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Romain Guy
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@@ -50,6 +50,10 @@ counter-increment: h6;margin-right:10px}</style><style>.hljs{display:block;overf
&#xA0;&#xA0;&#xA0;&#xA0;<a href="#materialmodels/litmodel/clearcoatnormal" class="level3"><span class="tocNumber">3.1.13&#xA0; </span>Clear coat normal</a><br>
&#xA0;&#xA0;&#xA0;&#xA0;<a href="#materialmodels/litmodel/emissive" class="level3"><span class="tocNumber">3.1.14&#xA0; </span>Emissive</a><br>
&#xA0;&#xA0;&#xA0;&#xA0;<a href="#materialmodels/litmodel/post-lightingcolor" class="level3"><span class="tocNumber">3.1.15&#xA0; </span>Post-lighting color</a><br>
&#xA0;&#xA0;&#xA0;&#xA0;<a href="#materialmodels/litmodel/indexofrefraction" class="level3"><span class="tocNumber">3.1.16&#xA0; </span>Index of refraction</a><br>
&#xA0;&#xA0;&#xA0;&#xA0;<a href="#materialmodels/litmodel/transmission" class="level3"><span class="tocNumber">3.1.17&#xA0; </span>Transmission</a><br>
&#xA0;&#xA0;&#xA0;&#xA0;<a href="#materialmodels/litmodel/absorption" class="level3"><span class="tocNumber">3.1.18&#xA0; </span>Absorption</a><br>
&#xA0;&#xA0;&#xA0;&#xA0;<a href="#materialmodels/litmodel/micro-thicknessandthickness" class="level3"><span class="tocNumber">3.1.19&#xA0; </span>Micro-thickness and thickness</a><br>
&#xA0;&#xA0;<a href="#materialmodels/subsurfacemodel" class="level2"><span class="tocNumber">3.2&#xA0; </span>Subsurface model</a><br>
&#xA0;&#xA0;&#xA0;&#xA0;<a href="#materialmodels/subsurfacemodel/thickness" class="level3"><span class="tocNumber">3.2.1&#xA0; </span>Thickness</a><br>
&#xA0;&#xA0;&#xA0;&#xA0;<a href="#materialmodels/subsurfacemodel/subsurfacecolor" class="level3"><span class="tocNumber">3.2.2&#xA0; </span>Subsurface color</a><br>
@@ -232,10 +236,11 @@ in <a href="#table_standardproperties">table&#xA0;1</a>.
<tr><td style="text-align:right"> <strong class="asterisk">clearCoatNormal</strong> </td><td style="text-align:left"> A detail normal used to perturb the clear coat layer using <em class="underscore">bump mapping</em> (<em class="underscore">normal mapping</em>) </td></tr>
<tr><td style="text-align:right"> <strong class="asterisk">emissive</strong> </td><td style="text-align:left"> Additional diffuse albedo to simulate emissive surfaces (such as neons, etc.) This property is mostly useful in an HDR pipeline with a bloom pass </td></tr>
<tr><td style="text-align:right"> <strong class="asterisk">postLightingColor</strong> </td><td style="text-align:left"> Additional color that can be blended with the result of the lighting computations. See <code>postLightingBlending</code> </td></tr>
<tr><td style="text-align:right"> <strong class="asterisk">ior</strong> </td><td style="text-align:left"> Index of refraction for refractive objects </td></tr>
<tr><td style="text-align:right"> <strong class="asterisk">transmission</strong> </td><td style="text-align:left"> Defines how much of the diffuse light of a dielectric is transmitted through the object, in other words this defines how transparent an object is </td></tr>
<tr><td style="text-align:right"> <strong class="asterisk">absorption</strong> </td><td style="text-align:left"> Absorption factor for refractive objects </td></tr>
<tr><td style="text-align:right"> <strong class="asterisk">ior</strong> </td><td style="text-align:left"> Index of refraction for refractive objects </td></tr>
<tr><td style="text-align:right"> <strong class="asterisk">microThickness</strong> </td><td style="text-align:left"> Thickness of the thin layer of refractive objects </td></tr>
<tr><td style="text-align:right"> <strong class="asterisk">thickness</strong> </td><td style="text-align:left"> Thickness of the solid volume of refractive objects </td></tr>
</tbody></table><div class="tablecaption"><a class="target" name="table_standardproperties">&#xA0;</a><b style="font-style:normal;">Table&#xA0;1:</b> Properties of the standard model</div></div>
<p></p><p>
@@ -256,10 +261,11 @@ The type and range of each property is described in <a href="#table_standardprop
<tr><td style="text-align:right"> <strong class="asterisk">clearCoatNormal</strong> </td><td style="text-align:center"> float3 </td><td style="text-align:center"> [0..1] </td><td style="text-align:left"> Linear RGB, encodes a direction vector in tangent space </td></tr>
<tr><td style="text-align:right"> <strong class="asterisk">emissive</strong> </td><td style="text-align:center"> float4 </td><td style="text-align:center"> rgb=[0..1], a=[-n..n] </td><td style="text-align:left"> Alpha is the exposure compensation </td></tr>
<tr><td style="text-align:right"> <strong class="asterisk">postLightingColor</strong> </td><td style="text-align:center"> float4 </td><td style="text-align:center"> [0..1] </td><td style="text-align:left"> Pre-multiplied linear RGB </td></tr>
<tr><td style="text-align:right"> <strong class="asterisk">ior</strong> </td><td style="text-align:center"> float </td><td style="text-align:center"> [1..n] </td><td style="text-align:left"> Optional, usually deduced from the reflectance </td></tr>
<tr><td style="text-align:right"> <strong class="asterisk">transmission</strong> </td><td style="text-align:center"> float </td><td style="text-align:center"> [0..1] </td><td style="text-align:left"> &#xA0; </td></tr>
<tr><td style="text-align:right"> <strong class="asterisk">absorption</strong> </td><td style="text-align:center"> float3 </td><td style="text-align:center"> [0..n] </td><td style="text-align:left"> &#xA0; </td></tr>
