I am doing, my first game, a 3D shooter, bla,bla and I came to the point where I need a skybox. Well, I robbed a game it''s skybox (where it looked great, unfortunately I don''t have the game''s code) and I used those pics in my little game. My problem is that if I fit those textures on a cube(with only 5 faces, TOP, FRONT, LEFT, RIGHT, BACK), I get some strange lines between them. If I get the pics and if I stick them together in msPant, they fit and look good.I believe I have to do something with the code, so help please! You can look at some screenshots and at the code I use at www.cavendish.home.ro.

clamp your textures...

instead of GL_WRAP, use GL_CLAMP or GL_CLAMP_TO_EDGE when loading.

<-- smile :-)

This is the function for loading textures:

void CreateTexture(UINT textureArray[], LPSTR strFileName, int textureID){  AUX_RGBImageRec *pBitmap = NULL;  if(!strFileName)									     return;  pBitmap = auxDIBImageLoad(strFileName);  if(pBitmap == NULL)    exit(0);  glGenTextures(1, &textureArray[textureID]);  glBindTexture(GL_TEXTURE_2D, textureArray[textureID]);  gluBuild2DMipmaps(GL_TEXTURE_2D, 3, pBitmap->sizeX, pBitmap->sizeY, GL_RGB, GL_UNSIGNED_BYTE, pBitmap->data);  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR_MIPMAP_LINEAR);  if (pBitmap)  {    if (pBitmap->data)        free(pBitmap->data);    free(pBitmap); }}

RipTorn, I can't find GL_WRAP here.


[edited by - cavendish on September 15, 2002 5:41:46 AM]

GL_LINEAR_MIPMAP_LINEAR is not a valid magnification filter. Only GL_LINEAR and GL_NEAREST are valid.

Anyways, try put these two lines in your code. This is what RipTorn was talking about.

Wow!!!
Thanks Brother Bob, RipTorn!!!!
It looks super!!!
Who thought I can solve my problem in 30min after 5 hours of veryfing .....
Thanks!!

Using GL_CLAMP will make lines appear just the way you described in non-nvidia cards.

The proper way, as someone suggested, is to use GL_CLAMP_TO_EDGE.
It's not part of OpenGL 1.1 but all major cards support this extension.

Just add the following before all your code:



The reason it works in nvidia cards is because they make GL_CLAMP act like GL_CLAMP_TO_EDGE, but they're different things. Anyway, there's some option in the new drivers that make it work properly.

[edited by - t0y on September 15, 2002 10:44:30 PM]

t0y: you''re absolutely right ! For more informations on clamping textures, read the short note that Patrick Brown (one of the driver developers from NVIDIA) wrote on OpenGL.org Discussion & Help Forums.
Though you have to know that GL_CLAMP_TO_EDGE is not supported by OpenGL1.0, that is you MAY not be able to use it on a few cards. As a positive note, almost all cards support it today.
You can find a non-exhaustive list of cards that support the extension GL_SGI_texture_edge_clamp, GL_SGIS_texture_edge_clamp and GL_EXT_texture_edge_clamp. All those extensions allow the usage of GL_CLAMP_TO_EDGE.

hmm. well. I''ve seen cases where CLAMP_TO_EDGE badly corrupted the textures... where GL_CLAMP didn''t.. but that was on a fairly dodgy laptop...

<-- smile :-)