4. Rolling image on BIG copperbar

Download LHA-package.

This time we will look at the same effec as last time, but this time on a larger copperbar. When we have a larger copperbar horizontalshifting of 16px will not be sufficent. Larger shifts could be done with bitplane modulos like in the Hshift tutorials, but here we know exactly where we need to get more than 16px shifts, and the copperbars are static, so this won't change from frame to frame. When knowing this we can use an other method instead of the slightly problematic modulos. We can set the startingpoint of the bitplane rasterline earlier than the rasterline before, and thus get 16px of Hshift to the right for every word we start earlier. This is very easy to do on an Amiga, we only have to change the BPLxPTH/L, and as we have to change the Hshift value on each rasterline we already have a suitable copperlistgenerator set up, and only need to add 2 copper MOVE-statement (BPLxPTH & BPLxPTL) for each used bitplane. For this tutorial I tested different routines to get the best looking effect, this time the more matemathically correct method rendered a much worse effect. In this tutorial we just move the image upwards, and every pixelline will be rendered until it "falls off the top of the copperbar. I include an executable for the mathematically more correct version, where not evrey pixelline is rendered, but according to what part of the image should be visible when moving along a circle. The pixellines that get skipped makes the rollereffect uglier. This goes to show, that it's good to test different approaches and chose the one that works best.

1	; Copperbarscroller-2
2
3	DMACONR EQU $dff002
4	ADKCONR EQU $dff010
5	INTENAR EQU $dff01c
6	INTREQR EQU $dff01e
7
8	DMACON EQU $dff096
9	ADKCON EQU $dff09e
10	INTENA EQU $dff09a
11	INTREQ EQU $dff09c
12
13	incdir "windows:amigavikke/"
14
15	; Optimizations could easily be made to the small/tight loops in the code by using incremental addressing (An)+ or decremental addressing -(An) and REPT <n> / ERPT
16
17	init:
18	; store hardware registers, store view- and copperaddresses, load blank view, wait 2x for top of frame, own blitter, wait for blitter AND finally forbid multitasking!
19	; all this just to be able to exit gracely
20
21	; store data in hardwareregisters ORed with $8000 (bit 15 is a write-set bit when values are written back into the system)
22	move.w DMACONR,d0
23	or.w #$8000,d0
24	move.w d0,olddmareq
25	move.w INTENAR,d0
26	or.w #$8000,d0
27	move.w d0,oldintena
28	move.w INTREQR,d0
29	or.w #$8000,d0
30	move.w d0,oldintreq
31	move.w ADKCONR,d0
32	or.w #$8000,d0
33	move.w d0,oldadkcon
34
35	move.l $4,a6 ; execBase ==> a6
36	move.l #gfxname,a1 ; pointer to gfxname ==> a1 : used in openLibrary
37	moveq #0,d0 ; d0 = 0 any version of graphics.library will do
38	jsr -552(a6) ; d0 = openLibrary(a1,d0)
39	move.l d0,gfxbase ; store the returned pointer ==> gfxbase
40	move.l d0,a6 ; d0 ==> a6 : a6 used as addressing base below
41	move.l 34(a6),oldview ; store old Viewport
42	move.l 38(a6),oldcopper ; store old Copperlist
43
44	move.l #0,a1
45	jsr -222(a6) ; LoadView
46	jsr -270(a6) ; WaitTOF
47	jsr -270(a6) ; WaitTOF
48	jsr -456(a6) ; OwnBlitter
49	jsr -228(a6) ; WaitBlit
50	move.l $4,a6
51	jsr -132(a6) ; Forbid
52
53	; end exit gracely preparations!