<tr><td style="text-align:right"> <strong class="asterisk">ior</strong> </td><td style="text-align:center"> float </td><td style="text-align:center"> [1..n] </td><td style="text-align:left"> Optional, usually deduced from the reflectance </td></tr>
<tr><td style="text-align:right"> <strong class="asterisk">microThickness</strong> </td><td style="text-align:center"> float </td><td style="text-align:center"> [0..n] </td><td style="text-align:left"> &#xA0; </td></tr>
<tr><td style="text-align:right"> <strong class="asterisk">thickness</strong> </td><td style="text-align:center"> float </td><td style="text-align:center"> [0..n] </td><td style="text-align:left"> &#xA0; </td></tr>
</tbody></table><div class="tablecaption"><a class="target" name="table_standardpropertiestypes">&#xA0;</a><b style="font-style:normal;">Table&#xA0;2:</b> Range and type of the standard model&apos;s properties</div></div>
<p></p><p>
@@ -312,10 +318,10 @@ The type and range of each property is described in <a href="#table_standardprop
<code>thickness</code> represents the thickness of solid objects in the direction of the normal, for
satisfactory results, this should be provided per fragment (e.g.: as a texture) or at least per
vertex. <code>microThickness</code> represent the thickness of the thin layer of an object, and can
vertex. <code>microThickness</code> represent the thickness of the thin layer of an object, and can
generally be provided as a constant value. For example, a 1mm thin hollow sphere of radius 1m,
would have a <code>thickness</code> of 1 and a <code>microThickness</code> of 0.001. Currently <code>thickness</code> is not
used when <code>refractionType</code> is set to &#x201C;thin&#x201D;.</p></div>
used when <code>refractionType</code> is set to <code>thin</code>.</p></div>
<p></p>
<a class="target" name="basecolor">&#xA0;</a><a class="target" name="materialmodels/litmodel/basecolor">&#xA0;</a><a class="target" name="toc3.1.1">&#xA0;</a><h3>Base color</h3>
@@ -432,10 +438,10 @@ The effect of <code>roughness</code> on metallic surfaces is shown in <a href="#
The <code>reflectance</code> property only affects non-metallic surfaces. This property can be used to control
the specular intensity. This value is defined between 0 and 1 and represents a remapping of a
percentage of reflectance. For instance, the default value of 0.5 corresponds to a reflectance of
4%. Values below 0.35 (2% reflectance) should be avoided as no real-world materials have such
low reflectance.
the specular intensity and index of refraction of materials. This value is defined
between 0 and 1 and represents a remapping of a percentage of reflectance. For instance, the
default value of 0.5 corresponds to a reflectance of 4%. Values below 0.35 (2% reflectance) should
be avoided as no real-world materials have such low reflectance.
</p><p>
@@ -477,7 +483,25 @@ to 1.0 (right)</div></div></center>
<tr><td style="text-align:right"> Default value </td><td style="text-align:left"> 4% </td><td style="text-align:left"> 1.5 </td><td style="text-align:left"> 0.5 </td></tr>
</tbody></table><div class="tablecaption"><a class="target" name="table_commonmatreflectance">&#xA0;</a><b style="font-style:normal;">Table&#xA0;5:</b> Reflectance of common materials</div></div>
<p></p>
<p></p><p>
Note that the <code>reflectance</code> property also defines the index of refraction of the surface.
When this property is defined it is not necessary to define the <code>ior</code> property. Setting
either of these properties will automatically compute the other property. It is possible
to specify both, in which case their values are kept as-is, which can lead to physically
impossible materials, however, this might be desirable for artistic reasons.
</p><p>
The <code>reflectance</code> property is designed as a normalized property in the range 0..1 which makes
it easy to define from a texture.
</p><p>
See the <a href="#indexofrefraction">Index of refraction</a> section for more information about the <code>ior</code> property and refractive
indices.
</p>
<a class="target" name="clearcoat">&#xA0;</a><a class="target" name="materialmodels/litmodel/clearcoat">&#xA0;</a><a class="target" name="toc3.1.7">&#xA0;</a><h3>Clear coat</h3>
<p>
@@ -709,6 +733,115 @@ this option for more information.
<code>postLightingBlending</code> to <code>add</code> and by providing an RGB color with alpha set to <code>0.0</code>.</div>
<p></p>
<a class="target" name="indexofrefraction">&#xA0;</a><a class="target" name="materialmodels/litmodel/indexofrefraction">&#xA0;</a><a class="target" name="toc3.1.16">&#xA0;</a><h3>Index of refraction</h3>
<p>
The <code>ior</code> property only affects non-metallic surfaces. This property can be used to control the
index of refraction and the specular intensity of materials. The <code>ior</code> property is intended to
be used with refractive (transmissive) materials, which are enabled when the <code>refractionMode</code> is
set to <code>cubemap</code> or <code>screenspace</code>.
</p><p>
The index of refraction (or refractive index) of a material is a dimensionless number that describes
how fast light travels through that material. The higher the number, the slower light travels
through the medium. More importantly for rendering materials, the refractive index determines how
the path light travels is bent when entering the material. Higher indices of refraction will cause
light to bend further away from the initial path.
</p><p>
<a href="#table_commonmatior">Table&#xA0;6</a> describes acceptable refractive indices for various types of materials.
