_________________________________________________

Introduction

 

This tutorial will give a brief introduction to the Quake 3 Arena Shader Editor
(q3ase) developed by Bert Peers.  We will go through how to set up the
editor and how it works, and we’ll make a couple of shaders using the
editor.

I am assuming a fairly good knowledge of
Q3radiant: if you have only just started with radiant then don’t go
learning about shaders yet.  Learn radiant and then learn shaders.

You will need a copy of the shader manual (from www.quake3world.com/editing). 
It is simply not possible to make shaders properly without having read
and understood most of it.  The shader manual is dense and often
technically difficult.  To most people it is at first impenetrable, but
part of the joy of q3ase is that it allows you to experiment with what
you find in the manual and get good understanding of how everything
works.

You should read as many basic tutorials on shaders
as you can find.  Read the tutorials.  Read the shader manual.  Don’t
worry if you don’t understand all of it (you won’t), but read it through
just to get a sense of how it is laid out and some of the basic
concepts.  And then start playing with q3ase.

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Installation

 

Extract
q3ase.zip file.  It would be sensible to place all files in a folder
called baseq3/tools/q3ase.  Run the q3ase.exe file to start the editor. 
I suggest that you create a shortcut pointing to q3ase.exe to sit on
your desktop or in your start bar.

When you run the editor
for the first time, there are a couple of things that need setting up. 
First, the editor has to try to see if it can do 32 bits per pixel. 
Then it will prompt you to set up your .pk3 files.  This is important
because otherwise you won’t be able to see any textures.  In the
dialogue box go to your baseq3 directory and select the pak0.pk3.  I
would then suggest you add any other .pk3 files you are likely to want
to use – including the q3ase.pk3 file.  From the File Menu select Edit
Pakfiles.  Add in any .pk3 files and also add in your baseq3 directory. 
This will allow you to use any textures that aren’t in .pk3 files. 
Don’t add the actual folder the textures are in – this will confuse
things – just the baseq3 directory.

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The Basics

 

The global keywords that are usually found at the start of a shader and which generally deal with how the shader behaves in the game world will be dealt with later in this tutorial.  For the moment we will concentrate on how the shader looks.

A
shader is built up of a number of stages.  Many shaders have only one
stage, some have as many as five or six.  Almost all stages will use a
texture and manipulate it to produce an effect.  We control how the
stage looks using the stage menu.

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The Tree view

When
you first load q3ase, there are no shaders in the tree view apart from a
default blank shader.  Click on the + symbols until the tree view is
fully expanded as shown here.  Clicking on a – symbol will contract that
part of the tree view – very useful as the tree view can get cluttered
when lots of shaders are loaded up.

To bring up the stage menu, right click on the words Stage 1 in the q3ase tree view.

Loading up a texture

Bring
up the stage menu and select Edit Texture Source.  This brings up a
dialogue box.  Map should already be selected so we’ll just click the
Texture button and the Texture selection box is brought up .  In the
bottom left hand corner make sure the Preview box is ticked, so that you
can see what the texture looks like.  In the main box you should see a
long list of files – we’ll use the filter option.  In the Prefix box,
type textures and click the Filter button.  This means that this box
only shows textures.  Now type textures/base_wall and press Filter.

Currently
the preview window (shown) shows the q3ase logo (you may need to
maximize it from the start bar).  Now select the
base_wall/atechengine_ax.tga texture from the window – it will appear in
the preview window.  Now click OK.  Note that a new keyword has been
entered under Stage 1 in the Tree View.

If we wanted to change the texture we could right click on that keyword and select Edit.

 _________________________________________________

The tcMods

 

Now
we want to play with how the texture looks.  We are going to do some
ugly things with this texture that we wouldn’t want to see in the game,
but there’s a lot of detail in the texture which allows us to see very
clearly what each tcMod does.

You create a tcMod keyword
by right clicking on the stage name (We only have Stage 1 at the
moment), select Add tcMod and then the particular tcMod you want to look
at.  This will bring up a dialogue box.  I’ve given some appropriate
values for each tcMod but these are just starting points.  Play around
with different values and refer to the shader manual (Section 7.6) for
full details.  Note that the relevant keyword is created automatically
in the tree view.  Right-clicking on the keyword will bring up a menu
where you can either Remove or Edit the tcMod.  Look at each tcMod
separately and don’t forget to try minus values where appropriate.  Then
try combining some tcMods.

