k3d/share/shaders/k3d_altitude_fog.sl:4:	color background = 0;
k3d/share/shaders/k3d_altitude_fog.sl:10:	Ci = mix(Ci, background, fog);
k3d/share/shaders/k3d_background.sl:26:imager k3d_background(
k3d/share/shaders/k3d_bluescreen.sl:3: *   puts a background color behind an image.
k3d/share/shaders/k3d_bluescreen.sl:6: *   background - the color of the background
k3d/share/shaders/k3d_bluescreen.sl:11:color background = color(0.0, 0.0, 1.0); 
k3d/share/shaders/k3d_bluescreen.sl:29:       Ci+=(1-alpha)*background;
k3d/share/shaders/k3d_contacshadow.sl:32:    /* transform the ground plane point into texture coordinates  
k3d/share/shaders/k3d_contacshadow.sl:47:	/* transform the point on the ground plane into the shadow
k3d/share/shaders/k3d_contacshadow.sl:49:	   camera to the ground plane */
k3d/share/shaders/k3d_crayon.sl:23:	color topcolor, basecolor - the color of the crayon strokes and the color of the ground
k3d/share/shaders/k3d_depthcue.sl:10:		    color background = 0;)
k3d/share/shaders/k3d_depthcue.sl:15:  Ci = mix(Ci, background, d);
k3d/share/shaders/k3d_fog.sl:9:volume k3d_fog(float distance = 1; color background = 0;)
k3d/share/shaders/k3d_fog.sl:12:  Ci = mix(Ci, background, d);
k3d/share/shaders/k3d_graphic_lines.sl:337:	/* background layer  */
k3d/share/shaders/k3d_imagelayergradient.sl:3:			       color ground = color(.6, .6, .1);
k3d/share/shaders/k3d_imagelayergradient.sl:14:      Ci = Cs * mix(ground, nadir, (v - 0.5) * 2.0);
k3d/share/shaders/k3d_lunette.sl:4: * lunette.sl -- A pretty surface shader ideal for "ground planes".
k3d/share/shaders/k3d_lunette.sl:8: *   surfaces placed beneath your scene which act as the ground.  The default
k3d/share/shaders/k3d_lunette.sl:11: *   pattern I saw in the background of another image entitled "Lunettes",
k3d/share/shaders/k3d_lunette.sl:19: *   colorA, colorB - colors used in the background fBm noise
k3d/share/shaders/k3d_lunette.sl:54: *   colorA, colorB - Two colors for the background pattern.
k3d/share/shaders/k3d_lunette.sl:55: *   noiseScale - Scale of the background fBm noise (relative to the size of
k3d/share/shaders/k3d_noisysmoke.sl:105:   * the background element.
k3d/share/shaders/k3d_noisysmoke.sl:107:   * opacity of the volume, i.e. (1-Ov)*Ci is the light from the background
k3d/share/shaders/k3d_oak.sl:16: *   Clightwood - the light, "background" wood color
k3d/share/shaders/k3d_oakplank.sl:23: *   Clightwood - the light, "background" wood color
k3d/share/shaders/k3d_sdixon.sl:24:	 *   metallic-green ink to a matte-yellow background. */
k3d/share/shaders/k3d_shifteddrtile.sl:16: *	cstate1 - foreground color
k3d/share/shaders/k3d_shifteddrtile.sl:57:	uniform color cstate1 = color(1, 0, 0);  /* foreground color */
k3d/share/shaders/k3d_skin2.sl:16: * for notes and background information.
k3d/share/shaders/k3d_smoke.sl:118:      /* Composite with exponential extinction of background light */
k3d/share/shaders/k3d_smoke.sl:125:  /* Ci & Oi are the color and opacity of the background element.
k3d/share/shaders/k3d_smoke.sl:127:   * opacity of the volume, i.e. (1-Ov)*Ci is the light from the background
k3d/share/shaders/k3d_smoke2.sl:148:   * the background element.
k3d/share/shaders/k3d_smoke2.sl:150:   * opacity of the volume, i.e. (1-Ov)*Ci is the light from the background
k3d/share/shaders/k3d_stones.sl:12: * trying to replicate the shader usr for the ground in "A BUGS LIFE".
k3d/share/shaders/k3d_stones.sl:26: * stonecolor, groundcolor = this is obvious, isn't it?
k3d/share/shaders/k3d_stones.sl:92:   color  groundcolor = color (.45,0.35,0.2);
k3d/share/shaders/k3d_stones.sl:109: surface_color = groundcolor;
k3d/share/shaders/k3d_toonmap.sl:131:/* background layer (layer 0) */
k3d/share/shaders/k3d_veinedmarble.sl:6: *   controls the color of the veins.  The background color is given by the
k3d/share/shaders/k3d_wallpaper_2stripe.sl:7: *   equal s.  The background color is given by the surface color.
k3d/share/shaders/k3d_wallpaper_2stripe.sl:13: *   bgcolor, stripecolor       color of background and stripes
