View source for User:VectorFluxion/Making Your Own Water

'''[[Water]]''' is one of the Source engine's most complex material types/shaders.

Water does not have a <code>$basetexture</code> value by default, but rather, is made up of a real-time transforming [[wp:normal map|normal map]], fog, a combination of reflection and refraction, a flow map (for dx90 users and below), and an [[env_cubemap]] to give the water surface a [[specular reflection]] effect.

Water in the Source engine, is composed of three different elements:
*A material for when the observer is above the water surface, facing down into it;
*A material for when the observer is beneath the water surface, looking upwards; and,
*A scrolling overlay screen effect that the observer sees when underwater.

=="Expensive" vs. "Cheap" Water==
Cheap water has all the properties of expensive water; however, there are some notable differences.
*Cheap water is completely opaque from the surface, does not refract, and has limited reflection.
*Cheap water is commonly used at at distance, solely for optimization purposes.
**The entity that controls the distance in hammer units, that the expensive water begins fading to cheap water, is the [[water_lod_control]].

==Generic VMT Files For Water==
[[File:TF2FlowMap.png|150px|thumb|The flow map used by TF2's water, for sub-dx90 users.]]
The general code for the three elements of water.

For color values, both RGB and HSV can be used. Use square brackets for denote a HSV value <code>"[H S V]"</code> and curly brackets to denote a RGB value <code>"{R G B}"</code>.

For sub-dx90 users, a flow map (pictured to the right) must be used, as this will be transformed instead of a normal map. A flow map is also called a du/dv map, a derivative map, and a movement map. The flow map will be specified using the <code>$bumpmap</code> material parameter. <code>$bumpmap</code> should only be used in [[fallback materials]], and specified in the main water file, using the <code><dx90</code> rule, with the <code>$fallbackmaterial</code> material parameter inside.

It is generally recommended to make a fallback material for water, as water can be a memory-hog on older computers.

===Above water material:===

<pre>
"Water"
{
	"%compilewater" 1
	"%keywords" "<string>"
	"%tooltexture" "<path> relative to <game abbr>/materials/"
	
	"$abovewater" 1
	"$underwateroverlay" "<path> relative to <game abbr>/materials/"
	"$refracttexture" "_rt_WaterRefraction"
	"$refracttint" "<RGB>" or "<HSV>"
	"$normalmap" "<path> relative to <game abbr>/materials/"
	"$refractamount" <value>
	"$envmap" "env_cubemap"
	"$refractblur" 1
	"$surfaceprop" water
	"$bottommaterial" "<path> relative to <game abbr>/materials/"
	"$scale" "[1 1]"
	"$bumpframe" 0
	"$fogenable" <bool>
	"$fogcolor" "<RGB>" or "<HSV>"
	"$fogstart" <value in HU>
	"$fogend" <value in HU>
	"$temp" "[0 0]"
	"$curr" 0
	"$curr2" 0
	
	"Proxies"
	{
		"AnimatedTexture"
		{
			"animatedtexturevar" "$normalmap"
			"animatedtextureframenumvar" "$bumpframe"
			"animatedtextureframerate" 30
		}
		"TextureTransform"
		{
			"translatevar" "$temp"
			"resultvar" "$bumptransform"
		}
		"Sine"
		{
			"sineperiod" 20
			"sinemax" .6
			"sinemin" -.6
			"resultvar" "$curr"
		}
		"Sine"
		{
			"sineperiod" 15
			"sinemax" -.6
			"sinemin" .6
			"resultvar" "$curr2"
		}
		"Equals"
		{
			"srcvar1" "$curr2"
			"resultvar" "$temp[0]"
		}
		"Equals"
		{
			"srcvar1" "$curr"
			"resultvar" "$temp[1]"
		}
		"WaterLOD"
		{
			"dummy" 0
		}
	}
}
</pre>

