* Program to draw a single pixel interposed on Single Playfield Code. * Submitted by Thomas J. Eshelman, Reading, Pa. 11/25/88 * * Purpose: Create a library routine to produces a single-playfield display * using system graphics primitives. * * Draw a pixel at predetermined location and color. * This particular example is written for an early DevPak assembler. * Please refer to accompanying Manx version for full comments. incdir "fh0:Asm_Include/" include exec/types.i include exec/exec_lib.i include graphics/gfx.i include graphics/gfxbase.i include graphics/rastport.i include graphics/view.i include graphics/graphics_lib.i include libraries/dosextens.i include libraries/dos_lib.i include workbench/workbench.i include workbench/startup.i include hardware/custom.i include tomesh.i NUMCOLS EQU 8 PLANEPTR EQUR d0 DEPTH EQU 3 Two sets of dimensions to remind that WIDTH EQU 401 the display is not the same as the HEIGHT EQU 201 bitmap. VPWIDTH EQU 321 The odd value chosen to remind never VPHEIGHT EQU 201 to draw >= size of the bitmap. start: suba.l a1,a1 Asm. doesn't provide the automatic CALLEXEC FindTask startup code of 'C'. Hence, we steal move.l d0,mytask this classic scheme from David Ashley. lea gfxname(pc),a1 moveq #0,d0 jsr _LVOOpenLibrary(a6) move.l d0,GfxBase movea.l d0,a1 move.l gb_ActiView(a1),oldview lea dosname(pc),a1 moveq #0,d0 jsr _LVOOpenLibrary(a6) move.l d0,DosBase clr.l returnmsg movea.l mytask(pc),a4 tst.l pr_CLI(a4) bne nowb lea pr_MsgPort(a4),a0 jsr _LVOWaitPort(a6) Must wait for WB to give a go-ahead. lea pr_MsgPort(a4),a0 jsr _LVOGetMsg(a6) Received. Get it off process port. move.l d0,returnmsg Save to reply with when closing. movea.l d0,a4 move.l sm_ArgList(a4),d0 (This won't happen. Is used as for beq nowb convenience only.) move.l d0,a4 move.l wa_Lock(a4),d1 movea.l DosBase(pc),a6 CALLDOS CurrentDir nowb: bsr playfields NOW YOU MAY CALL THE PROGRAM PROPER move.w #160,d0 move.w #100,d1 move.w #3,d2 bsr paint_pixel Draw un pixel. move.l #500,d1 CALLDOS Delay closeall: move.l returnmsg(pc),d4 To quit, we must retrieve the message. beq nowb2 If none, we came from the CLI. CALLEXEC Forbid May not multitask during the reply. move.l d4,a1 jsr _LVOReplyMsg(a6) Reply to the WorkBench! nowb2: lea bitmap+bm_Planes(pc),a2 Deallocate raster memory. moveq #DEPTH-1,d2 deallocate_1: move.l #WIDTH,d0 move.l #HEIGHT,d1 movea.l (a2),a0 Remember to dereference. move.l a0,d2 beq quit_0 CALLGRAF FreeRaster adda.l #4,a2 dbra d2,deallocate_1 quit_0: movea.l cm(pc),a0 move.l a0,d0 beq quit_1 CALLGRAF FreeColorMap quit_1: lea vport(pc),a0 move.l a0,d2 beq quit_2 CALLGRAF FreeVPortCopLists quit_2: lea view(pc),a0 movea.l v_LOFCprList(a0),a0 move.l a0,d2 beq quit_3 CALLGRAF FreeCprList quit_3: movea.l oldview(pc),a1 move.l a1,d2 beq quit_4 CALLGRAF LoadView quit_4: movea.l DosBase(pc),a1 move.l a1,d2 beq quit_5 CALLEXEC CloseLibrary quit_5: movea.l GfxBase(pc),a1 move.l a1,d2 beq quit_6 CALLEXEC CloseLibrary quit_6: rts Return to system. playfields: lea view(pc),a1 CALLGRAF InitView lea