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| + | #Redirect [[https://www.atari-forum.com/wiki/index.php/Line-A_Document]] |
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| − | <pre> |
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| − | THE LONG-AWAITED Line-A DOCUMENT |
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| − | |||
| − | |||
| − | In order to provide "quick-and-dirty" access to the assembler- |
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| − | level graphics routines, ATARI engineers have set up the 68000's |
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| − | Line-A exception as an interface to several useful routines. The |
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| − | Line-A interface is faster than going through GEM's VDI and has |
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| − | some extra features. Also, Line-A calls require less application |
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| − | code than their VDI counterparts. Of course, Line-A doesn't |
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| − | replace the VDI completely, but if an application only needs a |
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| − | few primitive graphics functions (and wants maximum performance), |
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| − | then Line-A is sufficient (and optimal). |
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| − | |||
| − | The Line-A interface is provided for the hacker-at-heart and |
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| − | no claims are made about its ease of use. The interface may seem |
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| − | unusually inconsistent, but it was not designed; it simply fell |
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| − | out as a freebie from the low-level VDI primitives interface. |
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| − | That is, these routines are the heart of the VDI. |
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| − | |||
| − | The Line-A interface consists of 15 opcodes. The calls to |
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| − | Line-A are assembled as 1-word instructions, the highest 4 bits |
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| − | of which are 1010 ($A, hence Line-A) and the lower 12 bits of |
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| − | which are used as the opcode field. Following is a description |
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| − | of the 15 opcodes: |
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| − | |||
| − | 0 = Initialization. |
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| − | 1 = Put pixel. |
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| − | 2 = Get pixel. |
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| − | 3 = Line. |
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| − | 4 = Horizontal line. |
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| − | 5 = Filled rectangle. |
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| − | 6 = Line-by-line filled polygon. |
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| − | 7 = BitBlt. |
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| − | 8 = TextBlt. |
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| − | 9 = Show mouse. |
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| − | 10 = Hide mouse. |
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| − | 11 = Transform mouse. |
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| − | 12 = Undraw sprite. |
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| − | 13 = Draw sprite. |
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| − | 14 = Copy raster form. |
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| − | |||
| − | 15 = Seedfill. (exists only in versions of TOS after the 1st release) |
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| − | |||
| − | The Line-A routines have some features that the VDI doesn't |
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| − | support. BitBlt supports half-tone patterns on the source and |
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| − | TextBlt supports all 16 BitBlt logic operations, not just the 4 |
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| − | GEM VDI writing modes. In addition to these straight-forward |
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| − | extensions Line-A also allows the adventurous programmer to |
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| − | experiment with special effects. The BitBlt is especially |
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| − | generous in this area. |
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| − | |||
| − | |||
| − | |||
| − | (0) Initialization |
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| − | |||
| − | ... ... |
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| − | dc.w $A000 ; Init the Line-A. |
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| − | ... ... |
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| − | |||
| − | input: none. |
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| − | |||
| − | output: d0 = ptr to the base address of Line-A interface variables. |
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| − | a0 = ptr to the base address of Line-A interface variables. |
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| − | a1 = ptr to array of ptrs to the 3 system font headers. |
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| − | a2 = ptr to array of ptrs to the 15 Line-A routines. |
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| − | |||
| − | note: The value returned in a0 is the sine qua non of the Line-A |
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| − | interface. Inputs to all the other Line-A operations are |
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| − | made relative to this value, i.e., the Line-A interface |
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| − | variables are contained in a structure pointed to by a0. |
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| − | The offsets of these variables in the structure are given |
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| − | below. |
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| − | |||
| − | bugs: In the first TOS release, a2 is not returned as described |
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| − | above. Instead, it is preserved across the Line-A call. |
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| − | See Example Program #2 at the end of this document for the |
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| − | technique that makes a2 point to the proper place. |
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| − | |||
| − | (1) Put pixel |
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| − | |||
| − | ... ... |
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| − | dc.w $A001 ; Plot a pixel at x,y. |
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| − | ... ... |
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| − | |||
| − | input: INTIN[0] = pixel value. |
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| − | PTSIN[0] = x coordinate. |
