3
                 rts
 
+; If the background is disabled, jump to a specialized BG routine
+
+                lda   GTEControlBits
+                bit   #CTRL_BKGND_DISABLE
+                beq   :normal
+                brl   DisabledBG
+:normal
+
                 phb                  ; preserve the bank register
                 clc`
 
@@ -63,17 +71,8 @@ _BltRange
                 bit   #ENGINE_MODE_TWO_LAYER
                 beq   :skip_bank
 
-; TODO: Switch to loading the selected BG1 bank. No special "Alt" bank
+; Load the BG1 data bank
-;
+
-;                lda   RenderFlags
-;                bit   #RENDER_ALT_BG1
-;                beq   :primary
-;
-;                lda   BG1AltBank
-;                bra   :alt
-;
-;:primary        lda   BG1DataBank
-;:alt
                 lda   BG1DataBank
                 pha
                 plb
@@ -108,6 +107,76 @@ stk_save        lda   #0000          ; load the stack
                 plb                  ; restore the bank
                 rts
 
+; Specialize routine that just slams a bunch of PHA instructions when background rendering is disabled
+DisabledBG
+                stx  tmp15
+                tya
+                sec
+                sbc  tmp15
+                tay                  ; Put the count in the y register
+
+                lda  ScreenWidth     ; Screen width in bytes (0 - 159)
+                lsr                  ; Convert to number of word
+                eor  #$FFFF
+                adc  #:blkend        ; subtract from the end of the PHA array
+                stal :patch+1
+
+                lda  #8              ; Enable interrups at least this many lines
+                sta  tmp14
+
+                txa                  ; multiply starting line by 2 for indexing
+                asl
+                tax
+
+                php                  ; save the current processor flags
+                sei                  ; disable interrupts
+                tsc                  ; save the stack pointer
+                sta  tmp15
+                _R0W1
+
+:loop
+                lda  RTable,x        ; Load the screen right edge
+                tcs
+                lda  #0
+:patch          jmp  $0000
+                lup  80
+                pha
+                --^
+:blkend
+                dec   tmp14
+                bmi   :enable_int
+
+:next
+                inx
+                inx
+                dey
+                bne  :loop
+
+                _R0W0
+                lda  tmp15
+                tcs
+                plp
+                rts
+
+:enable_int
+                lda   #8             ; Reset the counter
+                sta   tmp14
+
+                lda   tmp15         ; restore the stack
+                tcs
+                sep   #$30                       ; 8-bit mode
+                ldal  STATE_REG
+                tax                              ; Save the value
+                and   #$CF                       ; Read Bank 0 / Write Bank 0
+                stal  STATE_REG
+                cli
+                nop                              ; Give a couple of cycles
+                sei
+                txa                              ; Restore the state
+                stal  STATE_REG
+                rep   #$30
+                bra   :next
+
 ; External entry point.  Can be called directly from another bank
 BltRange
                 phd