2 ; Graphics driver for the 280x192x8 mode on the Apple II
4 ; Stefan Haubenthal <polluks@sdf.lonestar.org>
5 ; Oliver Schmidt <ol.sc@web.de>
8 .include "zeropage.inc"
10 .include "tgi-kernel.inc"
11 .include "tgi-error.inc"
14 ; ------------------------------------------------------------------------
24 ; Graphics entry points, by cbmnut (applenut??) cbmnut@hushmail.com
26 TEXT := $F399 ; Return to text screen
27 HGR2 := $F3D8 ; Initialize and clear hi-res page 2.
28 HGR := $F3E2 ; Initialize and clear hi-res page 1.
29 HCLR := $F3F2 ; Clear the current hi-res screen to black.
30 BKGND := $F3F6 ; Clear the current hi-res screen to the
31 ; last plotted color (from ($1C).
32 HPOSN := $F411 ; Positions the hi-res cursor without
34 ; Enter with (A) = Y-coordinate, and
35 ; (Y,X) = X-coordinate.
36 HPLOT := $F457 ; Calls HPOSN and tries to plot a dot at
37 ; the cursor's position. If you are
38 ; trying to plot a non-white color at
39 ; a complementary color position, no
40 ; dot will be plotted.
41 HLIN := $F53A ; Draws a line from the last plotted
42 ; point or line destination to:
43 ; (X,A) = X-coordinate, and
45 HFIND := $F5CB ; Converts the hi-res coursor's position
46 ; back to X- and Y-coordinates; stores
47 ; X-coordinate at $E0,E1 and Y-coordinate
49 DRAW := $F601 ; Draws a shape. Enter with (Y,X) = the
50 ; address of the shape table, and (A) =
51 ; the rotation factor. Uses the current
53 XDRAW := $F65D ; Draws a shape by inverting the existing
54 ; color of the dots the shape draws over.
55 ; Same entry parameters as DRAW.
56 SETHCOL := $F6EC ; Set the hi-res color to (X), where (X)
57 ; must be between 0 and 7.
59 ; ------------------------------------------------------------------------
61 ; Variables mapped to the zero page segment variables. Some of these are
62 ; used for passing parameters to the driver.
69 ; ------------------------------------------------------------------------
73 ; Header. Includes jump table and constants.
75 ; First part of the header is a structure that has a magic and defines the
76 ; capabilities of the driver
78 .byte $74, $67, $69 ; "tgi"
79 .byte TGI_API_VERSION ; TGI API version number
80 .addr $0000 ; Library reference
81 .word 280 ; X resolution
82 .word 192 ; Y resolution
83 .byte 8 ; Number of drawing colors
84 pages: .byte 2 ; Number of screens available
85 .byte 7 ; System font X size
86 .byte 8 ; System font Y size
87 .word $00EA ; Aspect ratio (based on 4/3 display)
88 .byte 0 ; TGI driver flags
90 ; Next comes the jump table. With the exception of IRQ, all entries must be
91 ; valid and may point to an RTS for test versions (function not implemented).
112 .addr 0 ; IRQ entry is unused
114 ; ------------------------------------------------------------------------
118 ; Absolute variables used in the code
120 ERROR: .res 1 ; Error code
122 ; ------------------------------------------------------------------------
126 ; Constants and tables
128 DEFPALETTE: .byte $00, $01, $02, $03, $04, $05, $06, $07
131 ; Beagle Bros Shape Mechanic font F.ASCII.SMALL
132 ; modified to exactly reproduce the text glyphs
135 ; ------------------------------------------------------------------------
139 ; INSTALL routine. Is called after the driver is loaded into memory. May
140 ; initialize anything that has to be done just once. Is probably empty
142 ; Must set an error code: NO
145 ; No page switching if 80 column store is enabled
154 ; UNINSTALL routine. Is called before the driver is removed from memory. May
155 ; clean up anything done by INSTALL but is probably empty most of the time.
156 ; Must set an error code: NO
160 ; INIT: Changes an already installed device from text mode to graphics mode.
161 ; Note that INIT/DONE may be called multiple times while the driver
162 ; is loaded, while INSTALL is only called once, so any code that is needed
163 ; to initializes variables and so on must go here. Setting palette and
164 ; clearing the screen is not needed because this is called by the graphics
166 ; The graphics kernel will never call INIT when a graphics mode is already
167 ; active, so there is no need to protect against that.
168 ; Must set an error code: YES
170 ; Switch into graphics mode
175 ; Beagle Bros Shape Mechanic fonts don't
176 ; scale well so use fixed scaling factor
180 ; Done, reset the error code
185 ; DONE: Will be called to switch the graphics device back into text mode.
186 ; The graphics kernel will never call DONE when no graphics mode is active,
187 ; so there is no need to protect against that.
188 ; Must set an error code: NO
190 ; Switch into text mode
195 ; Limit SET80COL-HISCR to text
199 ; Reset the text window top
204 ; GETERROR: Return the error code in A and clear it.
211 ; CONTROL: Platform/driver specific entry point.