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| − | PTSIN[1] = y coordinate. |
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| − | |||
| − | output: none. |
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| − | |||
| − | note: For a discussion of the CONTRL, INTIN, PTSIN, INTOUT, & PTSOUT |
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| − | arrays, see the GEM VDI manual. |
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| − | |||
| − | |||
| − | (2) Get pixel |
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| − | |||
| − | ... ... |
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| − | dc.w $A002 ; Get the pixel at x,y. |
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| − | ... ... |
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| − | |||
| − | input: PTSIN[0] = x coordinate. |
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| − | PTSIN[1] = y coordinate. |
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| − | |||
| − | output: d0 = pixel value. |
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| − | |||
| − | |||
| − | (3) Line |
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| − | |||
| − | ... ... |
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| − | dc.w $A003 ; Draw a line between (x1,y1) and (x2,y2). |
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| − | ... ... |
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| − | |||
| − | input: X1 = x1 coordinate. |
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| − | Y1 = y1 coordinate. |
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| − | X2 = x2 coordinate. |
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| − | Y2 = y2 coordinate. |
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| − | COLBIT0 = bit value for plane 0. |
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| − | COLBIT1 = bit value for plane 1. |
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| − | COLBIT2 = bit value for plane 2. |
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| − | COLBIT3 = bit value for plane 3. |
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| − | LNMASK = line style mask. |
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| − | WMODE = writing mode. |
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| − | LSTLIN = always set this to -1, if using xor mode. |
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| − | else ignore it. |
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| − | |||
| − | output: LNMASK is rotated to align with right-most endpoint. |
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| − | |||
| − | quirks: 1) If the line is horizontal, LNMASK is a word-aligned |
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| − | pattern, not a line style. That is, a bit other than |
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| − | bit 15 of LNMASK may be used at the left-most endpoint. |
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| − | |||
| − | 2) As the foregoing references imply, the line is always |
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| − | drawn from left to right, not from (X1,Y1) to (X2,Y2). |
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| − | Thus, LNMASK is always applied from left to right. |
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| − | |||
| − | note: Because of the quirks, an application cannot depend upon the |
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| − | phase of the LNMASK being properly updated between calls |
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| − | to line-drawing primitives. If the phase is critical, the |
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| − | application must compute and init LNMASK before each line |
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| − | is drawn. |
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| − | |||
| − | LNMASK is applied to the line-drawing DDA algorithm along |
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| − | the direction of greater delta. If delta Y is greater than |
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| − | delta X, then LNMASK is applied in the Y direction. |
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| − | |||
| − | These line-drawing quirks and notes apply to the GEM VDI, too. |
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| − | |||
| − | |||
| − | (4) Horizontal line |
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| − | |||
| − | ... ... |
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| − | dc.w $A004 ; Draw a line from (x1,y1) to (x2,y1). |
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| − | ... ... |
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| − | |||
| − | input: X1 = x1 coordinate. |
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| − | Y1 = y1 coordinate. |
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| − | X2 = x2 coordinate. |
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| − | COLBIT0 = bit value for plane 0. |
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| − | COLBIT1 = bit value for plane 1. |
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| − | COLBIT2 = bit value for plane 2. |
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| − | COLBIT3 = bit value for plane 3. |
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| − | WMODE = writing mode. |
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| − | PATPTR = ptr to the fill pattern. |
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| − | PATMSK = pattern index. |
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| − | MFILL = multi-plane pattern flag. |
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| − | |||
| − | |||
| − | output: none. |
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| − | |||
| − | |||
| − | (5) Filled rectangle |
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| − | |||
| − | ... ... |
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| − | dc.w $A005 ; Draw a filled rectangle with upper left corner at |
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| − | ; (x1,y1) and lower right corner at (x2,y2). |
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| − | ... ... |
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| − | |||
| − | input: X1 = x1 coordinate. |
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| − | Y1 = y1 coordinate. |
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| − | X2 = x2 coordinate. |
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| − | Y2 = y2 coordinate. |
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| − | COLBIT0 = bit value for plane 0. |
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| − | COLBIT1 = bit value for plane 1. |
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| − | COLBIT2 = bit value for plane 2. |
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| − | COLBIT3 = bit value for plane 3. |
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| − | WMODE = writing mode. |
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| − | PATPTR = ptr to the fill pattern. |
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| − | PATMSK = fill pattern index. |
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| − | MFILL = multi-plane fill pattern flag. |
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| − | CLIP = clipping flag. |
