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juglar

GL_TRIANGLE_STRIP and texcoord

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Hi guys!! y have the follows vertex to draw a square with triange strip, when i try to put the textcoord i get bat texture mapping, can anyone tell me what are the textcoord for this vertes liste in GL_TRIANGLE_STRIP txs in advance! vtx1: x: 0 y: 10 z: 0 vtx2: x:0 y:10 z:10 vtx3: x:10 y:10 z:0 vtx4: x:10 y:10 z:10

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The texture coordinates depend on how you want them to be mapped..

I guess you want vtx-1 to be the lower left corner of the texture image.
Your strip looks like that, when you look at it from above, cause its a square lying on the x-z-plane.


vtx3 -----> vtx4
^
|
|
|
|
vtx1 -----> vtx2


Sorry, the diagram is ugly [lol]

The texture coordinates now have to be set up so that the texture is mapped onto the strip in the right order, and that is:
vtx1 - glTexCoord2f( 0.0f, 0.0f );
vtx2 - glTexCoord2f( 1.0f, 0.0f );
vtx3 - glTexCoord2f( 0.0f, 1.0f );
vtx4 - glTexCoord2f( 1.0f, 1.0f );

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Hi! i draw the Trigles strip in that way (ignore de dots)

vtx2.........vtx4
^ |..........|^
|....|.......|
|.....|......|
|......|.....|
|.......|... |
|..........|.|
vtx1.........vtx3

te secuense is lije this: vtx1--> vtx2-->vtx3-->vtx4


that is the order i have now ... and i can't figure out how to put the corretct texture mapping coord :( can you help me?

txs! in advance
PS: My draw is worst!:P

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Hey,

textures are mapped onto a rectangle(as this is one) as if you'd glue them onto the vertices. A texture has coordinates in x and y direction (which are then calles s and t or u and v) like this:

t ^
1.0 |
|
| heres the image..
|
|
0.0 |________________>
0.0 1.0 s


That means if you put that onto your triangle strip it looks like that

t ^
1.0 | vtx2.........vtx4
| ^ |..........|^
| |....|.......|
| |.....|......|
| |......|.....|
| |.......|... |
| |..........|.|
0.0 | vtx1.........vtx3
--------------------->
0.0 1.0 s


So here you are (first parameter is s, second t):
vtx1 - glTexCoord2f( 0.0f, 0.0f );
vtx2 - glTexCoord2f( 0.0f, 1.0f );
vtx3 - glTexCoord2f( 1.0f, 0.0f );
vtx4 - glTexCoord2f( 1.0f, 1.0f );

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