AGA Mode 640 x 400

[rcman]

Hi,

I'm trying to load a 64 colour bitmap with the initcopList as follows. Is this correct? There is no sprites or scrolling.


Value Coplist Properties
$10 Enable smooth scrolling
$20 Dual playfield display
$40 Extra-halfbrite (EHB) display mode
$100 Make high resolution (640 pixels wide)
$400 Use low resolution sprites
$800 Use high resolution sprites
$1000 Enable fetch mode 1
$2000 Enable fetch mode 2
$3000 Enable fetch mode 3
$10000 Use AGA palette

#PLAYFIELD_DEPTH = 8
#COPPERLIST_DISPLAY = 0

InitCopList #COPPERLIST_DISPLAY,23,400,$10100,0,2^#PLAYFIELD_DEPTH,0

Thanks
RC

[Daedalus]

Hmmmm, well there are a couple of small issues. First, you're supposed to allocate all sprites anyway, even if you don't use them, so that parameter should be 8. Then, the number of bitplanes you want to use needs to be added to the flags. Then, the start position of the top of the display is generally recommended to be 44, to avoid losing the top of the display for low overscan monitors. Finally, high resolution ($100) makes it 640 pixels wide, but still the default height, so your display of 400 pixels high will extend beyond the bottom of your display. To increase the vertical resolution, you need to make it interlaced. Just how you can do that with the standard CopList commands, I don't know I'm afraid. Referring to the hardware reference manual on setting up a display might help you here as I'm sure other registers need to be set. But, that aside, your new InitCopList command might look like this:

#flgs = $10000 + $100 + #PLAYFIELD_DEPTH
InitCopList #COPPERLIST_DISPLAY, 44, 400, #flgs, 8, 2^#PLAYFIELD_DEPTH, 0

This should open a 256-colour display.

[rcman]

Originally Posted by Daedalus

Hmmmm, well there are a couple of small issues. First, you're supposed to allocate all sprites anyway, even if you don't use them, so that parameter should be 8. Then, the number of bitplanes you want to use needs to be added to the flags. Then, the start position of the top of the display is generally recommended to be 44, to avoid losing the top of the display for low overscan monitors. Finally, high resolution ($100) makes it 640 pixels wide, but still the default height, so your display of 400 pixels high will extend beyond the bottom of your display. To increase the vertical resolution, you need to make it interlaced. Just how you can do that with the standard CopList commands, I don't know I'm afraid. Referring to the hardware reference manual on setting up a display might help you here as I'm sure other registers need to be set. But, that aside, your new InitCopList command might look like this:

#flgs = $10000 + $100 + #PLAYFIELD_DEPTH
InitCopList #COPPERLIST_DISPLAY, 44, 400, #flgs, 8, 2^#PLAYFIELD_DEPTH, 0

This should open a 256-colour display.

Thank you! I'll keep you posted.

RC

[rcman]

Originally Posted by rcman

Thank you! I'll keep you posted.

RC

Okay I am not sure why I just get a black screen

WBStartup

#KEY_ESCAPE = $45
; Objects
#PALETTE_DISPLAY = 0
#BITMAP_SPRITESHEET = 0
#SHAPE_DUMMY = 0
#COPPERLIST_DISPLAY = 0

; Playfield specs

#PLAYFIELD_WIDTH = 640
#PLAYFIELD_HEIGHT = 400
#PLAYFIELD_DEPTH = 8

; Allocate Bitmaps

BitMap #BITMAP_SPRITESHEET , 640, 400, 6

; Load sprite sheet
LoadBitMap #BITMAP_SPRITESHEET, "Sewers640.iff",#PALETTE_DISPLAY

AutoCookie On

GetaShape #SHAPE_DUMMY,5*32,32,32,32

; getashape n,x,y,w,h
; where n is shape number, x and y are top left coordinates and w and h are width and height of the desired shape in pixels.

; goto blitzmode
BLITZ

#flgs = $10000 + $100 + #PLAYFIELD_DEPTH + $8

InitCopList #COPPERLIST_DISPLAY, 44, 400, #flgs, 8, 2^#PLAYFIELD_DEPTH, 0

DisplayPalette #COPPERLIST_DISPLAY,#PALETTE_DISPLAY
CreateDisplay #COPPERLIST_DISPLAY

DisplayBitMap 0,0

While NOT RawStatus(#KEY_ESCAPE)
VWait
Wend

End

[rcman]

Originally Posted by rcman

Okay I am not sure why I just get a black screen

WBStartup

#KEY_ESCAPE = $45
; Objects
#PALETTE_DISPLAY = 0
#BITMAP_SPRITESHEET = 0
#SHAPE_DUMMY = 0
#COPPERLIST_DISPLAY = 0

; Playfield specs

#PLAYFIELD_WIDTH = 640
#PLAYFIELD_HEIGHT = 400
#PLAYFIELD_DEPTH = 8

; Allocate Bitmaps

BitMap #BITMAP_SPRITESHEET , 640, 400, 6

; Load sprite sheet
LoadBitMap #BITMAP_SPRITESHEET, "Sewers640.iff",#PALETTE_DISPLAY

AutoCookie On

GetaShape #SHAPE_DUMMY,5*32,32,32,32

; getashape n,x,y,w,h
; where n is shape number, x and y are top left coordinates and w and h are width and height of the desired shape in pixels.