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| − | XMINCL = x minimum for clipping. |
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| − | XMAXCL = x maximum for clipping. |
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| − | YMINCL = y minimum for clipping. |
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| − | YMAXCL = y maximum for clipping. |
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| − | |||
| − | |||
| − | output: none. |
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| − | |||
| − | |||
| − | (6) Line-by-line filled polygon. |
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| − | |||
| − | ... ... |
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| − | dc.w $A006 ; Draw 1 scan-line of a filled polygon. |
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| − | ... ... |
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| − | |||
| − | input: PTSIN[] = array of polygon vertices. |
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| − | ((x1,y1),(x2,y2)...,(xn,yn),(x1,y1)) |
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| − | CONTRL[1] = n = number of vertices. |
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| − | Y1 = y coordinate of scan-line to fill. |
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| − | COLBIT0 = bit value for plane 0. |
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| − | COLBIT1 = bit value for plane 1. |
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| − | COLBIT2 = bit value for plane 2. |
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| − | COLBIT3 = bit value for plane 3. |
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| − | WMODE = writing mode. |
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| − | PATPTR = ptr to the fill pattern. |
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| − | PATMSK = fill pattern mask. |
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| − | MFILL = multi-plane fill pattern flag. |
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| − | CLIP = clipping flag. |
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| − | XMINCL = x minimum for clipping. |
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| − | XMAXCL = x maximum for clipping. |
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| − | YMINCL = y minimum for clipping. |
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| − | YMAXCL = y maximum for clipping. |
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| − | |||
| − | |||
| − | output: X1 and X2 are clobbered. |
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| − | |||
| − | note: The 1st endpoint must be repeated at the end of the list of |
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| − | n endpoints. |
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| − | |||
| − | |||
| − | (7) BitBlt |
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| − | |||
| − | ... ... |
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| − | dc.w $A007 ; Perform a BIT BLock Transfer. |
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| − | ... ... |
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| − | |||
| − | input: a6 = ptr to a structure of input parameters. |
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| − | |||
| − | output: none. |
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| − | |||
| − | |||
| − | BIT BLT PARAMETER BLOCK OFFSETS |
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| − | |||
| − | |||
| − | B_WD equ +00 ; width of block in pixels |
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| − | B_HT equ +02 ; height of block in pixels |
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| − | |||
| − | PLANE_CT equ +04 ; number of consecutive planes to blt {D} |
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| − | |||
| − | FG_COL equ +06 ; foreground color (logic op index:hi bit) {D} |
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| − | BG_COL equ +08 ; background color (logic op index:lo bit) {D} |
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| − | OP_TAB equ +10 ; logic ops for all fore and background combos |
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| − | S_XMIN equ +14 ; minimum X: source |
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| − | S_YMIN equ +16 ; minimum Y: source |
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| − | S_FORM equ +18 ; source form base address |
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| − | S_NXWD equ +22 ; offset to next word in line (in bytes) |
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| − | S_NXLN equ +24 ; offset to next line in plane (in bytes) |
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| − | S_NXPL equ +26 ; offset to next plane from start of current plane |
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| − | |||
| − | D_XMIN equ +28 ; minimum X: destination |
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| − | D_YMIN equ +30 ; minimum Y: destination |
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| − | D_FORM equ +32 ; destination form base address |
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| − | D_NXWD equ +36 ; offset to next word in line (in bytes) |
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| − | D_NXLN equ +38 ; offset to next line in plane (in bytes) |
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| − | D_NXPL equ +40 ; offset to next plane from start of current plane |
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| − | |||
| − | P_ADDR equ +42 ; address of pattern buffer (0:no pattern) {D} |
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| − | P_NXLN equ +46 ; offset to next line in pattern (in bytes) |
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| − | P_NXPL equ +48 ; offset to next plane in pattern (in bytes) |
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| − | P_MASK equ +50 ; pattern index mask |
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| − | |||
| − | P_BLOCK_LEN equ 76 ; the parameter block must be 76 bytes long |
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| − | |||
| − | |||
| − | *** notes *** |
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| − | |||
| − | parameters marked with {D} may be altered during the course |
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| − | of the BIT BLT execution |
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| − | |||
| − | |||
| − | |||
| − | contents of OP_TAB |
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| − | |||
| − | |||
| − | +00 byte logic operation employed when foreground and background color |
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| − | bits for current plane are both clear (0) |
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| − | |||
| − | +01 byte logic operation employed when current plane's foreground color |
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| − | bit is clear (0) and background color bit is set (1) |
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| − | |||
| − | +02 byte logic operation employed when current plane's foreground color |
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| − | bit is set (1) and background color bit is clear (0) |
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| − | |||