54
55	; clear Bitplanes from garbage - very slow routine! should be done with the Blitter, or unrolled loop
56	move.w #352/8*200/4,d0 ; d0 is a counter for number of longwords to get cleared
57	move.l #bpl0,a0 ; bpl0 => a0
58	move.l #bpl1,a1 ; bpl1 => a1
59	move.l #bpl2,a2 ; bpl2 => a2
60	screen_clear:
61	move.l #0,(a0)+ ; #0 => (a0), and increment a0 to next longword (a0=a0+4)
62	move.l #0,(a1)+ ; #0 => (a1), and increment a1 to next longword (a1=a1+4)
63	move.l #0,(a2)+ ; #0 => (a2), and increment a1 to next longword (a2=a2+4)
64	subq.w #1,d0
65	bne screen_clear
66
67	; copy bitmap to bitplanes
68	move.w #352/8*200/4,d0
69	move.l #bpl0,a0 ; bpl0 => a0
70	move.l #bpl1,a1 ; bpl1 => a1
71	move.l #bpl2,a2 ; bpl1 => a2
72	move.l #img_av,a6
73	; add.l #2,a6
74	copy_img:
75	move.l 352/82002(a6),(a2)+ ; bpl2
76	move.l 352/82001(a6),(a1)+ ; bpl1
77	move.l (a6)+,(a0)+ ; bpl0
78	subq.w #1,d0
79	bne copy_img
80
81
82	; setup displayhardware to show a 320x200px 3 bitplanes playfield, with zero horizontal scroll and 4 modulos
83	move.w #$3200,$dff100 ; 3 bitplane lowres
84	move.w #$0000,$dff102 ; horizontal scroll 0
85	move.w #$0002,$dff108 ; odd modulo 4
86	move.w #$0002,$dff10a ; even modulo 4
87	move.w #$2c81,$dff08e ; DIWSTRT - topleft corner (2c81)
88	move.w #$f4d1,$dff090 ; DIVSTOP - bottomright corner (f4d1)
89	move.w #$0030,$dff092 ; DDFSTRT - max overscan $0018
90	move.w #$00d0,$dff094 ; DDFSTOP - max overscan $00d8
91	move.w #%1000010111000000,DMACON ; DMA set ON
92	move.w #%0000000000111111,DMACON ; DMA set OFF
93	move.w #%1100000000000000,INTENA ; IRQ set ON
94	move.w #%0011111111111111,INTENA ; IRQ set OFF
95
96
97	mainloop:
98	; increase framecounter by 1
99	move.l frame,d0
100	addq.l #1,d0
101	move.l d0,frame
102
103
104	; make copperlist
105	; doubblebuffering of copperlists, defined at copper1 and copper2, chosen by LSB in framecounter
106	; copper (and a6) will hold the address to the copperlist we will write to (not the one currently in use)
107	and.l #1,d0
108	bne usecopper2
109	move.l #copper1,a6
110	bra usecopper1
111	usecopper2:
112	move.l #copper2,a6
113	usecopper1:
114	move.l a6,copper
115
116
117	; *********************************************************
118	;
119	; 32px high copperbars for scrolling (p=32*pi ==> p~100 ==> image 100px high)
120	;
121	; *********************************************************
122
123
124	move.l #$2c+$50,d2
125	jsr make_Copper_scrolly
126
127
128
129
130	; end of copperlist (copperlist ALWAYS ends with WAIT $fffffffe)
131	move.l #$fffffffe,(a6)+ ; end copperlist
132
133	testMouseButton:
134	; if mousebutton/joystick 1 or 2 pressed then exit
135	btst.b #6,$bfe001
136	beq exit
137	btst.b #7,$bfe001
138	beq exit
139
140	; display is ready, or atleast we have done everything we wanted and the copper continues on its own
