Texture coordinates

Hi,

I wrote a little tool [1] to make a terrain from brushes from an image. It is quite limited in usefulness, but I wondered for while about a central shortcoming: I couldn't figure out how to set texture coordinates correctly such the texture seams match.

[1] https://github.com/fps/map0

Is there a way to get the textures aligned correctly if considered as projected from the top? Patches welcome..

NOTE: Don't try this with images much larger than 100x100 pixels

Usually, as a mapper, one solve this by using texture projection at shader level.

heres an example from data/xonotic-maps.pk3dir/scripts/terrain01x.shader

Code:

textures/terrain01x/blends-mars-rock01-ground01-projected
{
    qer_editorimage textures/terrain01x/blends/mars-rock01-ground01.tga
    
    q3map_bounceScale  0.5
    dpoffsetmapping - 2 match8 229

    q3map_lightmapSampleOffset 8
    q3map_nonplanar
    q3map_shadeangle 95

    surfaceparm dust

    q3map_alphaMod dotproduct2 ( 0 0 0.95 )
    q3map_tcGen ivector ( 1024 0 0 ) ( 0 1024 0 )

    {
        map textures/terrain01x/rock/mars01.tga    // Primary
    }

    {
        map textures/terrain01x/ground/mars01.tga    // Secondary
        blendFunc GL_SRC_ALPHA GL_ONE_MINUS_SRC_ALPHA        
        alphaGen vertex
    }

    {
        map $lightmap
        blendFunc GL_DST_COLOR GL_ZERO
    }
}

the magic line here is

Code:

    q3map_tcGen ivector ( 1024 0 0 ) ( 0 1024 0 )

on which you can find more infi here

Thanks for your reply tZork. Using a shader to do the texture projection is a nice way around this problem I suppose. I must admit though that I was kind of lazy in my first post about this subject and while I described the consequence of my problem OK I should really have asked about the source.

The source of my problem really was that I didn't quite understand the texture coordinate mapping in .map files, especially in the brushDef format.

Interestingly enough that shader line you mention

Code:

    q3map_tcGen ivector ( 1024 0 0 ) ( 0 1024 0 )

looks suspiciously again like the interesting parts of the brushDefs.

From searching the web I found out that it's the two rows of a homogenous transform which is applied to the vertices after being transformed into a different basis. That transformation into a different basis is the missing part that is not well documented sadly. Can you maybe shed light on that issue, too?

I will also experiment with the shader you mentioned

Thanks again,
homs

unfortunately i only know how to use the .shaders, not how the code behind them works. if you manage to catch div0 on irc he may be able to give you some pointers.. thats abt the only option i can think of

unfortunately i only know how to use the .shaders, not how the code behind them works. if you manage to catch div0 on irc he may be able to give you some pointers.. thats abt the only option i can think of

Thanks for the replies anyways. Your input is highly appreciated