| − | +03 byte logic operation employed when foreground and background color |
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| − | bits for current plane are both set (1) |
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| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | 0. PREFACE |
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| − | |||
| − | Before one floggles one's tormented mind with this tangled nest of |
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| − | arcane knowledge, one ought to be intimately familiar with chapter 6 |
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| − | of the GEM VDI manual. the author assumes that one's knowledge of Raster |
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| − | matters is quite wide and that the rudiments of BIT BLTting are below |
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| − | discussion. If the author is mistaken then he's sorry (and you're |
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| − | about to become lost in the sea of woe, oh ho!). |
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| − | |||
| − | |||
| − | I. PARAMETER BLOCK |
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| − | |||
| − | the BIT BLT is accessed via a 76 byte parameter block. Register A6 points |
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| − | to the head of this block upon LINE A entry. Only the first 52 bytes of |
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| − | the block need be attended to by the abuser. The remaining space is |
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| − | maintained internally by the BLT. Note that in the following explanations, |
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| − | parameters will be refered to by their symbolic offsets into the parameter |
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| − | block. |
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| − | |||
| − | |||
| − | II. MEMORY FORMS |
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| − | |||
| − | memory forms are something like a cabbage patch. (a cabbage patch is a |
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| − | place for mentally retarded programmers). let's face it, forms are nothing |
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| − | like a cabbage patch. if you think they are, go back and read chapter 6 |
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| − | in the GEM VDI manual. if you know anything at all about memory forms, |
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| − | you know they are almost entirely but not totally unlike a garbage can. |
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| − | one difference is that memory forms are of two sexes, source and destination. |
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| − | each sex is defined by the same four parameters: form block address, |
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| − | form block width, offset to next contiguous word, and offset to next plane. |
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| − | |||
| − | S_FORM and D_FORM point to the first words of the source memory form |
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| − | and destination memory forms, respectively. these addresses must fall on |
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| − | word boundries or severe hardships will fall (as will address exceptions) |
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| − | like plagues upon the ancient egyptians. |
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| − | |||
| − | S_NXWD and D_NXWD are offsets to the next word in a plane of the memory |
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| − | form. for example, in the monochrome mode the value is 2 while a value |
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| − | of 4 is used in medium resolution and 8 is applicable to low resolution. |
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| − | |||
| − | S_NXLN and D_NXLN are form widths for source and destination. ( i can't |
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| − | remember which one belongs to the source form and which one belongs to the |
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| − | destination form). These widths must be even byte values, as you know, for |
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| − | they represent the offset from one row of the form to the next and forms |
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| − | must be word aligned and an integral number of words wide. (hint: the |
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| − | hi rez screen value is 90 while lo and medium rez values are 160) |
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| − | |||
| − | S_NXPL and D_NXPL are offsets from the start of one plane to the start of |
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| − | the next plane. because of the ST screen's interleaved plane structure, |
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| − | this value is always two (2). alternative universes allow for a series |
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| − | of contiguous planes where NXPL values are the number of bytes in each plane. |
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| − | thus , it is possible to BLT from the contiguous universe into the |
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| − | interleaved ST universe and vice versa. |
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| − | |||
| − | |||
| − | the actual bit alligned blocks of memory are defined within the form |
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| − | by an upper left anchor point, a pixel width, and a pixel height: |
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| − | (S_XMIN, S_YMIN, B_WD, and B_HT). the location in the destination form |
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| − | is defined by an anchor point (D_XMIN, D_YMIN). no harm will come if |
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| − | these two areas overlap. Note that no clipping is performed andthere is no |
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| − | checking to determine whether the bit blocks fall within the confines of |
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| − | the encompasing memory forms. finally, the number of planes to |
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| − | be transfered (the number of itterations of the BLT algorithm) is |
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| − | contained in the PLANE_CT word. |
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| − | |||
| − | |||
| − | |||
| − | |||
| − | III. RASTER OPERATIONS |
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| − | |||
| − | OP_TAB is a table of four RASTER OP codes. Each of the byte wide entries |
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| − | in OP_TAB contain a code for one of the sixteen logical operations between |
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| − | consenting source and destination blocks. For each plane, the logical |
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| − | operation is chosen by indexing into the OP_TAB with a value derived from |