141	; we have to wait for Vertical Blanking before making the next frame
142
143	waitVB:
144	move.l $dff004,d0
145	and.l #$1ff00,d0
146	cmp.l #300<<8,d0
147	bne waitVB
148
149	; use next copperlist - as we are using doubblebuffering on copperlists we now take the new one into use
150	move.l copper,d0
151	move.l d0,$dff080
152	bra mainloop
153
154	exit:
155	; exit gracely - reverse everything done in init
156	move.w #$7fff,DMACON ; set bits[0,14] = 0 (bit15 is a set/clear bit)
157	move.w olddmareq,DMACON ; and set bits[0,14] as they were at init
158	move.w #$7fff,INTENA ; set bits[0,14] = 0 (bit15 is a set/clear bit)
159	move.w oldintena,INTENA ; and set bits[0,14] as they were at init
160	move.w #$7fff,INTREQ ; set bits[0,14] = 0 (bit15 is a set/clear bit)
161	move.w oldintreq,INTREQ ; and set bits[0,14] as they were at init
162	move.w #$7fff,ADKCON ; set bits[0,14] = 0 (bit15 is a set/clear bit)
163	move.w oldadkcon,ADKCON ; and set bits[0,14] as they were at init
164
165	move.l oldcopper,$dff080 ; load old Copperlist
166	; graphics.library calls
167	move.l gfxbase,a6 ; gfxBase ==> a6
168	move.l oldview,a1 ; oldView ==> a1 (used in LoadView)
169	jsr -222(a6) ; LoadView : load back the view at start of program
170	jsr -270(a6) ; WaitTOF : Wait for Top Of Frame to get everything synced up
171	jsr -270(a6) ; WaitTOF : (2 times for interlaced screens)
172	jsr -228(a6) ; WaitBlit : wait for Blitter to finish running task (if any)
173	jsr -462(a6) ; DisownBlitter : release Blitter to system
174	; exec.library calls
175	move.l $4,a6 ; execBase ==> a6
176	move.l gfxbase,a1 ; gfxBase ==> a1 (used in closeLibrary)
177	jsr -414(a6) ; closeLibrary : close graphics.library
178	jsr -138(a6) ; Permit multitasking
179
180	; end program
181	rts
182
183	; subroutines
184
185	make_Copper_scrolly:
186
187	move.l #c0,a0 ; pointer to colortables ==> a0
188	move.l #hshift,a4
189	move.l #mshift,a5
190	move.l #$07<<16+$fffe,d1 ; this is optimized code compared to earlier tutorials
191	; $07<<16 = $00070000,
192	; and then +$fffe gives $0007fffe
193	lsl.l #8,d2 ; d2 = d2 * 2^24
194	lsl.l #8,d2
195	lsl.l #8,d2
196	add.l d2,d1 ; add d2 to d1 ==> first time: d1 = $2c07fffe, which is:
197	; Copper WAIT <$2c07>,<$fffe>: V:$2c & H:$07 & mask:$fffe
198
199	moveq #0,d0 ; d0 = 0
200	move.w cbar_img_line1,d0 ; startingline index ==> d0
201	add.w #44,d0 ; d0 = d0 + 44 (352px/8 = 44 bytes)
202	cmp.w #200*44,d0 ; compare if larger than the height of the image
203	bcs .10
204	sub.w #200*44,d0 ; if it is, then subract the overgoing part from it
205	.10:
206	move.w d0,cbar_img_line1 ; store new startingline index for next frame
207
208	moveq #64,d7
209	loop_cbar1:
210	move.l d1,(a6)+ ; copper WAIT
211	move.w #$0180,(a6)+ ; color0-