view(pc),a1 move.l #vport,v_ViewPort(a1) lea vport(pc),a0 jsr _LVOInitVPort(a6) moveq #NUMCOLS,d0 jsr _LVOGetColorMap(a6) Declares/allocates a struct ColorMap move.l d0,cm invisibly, and returns pointer to it. lea vport(pc),a0 move.l d0,vp_ColorMap(a0) move.w #VPWIDTH,vp_DWidth(a0) move.w #VPHEIGHT,vp_DHeight(a0) move.l #rasinfo,vp_RasInfo(a0) move.w #0,vp_Modes(a0) lea vport(pc),a0 lea colortable(pc),a1 moveq #NUMCOLS,d0 jsr _LVOLoadRGB4(a6) Loads the struct ColorMap, supra. lea bitmap(pc),a0 move.l #DEPTH,d0 move.l #WIDTH,d1 move.l #HEIGHT,d2 jsr _LVOInitBitMap(a6) allocate: lea bitmap+bm_Planes(pc),a2 moveq #DEPTH-1,d2 plane: move.l #WIDTH,d0 move.l #HEIGHT,d1 jsr _LVOAllocRaster(a6) move.l PLANEPTR,(a2) beq closeall movea.l PLANEPTR,a1 RASSIZE #WIDTH,#HEIGHT Macro returns in d0. moveq #0,d1 jsr _LVOBltClear(a6) adda.l #4,a2 dbra d2,plane lea rasinfo(pc),a0 move.l #bitmap,ri_BitMap(a0) move.w #0,ri_RxOffset(a0) move.w #0,ri_RyOffset(a0) move.l #0,ri_Next(a0) lea view(pc),a0 lea vport(pc),a1 jsr _LVOMakeVPort(a6) lea view(pc),a1 jsr _LVOMrgCop(a6) lea rastport(pc),a1 jsr _LVOInitRastPort(a6) lea rastport(pc),a1 move.l #bitmap,rp_BitMap(a1) lea rastport(pc),a1 moveq #0,d0 jsr _LVOSetRast(a6) lea view(pc),a1 jsr _LVOLoadView(a6) rts paint_pixel: * For my purposes, I will place x in d0, y in d1 and color in d2 prior to * calling the routine. See the Manx code accompanying this file for full * commentary. lea $dff000,a0 lea bitmap,a2 move.w d2,d3 Copy color. move.w d1,d7 Copy Y coordinate. mulu bm_BytesPerRow(a2),d7 Byte offset of line containing Y. move.w d0,d4 Copy X coordinate. lsr.w #4,d4 lsl.w #1,d4 Divide by 8 while clearing bit 0. add.w d4,d7 Add X byte offset to Y offset. ext.l d7 move.w d0,d4 Copy X coordinate. andi.w #$f,d4 Retrieve bit additional. move.w #$8000,d5 Set bit representing byte's 'base'. lsr.w d4,d5 Move right to precise draw position. move.w d5,d6 Mask to OR a one for color draw. not.w d6 Mask to AND a zero for Bg color erase. move.b bm_Depth(a2),d0 Number of planes to draw into. ext.w d0 subq.w #1,d0 Subtract one for dbra. clr.w d1 Begin counter at 0. Increment below. pixl61: move.w d1,d2 Place the 0 to whatever. lsl.w #2,d2 Multiply * 4 to increment plane ptr. movea.l bm_Planes(a2,d2.w),a3 Retrieve this plane pointer. add.l d7,a3 Come to our pixel. btst d1,d3 Test the color bit in our plane. beq pixl62 Branch if unset. or.w d5,(a3) Make sure the bit in the 'as shifted' * position is set to cause the draw. bra pixl63 Test next plane. pixl62: and.w d6,(a3) Make sure the bit in the 'as shifted' * position is NOT set to cause an erase. pixl63: addq.w #1,d1 Advance to next plane, and to the dbra d0,pixl61 corresponding bit in the binary color * number. rts gfxname: GRAFNAME dosname: DOSNAME colortable: dc.w $000,$fff,$f00,$0f0,$00f,$ff0,$0ff,$f0f GfxBase: ds.l 1 DosBase: ds.l 1 mytask: ds.l 1 returnmsg: ds.l 1 cm: ds.l 1 oldview: ds.l 1 view: ds.b v_SIZEOF vport: ds.b vp_SIZEOF bitmap: ds.b bm_SIZEOF rastport: ds.b rp_SIZEOF rasinfo: ds.b ri_SIZEOF fillcolor: ds.w 1 end