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| − | FG_COL and BG_COL words. For a given plane "n", bit "n" of FG_COL is the hi |
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| − | bit of the two bit index value and bit "n" of BG_COL is the lo bit of |
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| − | the index value. |
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| − | |||
| − | for those with a furniture fetish, here is a table: |
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| − | |||
| − | FG(n) BG(n) OP_TAB entry |
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| − | ----- ----- ------------ |
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| − | |||
| − | 0 0 first entry |
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| − | 0 1 second entry |
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| − | 1 0 third entry |
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| − | 1 1 fourth entry |
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| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | IV. PATTERNS |
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| − | |||
| − | Patterns are word wide, word aligned images that are logically anded |
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| − | with the source prior to the logical combination of source with destination. |
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| − | |||
| − | Patterns are packed in an imaginary grid anchored at the upper left corner |
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| − | (0,0) of the destination memory form. |
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| − | |||
| − | Patterns are 16 bits wide and repeated every 16 pixels horizontally. |
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| − | |||
| − | patterns are an integral power of 2 in height and repeat vertically |
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| − | at that frequency. |
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| − | |||
| − | The source is shifted into alignment with the destination rectangle prior |
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| − | to the combination of source with pattern. |
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| − | Thus, the relationship between source and pattern is dependent upon the |
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| − | X,Y positioning of the destination rectangle. |
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| − | |||
| − | |||
| − | P_ADDR points to the first word of the pattern. If this pointer is 0, a |
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| − | pattern is not combined with the source rectangle. |
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| − | |||
| − | P_NXLN is the offset (in bytes) between consecutive words in the pattern. |
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| − | For reasons too inane to go into here, this number should be an integral |
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| − | power of 2 (such as 2,4, or 8) |
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| − | |||
| − | P_NXPL is the offset (in bytes) from the beginning of a plane to the |
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| − | beginning of the next plane. In the case of a single plane pattern used |
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| − | in a multi plane environment, this value would be zero. thus, the same |
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| − | pattern is repeated through all planes. |
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| − | |||
| − | P_MASK works with P_NXLN to specify the length of the pattern. |
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| − | The length (in words) of the pattern must be an integral power of 2. |
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| − | |||
| − | if P_NXLN = 2 ** n |
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| − | |||
| − | then P_MASK = (length in words -1) << n |
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| − | |||
| − | ... i don't know why. go ask your father. |
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| − | |||
| − | |||
| − | |||
| − | V. BAG 'O TRICKS |
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| − | |||
| − | |||
| − | Q. I want to BLT from a single plane source to multi plane destination. |
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| − | |||
| − | A. That's not in the form of a question. And besides, i can't think |
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| − | with that water pick spurtin in my ear. Hey, that's my cat your puttin in |
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| − | the Cuisinart. Wha the fuh you think your doin bustin into my word processor |
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| − | like this. Hey bud, stay away from that delete key. Hey moe foe, i'm |
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| − | serious. How'd you like an unexpected interrupt ? |
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| − | |||
| − | Q. This key is loaded and it's pointed at your bonus check. |
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| − | |||
| − | A. ok,ok... i'll talk. |
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| − | |||
| − | S_NXPL =0 => the same source plane is BLTted to all destination planes |
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| − | |||
| − | Q. yea, i know that but what logic ops do i use ? |
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| − | |||
| − | A. to map 1's to foreground color and 0's to background color |
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| − | set OP_TAB to: |
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| − | |||
| − | offset logic op |
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| − | |||
| − | +00 00 all zeros |
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| − | +01 04 D' <- [not S] and D |
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| − | +02 07 D' <- S or D |
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| − | +03 15 all ones |
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| − | |||
| − | load foreground color into FG_COL and background color into BG_COL |
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| − | |||
| − | |||
| − | Q. you wanna buy some lake bottom property? |
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| − | |||
| − | A. to map 1's to foreground color and make 0's transparent |
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| − | set OP_TAB to: |
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| − | |||
| − | offset logic op |
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| − | |||
| − | +00 04 D' <- [not S] and D |
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| − | +01 04 D' <- [not S] and D |
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| − | +02 07 D' <- S or D |
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| − | +03 07 D' <- S or D |
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| − | |||
| − | |||
| − | load foreground color into FG_COL |
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| − | it doesn't matter what you put into BG_COL |
