Creating a Waterfall Material

This is a Tutorial to create a Waterfall material. It will scroll downward and refract the image behind it, and optionally reflect.

The bump map

For a waterfall you need a Normalmap which Refracts the light so that the things behind it gets distorted. I used The_GIMP with a normalmap plug-in for this Tutorial.

1. Make a new Image with a maximum size of 1024x1024, I used a size of 512x512 pixels.
2. 

   The 'solid noise' image
   We create now a solid Noise so you go to Filters → Render → Clouds → Solid noise. Set:
   • x to 16.0(the highest possible)
   • y to between 1.0 and 3.0
   • Detail to 15(highest possible)
   • Finally, you must check the Tileable box to make it seamless.
3. Save your file as TGA and open it with VTFEdit.
4. Check the texture config dialogue's Generate Normal map box and set:
   • Filter to 4 Sample
   • Height Source to Average RGB
   • Scale to 9.0
   • Normal Format and Alpha Format to RGBA8888.
5. Save this bump map in a folder like "nature/" in your mod materials folder or game materials folder and give it a name like "waterfall_n.vtf".

The Material

The basic Material

At first you have create a materialfile(vmt) and name it waterfall.vmt or similar. In the materialfile you should use the LightmappedReflective shader:

LightmappedReflective
{
}

So we don't need a $basetexture but we need a $RefractTexture and optionaly a $ReflectTexture.

The attribute for the $RefractTexture parameter is _rt_WaterRefraction and for $ReflectTexture is it _rt_WaterReflection.

Now it should look like this:

LightmappedReflective
{
	$RefractTexture _rt_WaterRefraction
}

That is now the base of our Material. Now we add the Normalmap with $normalmap and the path to it like "nature/waterfall_n".

For the right refraction amount we add $refractamount with a value between 0 and 1 like 0.08.

LightmappedReflective
{
	$RefractTexture _rt_WaterRefraction
	$normalmap nature/waterfall_n
 	$refractamount .08
}

See Water (shader) for more commands you'll want to use.

Scroll animation

When you use your material in a map you should see that the refraction looks frozen, so you must add a "Scrolling" effect.

We can do this with an animated texture, or for the easier way we can add the TextureScroll material proxy:

Proxies
{
	TextureScroll
	{
		texturescrollvar $bumpTransform
		texturescrollrate 1.3
		texturescrollangle 270.00
	}
}

So now the whole vmt should look like this

LightmappedReflective
{
	$RefractTexture _rt_WaterRefraction
	$normalmap nature/waterfall_n
	$refractamount .08
	Proxies
	{
		TextureScroll
		{
			texturescrollvar $bumpTransform
			texturescrollrate 1.3
			texturescrollangle 270.00
		}
	}
}

Optional: Reflection

When you want Reflections you must add $ReflectTexture, $reflectamount and $fresnelpower. Use for $fresnelpower a value of 5 because I think it looks the best. For $reflectamount you must find your own value because there is no "Perfect value".

"LightmappedReflective"
{
	"$RefractTexture" _rt_WaterRefraction
	"$ReflectTexture" _rt_WaterReflection
 	"$normalmap" "nature/waterfall_n"
 	"$refractamount" .08
 	"$reflectamount" .3
	"$fresnelpower" 5
 	"Proxies"
	{
		"TextureScroll"
		{
			"texturescrollvar" "$bumpTransform"
			"texturescrollrate" 1.3
			"texturescrollangle" 270.00
		}
	}
}

TODO

• embeding into a map