212 ; Must set an error code: YES
214 ; Check data msb and code to be 0
218 ; Check data lsb to be [0..1]
223 ; Set text window top
229 ; Switch 4 lines of text
230 .assert MIXCLR + 1 = MIXSET, error
231 lda MIXCLR,x ; No BIT absolute,X available
233 ; Done, reset the error code
235 beq :+ ; Branch always
237 ; Done, set the error code
238 err: lda #TGI_ERR_INV_ARG
242 ; CLEAR: Clears the screen.
243 ; Must set an error code: NO
245 bit $C082 ; Switch in ROM
247 bit $C080 ; Switch in LC bank 2 for R/O
250 ; SETVIEWPAGE: Set the visible page. Called with the new page in A (0..n).
251 ; The page number is already checked to be valid by the graphics kernel.
252 ; Must set an error code: NO (will only be called if page ok)
255 .assert LOWSCR + 1 = HISCR, error
256 lda LOWSCR,x ; No BIT absolute,X available
259 ; SETDRAWPAGE: Set the drawable page. Called with the new page in A (0..n).
260 ; The page number is already checked to be valid by the graphics kernel.
261 ; Must set an error code: NO (will only be called if page ok)
266 .byte $2C ; BIT absolute
267 : lda #>$2000 ; Page 1
271 ; SETCOLOR: Set the drawing color (in A). The new color is already checked
272 ; to be in a valid range (0..maxcolor-1).
273 ; Must set an error code: NO (will only be called if color ok)
275 bit $C082 ; Switch in ROM
278 bit $C080 ; Switch in LC bank 2 for R/O
281 ; SETPALETTE: Set the palette (not available with all drivers/hardware).
282 ; A pointer to the palette is passed in ptr1. Must set an error if palettes
284 ; Must set an error code: YES
286 lda #TGI_ERR_INV_FUNC
290 ; GETPALETTE: Return the current palette in A/X. Even drivers that cannot
291 ; set the palette should return the default palette here, so there's no
292 ; way for this function to fail.
293 ; Must set an error code: NO
297 ; GETDEFPALETTE: Return the default palette for the driver in A/X. All
298 ; drivers should return something reasonable here, even drivers that don't
299 ; support palettes, otherwise the caller has no way to determine the colors
300 ; of the (not changeable) palette.
301 ; Must set an error code: NO (all drivers must have a default palette)
307 ; SETPIXEL: Draw one pixel at X1/Y1 = ptr1/ptr2 with the current drawing
308 ; color. The coordinates passed to this function are never outside the
309 ; visible screen area, so there is no need for clipping inside this function.
310 ; Must set an error code: NO
312 bit $C082 ; Switch in ROM
317 bit $C080 ; Switch in LC bank 2 for R/O
320 ; GETPIXEL: Read the color value of a pixel and return it in A/X. The
321 ; coordinates passed to this function are never outside the visible screen
322 ; area, so there is no need for clipping inside this function.
324 bit $C082 ; Switch in ROM
335 adc #$03 ; += 4 (black -> black2, white -> white2)
337 bit $C080 ; Switch in LC bank 2 for R/O
340 ; LINE: Draw a line from X1/Y1 to X2/Y2, where X1/Y1 = ptr1/ptr2 and
341 ; X2/Y2 = ptr3/ptr4 using the current drawing color.
342 ; Must set an error code: NO
344 bit $C082 ; Switch in ROM
353 bit $C080 ; Switch in LC bank 2 for R/O
356 ; BAR: Draw a filled rectangle with the corners X1/Y1, X2/Y2, where
357 ; X1/Y1 = ptr1/ptr2 and X2/Y2 = ptr3/ptr4 using the current drawing color.
358 ; Contrary to most other functions, the graphics kernel will sort and clip
359 ; the coordinates before calling the driver, so on entry the following
360 ; conditions are valid:
363 ; (X1 >= 0) && (X1 < XRES)
364 ; (X2 >= 0) && (X2 < XRES)
365 ; (Y1 >= 0) && (Y1 < YRES)
366 ; (Y2 >= 0) && (Y2 < YRES)
367 ; Must set an error code: NO
382 ; TEXTSTYLE: Set the style used when calling OUTTEXT. Text scaling in X and Y
383 ; direction is passend in X/Y, the text direction is passed in A.
384 ; Must set an error code: NO
386 cmp #TGI_TEXT_VERTICAL
392 ; OUTTEXT: Output text at X/Y = ptr1/ptr2 using the current color and the
393 ; current text style. The text to output is given as a zero terminated
394 ; string with address in ptr3.
395 ; Must set an error code: NO
397 bit $C082 ; Switch in ROM
402 beq :+ ; Not horizontal
410 bne :+ ; Not vertical
415 lda FONT+2*99 ; "connection char"
418 lda FONT+2*99+1 ; "connection char"
424 sty tmp1 ; Save string index
426 sbc #$1F ; No control chars
437 jsr DRAW ; Draw char from string
441 jsr DRAW ; Draw "connection char"
442 ldy tmp1 ; Restore string index
444 bne :- ; Branch always
445 : bit $C080 ; Switch in LC bank 2 for R/O