Annihilation - more artists wanted

[Rebel-CD32]

It's all good, I got it, thanks mate. I PMed you too.

[Graham Humphrey]

I know, I sent you one back

[Calgor]

@Graham

How is this game going?

Also, how do you use the 16x16 tiles to scroll as the gaming area? I understand you can scroll a whole bitmap (like the background), but are there any code examples you have to scroll the 16x16 tiles as you move around? Just wondering if the 16x16 tiles are organised onto a bitmap, which is then scrolled around.

[Graham Humphrey]

It's not going badly at the moment, there's a lot happening "behind the scenes" That's all I will say for now...

As for the scrolling (I'm not very good at explaining these things so bear with me), what I tend to do is when the screen has scrolled 16 pixels is to place the same column of tiles either side of the screen (just to the left and to the right so you can't see it), so when the end of the bitmap is reached, the offset is reset to 0 (or whatever you want the extreme visible left-hand side to be) and as the blocks have been blitted on both sides of the bitmap you don't notice the jump back to the left-hand side, so it gives the illusion of continuous scrolling.

I hope that makes sense; as for example code I'll try and dig some out later on.

[Calgor]

I think I get part of it, the code example would be great. My understanding is you could do something like this, but doesn't sound the same as your description:

Say you have a horizontal scroller, where each letter represents a 16x16 tile.

AB|CDEF|GH

CDEF are currently visible.

Then the player moves to the right of screen:

ABC|DEFG|H

Then you reset the offset:

BC|DEFG|HA

Then you replace the A tile with the next new tile:

BC|DEFG|HI

Is this similar to what you were saying, and will it work?

[Codetapper]

I don't think that's quite right. There are 2 things here, positions and tiles. In your example you have a screen width that is twice the maximum width, so for interests sake we will say there are 8 positions 1-8. You are currently viewing ABCD on the screen and the x's are just random crap for the time being:

|ABCD|xxxx

You want to copy the next set of tile data into 2 positions, into the next scroll position on the right hand side, and once A has scrolled off the screen, we erase A with E. We can't erase A just yet as if you do, the tiles on the far left of the screen will change too early:

|ABCD|Exxx   Put the new tile E on the right
A|BCDE|xxx   Scroll
E|BCDE|Fxx   Copy E over A, and put the new tile F on the right
EB|CDEF|xx   Scroll
EF|CDEF|Gx   Copy F over B, and put the new tile G on the right
EFC|DEFG|x   Scroll
EFG|DEFG|H   Copy G over C, and put the new tile H on the right
EFGD|EFGH|   Scroll
EFGH|EFGH|   Copy H over D
|EFGH|EFGH   Reset the pointers so we are back at the first block

Now you can scroll to the right "forever" and only use 2 screen widths of memory.

[Graham Humphrey]

Thanks Codetapper, you've explained it better than I could.

@Calgor

I'll try and dig something out code-wise today, if not I'll just knock an example out myself... I hope Blitz Basic is okay

[Graham Humphrey]

Right, I managed to find a very simple example that comes with Blitz Basic 2.1 that demonstrates map scrolling. I've put it in the Zone if you're interested, Calgor, and includes the Blitz source code, the code in ASCII format and an executable file compiled from the code. Enjoy

[Calgor]

Thanks heaps guys. I understand codetapper's explanation, from which I now understand Graham's! So that would work for a never ending one-way scrolling.
I will go through the blitz basic source code which seems so much smaller than I imagined (I am coding in C). I will be trying to do 8-way scrolling to which it seems I will need to use a different method, but I will open a new thread if I have any more questions.

[Joe Maroni]

Originally Posted by Graham Humphrey

Right, I managed to find a very simple example that comes with Blitz Basic 2.1 that demonstrates map scrolling. I've put it in the Zone if you're interested, Calgor, and includes the Blitz source code, the code in ASCII format and an executable file compiled from the code. Enjoy

this is not the best way of mapscrolling...

don´t forget to double buffering the screen for smooth scrolling.

i never saw this thread before..if you need any help i would offer it...

believe me, i have much experience with maps in amiga games...

[Graham Humphrey]

What, help for scrolling, or graphics? I've got the scrolling sorted anyway

And yes, I know, but it is only an example (I didn't say it was the best ) - double-buffering's not difficult to add, anyway.

[CFou!]

no news about this project?

[Graham Humphrey]

Dead for four years No intention of going back to it. Thanks for asking though

I've only recently found my programming mojo again. Released Downfall, AGA version in (slow) progress, plus new project to follow after that's done and dusted...