Note: if some tcMods have no effect, go here.

Scroll

This is an obvious one to start with.  Scrolls the texture.  Start with s=1, t=0.  Don’t forget to try out minus values.

Scale.

There
appears to be an error in the shader manual here.  A value of 0.5 will
double the size of the texture on that axis.  A value of 2 will halve
it.  It’s not much fun to play with but it’s very useful.

Stretch

For
a detailed understanding you will need to refer to the shader manual.  A
base value of 1, will make the texture stretch and contract around its
normal size.  Start with values of base value=0.8, amplitude = 0.4,
phase = 0, frequency = 0.2, waveform = sin.  And then play.  With some
values, you will get very ugly looking effects.  If you are using a
Scroll in the same stage, I have found it better to have the Scroll after the Stretch.

Turbulence.

Back
and forth, side to side, swirling motion.  The base value is ignored,
so best to leave it on 0.  Start with base value=0, amplitude=0.4,
phase=0, frequency = 0.2, waveform = sin.  Refer to the shader manual
for full details.

Rotate

This is just what it says.  Stick a value in and watch it spin.  Make it a negative value and it spins the other way.

Transform

Like the manual says – this is not for level designers.  But you could play with it anyway.

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Blending

 

Now
we are going to blend two stages together.  First of all, get rid of
what we have so far by right clicking on Stage 1 and selecting Remove. 
We should be right back where we started, with the q3ase logo in the
preview window.

Let’s create a stage like the one on the right –
you should see moving blue flames in the preview window – if not refer
to the sections above.  We add a second stage by bringing up the Stage
Menu and selecting New Stage and then after this.  Stage 2 should appear
and the Preview window should revert to the q3ase logo.  This is
because no texture has been loaded up for this stage and at the moment
this stage is completely opaque – we can’t see through it to the stage
below.

Let’s load up the base_wall/atechengine_ax.tga
texture again but this time in Stage 2.  Now bring up the stage menu by
right-clicking on the words Stage 2, select blendfunc and then add.  We
can now see both stages at the same time.  The blendfuncs can be edited
and removed just like the tcMods.  Look at each of them in turn.

Add:
simply adds the stage to whatever lies beneath it (which in this case
is only Stage 1).  It is very commonly used.  If you want to make
transparent shaders (e.g. Water or glass) then you need to have a
blendfunc add in Stage 1.

Filter: the texture in this
stage will act as a filter.  A dark part of a texture in either stage
will appear dark in the final mix.  Blendfunc filter is always used in
lightmap stages and is otherwise relatively rare.

Blend:
allows parts of the texture to be transparent so that we can see
through to the stage below.  This is clearly what we want to use here. 
The texture must have an alpha channel (usually indicated by the .tga
extension) otherwise there will be no transparency.  Refer to the shader
manual for more information.

Custom: this allows complete
control over the mixing.  Refer to the shader manual for full details. 
The best way to understand the relevant section (7.2.2) is to read it
in conjunction with playing with this blendfunc.

 _________________________________________________

rgbGen

 

The
rgbGen allows us to change the brightness of a texture.  An rgbGen
Identity keyword is normally added by q3ase to every stage – you can
ignore it unless you need to change it.  Many of the rgbGen options are
not designed to be used by level designers – but what we will use is the
rgbGen wave function.

Load up a texture and select Edit
RGB Source from the Stage Menu.  Identity will be selected but change
that to Waveform – the texture in the preview window should pulsate.  If
we click the Edit button we can change the way it pulsates.  The
variables should be familiar by now.  A base value of 1 is the normal
brightness of the texture, 0 is blackness.  The rest are obvious. 
Experiment with the different wave forms.

The other use of
rgbGen is to dim a texture without pulsating it.  To do this set
base=0.5 (or whatever) and everything else to 0.  You will see countless
examples of this in the id shaders.

 _________________________________________________

tcGen environment

 

This
is how we get those cool reflections.  Load up effects/tinfx.  Then
bring up the Stage Menu and select tcGen/environment.  The texture will
stretch but will otherwise look unimpressive.  To see the tcGen in all
its glory, select Geometry/Spinning Box from the Preview menu.  If you
don’t see what is different – remove the tcGen environment.