</p><div class="table">
<table class="table"><tbody><tr><th style="text-align:right"> Material </th><th style="text-align:left"> IOR </th></tr>
<tr><td style="text-align:right"> Air </td><td style="text-align:left"> 1.0 </td></tr>
<tr><td style="text-align:right"> Water </td><td style="text-align:left"> 1.33 </td></tr>
<tr><td style="text-align:right"> Common liquids </td><td style="text-align:left"> 1.33 to 1.5 </td></tr>
<tr><td style="text-align:right"> Common gemstones </td><td style="text-align:left"> 1.58 to 2.33 </td></tr>
<tr><td style="text-align:right"> Plastics, glass </td><td style="text-align:left"> 1.5 to 1.58 </td></tr>
<tr><td style="text-align:right"> Other dielectric materials </td><td style="text-align:left"> 1.33 to 1.58 </td></tr>
</tbody></table><div class="tablecaption"><a class="target" name="table_commonmatior">&#xA0;</a><b style="font-style:normal;">Table&#xA0;6:</b> Index of refraction of common materials</div></div>
<p></p><p>
The appearance of a refractive material will greatly depend on the <code>refractionType</code> and
<code>refractionMode</code> settings of the material. Refer to the <a href="#blendingandtransparency:refractiontype">Blending and transparency: refractionType</a> section and the <a href="#blendingandtransparency:refractionmode">Blending and transparency: refractionMode</a> section for more information.
</p><p>
The effect of <code>ior</code> when <code>refractionMode</code> is set to <code>cubemap</code> and <code>refractionType</code> is set to <code>solid</code>
can be seen in <a href="#figure_iorproperty2">figure&#xA0;17</a> (click on the image to see a larger version).
</p><p>
</p><center><div class="image" style><a href="images/materials/ior.png" target="_blank"><img class="markdeep" src="images/materials/ior.png"></a><div class="imagecaption"><a class="target" name="figure_iorproperty2">&#xA0;</a><b style="font-style:normal;">Figure&#xA0;17:</b> <code>transmission</code> varying from 1.0
(left) to 1.5 (right)</div></div></center>
<p></p><p>
<a href="#figure_iorproperty">Figure&#xA0;18</a> shows the comparison of a sphere of <code>ior</code> 1.0 with a sphere of <code>ior</code> 1.33, with
the <code>refractionMode</code> set to <code>screenspace</code> and the <code>refractionType</code> set to <code>solid</code>
(click on the image to see a larger version).
</p><p>
</p><center><div class="image" style><a href="images/material_ior.png" target="_blank"><img class="markdeep" src="images/material_ior.png"></a><div class="imagecaption"><a class="target" name="figure_iorproperty">&#xA0;</a><b style="font-style:normal;">Figure&#xA0;18:</b> <code>ior</code> of 1.0 (left) and 1.33 (right)</div></div></center>
<p></p><p>
Note that the <code>ior</code> property also defines the reflectance (or specular intensity) of the surface.
When this property is defined it is not necessary to define the <code>reflectance</code> property. Setting
either of these properties will automatically compute the other property. It is possible to specify
both, in which case their values are kept as-is, which can lead to physically impossible materials,
however, this might be desirable for artistic reasons.
</p><p>
See the <a href="#reflectance">Reflectance</a> section for more information on the <code>reflectance</code> property.
</p><p>
</p><div class="admonition tip">Refractive materials are affected by the <code>roughness</code> property. Rough materials will scatter
light, creating a diffusion effect useful to recreate &#x201C;blurry&#x201D; appearances such as frosted
glass, certain plastics, etc.</div>
<p></p>
<a class="target" name="transmission">&#xA0;</a><a class="target" name="materialmodels/litmodel/transmission">&#xA0;</a><a class="target" name="toc3.1.17">&#xA0;</a><h3>Transmission</h3>
<p>
The <code>transmission</code> property defines what ratio of diffuse light is transmitted through a refractive
material. This property only affects materials with a <code>refractionMode</code> set to <code>cubemap</code> or
<code>screenspace</code>.
</p><p>
When <code>transmission</code> is set to 0, no amount of light is transmitted and the diffuse component of
the surface is 100% visible. When <code>transmission</code> is set to 1, all the light is transmitted and the
diffuse component is not visible anymore, only the specular component is.
</p><p>
The effect of <code>transmission</code> on a glossy dielectric (<code>ior</code> of 1.5, <code>refractionMode</code> set to
<code>cubemap</code>, <code>refractionType</code> set to <code>solid</code>) is shown in <a href="#figure_transmissionproperty">figure&#xA0;19</a>
(click on the image to see a larger version).
</p><p>
</p><center><div class="image" style><a href="images/materials/transmission.png" target="_blank"><img class="markdeep" src="images/materials/transmission.png"></a><div class="imagecaption"><a class="target" name="figure_transmissionproperty">&#xA0;</a><b style="font-style:normal;">Figure&#xA0;19:</b> <code>transmission</code> varying from 0.0
(left) to 1.0 (right)</div></div></center>
<p></p><p>
</p><div class="admonition tip">The <code>transmission</code> property is useful to create decals, paint, etc. at the surface of refractive
materials.</div>
<p></p>
<a class="target" name="absorption">&#xA0;</a><a class="target" name="materialmodels/litmodel/absorption">&#xA0;</a><a class="target" name="toc3.1.18">&#xA0;</a><h3>Absorption</h3>
<a class="target" name="micro-thicknessandthickness">&#xA0;</a><a class="target" name="materialmodels/litmodel/micro-thicknessandthickness">&#xA0;</a><a class="target" name="toc3.1.19">&#xA0;</a><h3>Micro-thickness and thickness</h3>
<a class="target" name="subsurfacemodel">&#xA0;</a><a class="target" name="materialmodels/subsurfacemodel">&#xA0;</a><a class="target" name="toc3.2">&#xA0;</a><h2>Subsurface model</h2>
<a class="target" name="thickness">&#xA0;</a><a class="target" name="materialmodels/subsurfacemodel/thickness">&#xA0;</a><a class="target" name="toc3.2.1">&#xA0;</a><h3>Thickness</h3>
@@ -730,19 +863,19 @@ forward/backward scattering. Some fabrics also exhibit two-tone specular colors
</p><p>
<a href="#figure_materialcloth">Figure&#xA0;17</a> shows how the standard material model fails to capture the appearance of a
<a href="#figure_materialcloth">Figure&#xA0;20</a> shows how the standard material model fails to capture the appearance of a
sample of denim fabric. The surface appears rigid (almost plastic-like), more similar to a tarp
than a piece of clothing. This figure also shows how important the softer specular lobe caused by
absorption and scattering is to the faithful recreation of the fabric.