212	move.w 0*128(a0),(a6)+ ; value
213	move.w #$0102,(a6)+ ; h-shift-
214	move.w (a4)+,(a6)+ ; value
215
216	moveq #0,d3
217	move.w (a5)+,d3
218	; bitplane 0
219	move.l #bpl0,d2
220	add.l d0,d2 ; add startingline index to address
221	add.l d3,d2 ; add 16-bit Hshift
222	move.w #$00e2,(a6)+ ; LO-bits of start of bitplane
223	move.w d2,(a6)+ ; go into $dff0e2
224	swap d2
225	move.w #$00e0,(a6)+ ; HI-bits of start of bitplane
226	move.w d2,(a6)+ ; go into $dff0e0
227
228	; bitplane 1
229	move.l #bpl1,d2
230	add.l d0,d2 ; add startingline index to address
231	add.l d3,d2 ; add 16-bit Hshift
232	move.w #$00e6,(a6)+ ; LO-bits of start of bitplane
233	move.w d2,(a6)+ ; go into $dff0e6
234	swap d2
235	move.w #$00e4,(a6)+ ; HI-bits of start of bitplane
236	move.w d2,(a6)+ ; go into $dff0e4
237
238	; bitplane 2
239	move.l #bpl2,d2
240	add.l d0,d2 ; add startingline index to address
241	add.l d3,d2 ; add 16-bit Hshift
242	move.w #$00ea,(a6)+ ; LO-bits of start of bitplane
243	move.w d2,(a6)+ ; go into $dff0e6
244	swap d2
245	move.w #$00e8,(a6)+ ; HI-bits of start of bitplane
246	move.w d2,(a6)+ ; go into $dff0e4
247
248	move.w #$0182,(a6)+ ; color1-
249	move.w 1*128(a0),(a6)+ ; value
250	move.w #$0184,(a6)+ ; color2-
251	move.w 2*128(a0),(a6)+ ; value
252	move.w #$0186,(a6)+ ; color3-
253	move.w 3*128(a0),(a6)+ ; value
254	move.w #$0188,(a6)+ ; color4-
255	move.w 4*128(a0),(a6)+ ; value
256	move.w #$018a,(a6)+ ; color5-
257	move.w 5*128(a0),(a6)+ ; value
258	move.w #$018c,(a6)+ ; color6-
259	move.w 6*128(a0),(a6)+ ; value
260	move.w #$018e,(a6)+ ; color7-
261	move.w 7*128(a0),(a6)+ ; value
262	add.l #2,a0
263
264
265	add.l #1<<24,d1 ; here the optimization continues,
266	; we know that the verticalvalues are in bits[24,31],
267	; so we add 1*2^24 to get to the next line
268
269	add.w #44,d0 ; d0 = d0 + 44 (352px/8 = 44 bytes)
270	cmp.w #200*44,d0 ; compare if larger than the height of the image
271	bcs .20
272	sub.w #200*44,d0 ; if it is, then subract the overgoing part from it
273	.20:
274
275	subq #1,d7
276	bne loop_cbar1
277
278	rts ; end subroutine and get back to main code
279
280
281
282	; *******************************************************************************
283	; *******************************************************************************
284	; DATA
285	; *******************************************************************************
286	; *******************************************************************************
287
288
289	; storage for 32-bit addresses and data
290	CNOP 0,4
291	oldview: dc.l 0
292	oldcopper: dc.l 0
293	gfxbase: dc.l 0
294	frame: dc.l 0
295	copper: dc.l 0
296
297	; storage for 16-bit data
298	CNOP 0,4
299	olddmareq: dc.w 0
300	oldintreq: dc.w 0
301	oldintena: dc.w 0
302	oldadkcon: dc.w 0
303
304	CNOP 0,4
