doom3-bfg/base/materials/fogs.mtr

// the calculated alpha value will be the distance that the fog texture
// extends from the viewer, unless it equals the default 1.0, in which case
// it will be set to 500

// If you replace the default internal fog projection image with your own
// texture, make sure that the alpha starts at 0 in the center, reaches
// 255 at the borders, and is generally radially symetrical.
// The color channel can be left solid white, or it can have additional
// color changes with position.

// you are free to modify the color or distance with math in the shaders

fogs/basicFog
{
	fogLight			// tell the engine it is fog and not a light
	noShadows
	{
		map		_fog	// the internal fog image
		colored			// take rgba from entity shaderparms
	}
}

//==================================================================================


// blendLight allows a light projection with an arbitrary blend to be
// applied to everything inside it, allowing simple fogs that increase
// in a given direction without caring about the viewer position



fogs/sentest
{
	blendLight
	noShadows
	lightFalloffImage		shapes/pitFalloff2.tga	
	{
		blend		blend		
		map			shapes/alphaSquare.tga
		alphazeroclamp
		colored
	}
}


fogs/pitFog
{
	blendLight
	noShadows
	lightFalloffImage		shapes/pitFalloff.tga	// white in color channel, 
											// alpha ramps from 0 to 255, then stays at 255 a bit,
											// than has another 0 at the other end
	{
		blend		blend		// alpha blend on surfaces
		map			shapes/alphaSquare.tga		// solid white in color, single pixel alpha border
		alphazeroclamp			// make sure it doesn't bleed over the edges
		colored					// take rgba from entity shaderparms
	}
}

fogs/pitFog_to_black
{
	lightFalloffImage		lights/xfalloff.tga
	//lightFalloffImage		lights/fogoff.tga
	fogLight			// tell the engine it is fog and not a light
	noShadows
	{
		map		_fog	// the internal fog image
		colored			// take rgba from entity shaderparms
	}
}

fogs/glare2
{
	blendLight
	noShadows
	lightFalloffImage	lights/squarelight1a
	{
		blend		add			// add on top of alpha blend on surfaces
		map			lights/spot01
		zeroclamp				// make sure it doesn't bleed over the edges
		colored					// take rgba from entity shaderparms
	}
}

fogs/glare
{
	blendLight
	noShadows
	lightFalloffImage	lights/squarelight1a
	{
		blend		add			// add on top of alpha blend on surfaces
		map			lights/squarelight1
		zeroclamp				// make sure it doesn't bleed over the edges
		colored					// take rgba from entity shaderparms
	}
}

fogs/glare_snd
{
	blendLight
	noShadows
	lightFalloffImage	lights/squarelight1a
	{
		blend		add			// add on top of alpha blend on surfaces
		map			lights/squarelight1
		zeroclamp				// make sure it doesn't bleed over the edges
		red 		sound * Parm0
		green 		sound * Parm1
		blue 		sound * Parm2
	}
}

fogs/filter
{
	blendLight
	noShadows
	lightFalloffImage	lights/squarelight1a
	{
		blend		GL_ZERO, GL_ONE_MINUS_SRC_COLOR	// get dimmer as the textures get brighter
		map			lights/squarelight1
		zeroclamp				// make sure it doesn't bleed over the edges
		colored					// take rgba from entity shaderparms
	}
}