</p><p>
</p><center><div class="image" style><a href="images/screenshot_cloth.png" target="_blank"><img class="markdeep" src="images/screenshot_cloth.png"></a><div class="imagecaption"><a class="target" name="figure_materialcloth">&#xA0;</a><b style="font-style:normal;">Figure&#xA0;17:</b> Comparison of denim fabric rendered using the standard model
</p><center><div class="image" style><a href="images/screenshot_cloth.png" target="_blank"><img class="markdeep" src="images/screenshot_cloth.png"></a><div class="imagecaption"><a class="target" name="figure_materialcloth">&#xA0;</a><b style="font-style:normal;">Figure&#xA0;20:</b> Comparison of denim fabric rendered using the standard model
(left) and the cloth model (right)</div></div></center>
<p></p><p>
Velvet is an interesting use case for a cloth material model. As shown in <a href="#figure_materialvelvet">figure&#xA0;18</a>
Velvet is an interesting use case for a cloth material model. As shown in <a href="#figure_materialvelvet">figure&#xA0;21</a>
this type of fabric exhibits strong rim lighting due to forward and backward scattering. These
scattering events are caused by fibers standing straight at the surface of the fabric. When the
incident light comes from the direction opposite to the view direction, the fibers will forward
@@ -751,7 +884,7 @@ direction, the fibers will scatter the light backward.
</p><p>
</p><center><div class="image" style><a href="images/screenshot_cloth_velvet.png" target="_blank"><img class="markdeep" src="images/screenshot_cloth_velvet.png"></a><div class="imagecaption"><a class="target" name="figure_materialvelvet">&#xA0;</a><b style="font-style:normal;">Figure&#xA0;18:</b> Velvet fabric showcasing forward and
</p><center><div class="image" style><a href="images/screenshot_cloth_velvet.png" target="_blank"><img class="markdeep" src="images/screenshot_cloth_velvet.png"></a><div class="imagecaption"><a class="target" name="figure_materialvelvet">&#xA0;</a><b style="font-style:normal;">Figure&#xA0;21:</b> Velvet fabric showcasing forward and
backward scattering</div></div></center>
<p></p><p>
@@ -764,7 +897,7 @@ anisotropic material models.
The cloth material model encompasses all the parameters previously defined for the standard
material mode except for <em class="underscore">metallic</em> and <em class="underscore">reflectance</em>. Two extra parameters described in
<a href="#table_clothproperties">table&#xA0;6</a> are also available.
<a href="#table_clothproperties">table&#xA0;7</a> are also available.
</p><p>
@@ -772,16 +905,16 @@ material mode except for <em class="underscore">metallic</em> and <em class="und
<table class="table"><tbody><tr><th style="text-align:right"> Parameter </th><th style="text-align:left"> Definition </th></tr>
<tr><td style="text-align:right"> <strong class="asterisk">sheenColor</strong> </td><td style="text-align:left"> Specular tint to create two-tone specular fabrics (defaults to \(\sqrt{baseColor}\)) </td></tr>
<tr><td style="text-align:right"> <strong class="asterisk">subsurfaceColor</strong> </td><td style="text-align:left"> Tint for the diffuse color after scattering and absorption through the material </td></tr>
</tbody></table><div class="tablecaption"><a class="target" name="table_clothproperties">&#xA0;</a><b style="font-style:normal;">Table&#xA0;6:</b> Cloth model parameters</div></div>
</tbody></table><div class="tablecaption"><a class="target" name="table_clothproperties">&#xA0;</a><b style="font-style:normal;">Table&#xA0;7:</b> Cloth model parameters</div></div>
<p></p><p>
The type and range of each property is described in <a href="#table_clothpropertiestypes">table&#xA0;7</a>.
The type and range of each property is described in <a href="#table_clothpropertiestypes">table&#xA0;8</a>.
</p><div class="table">
<table class="table"><tbody><tr><th style="text-align:right"> Property </th><th style="text-align:center"> Type </th><th style="text-align:center"> Range </th><th style="text-align:left"> Note </th></tr>
<tr><td style="text-align:right"> <strong class="asterisk">sheenColor</strong> </td><td style="text-align:center"> float3 </td><td style="text-align:center"> [0..1] </td><td style="text-align:left"> Linear RGB </td></tr>
<tr><td style="text-align:right"> <strong class="asterisk">subsurfaceColor</strong> </td><td style="text-align:center"> float3 </td><td style="text-align:center"> [0..1] </td><td style="text-align:left"> Linear RGB </td></tr>
</tbody></table><div class="tablecaption"><a class="target" name="table_clothpropertiestypes">&#xA0;</a><b style="font-style:normal;">Table&#xA0;7:</b> Range and type of the cloth model&apos;s properties</div></div>
</tbody></table><div class="tablecaption"><a class="target" name="table_clothpropertiestypes">&#xA0;</a><b style="font-style:normal;">Table&#xA0;8:</b> Range and type of the cloth model&apos;s properties</div></div>
<p></p><p>
@@ -813,12 +946,12 @@ two-tone specular materials.
</p><p>
The effect of <code>sheenColor</code> is shown in <a href="#figure_materialclothsheen">figure&#xA0;19</a>
The effect of <code>sheenColor</code> is shown in <a href="#figure_materialclothsheen">figure&#xA0;22</a>
(click on the image to see a larger version).