 _________________________________________________

Animation

 

A
stage can have up to 8 animation frames.  From the Stage Menu select
Edit Texture Source.  Select Animation and then click the Frames
button.  The Texture Animation window is very similar to the Texture
window.  The only difference is that you select a texture and then click
the arrow to put it into one of the 8 frames.  You don’t need to use
all 8.  Load in the sfx/b_flame set in order, then click OK.  In the
Texture Source box, you can adjust the frames per second.  The default
is 1, which is too slow for this animation.  Try setting it to 10.

 _________________________________________________

The Lightmap Stage

 

Most
shaders have a lightmap stage, which causes the shader to be affected
by the surrounding lighting.  Bring down the Stage Menu and select Edit
Texture Source.  Select Lightmap.  The Preview Window will go white. 
The lightmap needs to be combined with a blendfunc filter.  If the
lightmap is the first stage then the next stage up should have a
blendfunc filter.  If the lightmap is not the first stage then there
should be a blendfunc filter in the lightmap stage.

If you
forget to put a lightmap stage in then when you save the shader q3ase
will prompt you to put a lightmap stage as the last stage of the
shader.  This is usually fine, though with light blend effects you may
want to put it earlier.

If this seems complicated, then
don’t worry about it for now, just leave the lightmap stage out and
accept the prompt when you save.

Q3ase v0.6 allows you to see how your shader will look under different lighting states.  Click here.

 _________________________________________________

Other Stage Specific Keywords

 

That’s
as far as this tutorial goes in regard to the Stage Specific Keywords. 
It’s enough to get you going.  The rest of the Keywords are covered in
the Shader Manual and they are set in exactly the same way, through the
Stage Menu.

General Shader Keywords

 

These
are all set by right-clicking on General Keywords in the Tree View. 
All these Keywords are covered in Sections 3, 4, and 5 of the Shader
Manual.  It is in most cases obvious how to set them.  If you don’t
understand a particular Keyword then it’s the Shader Manual for you, and
then the id shaders and then the editing forums.  Just as in the stage
menu, when you set a Keyword it appears in the tree view and you can
edit it or remove it by right-clicking.

 _________________________________________________

The Preview modes

 

The Preview menu let’s you control how q3ase previews a shader.

Geometry

Flat: the default mode.  The texture as it is…

Box:  essential if you are using the deformVertexes keyword.

Spinning Box:  essential if you use the tcGen environment keyword

Cascade:  will show each stage separately.  I haven’t used it much, but perhaps useful for analysing complex blend effects.

Sky:  (doh) for making skies.

Render

These allow you to look at the separate stages of a shader.  Very useful for tweaking how a shader looks.

Lighmaps

Select
different lightmap previews to see how the shader would look in
different lighting states.  Note that changing the lightmap preview will
change how the shader looks in the editor not in the game.  It’s very
useful when making shaders for lights for checking that the lightmap
stage is in the right place.  (If you get it wrong your light won’t be
seen if it’s in a dark corner!)

Buffer Colour

You
can change the buffer colour.  Most of the time you won’t notice the
difference, but it can be useful when playing with alpha blends.  And
it’s necessary to see what a transparent shader looks like.

Bypass Driver for tcMod

If
some of the tcMods don’t function, for example, you set a rotate but
the texture doesn’t rotate, then select this option.  It’s a video card
issue.  If, like me, you have a Matrox G400, you will want to leave this
ticked permanently.

 _________________________________________________

Opening and saving shaders

 

Version
0.6 of q3ase has greatly simplified the process of saving shaders and
allows the invaluable option of opening pre-existing shader files.

Opening

It
couldn’t be simpler.  Click on the File menu and select Open….  You are
presented with a dialogue box listing all the shader files available to
you.  If you can’t find the shader file you’re looking for in here then
you may need to use the Edit pakfiles… option, also under the File
menu.

Let’s select the base_floor.shader file.  And press
OK.  The file opens but we’re presented with a warning dialogue box. 
This can usually be ignored but provides useful information for
debugging.  Press OK.  Once we expand the tree view we can see all the
shaders in the base_floor group for us to edit and learn from at our
leisure.  You can have as many shader files open at one time as you
like.

Saving

We’re going to cover how to save a shader and how to make it show up in q3r.  First make the shader on the right.

You
should see a blue fuzz through a hole in the floor.  If you have any
problems getting that then refer back to earlier sections of this
tutorial.

The surfaceparm and the qer_editorimage were added by right clicking on General Keywords.

Note
the name (added by right-clicking).  It’s important to include a path
from the baseq3 directory in the name.  This will cause the shader to
show up in the tutorial folder in q3r.  If a shader doesn’t show up in
q3r, the first thing to check is that you have not just typed a name but
that you have typed a pathname.