; goto blitzmode
BLITZ

#flgs = $10000 + $100 + #PLAYFIELD_DEPTH + $8

InitCopList #COPPERLIST_DISPLAY, 44, 400, #flgs, 8, 2^#PLAYFIELD_DEPTH, 0

DisplayPalette #COPPERLIST_DISPLAY,#PALETTE_DISPLAY
CreateDisplay #COPPERLIST_DISPLAY

DisplayBitMap 0,0

While NOT RawStatus(#KEY_ESCAPE)
VWait
Wend

End

Looks like InitcopList is suppose to be $11108

it displays but it seems stretched. When I bring it in to Dpaint it looks good. I am also using the 64 color iff as the 256 one doesn't seem to load. I still know something is wrong

RC

[Daedalus]

$10108 should be fine. You were adding the depth on twice with the + #PLAYFIELD_DEPTH *and* + $8, which won't work.

When you say it looks stretched, are you opening the same sort of screen in DPaint? 640x256?

[rcman]

Originally Posted by Daedalus

$10108 should be fine. You were adding the depth on twice with the + #PLAYFIELD_DEPTH *and* + $8, which won't work.

When you say it looks stretched, are you opening the same sort of screen in DPaint? 640x256?

Um no, I'm opening a 640 x 400 screen in dpaint. I thought since the iff was that size that's what I was opening?

RC

[Daedalus]

No, the screen opened by the Display Library will be 256-ish pixels high, since it's not interlaced or productivity. The screen DPaint opens is likely one or the other of those.

[rcman]

Originally Posted by Daedalus

No, the screen opened by the Display Library will be 256-ish pixels high, since it's not interlaced or productivity. The screen DPaint opens is likely one or the other of those.

Maybe I'm missing something. When I open Dpaint I select a display which is 640x400 256 color. Can I not open this up in Blitz? You're saying it's only 640x200 I'm a little confused.

Can blitz not display a 640x400 image?

RC

[dodke]

So, I don't know anything about blitz but the thing is, regular NTSC or PAL output is interlaced. Basically the resolution is half of the full one and you're alternating between showing odd and even lines of the full res image. If you set the hardware interlace bit then the chipset will automatically toggle the 'frame flop' bit (in VPOS) which will cause the frame to appear half a line lower on every other frame. You'll probably need a CRT screen to see this correctly.

[Daedalus]

Not directly in Blitz mode, no. The standard vertical resolution is 200 in NTSC mode and 256 in PAL mode. A little bit more is possible by moving the display up a little and using the overscan area, but ultimately, double-height displays require either a doubled pixel clock (like DblPAL, DblNTSC & Productivity modes), or an interlaced screen, neither of which Blitz supports in Blitz mode. In Amiga mode you can open any type of screen you like in an OS-friendly way, but in Blitz mode you have to do it manually. Earok appears to have devised a clever way of doing it here by swapping coplists every frame, but even then you have to sort your even and odd fields yourself. So it's not easy.

If DPaint is opening a 400 pixel screenmode, I suspect it's interlaced, though it might not look flickery due to your display.

[rcman]

Originally Posted by Daedalus

Not directly in Blitz mode, no. The standard vertical resolution is 200 in NTSC mode and 256 in PAL mode. A little bit more is possible by moving the display up a little and using the overscan area, but ultimately, double-height displays require either a doubled pixel clock (like DblPAL, DblNTSC & Productivity modes), or an interlaced screen, neither of which Blitz supports in Blitz mode. In Amiga mode you can open any type of screen you like in an OS-friendly way, but in Blitz mode you have to do it manually. Earok appears to have devised a clever way of doing it here by swapping coplists every frame, but even then you have to sort your even and odd fields yourself. So it's not easy.

If DPaint is opening a 400 pixel screenmode, I suspect it's interlaced, though it might not look flickery due to your display.

Thank you for your help!


RC

[earok]

This will display an AGA image in interlaced (640x512), maybe not as cleanly as possible since I'm using VPOS rather than BPLCON0. I'll post the complete example with image to GitHub.

WBStartup
DEFTYPE .w

;The interlaced bitmap
BitMap 0,640,512,8

;The original bitmap
BitMap 1,640,512,8
LoadBitMap 1,"image.iff",0

;Convert the original bitmap to interlaced
Use BitMap 0
for i = 0 to 255
BlockScroll 0,i*2,640,1,0,i,1
BlockScroll 0,1+i*2,640,1,0,i+256,1
next

;Configure two copper lists
for i = 0 to 1

InitCopList i,44,DispHeight,$10000 + $1000 + $100 + $8,8,256,0
DisplayBitMap i,0,0,i*256
DisplayPalette i,0

next

BLITZ

;Repeatedly recreate the display and toggle the LOF bit
SetInt 5

VP = Peek.w($DFF004)

X=1-X
if X=0
CreateDisplay 0
VP = VP BITSET 15
else
CreateDisplay 1
VP = VP BITCLR 15
endif

Poke.w $DFF02A,VP


End SetInt

While Joyb(0)+Joyb(1) = 0
Wend

End

[rcman]

Originally Posted by earok

This will display an AGA image in interlaced (640x512), maybe not as cleanly as possible since I'm using VPOS rather than BPLCON0. I'll post the complete example with image to GitHub.

Thank you!

RC

[rcman]

Earok I have a question for you.

I asked directly on twitter but you didn't reply. I am looking at the game Crystal Kingdoms. What mode is this running in?

Thanks
RC

[earok]

Sorry, I must have missed that message! I didn't write Crystal Kingdoms myself (I can only claim credit for finding it in an old hard drive backup) and no source was provided so I'm not sure.

[idrougge]

Blitz doesn't directly support interlace modes (it was probably too much of a chore to implement for the Acid programmers), so you will have to implement it totally by yourself, probably by allocating a sufficiently tall bitmap, setting the modulo to an entire line, and adding a custom coplist to set the starting position alternatingly at line 0 or line 1.