</p><p>
</p><center><div class="image" style><a href="images/screenshot_cloth_sheen.png" target="_blank"><img class="markdeep" src="images/screenshot_cloth_sheen.png"></a><div class="imagecaption"><a class="target" name="figure_materialclothsheen">&#xA0;</a><b style="font-style:normal;">Figure&#xA0;19:</b> Blue fabric without (left) and with (right) sheen</div></div></center>
</p><center><div class="image" style><a href="images/screenshot_cloth_sheen.png" target="_blank"><img class="markdeep" src="images/screenshot_cloth_sheen.png"></a><div class="imagecaption"><a class="target" name="figure_materialclothsheen">&#xA0;</a><b style="font-style:normal;">Figure&#xA0;22:</b> Blue fabric without (left) and with (right) sheen</div></div></center>
<p></p>
<a class="target" name="subsurfacecolor">&#xA0;</a><a class="target" name="materialmodels/clothmodel/subsurfacecolor">&#xA0;</a><a class="target" name="toc3.3.2">&#xA0;</a><h3>Subsurface color</h3>
@@ -835,12 +968,12 @@ useful to create softer fabrics.
<p></p><p>
The effect of <code>subsurfaceColor</code> is shown in <a href="#figure_materialclothsubsurface">figure&#xA0;20</a>
The effect of <code>subsurfaceColor</code> is shown in <a href="#figure_materialclothsubsurface">figure&#xA0;23</a>
(click on the image to see a larger version).
</p><p>
</p><center><div class="image" style><a href="images/screenshot_cloth_subsurface.png" target="_blank"><img class="markdeep" src="images/screenshot_cloth_subsurface.png"></a><div class="imagecaption"><a class="target" name="figure_materialclothsubsurface">&#xA0;</a><b style="font-style:normal;">Figure&#xA0;20:</b> White cloth (left column) vs white cloth with
</p><center><div class="image" style><a href="images/screenshot_cloth_subsurface.png" target="_blank"><img class="markdeep" src="images/screenshot_cloth_subsurface.png"></a><div class="imagecaption"><a class="target" name="figure_materialclothsubsurface">&#xA0;</a><b style="font-style:normal;">Figure&#xA0;23:</b> White cloth (left column) vs white cloth with
brown subsurface scatting (right)</div></div></center>
<p></p>
@@ -851,23 +984,23 @@ brown subsurface scatting (right)</div></div></center>
The unlit material model can be used to turn off all lighting computations. Its primary purpose is
to render pre-lit elements such as a cubemap, external content (such as a video or camera stream),
user interfaces, visualization/debugging etc. The unlit model exposes only two properties described
in <a href="#table_unlitproperties">table&#xA0;8</a>.
in <a href="#table_unlitproperties">table&#xA0;9</a>.
</p><div class="table">
<table class="table"><tbody><tr><th style="text-align:right"> Property </th><th style="text-align:left"> Definition </th></tr>
<tr><td style="text-align:right"> <strong class="asterisk">baseColor</strong> </td><td style="text-align:left"> Surface diffuse color </td></tr>
<tr><td style="text-align:right"> <strong class="asterisk">emissive</strong> </td><td style="text-align:left"> Additional diffuse color to simulate emissive surfaces. This property is mostly useful in an HDR pipeline with a bloom pass </td></tr>
<tr><td style="text-align:right"> <strong class="asterisk">postLightingColor</strong> </td><td style="text-align:left"> Additional color to blend with base color and emissive </td></tr>
</tbody></table><div class="tablecaption"><a class="target" name="table_unlitproperties">&#xA0;</a><b style="font-style:normal;">Table&#xA0;8:</b> Properties of the standard model</div></div>
</tbody></table><div class="tablecaption"><a class="target" name="table_unlitproperties">&#xA0;</a><b style="font-style:normal;">Table&#xA0;9:</b> Properties of the standard model</div></div>
<p></p><p>
The type and range of each property is described in <a href="#table_unlitpropertiestypes">table&#xA0;9</a>.
The type and range of each property is described in <a href="#table_unlitpropertiestypes">table&#xA0;10</a>.
</p><div class="table">
<table class="table"><tbody><tr><th style="text-align:right"> Property </th><th style="text-align:center"> Type </th><th style="text-align:center"> Range </th><th style="text-align:left"> Note </th></tr>
<tr><td style="text-align:right"> <strong class="asterisk">baseColor</strong> </td><td style="text-align:center"> float4 </td><td style="text-align:center"> [0..1] </td><td style="text-align:left"> Pre-multiplied linear RGB </td></tr>
<tr><td style="text-align:right"> <strong class="asterisk">emissive</strong> </td><td style="text-align:center"> float4 </td><td style="text-align:center"> rgb=[0..1], a=N/A </td><td style="text-align:left"> Pre-multiplied linear RGB, alpha is ignored </td></tr>
<tr><td style="text-align:right"> <strong class="asterisk">postLightingColor</strong> </td><td style="text-align:center"> float4 </td><td style="text-align:center"> [0..1] </td><td style="text-align:left"> Pre-multiplied linear RGB </td></tr>
</tbody></table><div class="tablecaption"><a class="target" name="table_unlitpropertiestypes">&#xA0;</a><b style="font-style:normal;">Table&#xA0;9:</b> Range and type of the unlit model&apos;s properties</div></div>
</tbody></table><div class="tablecaption"><a class="target" name="table_unlitpropertiestypes">&#xA0;</a><b style="font-style:normal;">Table&#xA0;10:</b> Range and type of the unlit model&apos;s properties</div></div>
<p></p><p>
@@ -878,12 +1011,12 @@ blending mode specified by the <code>postLightingBlending</code> material option
</p><p>
<a href="#figure_materialunlit">Figure&#xA0;21</a> shows an example of the unlit material model
<a href="#figure_materialunlit">Figure&#xA0;24</a> shows an example of the unlit material model
(click on the image to see a larger version).