305	; storage for 8-bit data and text
306	gfxname: dc.b 'graphics.library',0
307	author: dc.b 'AmigaVikke',0
308
309	CNOP 0,4
310	c0: dc.w $000,$100,$101,$201,$202,$302,$303,$403,$404,$504,$505,$605,$606,$706,$707,$807, $808,$908,$909,$a09,$a0a,$b0a,$b0b,$c0b,$c0b,$c0c,$d0c,$d0d,$e0d,$e0e,$f0e,$f0f,$f0f,$f0e,$e0e, $e0d,$d0d,$d0c,$c0c,$c0b,$c0b,$b0b,$b0a,$a0a,$a09,$909,$908,$808,$807,$707,$706,$606,$605, $505,$504,$404,$403,$303,$302,$202,$201,$101,$100,$000
311	c1: dc.w $000,$000,$000,$000,$000,$000,$000,$000,$000,$000,$000,$000,$000,$000,$000,$000, $000,$000,$000,$000,$000,$000,$000,$000,$111,$111,$111,$111,$222,$222,$222,$333,$333,$222, $222,$222,$111,$111,$111,$111,$000,$000,$000,$000,$000,$000,$000,$000,$000,$000,$000,$000, $000,$000,$000,$000,$000,$000,$000,$000,$000,$000,$000,$000
312	c2: dc.w $000,$000,$100,$100,$200,$200,$300,$300,$400,$400,$500,$500,$600,$600,$700,$700, $800,$800,$900,$900,$A00,$A00,$B00,$B00,$C00,$C00,$D00,$D00,$E00,$E00,$F00,$F00,$F00, $F00,$E00,$E00,$D00,$D00,$C00,$C00,$B00,$B00,$A00,$A00,$900,$900,$800,$800,$700,$700, $600,$600,$500,$500,$400,$400,$300,$300,$200,$200,$100,$100,$000,$000
313	c3: dc.w $000,$000,$010,$010,$020,$020,$030,$030,$040,$040,$050,$050,$060,$060,$070,$070, $080,$080,$090,$090,$0A0,$0A0,$0B0,$0B0,$0C0,$0C0,$0D0,$0D0,$0E0,$0E0,$0F0,$0F0,$0F0, $0F0,$0E0,$0E0,$0D0,$0D0,$0C0,$0C0,$0B0,$0B0,$0A0,$0A0,$090,$090,$080,$080,$070,$070, $060,$060,$050,$050,$040,$040,$030,$030,$020,$020,$010,$010,$000,$000
314	c4: dc.w $000,$000,$001,$001,$002,$002,$003,$003,$004,$004,$005,$005,$006,$006,$007,$007, $008,$008,$009,$009,$00A,$00A,$00B,$00B,$00C,$00C,$00D,$00D,$00E,$00E,$00F,$00F,$00F, $00F,$00E,$00E,$00D,$00D,$00C,$00C,$00B,$00B,$00A,$00A,$009,$009,$008,$008,$007,$007, $006,$006,$005,$005,$004,$004,$003,$003,$002,$002,$001,$001,$000,$000
315	c5: dc.w $000,$000,$110,$110,$220,$220,$330,$330,$440,$440,$550,$550,$660,$660,$770,$770, $880,$880,$990,$990,$AA0,$AA0,$BB0,$BB0,$CC0,$CC0,$DD0,$DD0,$EE0,$EE0,$FF0,$FF0, $FF0,$FF0,$EE0,$EE0,$DD0,$DD0,$CC0,$CC0,$BB0,$BB0,$AA0,$AA0,$990,$990,$880,$880, $770,$770,$660,$660,$550,$550,$440,$440,$330,$330,$220,$220,$110,$110,$000,$000
316	c6: dc.w $000,$000,$111,$111,$222,$222,$333,$333,$444,$444,$555,$555,$666,$666,$777,$777, $888,$888,$999,$999,$AAA,$AAA,$BBB,$BBB,$CCC,$CCC,$DDD,$DDD,$EEE,$EEE,$FFF,$FFF, $FFF,$FFF,$EEE,$EEE,$DDD,$DDD,$CCC,$CCC,$BBB,$BBB,$AAA,$AAA,$999,$999,$888,$888, $777,$777,$666,$666,$555,$555,$444,$444,$333,$333,$222,$222,$111,$111,$000,$000
317	c7: dc.w $000,$000,$011,$011,$022,$022,$033,$033,$044,$044,$055,$055,$066,$066,$077,$077, $088,$088,$099,$099,$0AA,$0AA,$0BB,$0BB,$0CC,$0CC,$0DD,$0DD,$0EE,$0EE,$0FF,$0FF,$0FF, $0FF,$0EE,$0EE,$0DD,$0DD,$0CC,$0CC,$0BB,$0BB,$0AA,$0AA,$099,$099,$088,$088,$077,$077, $066,$066,$055,$055,$044,$044,$033,$033,$022,$022,$011,$011,$000,$000
