; ; Graphics driver for the 280x192x8 mode on the Apple II ; ; Stefan Haubenthal ; Oliver Schmidt ; .include "zeropage.inc" .include "tgi-kernel.inc" .include "tgi-mode.inc" .include "tgi-error.inc" .include "apple2.inc" ; ------------------------------------------------------------------------ ; Zero page stuff HBASL := $26 HMASK := $30 PAGE := $E6 SCALE := $E7 ROT := $F9 ; Graphics entry points, by cbmnut (applenut??) cbmnut@hushmail.com TEXT := $F399 ; Return to text screen HGR2 := $F3D8 ; Initialize and clear hi-res page 2. HGR := $F3E2 ; Initialize and clear hi-res page 1. HCLR := $F3F2 ; Clear the current hi-res screen to black. BKGND := $F3F6 ; Clear the current hi-res screen to the ; last plotted color (from ($1C). HPOSN := $F411 ; Positions the hi-res cursor without ; plotting a point. ; Enter with (A) = Y-coordinate, and ; (Y,X) = X-coordinate. HPLOT := $F457 ; Calls HPOSN and tries to plot a dot at ; the cursor's position. If you are ; trying to plot a non-white color at ; a complementary color position, no ; dot will be plotted. HLIN := $F53A ; Draws a line from the last plotted ; point or line destination to: ; (X,A) = X-coordinate, and ; (Y) = Y-coordinate. HFIND := $F5CB ; Converts the hi-res coursor's position ; back to X- and Y-coordinates; stores ; X-coordinate at $E0,E1 and Y-coordinate ; at $E2. DRAW := $F601 ; Draws a shape. Enter with (Y,X) = the ; address of the shape table, and (A) = ; the rotation factor. Uses the current ; color. XDRAW := $F65D ; Draws a shape by inverting the existing ; color of the dots the shape draws over. ; Same entry parameters as DRAW. SETHCOL := $F6EC ; Set the hi-res color to (X), where (X) ; must be between 0 and 7. ; ------------------------------------------------------------------------ ; 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 ; ------------------------------------------------------------------------ .segment "JUMPTABLE" ; Header. Includes jump table and constants. ; First part of the header is a structure that has a magic and defines the ; capabilities of the driver .byte $74, $67, $69 ; "tgi" .byte TGI_API_VERSION ; TGI API version number .word 280 ; X resolution .word 192 ; Y resolution .byte 8 ; Number of drawing colors pages: .byte 2 ; Number of screens available .byte 7 ; System font X size .byte 8 ; System font Y size .word $100 ; Aspect ratio ; Next comes the jump table. With the exception of IRQ, 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 .addr 0 ; IRQ entry is unused ; ------------------------------------------------------------------------ .bss ; Absolute variables used in the code ERROR: .res 1 ; Error code ; ------------------------------------------------------------------------ .rodata ; Constants and tables DEFPALETTE: .byte $00, $01, $02, $03, $04, $05, $06, $07 FONT: ; Beagle Bros Shape Mechanic font F.ASCII.SMALL ; modified to exactly reproduce the text glyphs .incbin "../apple2/apple2-280-192-8.fnt" ; ------------------------------------------------------------------------ .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: .ifdef __APPLE2ENH__ ; No page switching if 80 column store is enabled lda #$02 bit RD80COL bpl :+ lda #$01 : sta pages .endif ; 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 only called once, so any code that is needed ; to initializes variables and so on must go here. Setting palette and ; clearing the screen is not needed because this is called by the graphics ; kernel later. ; The graphics kernel will never call INIT when a graphics mode is already ; active, so there is no need to protect against that. ; Must set an error code: YES INIT: ; Switch into graphics mode bit MIXCLR bit LOWSCR bit HIRES bit TXTCLR ; Beagle Bros Shape Mechanic fonts don't ; scale well so use fixed scaling factor lda #1 sta SCALE ; Done, reset the error code lda #TGI_ERR_OK sta ERROR rts ; DONE: Will be called to switch the graphics device back into text mode. ; The graphics kernel will never call DONE when no graphics mode is active, ; so there is no need to protect against that. ; Must set an error code: NO DONE: ; Switch into text mode bit TXTSET bit LOWSCR .ifdef __APPLE2ENH__ ; Limit SET80COL-HISCR to text bit LORES .endif ; Reset the text window top lda #$00 sta WNDTOP rts ; GETERROR: Return the error code in A and clear it. GETERROR: lda ERROR ldx #TGI_ERR_OK stx ERROR rts ; CONTROL: Platform/driver specific entry point. ; Must set an error code: YES CONTROL: ; Check data msb and code to be 0 ora ptr1+1 bne err ; Check data lsb to be [0..1] lda ptr1 cmp #1+1 bcs err ; Set text window top tax beq :+ lda #20 : sta WNDTOP ; Switch 4 lines of text .assert MIXCLR + 1 = MIXSET, error lda MIXCLR,x ; No BIT absolute,X available ; Done, reset the error code lda #TGI_ERR_OK beq :+ ; Branch always ; Done, set the error code err: lda #TGI_ERR_INV_ARG : sta ERROR rts ; CLEAR: Clears the screen. ; Must set an error code: NO CLEAR: bit $C082 ; Switch in ROM jsr HCLR bit $C080 ; Switch in LC bank 2 for R/O rts ; SETVIEWPAGE: Set the visible page. Called with the new page in A (0..n). ; The page number is already checked to be valid by the graphics kernel. ; Must set an error code: NO (will only be called if page ok) SETVIEWPAGE: tax .assert LOWSCR + 1 = HISCR, error lda LOWSCR,x ; No BIT absolute,X available rts ; SETDRAWPAGE: Set the drawable page. Called with the new page in A (0..n). ; The page number is already checked to be valid by the graphics kernel. ; Must set an error code: NO (will only be called if page ok) SETDRAWPAGE: tax beq :+ lda #>$4000 ; Page 2 .byte $2C ; BIT absolute : lda #>$2000 ; Page 1 sta PAGE rts ; SETCOLOR: Set the drawing color (in A). The new color is already checked ; to be in a valid range (0..maxcolor-1). ; Must set an error code: NO (will only be called if color ok) SETCOLOR: bit $C082 ; Switch in ROM tax jsr SETHCOL bit $C080 ; Switch in LC bank 2 for R/O 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: lda #TGI_ERR_INV_FUNC sta ERROR rts ; GETPALETTE: Return the current palette in A/X. 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: ; Fall through ; GETDEFPALETTE: Return the default palette for the driver in A/X. 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 changeable) 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 coordinates passed to this function are never outside the ; visible screen area, so there is no need for clipping inside this function. ; Must set an error code: NO SETPIXEL: bit $C082 ; Switch in ROM ldx X1 ldy X1+1 lda Y1 jsr HPLOT bit $C080 ; Switch in LC bank 2 for R/O rts ; GETPIXEL: Read the color value of a pixel and return it in A/X. The ; coordinates passed to this function are never outside the visible screen ; area, so there is no need for clipping inside this function. GETPIXEL: bit $C082 ; Switch in ROM ldx X1 ldy X1+1 lda Y1 jsr HPOSN lda (HBASL),y and HMASK asl beq :+ ; 0 (black) lda #$03 ; 3 (white) : bcc :+ adc #$03 ; += 4 (black -> black2, white -> white2) : ldx #$00 bit $C080 ; Switch in LC bank 2 for R/O 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: bit $C082 ; Switch in ROM ldx X1 ldy X1+1 lda Y1 jsr HPOSN lda X2 ldx X2+1 ldy Y2 jsr HLIN bit $C080 ; Switch in LC bank 2 for R/O rts ; 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 coordinates 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: inc Y2 : lda Y2 pha lda Y1 sta Y2 jsr LINE pla sta Y2 inc Y1 cmp Y1 bne :- rts ; TEXTSTYLE: Set the style used when calling OUTTEXT. Text scaling in X and Y ; direction is passend in X/Y, the text direction is passed in A. ; Must set an error code: NO TEXTSTYLE: cmp #TGI_TEXT_VERTICAL bne :+ lda #48 : sta ROT 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: bit $C082 ; Switch in ROM lda X1 ldy X1+1 ldx ROT php ; Save Z flag beq :+ ; Not horizontal sec sbc #7 ; Adjust X bcs :+ dey : tax lda Y1 plp ; Restore Z flag bne :+ ; Not vertical sec sbc #7 ; Adjust Y : jsr HPOSN clc lda FONT+2*99 ; "connection char" adc #FONT sta ptr4+1 ldy #$00 : lda (ptr3),y beq :+ sty tmp1 ; Save string index sec sbc #$1F ; No control chars asl ; Offset * 2 tay clc lda FONT,y adc #FONT tay lda ROT jsr DRAW ; Draw char from string ldx ptr4 ldy ptr4+1 lda ROT jsr DRAW ; Draw "connection char" ldy tmp1 ; Restore string index iny bne :- ; Branch always : bit $C080 ; Switch in LC bank 2 for R/O rts