Help with tilemap collision?

[LincolnB]

haha that's totally fine. Everyone forgets these things, most especially me.

[thydowulays]

Wait, I have a question. If I had the routine GT, with {r2/8*12+(r1/8)+GBD1}=r3, and I did this:
If sub(GT,X,Y-8,2)
End
Would that test to see if the tile had a number 02? Like I could do this:
If sub(GT,X,Y-8,2)
Y-8->Y
Pause 500
End
ElseIf sub(GT,X,Y-8,3)
Pause 500
End


Nevermind, I got it. However, does anyone know a routine to say, move a tile up or down, or left or right? Like, edit the little [01000000000000001]->GBD1 sorta thing via a routine in game?
That would make it so I could move through tile 02, but not tile 03. Would that work?

[LincolnB]

yes, but you'll want to make a copy of your map data and modify that, so you don't screw up your map for permanent.

To acces the Yth element down and the Xth element across, go like this:

{Y*WIDTH_OF_MAP + X + START_OF_MAP_DATA}

So, to move a tile to the left, say:

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1 2	{Y*WIDTH_OF_MAP + X + START_OF_MAP_DATA}->{Y*WIDTH_OF_MAP + X-1 + START_OF_MAP_DATA}

And so on

[C0deH4cker]

In my programs where I want to edit my maps, I first copy the maps to L1 or some other free ram area during level loading. I usually have three map functions:

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DrawMap(mapPtr, tilePics) GetTile(mapPtr, x, y) .x and y are actual screen coords. Function just divides each by 8 to get the tile that contains the point specified. SetTile(mapPtr, row, col, value)

Then you can access and modify your map very easily.

[parserp]

hmmm, I can't think of a good way to erase a tile from the map. Is there a fast way to draw it every frame?
Every way that I've tried it, it is too slow.

[thydowulays]

Parser, to erase an individual tile from the map, you basically take leafy's routine:

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Lbl GT {r2/8*12+(r1/8)+GDB1} Return

And turn it into this:

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Lbl ST {r2/8*12+(r1/8)+GDB1}->r3 Return

Then, you would just have to do ST(X,Y,0 and the tile at position X,Y will be converted into 00.
What do you mean by fast drawing?

EDIT: Leveled up! W00t!

[leafy]

Did you mean:

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Lbl ST r3->{r2*12+r1+GDB1} Return

Also I think he meant actually erasing the tile from the screen. Parser you can do that by drawing a Rect( and a RectI( at the coordinates of the tile.

[Quigibo]

Also I think he meant actually erasing the tile from the screen. Parser you can do that by drawing a Rect( and a RectI( at the coordinates of the tile.

...or a single Pt-Off() if the tile is 8x8.  If its smaller than 8x8 you can use Pt-Mask()r to erase and redraw the new tile just like Pt-Off().

[parserp]

actually yes, I was referring to physically erasing a tile from the buffer. I'll try trying using 'Rect' and 'Pt-Mask'. Thanks guys!

[Eiyeron]

Just a little optimisation:

x+1->x

Becomes:

x++

Same with x--


But is faster

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getKey(4)?Y-- End

than?

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If getKey(4) Y-1->Y End

i think there should be many bytes and cycles won, but not much

[kindermoumoute]

But is faster

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getKey(4)?Y-- End

than?

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If getKey(4) Y-1->Y End

Nope, that's the same.

[Eiyeron]

Really? I thought that would be faster, or lighter...

[hellninjas]

This has been alot of help!

[Eiyeron]

You'r welcome!