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| − | |||
| − | don't forget to set S_NXPL to 0 |
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| − | |||
| − | |||
| − | |||
| − | |||
| − | enough smalltalk, let's get down to the core of the issue. |
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| − | Here are some of my Aunt Marge's flavorful BIT BLT recipes: |
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| − | |||
| − | |||
| − | 1. BLT a pattern without Source to the Destination. |
||
| − | |||
| − | For this number, we'll need a word of ones. Label it "ones:" |
||
| − | next, point S_FORM at "ones". Set S_NXLN, S_NXPL, S_NXWD, |
||
| − | S_XMIN, and S_YMIN to 0. Set up the pattern as you usually would |
||
| − | and before you know it, you'll have a wonderful steaming pattern |
||
| − | filled rectangle. |
||
| − | |||
| − | |||
| − | 2. this is a nice way to make a sprite like device. |
||
| − | |||
| − | o you will need to bake a monoplane mask. everywhere there is a |
||
| − | 1 in the mask, the background will be removed. wherever a 0 falls, |
||
| − | the background is left intact. |
||
| − | |||
| − | set OP_TAB to: |
||
| − | |||
| − | offset logic op |
||
| − | |||
| − | +00 04 D' <- [not S] and D |
||
| − | +01 04 D' <- [not S] and D |
||
| − | +02 07 D' <- S or D |
||
| − | +03 07 D' <- S or D |
||
| − | |||
| − | |||
| − | load foreground color into FG_COL |
||
| − | it doesn't matter what you put into BG_COL |
||
| − | |||
| − | |||
| − | o next, take a monoplane form (or multiplane form) and "or" it (OP 07) |
||
| − | into the area that you just scooped out with the mask |
||
| − | |||
| − | feeds a family of four. |
||
| − | |||
| − | |||
| − | (8) TextBlt |
||
| − | |||
| − | ... ... |
||
| − | dc.w $A008 ; Perform a TEXT BLock Transfer of 1 character. |
||
| − | ... ... |
||
| − | |||
| − | input: |
||
| − | WMODE = writing mode.(0-3 => VDI modes |
||
| − | 4-19 => BitBlt modes) |
||
| − | TEXTFG = text foreground color. |
||
| − | TEXTBG = text background color. (used for modes 4-19) |
||
| − | FBASE = ptr to start of font data. (font form) |
||
| − | FWIDTH = width of font form. |
||
| − | SOURCEX = x coord of character in font form. |
||
| − | SOURCEY = y coord of character in font form. |
||
| − | DESTX = x coord of character on screen. |
||
| − | DESTY = y coord of character on screen. |
||
| − | DELX = width of character. |
||
| − | DELY = height of character. |
||
| − | STYLE = vector of TextBlt special effects flags. |
||
| − | LITEMASK = the mask to use in lightening text. |
||
| − | SKEWMASK = the mask to use in skewing text. |
||
| − | WEIGHT = the width by which to thicken text. |
||
| − | ROFF = offset above character baseline when skewing. |
||
| − | LOFF = offset below character baseline when skewing. |
||
| − | SCALE = scaling flag. (0 => no scaling.) |
||
| − | XDDA = accumulator for x dda. |
||
| − | DDAINC = fractional amount to scale up or down. |
||
| − | SCALDIR = scale direction flag. (0 => down) |
||
| − | CHUP = character rotation vector. |
||
| − | MONO = monospaced font flag. |
||
| − | SCRTCHP = ptr to start of text special effects buffer. |
||
| − | SCRPT2 = offset of scaling buffer in above buffer. |
||
| − | |||
| − | output: none. |
||
| − | |||
| − | |||
| − | (9) Show mouse |
||
| − | |||
| − | ... ... |
||
| − | dc.w $A009 ; Show the mouse. |
||
| − | ... ... |
||
| − | |||
| − | input: see GEM VDI manual. |
||
| − | |||
| − | |||
| − | output: none. |
||
| − | |||
| − | |||
| − | (10) Hide mouse |
||
| − | |||
| − | ... ... |
||
| − | dc.w $A00A ; Hide the mouse. |
||
| − | ... ... |
||
| − | |||
| − | input: see GEM VDI manual. |
||
| − | |||
| − | |||
| − | output: none. |
||
| − | |||
| − | |||
| − | (11) Transform mouse |
||
| − | |||
| − | ... ... |
||
| − | dc.w $A00B ; Transform the mouse's form. |
||
| − | ... ... |
||
| − | |||
| − | input: see GEM VDI manual. |
||
| − | |||
| − | |||
| − | output: none. |
||
| − | |||
| − | |||
| − | (12) Undraw sprite |
||
| − | |||
| − | ... ... |
||
| − | dc.w $A00C ; Undraw the previously drawn sprite. |
||
| − | ... ... |
||
| − | |||
| − | input: a2 = ptr to sprite save block. |
||
| − | |||
| − | note: The sprite save block is used to save the screen |
||
| − | underneath the sprite. Its size is 10 bytes + 64 bytes |
||
| − | per plane, i.e. (10 + VPLANES * 64) bytes. |
||
| − | |||
| − | output: clobbers a6. ("C" programmers beware.) |
||
| − | |||
| − | |||
| − | (13) Draw sprite |
||
| − | |||
| − | ... ... |
||
| − | dc.w $A00D ; Draw a sprite. |
||
| − | ... ... |
||
| − | |||
| − | input: d0 = x hot-spot. |
||
| − | d1 = y hot_spot. |
||
| − | a0 = ptr to sprite definition block. |
||
| − | a2 = ptr to sprite save block. |
||
| − | |||
| − | SPRITE DEFINTION BLOCK LAYOUT |
||
| − | |||
| − | ds.w 1 x offset of hot-spot. |
||
| − | ds.w 1 y offset of hot-spot. |
||
| − | ds.w 1 format flag. (1 => VDI Format, |
||
| − | -1 => XOR Format) |
||
| − | |||
| − | VDI Format |
||
| − | |||
| − | fg bit bg bit action |
||
| − | 0 0 transparent to screen |
||
| − | 0 1 background color plotted |
||
| − | 1 0 foreground color plotted |
||
| − | 1 1 foreground color plotted |
||
| − | |||
| − | |||
| − | XOR Format |
||
| − | |||
| − | fg bit bg bit action |
||
| − | 0 0 transparent to screen |
||
| − | 0 1 background color plotted |
||
| − | 1 0 xor screen |
||
| − | 1 1 foreground color plotted |
||
| − | |||
| − | ds.w 1 background color (color table index) |
||
| − | ds.w 1 foreground color (color table index) |
||
| − | ds.w 32 interleaved background/foreground image. |
||
| − | (word 0 = background line 0. |
||
| − | word 1 = foreground line 0. |
||
| − | word 2 = background line 1. |
||
| − | word 3 = foreground line 1. |
||
| − | etc.) |
||
| − | |||
| − | output: clobbers a6. ("C" programmers beware.) |
||
| − | |||
| − | bugs: This function is not usable as a Line-A call in the 1st |
||
| − | release of TOS. See Example Program #2 below for the |
||
| − | technique one must adopt to use this function. |
||
| − | |||
| − | |||
| − | (14) Copy raster form |
||
| − | |||
| − | ... ... |
||
| − | dc.w $A00E ; Copy a raster form from source to destination. |
||
| − | ... ... |
||
| − | |||
| − | input: See the VDI discussion of Copy Raster, Opaque & Transparent, |
||
| − | EXCEPT, CONTRL(0), CONTRL(1), CONTRL(3), and CONTRL(6) are |
||
| − | ignored. |
||
| − | COPYTRAN = Opaque/Transparent mode flag. (0 => Opaque) |
||
| − | |||
| − | output: none. |
||
| − | |||
| − | note: See the BitBlt discussion above. |
||
| − | |||
| − | |||
| − | |||
| − | |||
| − | USING THE Line-A INTERFACE |
||
| − | |||
| − | |||
| − | The inputs to the Line-A routines are contained in a structure pointed |
||
| − | to by the value returned in a0 after an initialization call ($A000) has |
||
| − | been made. This initialization only needs to be done once and any returned |
||
| − | values can be saved and used as needed. |
||
| − | |||
| − | The Line-A interface can be used in cooperation with the VDI and AES, |
||
| − | however, one cannot expect the variables below to be unchanged after the |
||
| − | VDI or AES has been used. Therefore, if an application wants to mix calls |
||
| − | to Line-A and VDI/AES, it must reload any variables that it uses as input |
||
| − | to the Line-A routines. |
||
| − | |||
| − | The caller should assume that registers d0-d2 and a0-a2 are clobbered |
