; ; Graphics driver for the 320 pixels across, 240 pixels down, 256 colors mode ; on the Commander X16 ; ; 2022-03-30, Greg King ; .include "zeropage.inc" .include "tgi-kernel.inc" .include "tgi-error.inc" .include "cbm_kernal.inc" .include "cx16.inc" .macpack generic .macpack module ; Macro that copies a word into a pseudo-register .mac setReg reg, src lda src ldx src+1 sta gREG::reg stx gREG::reg+1 .endmac ; ------------------------------------------------------------------------ ; Header. Includes jump table and constants. module_header _cx320p1_tgi ; 320 pixels across, 1 pixel per byte ; First part of the header is a structure that has a signature, ; and defines the capabilities of the driver. .byte $74, $67, $69 ; ASCII "tgi" .byte TGI_API_VERSION ; TGI API version number .addr $0000 ; Library reference .word 320 ; X resolution .word 240 ; Y resolution .byte <$0100 ; Number of drawing colors .byte 1 ; Number of screens available .byte 8 ; System font X size .byte 8 ; System font Y size .word $0100 ; Aspect ratio (based on VGA display) .byte 0 ; TGI driver flags ; Next, comes the jump table. Currently, all entries must be valid, ; and may point to an RTS for test versions (function not implemented). .addr INSTALL .addr UNINSTALL .addr INIT .addr DONE .addr GETERROR .addr CONTROL .addr CLEAR .addr SETVIEWPAGE .addr SETDRAWPAGE .addr SETCOLOR .addr SETPALETTE .addr GETPALETTE .addr GETDEFPALETTE .addr SETPIXEL .addr GETPIXEL .addr LINE .addr BAR .addr TEXTSTYLE .addr OUTTEXT ; ------------------------------------------------------------------------ ; Constant GRAPH320 = $80 ; ------------------------------------------------------------------------ ; Data ; Variables mapped to the zero-page segment variables. Some of these are ; used for passing parameters to the driver. X1 := ptr1 Y1 := ptr2 X2 := ptr3 Y2 := ptr4 ; Absolute variables used in the code .bss ; The colors are indicies into a TGI palette. The TGI palette is indicies into ; VERA's palette. Vera's palette is a table of Red, Green, and Blue levels. ; The first 16 RGB elements mimic the Commodore 64's colors. defpalette: .res $0100 palette: .res $0100 bcolor := palette + 0 ; Background color color: .res 1 ; Stroke and fill index text_mode: .res 1 ; Old text mode .data error: .byte TGI_ERR_OK ; Error code .code ; ------------------------------------------------------------------------ ; INSTALL routine. Is called after the driver is loaded into memory. May ; initialize anything that has to be done just once. Is probably empty ; most of the time. ; ; Must set an error code: NO INSTALL: ; Create the default palette. ldx #$00 : txa sta defpalette,x inx bnz :- ; Fall through. ; ------------------------------------------------------------------------ ; UNINSTALL routine. Is called before the driver is removed from memory. May ; clean up anything done by INSTALL, but is probably empty most of the time. ; ; Must set an error code: NO UNINSTALL: rts ; ------------------------------------------------------------------------ ; INIT: Changes an already installed device from text mode to graphics ; mode. ; Note that INIT/DONE may be called multiple times while the driver ; is loaded, while INSTALL is called only once; so, any code that is needed ; to initiate variables and so on must go here. Setting the palette is not ; needed because that is called by the graphics kernel later. ; The graphics kernel never will call INIT when a graphics mode already is ; active, so there is no need to protect against that. ; ; Must set an error code: YES INIT: stz error ; #TGI_ERR_OK ; Save the current text mode. sec jsr SCREEN_MODE sta text_mode ; Switch into (320 x 240 x 256) graphics mode. lda #GRAPH320 clc jmp SCREEN_MODE ; ------------------------------------------------------------------------ ; DONE: Will be called to switch the graphics device back into text mode. ; The graphics kernel never will call DONE when no graphics mode is active, ; so there is no need to protect against that. ; ; Must set an error code: NO DONE: lda text_mode clc jmp SCREEN_MODE ; ------------------------------------------------------------------------ ; GETERROR: Return the error code in .A, and clear it. GETERROR: lda error stz error rts ; ------------------------------------------------------------------------ ; CONTROL: Platform-/driver-specific entry point. ; ; Must set an error code: YES CONTROL: lda #TGI_ERR_INV_FUNC sta error rts ; ------------------------------------------------------------------------ ; CLEAR: Clear the screen. ; ; Must set an error code: NO CLEAR := GRAPH_CLEAR ; ------------------------------------------------------------------------ ; SETVIEWPAGE: Set the visible page. Called with the new page in .A (0..n-1). ; The page number already