</p><p>
</p><center><div class="image" style><a href="images/screenshot_unlit.jpg" target="_blank"><img class="markdeep" src="images/screenshot_unlit.jpg"></a><div class="imagecaption"><a class="target" name="figure_materialunlit">&#xA0;</a><b style="font-style:normal;">Figure&#xA0;21:</b> The unlit model is used to render debug information</div></div></center>
</p><center><div class="image" style><a href="images/screenshot_unlit.jpg" target="_blank"><img class="markdeep" src="images/screenshot_unlit.jpg"></a><div class="imagecaption"><a class="target" name="figure_materialunlit">&#xA0;</a><b style="font-style:normal;">Figure&#xA0;24:</b> The unlit model is used to render debug information</div></div></center>
<p></p>
<a class="target" name="specularglossiness">&#xA0;</a><a class="target" name="materialmodels/specularglossiness">&#xA0;</a><a class="target" name="toc3.5">&#xA0;</a><h2>Specular glossiness</h2>
@@ -902,17 +1035,17 @@ This model encompasses the parameters previously defined for the standard lit mo
<tr><td style="text-align:right"> <strong class="asterisk">baseColor</strong> </td><td style="text-align:left"> Surface diffuse color </td></tr>
<tr><td style="text-align:right"> <strong class="asterisk">specularColor</strong> </td><td style="text-align:left"> Specular tint (defaults to black) </td></tr>
<tr><td style="text-align:right"> <strong class="asterisk">glossiness</strong> </td><td style="text-align:left"> Glossiness (defaults to 0.0) </td></tr>
</tbody></table><div class="tablecaption"><a class="target" name="table_glossinessproperties">&#xA0;</a><b style="font-style:normal;">Table&#xA0;10:</b> Properties of the specular-glossiness shading model</div></div>
</tbody></table><div class="tablecaption"><a class="target" name="table_glossinessproperties">&#xA0;</a><b style="font-style:normal;">Table&#xA0;11:</b> Properties of the specular-glossiness shading model</div></div>
<p></p><p>
The type and range of each property is described in <a href="#table_glossinesspropertiestypes">table&#xA0;11</a>.
The type and range of each property is described in <a href="#table_glossinesspropertiestypes">table&#xA0;12</a>.
</p><div class="table">
<table class="table"><tbody><tr><th style="text-align:right"> Property </th><th style="text-align:center"> Type </th><th style="text-align:center"> Range </th><th style="text-align:left"> Note </th></tr>
<tr><td style="text-align:right"> <strong class="asterisk">baseColor</strong> </td><td style="text-align:center"> float4 </td><td style="text-align:center"> [0..1] </td><td style="text-align:left"> Pre-multiplied linear RGB </td></tr>
<tr><td style="text-align:right"> <strong class="asterisk">specularColor</strong> </td><td style="text-align:center"> float3 </td><td style="text-align:center"> [0..1] </td><td style="text-align:left"> Linear RGB </td></tr>
<tr><td style="text-align:right"> <strong class="asterisk">glossiness</strong> </td><td style="text-align:center"> float </td><td style="text-align:center"> [0..1] </td><td style="text-align:left"> Inverse of roughness </td></tr>
</tbody></table><div class="tablecaption"><a class="target" name="table_glossinesspropertiestypes">&#xA0;</a><b style="font-style:normal;">Table&#xA0;11:</b> Range and type of the specular-glossiness model&apos;s properties</div></div>
</tbody></table><div class="tablecaption"><a class="target" name="table_glossinesspropertiestypes">&#xA0;</a><b style="font-style:normal;">Table&#xA0;12:</b> Range and type of the specular-glossiness model&apos;s properties</div></div>
<p></p>
<a class="target" name="materialdefinitions">&#xA0;</a><a class="target" name="materialdefinitions">&#xA0;</a><a class="target" name="toc4">&#xA0;</a><h1>Material definitions</h1>
@@ -1086,7 +1219,7 @@ non-shader data.
</p></dd><dt>Value</dt><dd><p> Each entry is an object with the properties <code>name</code> and <code>type</code>, both of <code>string</code> type. The
name must be a valid GLSL identifier. The type must be one of the types described in
<a href="#table_materialparamstypes">table&#xA0;12</a>.
<a href="#table_materialparamstypes">table&#xA0;13</a>.
</p></dd></dl><div class="table">
<table class="table"><tbody><tr><th style="text-align:left"> Type </th><th style="text-align:left"> Description </th></tr>
@@ -1111,7 +1244,7 @@ non-shader data.
<tr><td style="text-align:left"> sampler2d </td><td style="text-align:left"> 2D texture </td></tr>
<tr><td style="text-align:left"> samplerExternal </td><td style="text-align:left"> External texture (platform-specific) </td></tr>
<tr><td style="text-align:left"> samplerCubemap </td><td style="text-align:left"> Cubemap texture </td></tr>
</tbody></table><div class="tablecaption"><a class="target" name="table_materialparamstypes">&#xA0;</a><b style="font-style:normal;">Table&#xA0;12:</b> Material parameter types</div></div>
</tbody></table><div class="tablecaption"><a class="target" name="table_materialparamstypes">&#xA0;</a><b style="font-style:normal;">Table&#xA0;13:</b> Material parameter types</div></div>
<p></p><p>
@@ -1431,33 +1564,33 @@ non-shader data.
<p></p><p>
</p><ul>
<li class="minus"><code>default</code>: the transparent object is rendered normally (as seen in <a href="#figure_transparencydefault">figure&#xA0;22</a>),
<li class="minus"><code>default</code>: the transparent object is rendered normally (as seen in <a href="#figure_transparencydefault">figure&#xA0;25</a>),
honoring the <code>culling</code> mode, etc.
</li>
<li class="minus"><code>twoPassesOneSide</code>: the transparent object is first rendered in the depth buffer, then again in
the color buffer, honoring the <code>cullling</code> mode. This effectively renders only half of the
transparent object as shown in <a href="#figure_transparencytwopassesoneside">figure&#xA0;23</a>.
transparent object as shown in <a href="#figure_transparencytwopassesoneside">figure&#xA0;26</a>.