||
| − | upon return. The rest are preserved. |
||
| − | |||
| − | |||
| − | |||
| − | The LINE"A" input variables structure: |
||
| − | |||
| − | offset name type description |
||
| − | |||
| − | 0 VPLANES word number of video planes. |
||
| − | 2 VWRAP word number of bytes/video line. |
||
| − | |||
| − | note: These variables can be changed to implement special effects, |
||
| − | e.g.,doubling VWRAP will cause the routines to skip 1 scan- |
||
| − | line between every scanline that is output to the screen. |
||
| − | Of course, any modifications made to these variables must be |
||
| − | undone when normal operation of the Line-A (or VDI) is |
||
| − | desired. |
||
| − | |||
| − | 4 CONTRL long ptr to the CONTRL array. |
||
| − | 8 INTIN long ptr to the INTIN array. |
||
| − | 12 PTSIN long ptr to the PTSIN array. |
||
| − | 16 INTOUT long ptr to the INTOUT array. |
||
| − | 20 PTSOUT long ptr to the PTSOUT array. |
||
| − | |||
| − | note: See the GEM VDI manual for a discussion of the above arrays. |
||
| − | |||
| − | 24 COLBIT0 word current color bit-plane 0 value. |
||
| − | 26 COLBIT1 word current color bit-plane 1 value. |
||
| − | 28 COLBIT2 word current color bit-plane 2 value. |
||
| − | 30 COLBIT3 word current color bit-plane 3 value. |
||
| − | |||
| − | note: current foreground writing color = 1*COLBIT0 + |
||
| − | 2*COLBIT1 + |
||
| − | 4*COLBIT2 + |
||
| − | 8*COLBIT3. |
||
| − | |||
| − | 32 LSTLIN word set this to -1 and forget it. |
||
| − | 34 LNMASK word equivalent to VDI's line style. |
||
| − | 36 WMODE word writing mode. (0 => replace mode, |
||
| − | 1 => transparent mode, |
||
| − | 2 => xor mode, |
||
| − | 3 => inverse trans mode.) |
||
| − | |||
| − | note: see VDI manual for discussion of writing modes. |
||
| − | |||
| − | 38 X1 word x1 coordinate. |
||
| − | 40 Y1 word y1 coordinate. |
||
| − | 42 X2 word x2 coordinate. |
||
| − | 44 Y2 word y2 coordinate. |
||
| − | 46 PATPTR long ptr to the current fill pattern. |
||
| − | 50 PATMSK word fill pattern "mask". |
||
| − | 52 MFILL word multi-plane fill flag. |
||
| − | (0 => current fill pattern is single plane) |
||
| − | (1 => current fill pattern is multi-plane) |
||
| − | |||
| − | 54 CLIP word clipping flag (0 => no clipping) |
||
| − | 56 XMINCL word minimum x clipping value. |
||
| − | 58 YMINCL word minimum y clipping value. |
||
| − | 60 XMAXCL word maximum x clipping value. |
||
| − | 62 YMAXCL word maximum y clipping value. |
||
| − | |||
| − | 64 XDDA word accumulator for textblt x dda. |
||
| − | |||
| − | note: Should be inited to 8000H (.5) before each invocation |
||
| − | of TextBlt. |
||
| − | |||
| − | 66 DDAINC word fractional amount to scale up or down. |
||
| − | |||
| − | note: If scaling up, set DDAINC to |
||
| − | 256*(Intended size-Actual size)/Actual size. |
||
| − | |||
| − | If scaling down, set DDAINC to |
||
| − | 256*Intended size/Actual size. |
||
| − | |||
| − | 68 SCALDIR word scale direction flag. (0 => down) |
||
| − | 70 MONO word 0 => current font is not monospaced OR |
||
| − | its OK for thickening to increase the |
||
| − | width of the current font. |
||
| − | 1 => current font is monospaced AND thickening |
||
| − | may not increase the width of the font. |
||
| − | |||
| − | 72 SOURCEX word x coord of character in font form. |
||
| − | 74 SOURCEY word y coord of character in font form. |
||
| − | |||
| − | note: SOURCEX can be computed from the information held in the |
||
| − | font header. (see Appendix G of VDI manual for header def) |
||
| − | e.g. temp = character value; |
||
| − | temp -= fnt_ptr->first_ade; |
||
| − | SOURCEX = fnt_ptr->off_table(temp); |
||
| − | |||
| − | SOURCEY is typically set to 0. (top line of font form) |
||
| − | |||
| − | 76 DESTX word x coord of character on screen. |
||
| − | 78 DESTY word y coord of character on screen. |
||
| − | 80 DELX word width of character. |
||
| − | 82 DELY word height of character. |
||
| − | |||
| − | note: DELX & DELY can be computed from the font header. |
||
| − | e.g. temp = character value; |
||
| − | temp -= fnt_ptr->first_ade; |
||
| − | SOURCEX = fnt_ptr->off_table(temp); |
||
| − | DELX = fnt_ptr->offtable(temp+1)-SOURCEX; |
||
| − | DELY = fnt_ptr->form_height; |
||
| − | |||
| − | 84 FBASE long ptr to start of font data. (font form) |
||
| − | 88 FWIDTH word width of font form. |
||
| − | |||
| − | note: FBASE & FWIDTH can be computed from the font header. |
||
| − | e.g. FBASE = fnt_ptr->dat_table; |
||
| − | FWIDTH = fnt_ptr->form_width; |
||
| − | |||
| − | 90 STYLE word vector of TextBlt special effects flags. |
||
| − | Bit 0 = Thicken flag. |
||
| − | Bit 1 = Lighten flag. |
||
| − | Bit 2 = Skewing flag. |
||
| − | Bit 3 = Underline flag. (ignored) |
||
| − | Bit 4 = Outline flag. |
||
| − | |||
| − | note: Set the bits to select the desired effects. |
||
| − | Underlining must be done by the application. |
||
| − | |||
| − | 92 LITEMASK word the mask to use in lightening text. |
||
| − | 94 SKEWMASK word the mask to use in skewing text. |
||
| − | 96 WEIGHT word the width by which to thicken text. |
||
| − | 98 ROFF word offset above character baseline when skewing. |
||
| − | 100 LOFF word offset below character baseline when skewing. |
||
| − | |||
| − | note: The above 5 input variables can be computed from the font |
||
| − | header. |
||
| − | e.g. LITEMASK = fnt_ptr->lighten; |
||
| − | SKEWMASK = fnt_ptr->skew; |
||
| − | WEIGHT = fnt_ptr->thicken; |
||
| − | if (skewing) { |
||
| − | ROFF = fnt_ptr->right_offset; |
||
| − | LOFF = fnt_ptr->left_offset; |
||
| − | } |
||
| − | else { |
||
| − | ROFF = 0; |
||
| − | LOFF = 0; |
||
| − | } |
||
| − | |||
| − | 102 SCALE word scaling flag. (0 => no scaling.) |
||
| − | 104 CHUP word character rotation vector. |
||
| − | 0 => normal horizontal orientation. |
||
| − | 900 => rotated 90 degrees clockwise. |
||
| − | 1800 => rotated 180 degrees clockwise. |
||
| − | 2700 => rotated 270 degrees clockwise. |
||
| − | |||
| − | 106 TEXTFG word text foreground color. |
||
| − | |||
| − | 108 SCRTCHP long ptr to start of text special effects buffer. |
||
| − | 112 SCRPT2 word offset of scaling buffer in above buffer. |
||
| − | |||
| − | note: These special effects buffer pointers must be initialized |
||
| − | before TextBlt effects can be used. |
||
| − | |||
| − | 114 TEXTBG word text background color. (4/20/85) RAMVDI only. |
||
| − | 116 COPYTRAN word copy raster form type flag. (4/26/85) RAMVDI. |
||
| − | 0 => Opaque type |
||
| − | n-plane source -> n-plane dest |
||
| − | BitBlt writing modes |
||
| − | ~0 => Transparent type |
||
| − | 1-plane source -> n-plane dest |
||
| − | VDI writing modes |
||
| − | |||
| − | 118 SEEDABORT long ptr to routine which is called within the |
||
| − | seedfill logic to allow the fill to be |
||
| − | aborted. Initialized to point to a |
||
| − | dummy routine which returns FALSE. |
||
| − | Returning TRUE aborts the seedfill. |
||
| − | |||
| − | note: This ptr doesn't exist in 1st release of TOS. See Example |
||
| − | Program #2 for the technique to use to identify the 1st TOS |
||
| − | release. |
||
| − | |||
| − | |||
| − | |||
| − | |||
| − | EXAMPLE Line-A EQUATES |
||
| − | |||
| − | * |
||
| − | * |
||
| − | * |
||
| − | VPLANES equ 0 |
||
| − | VWRAP equ 2 |
||
| − | CONTRL equ 4 |
||
| − | INTIN equ 8 |
||
| − | PTSIN equ 12 |
||
| − | INTOUT equ 16 |
