GL_TRIANGLE_STRIP and texcoord
Author
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
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.
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 );
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 -----> vtx2Sorry, 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 );
Author
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
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
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:
That means if you put that onto your triangle strip it looks like that
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 );
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 sThat 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 sSo 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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