318
319
320	cbar_img_line1: dc.w 0
321
322	shift1: dc.w $00,$11,$33,$44,$66,$77,$99,$AA,$BB,$CC,$DD,$EE,$FF,$FF,$FF,$FF,$FF,$FF,$FF, $FF,$EE,$DD,$CC,$BB,$AA,$99,$77,$66,$44,$33,$11,$00
323
324
325	sin255_60: dc.b 30,31,31,32,33,34,34,35,36,37,37,38,39,39,40,41,42,42,43,44,44,45,45,46,47,47,48, 49,49,50,50,51,51,52,52,53,53,54,54,55,55,55,56,56,57,57,57,57,58,58,58,59,59,59,59,59,59,60,60,60, 60,60,60,60,60,60,60,60,60,60,60,60,59,59,59,59,59,58,58,58,58,57,57,57,56,56,56,55,55,54,54,53,53, 53,52,52,51,50,50,49,49,48,48,47,46,46,45,45,44,43,43,42,41,40,40,39,38,38,37,36,36,35,34,33,33,32, 31,30,30,29,28,27,27,26,25,24,24,23,22,22,21,20,20,19,18,17,17,16,15,15,14,14,13,12,12,11,11,10,10, 9,8,8,7,7,7,6,6,5,5,4,4,4,3,3,3,2,2,2,2,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,2,2,2,3,3,3,3,4,4,5,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,13,13,14,15,15,16,16,17,18,18,19,20,21,21,22,23,23,24,25,26,26,27, 28,29,29,30
326	CNOP 0,4
327	cos255: dc.b 255,255,255,255,254,254,254,253,253,252,251,250,249,249,248,246,245,244,243, 241,240,238,237,235,233,232,230,228,226,224,222,220,218,215,213,211,208,206,203,201,198,196, 193,190,187,185,182,179,176,173,170,167,164,161,158,155,152,149,146,143,140,137,133,130,127, 124,121,118,115,112,109,105,102,99,96,93,90,87,84,81,78,76,73,70,67,65,62,59,57,54,51,49,47,44, 42,40,37,35,33,31,29,27,25,23,22,20,18,17,15,14,13,11,10,9,8,7,6,5,4,4,3,3,2,2,1,1,1,1,1,1,1,1,2,2,3, 3,4,4,5,6,7,8,9,10,11,13,14,15,17,18,20,22,23,25,27,29,31,33,35,37,40,42,44,47,49,51,54,57,59,62,64, 67,70,73,76,78,81,84,87,90,93,96,99,102,105,109,112,115,118,121,124,127,130,133,137,140,143,146, 149,152,155,158,161,164,167,170,173,176,179,182,185,187,190,193,196,198,201,203,206,208,211,213, 215,218,220,222,224,226,228,230,232,233,235,237,238,240,241,243,244,245,246,248,249,249,250,251, 252,253,253,254,254,254,255,255,255,255
328	CNOP 0,4
329
330	hshift: dc.w $00,$88,$BB,$DD,$FF,$11,$22,$44,$55,$66,$77,$88,$88,$99,$AA,$BB,$BB,$CC,$CC, $DD,$DD,$DD,$EE,$EE,$EE,$EE,$FF,$FF,$FF,$FF,$FF,$FF,$FF,$FF,$FF,$FF,$FF,$FF,$EE,$EE, $EE,$EE,$DD,$DD,$DD,$CC,$CC,$BB,$BB,$AA,$99,$88,$88,$77,$66,$55,$44,$22,$11,$FF,$DD, $BB,$88,$00
331
332	mshift: dc.w 4,4,4,4,4,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,4,4,4,4,4
333
334
335
336	Section ChipRAM,Data_c
337
338	; bitplanes aligned to 32-bit
339	CNOP 0,4
340	bpl0: blk.b 352/8*200,0
341	bpl1: blk.b 352/8*200,0
342	bpl2: blk.b 352/8*200,0
343
344	; datalists aligned to 32-bit
345	CNOP 0,4
346	copper1:
347	dc.l $ffffffe ; CHIPMEM!
348	blk.l 2047,0 ; CHIPMEM!
349	CNOP 0,4
350	copper2:
351	dc.l $ffffffe ; CHIPMEM!
352	blk.l 2047,0 ; CHIPMEM!
353
354	CNOP 0,4
355	img_av: incbin "amigavikke-flowers.raw"

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Published on April 1st, 2013