||
| − | PTSOUT equ 20 |
||
| − | COLBIT0 equ 24 |
||
| − | COLBIT1 equ 26 |
||
| − | COLBIT2 equ 28 |
||
| − | COLBIT3 equ 30 |
||
| − | LSTLIN equ 32 |
||
| − | LNMASK equ 34 |
||
| − | WMODE equ 36 |
||
| − | X1 equ 38 |
||
| − | Y1 equ 40 |
||
| − | X2 equ 42 |
||
| − | Y2 equ 44 |
||
| − | PATPTR equ 46 |
||
| − | PATMSK equ 50 |
||
| − | MFILL equ 52 |
||
| − | CLIP equ 54 |
||
| − | XMINCL equ 56 |
||
| − | YMINCL equ 58 |
||
| − | XMAXCL equ 60 |
||
| − | YMAXCL equ 62 |
||
| − | XDDA equ 64 |
||
| − | DDAINC equ 66 |
||
| − | SCALDIR equ 68 |
||
| − | MONO equ 70 |
||
| − | SRCX equ 72 |
||
| − | SRCY equ 74 |
||
| − | DSTX equ 76 |
||
| − | DSTY equ 78 |
||
| − | DELX equ 80 |
||
| − | DELY equ 82 |
||
| − | FBASE equ 84 |
||
| − | FWIDTH equ 88 |
||
| − | STYLE equ 90 |
||
| − | LITEMSK equ 92 |
||
| − | SKEWMSK equ 94 |
||
| − | WEIGHT equ 96 |
||
| − | ROFF equ 98 |
||
| − | LOFF equ 100 |
||
| − | SCALE equ 102 |
||
| − | CHUP equ 104 |
||
| − | TEXTFG equ 106 |
||
| − | SCRTCHP equ 108 |
||
| − | SCRPT2 equ 112 |
||
| − | TEXTBG equ 114 |
||
| − | COPYTRAN equ 116 |
||
| − | SEEDABORT equ 118 |
||
| − | * |
||
| − | * |
||
| − | * |
||
| − | INIT equ $A000 |
||
| − | PUTPIX equ INIT+1 |
||
| − | GETPIX equ INIT+2 |
||
| − | ABLINE equ INIT+3 |
||
| − | HABLINE equ INIT+4 |
||
| − | RECTFILL equ INIT+5 |
||
| − | POLYFILL equ INIT+6 |
||
| − | BITBLT equ INIT+7 |
||
| − | TEXTBLT equ INIT+8 |
||
| − | SHOWCUR equ INIT+9 |
||
| − | HIDECUR equ INIT+10 |
||
| − | CHGCUR equ INIT+11 |
||
| − | DRSPRITE equ INIT+12 |
||
| − | UNSPRITE equ INIT+13 |
||
| − | COPYRSTR equ INIT+14 |
||
| − | SEEDFILL equ INIT+15 |
||
| − | |||
| − | |||
| − | |||
| − | EXAMPLE PROGRAM #1 |
||
| − | |||
| − | text |
||
| − | |||
| − | start: dc.w INIT ; initialize. |
||
| − | move.w #-1,LSTLIN(a0) ; once and for all. |
||
| − | move.w #$5555,LNMASK(a0) ; dithered line. |
||
| − | move.w #0,WMODE(a0) ; replace mode. |
||
| − | move.w #1,COLBIT0(a0) |
||
| − | move.w #1,COLBIT1(a0) |
||
| − | move.w #1,COLBIT2(a0) |
||
| − | move.w #0,COLBIT3(a0) ; drawing color = 7. |
||
| − | move.w #0,X1(a0) ; X1 = 0. |
||
| − | move.w #0,Y1(a0) ; Y1 = 0. |
||
| − | move.w #99,X2(a0) ; X2 = 99. |
||
| − | move.w #99,Y2(a0) ; Y2 = 99. |
||
| − | dc.w ABLINE ; draw line. |
||
| − | . |
||
| − | . |
||
| − | . |
||
| − | move.w #0,-(sp) |
||
| − | trap #1 ; exit. |
||
| − | end |
||
| − | |||
| − | |||
| − | |||
| − | EXAMPLE PROGRAM #2 |
||
| − | |||
| − | text |
||
| − | * |
||
| − | * |
||
| − | * |
||
| − | start: clr.l -(sp) |
||
| − | move.w #$20,-(sp) |
||
| − | trap #1 ; supervisor mode required to use |
||
| − | * ; Line-A routines via jsr. |
||
| − | addq #6,sp |
||
| − | move.l d0,stksave ; save old stack ptr. |
||
| − | * |
||
| − | * Find out which version of Line-A handler exists. |
||
| − | * |
||
| − | move.l #0,a2 ; convenient value for testing. |
||
| − | dc.w INIT ; Line-A initialization. |
||
| − | move.l a2,d2 ; old version? |
||
| − | bne a2ok ; no, a2 points to array of Line-A |
||
| − | * ; routine addresses. |
||
| − | lea -4*15(a1),a2 ; yes, a2 is untouched, so use a1 plus |
||
| − | * ; displacement (15 addresses). |
||
| − | * |
||
| − | * a2 now points to array of Line-A routine addresses. |
||
| − | * |
||
| − | a2ok: move.l 4*$D(a2),drawaddr ; fetch draw routine address. |
||
| − | * |
||
| − | * Bug-workaround/Initialization complete. |
||
| − | * |
||
| − | move.w #0,d0 ; init x. |
||
| − | move.w #0,d1 ; init y. |
||
| − | lea sprite,a0 ; point to sprite. |
||
| − | lea save,a2 ; point to save area. |
||
| − | |||
| − | loop: movem.w d0-d1,-(sp) ; save x,y. |
||
| − | movem.l a0/a2,-(sp) ; save ptrs. |
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| − | move.l a6,-(sp) ; draw clobbers a6. |
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| − | tst.w old_linea ; old or new Line-A handler? |
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| − | beq new ; new, branch. |
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| − | move.l drawaddr,a3 ; fetch draw routine address. |
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| − | jsr (a3) ; draw the old way. |
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| − | bra merge |
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| − | * |
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| − | new: dc.w DRSPRITE ; draw the new way. |
||
| − | * |
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| − | merge: move.l (sp)+,a6 |
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| − | movem.l (sp)+,a0/a2 ; restore ptrs. |
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| − | * |
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| − | move.w #2000,d2 |
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| − | wait: dbra d2,wait ; wait a bit. |
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| − | * |
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| − | movem.l a0/a2,-(sp) ; save ptrs. |
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| − | move.l a6,-(sp) ; undraw clobbers a6. |
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| − | dc.w UNSPRITE |
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| − | move.l (sp)+,a6 |
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| − | movem.l (sp)+,a0/a2 ; restore ptrs. |
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| − | movem.w (sp)+,d0-d1 ; restore x,y. |
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| − | addq.w #1,d0 ; inc x. |
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| − | cmp.w #640,d0 |
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| − | ble loop |
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| − | * |
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| − | move.l stksave,-(sp) |
||
| − | move.w #$20,-(sp) |
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| − | trap #1 ; user mode. |
||
| − | addq #6,sp |
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| − | * |
||
| − | move.w #0,-(sp) |
||
| − | trap #1 ; exit. |
||
| − | |||
| − | data |
||
| − | * |
||
| − | * |
||
| − | * |
||
| − | sprite: dc.w 0,0 ; x,y offsets of hotspot. |
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| − | dc.w 1,0,1 ; format, background, foreground. |
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| − | bob: dc.w $FFFF ; background line 0. |
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| − | dc.w $07F0 ; foreground line 0. |
||
| − | dc.w $FFFF |
||
| − | dc.w $0ff8 |
||
| − | dc.w $FFFF |
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| − | dc.w $1fec |
||
| − | dc.w $FFFF |
||
| − | dc.w $1804 |
||
| − | dc.w $FFFF |
||
| − | dc.w $1804 |
||
| − | dc.w $FFFF |
||
| − | dc.w $1004 |
||
| − | dc.w $FFFF |
||
| − | dc.w $1e3c |
||
| − | dc.w $FFFF |
||
| − | dc.w $1754 |
||
| − | dc.w $FFFF |
||
| − | dc.w $1104 |
||
| − | dc.w $FFFF |
||
| − | dc.w $0b28 |
||
| − | dc.w $FFFF |
||
| − | dc.w $0dd8 |
||
| − | dc.w $FFFF |
||
| − | dc.w $0628 |
||
| − | dc.w $FFFF |
||
| − | dc.w $07d0 |
||
| − | dc.w $FFFF |
||
| − | dc.w $2e10 |
||
| − | dc.w $FFFF |
||
| − | dc.w $39e0 |
||
| − | dc.w $FFFF |
||
| − | dc.w $3800 |
||
| − | |||
| − | |||
| − | bss |
||
| − | * |
||
| − | * |
||
| − | * |
||
| − | stksave: ds.l 1 |
||
| − | save: ds.b 10+64 |
||
| − | old_linea: ds.w 1 |
||
| − | drawaddr: ds.l 1 |
||
| − | end |
||
| − | |||
| − | </pre> |
||