is checked to be valid by the graphics kernel. ; ; Must set an error code: NO (will be called only if page OK) SETVIEWPAGE: ; Fall through. ; ------------------------------------------------------------------------ ; SETDRAWPAGE: Set the drawable page. Called with the new page in .A (0..n-1). ; The page number already is checked to be valid by the graphics kernel. ; ; Must set an error code: NO (will be called only if page OK) SETDRAWPAGE: rts ; ------------------------------------------------------------------------ ; SETPALETTE: Set the palette (not available with all drivers/hardware). ; A pointer to the palette is passed in ptr1. Must set an error if palettes ; are not supported ; ; Must set an error code: YES SETPALETTE: stz error ; #TGI_ERR_OK ldy #$00 : lda (ptr1),y sta palette,y iny bnz :- lda color ; Get stroke and fill index ; Fall through. ; ------------------------------------------------------------------------ ; SETCOLOR: Set the drawing color (in .A). The new color already is checked ; to be in a valid range (0..maxcolor). ; ; Must set an error code: NO (will be called only if color OK) SETCOLOR: tax sta color lda palette,x ; Set stroke and fill color tax ldy bcolor ; Get background color jmp GRAPH_SET_COLORS ; ------------------------------------------------------------------------ ; GETPALETTE: Return the current palette in .XA. Even drivers that cannot ; set the palette should return the default palette here, so there's no ; way for this function to fail. ; ; Must set an error code: NO GETPALETTE: lda #palette rts ; ------------------------------------------------------------------------ ; GETDEFPALETTE: Return the default palette for the driver in .XA. All ; drivers should return something reasonable here, even drivers that don't ; support palettes, otherwise the caller has no way to determine the colors ; of the (not changable) palette. ; ; Must set an error code: NO (all drivers must have a default palette) GETDEFPALETTE: lda #defpalette rts ; ------------------------------------------------------------------------ ; SETPIXEL: Draw one pixel at X1/Y1 = ptr1/ptr2 with the current drawing ; color. The co-ordinates passed to this function never are outside the ; visible screen area, so there is no need for clipping inside this function. ; ; Must set an error code: NO SETPIXEL: jsr Point jsr FB_CURSOR_POSITION ldx color lda palette,x jmp FB_SET_PIXEL ; ------------------------------------------------------------------------ ; GETPIXEL: Read the color value of a pixel, and return it in .XA. The ; co-ordinates passed to this function never are outside the visible screen ; area, so there is no need for clipping inside this function. GETPIXEL: jsr Point jsr FB_CURSOR_POSITION jsr FB_GET_PIXEL ldx #>$0000 rts ; ------------------------------------------------------------------------ ; LINE: Draw a line from X1/Y1 to X2/Y2, where X1/Y1 = ptr1/ptr2 and ; X2/Y2 = ptr3/ptr4, using the current drawing color. ; ; Must set an error code: NO LINE: jsr Point setReg r2, X2 setReg r3, Y2 jmp GRAPH_DRAW_LINE ; ------------------------------------------------------------------------ ; BAR: Draw a filled rectangle with the corners X1/Y1, X2/Y2, where ; X1/Y1 = ptr1/ptr2 and X2/Y2 = ptr3/ptr4, using the current drawing color. ; Contrary to most other functions, the graphics kernel will sort and clip ; the co-ordinates before calling the driver; so on entry, the following ; conditions are valid: ; X1 <= X2 ; Y1 <= Y2 ; (X1 >= 0) && (X1 < XRES) ; (X2 >= 0) && (X2 < XRES) ; (Y1 >= 0) && (Y1 < YRES) ; (Y2 >= 0) && (Y2 < YRES) ; ; Must set an error code: NO BAR: ; Set the starting corner. jsr Point ; Set the width. lda X2 sub X1 sta gREG::r2 lda X2+1 sbc X1+1 sta gREG::r2+1 ; Set the height. lda Y2 sub Y1 sta gREG::r3 lda Y2+1 sbc Y1+1 sta gREG::r3+1 ; Set the corner radius. stz gREG::r4 stz gREG::r4+1 sec ; Fill the rectangle jmp GRAPH_DRAW_RECT ; ------------------------------------------------------------------------ ; TEXTSTYLE: Set the style used when calling OUTTEXT. Text scaling in X and Y ; directions are passed in .X and .Y, the text direction is passed in .A. ; ; Must set an error code: NO TEXTSTYLE: rts ; ------------------------------------------------------------------------ ; OUTTEXT: Output text at X/Y = ptr1/ptr2 using the current color and the ; current text style. The text to output is given as a zero-terminated ; string with address in ptr3. ; ; Must set an error code: NO OUTTEXT: jsr Point ldy #$00 @next: lda (ptr3),y bze @end phy jsr GRAPH_PUT_CHAR ply iny bnz @next @end: rts ; ------------------------------------------------------------------------ ; Point: Set the arguments for the first point of a Kernal graphics function. Point: setReg r0, X1 setReg r1, Y1 rts