</li>
<li class="minus"><code>twoPassesTwoSides</code>: the transparent object is rendered twice in the color buffer: first with its
back faces, then with its front faces. This mode lets you render both set of faces while reducing
or eliminating sorting issues, as shown in <a href="#figure_transparencytwopassestwosides">figure&#xA0;24</a>.
or eliminating sorting issues, as shown in <a href="#figure_transparencytwopassestwosides">figure&#xA0;27</a>.
<code>twoPassesTwoSides</code> can be combined with <code>doubleSided</code> for better effect.</li></ul>
<p></p><pre class="listing tilde"><code><span class="line">material {</span>
<span class="line"> transparency : twoPassesOneSide</span>
<span class="line">}</span></code></pre><p>
</p><center><div class="image" style><a href="images/screenshot_transparency_default.png" target="_blank"><img class="markdeep" src="images/screenshot_transparency_default.png"></a><div class="imagecaption"><a class="target" name="figure_transparencydefault">&#xA0;</a><b style="font-style:normal;">Figure&#xA0;22:</b> This double sided model shows the type of sorting issues transparent
</p><center><div class="image" style><a href="images/screenshot_transparency_default.png" target="_blank"><img class="markdeep" src="images/screenshot_transparency_default.png"></a><div class="imagecaption"><a class="target" name="figure_transparencydefault">&#xA0;</a><b style="font-style:normal;">Figure&#xA0;25:</b> This double sided model shows the type of sorting issues transparent
objects can be subject to in <code>default</code> mode</div></div></center>
<p></p><p>
</p><center><div class="image" style><a href="images/screenshot_twopasses_oneside.png" target="_blank"><img class="markdeep" src="images/screenshot_twopasses_oneside.png"></a><div class="imagecaption"><a class="target" name="figure_transparencytwopassesoneside">&#xA0;</a><b style="font-style:normal;">Figure&#xA0;23:</b> In <code>twoPassesOneSide</code> mode, only one set of faces is visible
</p><center><div class="image" style><a href="images/screenshot_twopasses_oneside.png" target="_blank"><img class="markdeep" src="images/screenshot_twopasses_oneside.png"></a><div class="imagecaption"><a class="target" name="figure_transparencytwopassesoneside">&#xA0;</a><b style="font-style:normal;">Figure&#xA0;26:</b> In <code>twoPassesOneSide</code> mode, only one set of faces is visible
and correctly sorted</div></div></center>
<p></p><p>
</p><center><div class="image" style><a href="images/screenshot_twopasses_twosides.png" target="_blank"><img class="markdeep" src="images/screenshot_twopasses_twosides.png"></a><div class="imagecaption"><a class="target" name="figure_transparencytwopassestwosides">&#xA0;</a><b style="font-style:normal;">Figure&#xA0;24:</b> In <code>twoPassesTwoSides</code> mode, both set of faces are visible
</p><center><div class="image" style><a href="images/screenshot_twopasses_twosides.png" target="_blank"><img class="markdeep" src="images/screenshot_twopasses_twosides.png"></a><div class="imagecaption"><a class="target" name="figure_transparencytwopassestwosides">&#xA0;</a><b style="font-style:normal;">Figure&#xA0;27:</b> In <code>twoPassesTwoSides</code> mode, both set of faces are visible
and sorting issues are minimized or eliminated</div></div></center>
<p></p>
@@ -1623,14 +1756,14 @@ and sorting issues are minimized or eliminated</div></div></center>
</p></dd><dt>Description</dt><dd><p> When adding a clear coat layer, the change in index of refraction (IoR) is taken into account
to modify the specular color of the base layer. This appears to darken <code>baseColor</code>. When this
effect is disabled, <code>baseColor</code> is left unmodified. See <a href="#figure_clearcoatiorchange">figure&#xA0;25</a> for an
effect is disabled, <code>baseColor</code> is left unmodified. See <a href="#figure_clearcoatiorchange">figure&#xA0;28</a> for an
example of how this property can affect a red metallic base layer.
</p></dd></dl><p></p><pre class="listing tilde"><code><span class="line">material {</span>
<span class="line"> clearCoatIorChange : false</span>
<span class="line">}</span></code></pre><p>
</p><center><div class="image" style><a href="images/screenshot_clear_coat_ior_change.jpg" target="_blank"><img class="markdeep" src="images/screenshot_clear_coat_ior_change.jpg"></a><div class="imagecaption"><a class="target" name="figure_clearcoatiorchange">&#xA0;</a><b style="font-style:normal;">Figure&#xA0;25:</b> The same rough metallic ball with a clear coat layer rendered
</p><center><div class="image" style><a href="images/screenshot_clear_coat_ior_change.jpg" target="_blank"><img class="markdeep" src="images/screenshot_clear_coat_ior_change.jpg"></a><div class="imagecaption"><a class="target" name="figure_clearcoatiorchange">&#xA0;</a><b style="font-style:normal;">Figure&#xA0;28:</b> The same rough metallic ball with a clear coat layer rendered
with <code>clearCoatIorChange</code> enabled (left) and disabled
(right).</div></div></center>
@@ -1646,21 +1779,21 @@ with <code>clearCoatIorChange</code> enabled (left) and disabled
</p></dd><dt>Description</dt><dd><p> Multi-bounce ambient occlusion takes into account interreflections when applying ambient
occlusion to image-based lighting. Turning this feature on avoids over-darkening occluded
areas. It also takes the surface color into account to generate colored ambient occlusion.
<a href="#figure_multibounceao">Figure&#xA0;26</a> compares the ambient occlusion term of a surface with and without
<a href="#figure_multibounceao">Figure&#xA0;29</a> compares the ambient occlusion term of a surface with and without
multi-bounce ambient occlusion. Notice how multi-bounce ambient occlusion introduces color
in the occluded areas. <a href="#figure_multibounceaoanimated">Figure&#xA0;27</a> toggles between multi-bounce ambient
in the occluded areas. <a href="#figure_multibounceaoanimated">Figure&#xA0;30</a> toggles between multi-bounce ambient
occlusion on and off on a lit brick material to highlight the effects of this property.
