Rainbow

The Texture

First you create an image (Paint does the job here) with the size of a texture (here: 256x512), by drawing straight lines (hold down Shift) in colors of a rainbow. (You can see the order by looking closely at real pictures of rainbows)

Important: Center the lines and make sure they have he same distance to each other!

http://i27.photobucket.com/albums/c167/EAWpics/1.jpg

Then you open the image in a "better" image manipulation program. I used Photoshop and the blur filter "Motion Blur": twice at 0 degrees (with 50 pixel disort) and twice at 90 degrees (again 50 pixel disort).

http://i27.photobucket.com/albums/c167/EAWpics/3.jpg

Save it all as a Baseline - Standard ".jpg" and the texture is ready.

http://i27.photobucket.com/albums/c167/EAWpics/4.jpg

The Shader

Now you just have to equip the texture with a shader.

textures/meinemap/regenbogen // Name of the texture (in Radiant)
{
q3map_nolightmap // No shadows on the texture
surfaceparm nolightmap // No shadows on the texture
surfaceparm nonsolid // Makes it non-solid
surfaceparm nonopaque // Transparency
surfaceparm nomarks // No weapon marks
surfaceparm trans // Transparency
cull twosided // Patch is visible from both sides
{
map textures/mymap/rainbow // Path of the texture
blendFunc GL_ONE GL_SRC_ALPHA // Transparency
rgbGen const ( 0.5 0.5 0.5 ) // Less saturated colors
alphaFunc GE128 // Filters out black
alphaGen const 1.0 // Alpha channel property
}
}

Texture and shader are now packaged into a .pk3 and moved to …GameData/Base/.

Important: Don’t forget the entry in the shaderlist.txt (…Base/shaders)!

Ingame

To put the rainbow into a map, just make a big patch and apply the rainbow texture (press Shift+S and click on "Fit" to strech the texture). Now just disort (press V, then manipulate) and move it to the right place.

http://i27.photobucket.com/albums/c167/EAWpics/5.jpg

Now, that we have the rainbow in the map, lets compile (see: Q3map2GUI tutorial).http://i27.photobucket.com/albums/c167/EAWpics/6.jpg

Comparison:

http://i27.photobucket.com/albums/c167/EAWpics/2.jpg