<#742#><#2015#>Rayshade<#2015#><#742#> also supports an <#743#>image<#743#> texture. This texture
allows you to use images to modify the characteristics of a surface. You
can use three-channel images to modify the any or all of
the ambient, diffuse, and specular colors of a surface.
If you are using the Utah Raster Toolkit,
you can also use single-channel images to modify surface reflectance,
transparency, and the specular exponent. You can also use a single-channel
image to apply a bump map to a surface.
In all but the bump-mapping case,
a component is modified by multiplying the given value by the value
computed by the texturing function. When using the Utah Raster Toolkit,
surface characteristics are modified in proportion to the value of
the <#744#>alpha<#744#> channel in the image. If there is no <#745#>alpha<#745#> channel,
or you are not using the Utah Raster Toolkit, <#746#>alpha<#746#> is assumed to be
everywhere
equal to 1.
- <#5011#><#5011#>
- <#1522#>component<#1522#> ;SPMlt;<#1523#>Component<#1523#>;SPMgt;
The named component will be modified.
Possible surface components are:
<#751#>ambient<#751#> (modify ambient color),
<#752#>diffuse<#752#> (modify diffuse color),
<#753#>specular<#753#> (modify specular color),
<#754#>specpow<#754#>, (modify specular exponent),
<#755#>reflect<#755#>, (modify reflectivity),
<#756#>transp<#756#> (modify transparency),
<#757#>bump<#757#>, (modify surface normal).
The <#758#>specpow<#758#>, <#759#>reflect<#759#>, <#760#>transp<#760#>, and <#761#>bump<#761#>
components require the use of a single-channel image.
- <#5014#><#5014#>
- <#1526#>range<#1526#> <#1527#>high low<#1527#>
Specify the range of values to which the values in the
image should be mapped. An value of 1 will
be mapped <#765#>high<#765#>, 0 to <#766#>low<#766#>. Intermediate
values will be linearly interpolated.
- <#5017#><#5017#>
- <#1530#>smooth<#1530#>
When given, pixel averaging will be performed in order
to smooth the sampled image. If not specified, no averaging
will occur.
- <#5018#><#5018#>
- <#1533#>textsurf<#1533#> ;SPMlt;<#1534#>Surface Specification<#1534#>;SPMgt;
For use when modifying surface colors, this keyword specifies
that the given surface should be used as the base
to be modified when the <#775#>alpha<#775#> value in the image
is non-zero. When <#776#>alpha<#776#> is zero, the object's
unmodified default surface characteristics are retained.
The usual behavior is for the object's default surface properties to
be used.
- <#5021#><#5021#>
- <#1537#>tile<#1537#> <#1538#>un vn<#1538#>
Specify how the image should be tiled (repeated) along the
u and v axes.
If positive, the value of <#781#>un<#781#> gives the number of
times the image should be repeated along the u axis, starting
from the origin of the texture, and positive <#782#>vn<#782#> gives the
number of times it
should be repeated along the v axis. If either value is zero,
the image is repeated infinitely along the appropriate axis.
Tiling is usually only a concern when planar mapping is being used,
though it may also be used if image textures are being scaled. By default
<#784#>un<#784#> and <#785#>vn<#785#> are both zero.
A mapping function may also be associated with an image texture.