===Below water material:===
<pre>
"Water"
{
	"%compilewater" 1
	"%keywords" "<string>"
	"%tooltexture" "<path> relative to <game abbr>/materials/"
	
	"$abovewater" 0
	"$cheapwaterstartdistance" <value in HU>
	"$cheapwaterenddistance" <value in HU>
	"$refractamount" <value>
	"$reflectamount" 1
	"$refracttint" "<RGB>" or "<HSV>"
	"$reflecttint" "<RGB>" or "<HSV>"
	"$refracttexture" "_rt_WaterRefraction"
	"$scale" "[1 1]"
	"$blurrefract" 1
	"$normalmap" "<path> relative to <game abbr>/materials/"
	"$underwateroverlay" "<path> relative to <game abbr>/materials/"
	"$surfaceprop" "water"
	"$bumpframe" 0
	"$fogenable" <bool>
	"$fogcolor" "<RGB>" or "<HSV>"
	"$fogstart" <value in HU>
	"$fogend" <value in HU>
	
	"Proxies"
	{
		"AnimatedTexture"
		{
			"animatedtexturevar" "$normalmap"
			"animatedtextureframenumvar" "$bumpframe"
			"animatedtextureframerate" 30
		}
		"TextureScroll"
		{
			"texturescrollvar" "$bumptransform"
			"texturescrollrate" .3
			"texturescrollangle" 60
		}
	}
}
</pre>

===Screen distortion overlay effect:===
<pre>
"Refract"
{
	"%keywords" "<string>"
	"%tooltexture" "<path> relative to <game abbr>/materials/"
	
	"$refractamount" <value>
	"$refracttint" "<RGB>" or "<HSV>"
	"$refractblur" <bool>
	"$bluramount" <0, 1, 2>
	"$ignorez" <bool>
	"$scale" "[1 1]"
	"$bumpmap" "<path> relative to <game abbr>/materials/"
	"$normalmap" "<path> relative to <game abbr>/materials/"
	"$bumpframe" 0
	
	"Proxies"
	{
		"AnimatedTexture"
		{
			"animatedtexturevar" "$normalmap"
			"animatedtextureframenumvar" "$bumpframe"
			"animatedtextureframerate" 30
		}
		"TextureScroll"
		{
			"texturescrollvar" "$bumptransform"
			"texturescrollrate" .2
			"texturescrollangle" 45
		}
	}
}
</pre>

==Fallback Materials==
Fallback materials are versions of existing materials that players will see if they are running older versions of DirectX. Fallback materials are invoked in the main material's VMT file, using a "fallback rule" and the <code>$fallbackmaterial</code> material parameter. Because of its complex nature, it is generally recommended to make a fallback material for custom water materials. The code for the fallback material is roughly the same as the main material file; however, instead of using a normal map, a flow map is used. It is invoked using the <code>$bumpmap</code> material parameter.

<pre>
"Water"
{
	...
	<dx90
	{
		"$fallbackmaterial" "<path> relative to <game abbr>/materials/"
	}
}
</pre>

===The difference between bump maps and normal maps===
There is a lot of confusion in determining the difference between a normal map and a bump map, moreover the difference between <code>$bumpmap</code> and <code>$normalmap</code>. Although the terms "normal map" and "bump map" are often incorrectly used interchangeably, they are in fact, different things.

A '''normal map''' is actually a type of bump map. <code>$bumpmap</code> can be used to invoke a normal map in most cases; however, in cases like these where both <code>$normalmap</code> and <code>$bumpmap</code> are used, using the <code>$bumpmap</code> parameter too liberally will cause problems with your material. In this case, we used <code>$normalmap</code> to invoke the normal map, because <code>$bumpmap</code> is used to invoke a flow map in fallback materials. A flow map is just another type of bump map. For <code>LightmappedGeneric</code> textures, using either one will suffice. Think of the <code>$normalmap</code> parameter as just a more specific version of <code>$bumpmap.</code>

==See Also==
*[[Water]]
*[[Normal]] mapping