</p></dd></dl><p></p><pre class="listing tilde"><code><span class="line">material {</span>
<span class="line"> multiBounceAmbientOcclusion : true</span>
<span class="line">}</span></code></pre><p>
</p><center><div class="image" style><a href="images/screenshot_multi_bounce_ao.jpg" target="_blank"><img class="markdeep" src="images/screenshot_multi_bounce_ao.jpg"></a><div class="imagecaption"><a class="target" name="figure_multibounceao">&#xA0;</a><b style="font-style:normal;">Figure&#xA0;26:</b> Brick texture amient occlusion map rendered with multi-bounce ambient
</p><center><div class="image" style><a href="images/screenshot_multi_bounce_ao.jpg" target="_blank"><img class="markdeep" src="images/screenshot_multi_bounce_ao.jpg"></a><div class="imagecaption"><a class="target" name="figure_multibounceao">&#xA0;</a><b style="font-style:normal;">Figure&#xA0;29:</b> Brick texture amient occlusion map rendered with multi-bounce ambient
occclusion enabled (left) and disabled (right).</div></div></center>
<p></p><p>
</p><center><div class="image" style><a href="images/screenshot_multi_bounce_ao.gif" target="_blank"><img class="markdeep" src="images/screenshot_multi_bounce_ao.gif"></a><div class="imagecaption"><a class="target" name="figure_multibounceaoanimated">&#xA0;</a><b style="font-style:normal;">Figure&#xA0;27:</b> Brick texture rendered with multi-bounce ambient
</p><center><div class="image" style><a href="images/screenshot_multi_bounce_ao.gif" target="_blank"><img class="markdeep" src="images/screenshot_multi_bounce_ao.gif"></a><div class="imagecaption"><a class="target" name="figure_multibounceaoanimated">&#xA0;</a><b style="font-style:normal;">Figure&#xA0;30:</b> Brick texture rendered with multi-bounce ambient
occclusion enabled and disabled.</div></div></center>
<p></p>
@@ -1675,13 +1808,13 @@ occclusion enabled and disabled.</div></div></center>
</p></dd><dt>Description</dt><dd><p> Static ambient occlusion maps and dynamic ambient occlusion (SSAO, etc.) apply to diffuse
indirect lighting. When setting this property to true, a new ambient occlusion term is
derived from the surface roughness and applied to specular indirec lighting. This effect
helps remove unwanted specular reflections as shown in <a href="#figure_specularao">figure&#xA0;28</a>.
helps remove unwanted specular reflections as shown in <a href="#figure_specularao">figure&#xA0;31</a>.
</p></dd></dl><p></p><pre class="listing tilde"><code><span class="line">material {</span>
<span class="line"> specularAmbientOcclusion : true</span>
<span class="line">}</span></code></pre><p>
</p><center><div class="image" style><a href="images/screenshot_specular_ao.gif" target="_blank"><img class="markdeep" src="images/screenshot_specular_ao.gif"></a><div class="imagecaption"><a class="target" name="figure_specularao">&#xA0;</a><b style="font-style:normal;">Figure&#xA0;28:</b> Comparison of specular ambient occlusion on and off. The effect is
</p><center><div class="image" style><a href="images/screenshot_specular_ao.gif" target="_blank"><img class="markdeep" src="images/screenshot_specular_ao.gif"></a><div class="imagecaption"><a class="target" name="figure_specularao">&#xA0;</a><b style="font-style:normal;">Figure&#xA0;31:</b> Comparison of specular ambient occlusion on and off. The effect is
particularly visible under the hose.</div></div></center>
<p></p>
@@ -2083,7 +2216,7 @@ source material definition file.
<p>
The command line flags relevant to application development are described in <a href="#table_matcflags">table&#xA0;13</a>.
The command line flags relevant to application development are described in <a href="#table_matcflags">table&#xA0;14</a>.
</p><div class="table">
<table class="table"><tbody><tr><th style="text-align:right"> Flag </th><th style="text-align:center"> Value </th><th style="text-align:left"> Usage </th></tr>
<tr><td style="text-align:right"> <strong class="asterisk">-o</strong>, <strong class="asterisk">&#x2014;output</strong> </td><td style="text-align:center"> [path] </td><td style="text-align:left"> Specify the output file path </td></tr>
@@ -2092,7 +2225,7 @@ The command line flags relevant to application development are described in <a h
<tr><td style="text-align:right"> <strong class="asterisk">-S</strong>, <strong class="asterisk">&#x2014;optimize-size</strong> </td><td style="text-align:center"> N/A </td><td style="text-align:left"> Optimize compiled material for size instead of just performance </td></tr>
<tr><td style="text-align:right"> <strong class="asterisk">-r</strong>, <strong class="asterisk">&#x2014;reflect</strong> </td><td style="text-align:center"> parameters </td><td style="text-align:left"> Outputs the specified metadata as JSON </td></tr>
<tr><td style="text-align:right"> <strong class="asterisk">-v</strong>, <strong class="asterisk">&#x2014;variant-filter</strong> </td><td style="text-align:center"> [variant] </td><td style="text-align:left"> Filters out the specified, comma-separated variants </td></tr>
</tbody></table><div class="tablecaption"><a class="target" name="table_matcflags">&#xA0;</a><b style="font-style:normal;">Table&#xA0;13:</b> List of <code>matc</code> flags</div></div>
</tbody></table><div class="tablecaption"><a class="target" name="table_matcflags">&#xA0;</a><b style="font-style:normal;">Table&#xA0;14:</b> List of <code>matc</code> flags</div></div>
<p></p><p>