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View Full Version : Tiled Height Field question?

ironduke
03-14-2000, 06:04 PM
I am writing a terrain editor, the terrain is editable by squares.
ie 100 x 100 = 10000 editable terrain squares, in one square you could place a grass tile, in another water etc...

my problem is the number of polygons 20,000 if I use quads.

I was hoping to use tessalation to remove unneeded triangles by joing squares that have the same elevation.

BUT then I will loose my tile coordinates for the squares, so I will not be able to have 100 tiles by 100.

example normal
(a letter = tile)

ABCDE
FGHIJ
KLMNO

But if I use tesselation
ABBCC
DEFCC
GHIJK

I will have to texture B and C as one quad
wont I?

as certain tiles will have been eaten up into a larger one, Is there a way round this?

Ironduke

03-15-2000, 01:20 AM
>I was hoping to use tessalation to remove >unneeded triangles by joing squares that >have the same elevation.
>BUT then I will loose my tile coordinates >for the squares, so I will not be able to >have 100 tiles by 100.
> <cut>
>I will have to texture B and C as one quad
>wont I?

Could you not detect the fact that you've merged two quads together, and then modify texture coordinates appropriately?

eg. normal quad has texture coordinates http://www.opengl.org/discussion_boards/ubb/frown.gif0,0) (1,0) (1,1) and (0,1);

merge two together:
(0,0) (2,0) (2,1) and (0,1);

That would draw the texture twice, side by side, as if there were two separate quads.

You'd need to set texture properties to GL_REPEAT rather than clamp.

Hope that helps,

Steve

ironduke
03-15-2000, 09:44 AM
Thanx.

There is still a problem what if the larger squares requires more then 1 tiles as it is taking up four cells.

I suppose I create a texture by fusing the two tiles together and then applying it right?