[ODE] Creating a TriList heightmap geom
Aras Pranckevicius
nearaz at interamotion.com
Mon May 12 05:06:02 2003
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> So, now I'm faced with the problem of how to create the Tri-mesh for =
my
> heightmap. I'm sure there's a really simple solution, but I can't seem
> ...
> I have the vertices in correctly (just transferred them from my
> heightmap into a dcVector3 array) but the Indices have me stumped. How
> do I find / generate these? I tried a couple of things, but they
It's the same idea as in rendering (vertex&index buffers): the vertices =
are the vertices, and the indices represent the "faces" (triangles). 3 =
indices form a triangle, and their values are vertex indices in the =
vertices array.
Eg. in ASCII-art: a small (2x3) heightfield of 6 vertices:
0--1--2
|\ |\ |
| \| \|
3--4--5
The vertices are just these 6 vertices, and the indices are the 4 =
triangles that we need:
0,4,3; 0,1,4; 1,5,4; 1,2,5; (I've specified vertices in clockwise =
order, you may want to do otherwise).
Generally for OPCODE you just have to supply vertex xyz's and indices, =
both can be taken directly from your vertex/index buffers/arrays (though =
OPCODE uses 32 bit indices, not 16 bit that are often used for =
rendering).
Aras Pranckevicius aka NeARAZ
http://www.gim.ktu.lt/nesnausk/nearaz/
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<DIV><FONT face=3D"Courier New" size=3D2>> So, now I'm faced with the =
problem of=20
how to create the Tri-mesh for my<BR>> heightmap. I'm sure there's a =
really=20
simple solution, but I can't seem</FONT></DIV>
<DIV><FONT face=3D"Courier New" size=3D2>> ...<BR>> I have the =
vertices in=20
correctly (just transferred them from my<BR>> heightmap into a =
dcVector3=20
array) but the Indices have me stumped. How<BR>> do I find / generate =
these?=20
I tried a couple of things, but they</FONT></DIV>
<DIV><FONT face=3D"Courier New" size=3D2></FONT> </DIV>
<DIV><FONT face=3D"Courier New" size=3D2>It's the same idea as in =
rendering=20
(vertex&index buffers): the vertices are the vertices, and the =
indices=20
represent the "faces" (triangles). 3 indices form a triangle, and =
their=20
values are vertex indices in the vertices array.</FONT></DIV>
<DIV><FONT face=3D"Courier New" size=3D2></FONT> </DIV>
<DIV><FONT size=3D2><FONT face=3D"Courier New">Eg. in ASCII-art: a small =
(2x3)=20
heightfield of 6 vertices:</FONT></FONT></DIV>
<DIV><FONT size=3D2><FONT face=3D"Courier =
New">0--1--2</FONT></FONT></DIV>
<DIV><FONT size=3D2><FONT face=3D"Courier New">|\ |\ =
|</FONT></FONT></DIV>
<DIV><FONT size=3D2><FONT face=3D"Courier New">| \| =
\|</FONT></FONT></DIV>
<DIV><FONT size=3D2><FONT face=3D"Courier =
New">3--4--5</FONT></FONT></DIV>
<DIV><FONT size=3D2><FONT face=3D"Courier New">The vertices are just =
these 6=20
vertices, and the indices are the 4 triangles that we =
need:</FONT></FONT></DIV>
<DIV><FONT size=3D2><FONT face=3D"Courier New">0,4,3; 0,1,4; =
1,5,4; 1,2,5; (I've specified vertices in clockwise order, you may =
want to=20
do otherwise).</FONT></FONT></DIV>
<DIV><FONT size=3D2><FONT face=3D"Courier =
New"></FONT></FONT> </DIV>
<DIV><FONT face=3D"Courier New" size=3D2></FONT> </DIV>
<DIV><FONT face=3D"Courier New" size=3D2>Generally for OPCODE you just =
have to=20
supply vertex xyz's and indices, both can be taken directly from your=20
vertex/index buffers/arrays (though OPCODE uses 32 bit indices, not 16 =
bit=20
that are often used for rendering).</FONT></DIV>
<DIV><FONT size=3D2><FONT face=3D"Courier New"></FONT> </DIV>
<DIV><FONT face=3D"Courier New"><BR></FONT></DIV></FONT>
<DIV>
<DIV><FONT face=3D"Courier New" size=3D2>Aras Pranckevicius aka =
NeARAZ<BR></FONT><A=20
href=3D"http://www.gim.ktu.lt/nesnausk/nearaz/"><FONT face=3D"Courier =
New"=20
size=3D2>http://www.gim.ktu.lt/nesnausk/nearaz/</FONT></A></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV></DIV></BODY></HTML>
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