To save the shader
right-click where it says File: and choose Save As… and then save the
file as normal with a Windows document.  You should, of course, save it
in your baseq3/scripts folder.  For the purposes of this tutorial name
the new file tutorial.shader.

You’ll be prompted to save a lightmap stage.  Click Yes.

Our shader has now been saved.

If
you are working with a file that already exists (ie one opened from the
File menu) then you can use the Save option rather than the Save As…. 
The id shader files that shipped with the game are write-protected by
the editor.  You can only save them as a new file.

Before we can use the shader in q3radiant there are a couple of things we must do.

1. 
In the baseq3/scripts folder, open shaderlist.txt and add the word
tutorial to the list.  Make sure you keep the last line of this file
blank – it seems to be important.

3.  Now go to your
baseq3/textures folder and create a new folder called tutorial.  When
you’re making your own shaders then any custom textures would go in
here.  We’re going to leave it empty – but it’s important that we create
it anyway because the name of our shader is going to include the path
to this directory and if it doesn’t exist then the shader won’t show up
in q3radiant.

Obviously you will name all these files and
folders something different when you’re working on a map and not the
tutorial (something like l33tdm24.shader?).

Comparing the Tree View and the Shader script

Let’s see what our shader really looks like.  Open up tutorial.shader using a text editor.

You should see something like this…

textures/tutorial/testshader

{

      qer_editorimage textures/base_floor/clangdark_ow3.tga

      surfaceparm metalsteps

      {

            map textures/sfx/proto_zzztblu2.tga

            rgbGen identity

            tcMod turb 0 0.5 0 9.6

            tcMod scale 2 2

            tcMod scroll 9 5

      }

      {

            map textures/base_floor/clangdark_ow3.tga

            blendfunc blend

            rgbGen identity

      }

      {

            map $lightmap

            rgbGen identity

            blendfunc filter

      }

}

The similarity to the Tree View in q3ase is obvious.  But there are a couple of things to note.

1.  A lightmap stage has been added at the end.  Generally, as I said earlier, this is fine.

2.  An rgbGen identity has been added to every stage.

A comparison with the original id shader.

This shader is an exact copy of an id shader, so let’s compare our shader with id’s.

textures/base_floor/clangdark_ow3

{   

     surfaceparm  metalsteps    

     // This makes a noise like running on metal

        {

            map textures/sfx/proto_zzztblu2.tga

            tcMod turb 0 .5 0 9.6

            tcmod scale 2 2

            tcmod scroll 9 5

            blendFunc GL_ONE GL_ZERO

            rgbGen identity

      }

        {

            map textures/base_floor/clangdark_ow3.tga

            blendFunc GL_SRC_ALPHA GL_ONE_MINUS_SRC_ALPHA

            rgbGen identity

      }

        {

            map $lightmap

            blendFunc GL_DST_COLOR GL_ONE_MINUS_DST_ALPHA

            rgbGen identity

      }

}

Note the following:

1. 
The id shader has no qer_editorimage keyword.  This is because the name
of the texture has an exact equivalent texture and it will use this in
the editor.  However this can cause problems with texture robbing and I
would advise you to use a qer_editorimage keyword.

2.  In
the first stage, id has a blendFunc GL_ONE GL_ZERO which we don’t have. 
It’s not necessary – it simply means make the texture opaque, which it
is anyway.

3.  The blendFuncs are different in stages 2
and 3.  They are equivalent.  Refer to the Shader Manual (Section 7.2)
for further details.

4.  The rgbGen identity keyword is in a different place.  It’s not important where this appears within the stage.

5. 
There is a comment.  Actually there isn’t in the original shader
script, but I added it to make a point.  Anything after // on a line
will be ignored.

 _________________________________________________

What next?

 

This
is as far as this tutorial goes.  We’ve covered how to make a basic
shader using the q3ase tool.  The many other features and keywords are
all covered in the Shader Manual and/or the q3radiant Manual – and to
use them within q3ase should now be reasonably obvious.  (The sky
features are particularly good).

The best way to go
forward from here is to study the id shaders and recreate them using
q3ase.  It’s difficult to see how some effects are achieved until you
break them down using q3ase.  In conjunction with the Shader Manual, you
should quickly build up a good working knowledge of shader scripts and
that’s the best time to start making your own…

Article was written by :    -fatmanfat-            

 

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