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gamedev:textureproperties:reflectivity

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gamedev:textureproperties:reflectivity [2013/01/03 19:28] – [Examples] dragonlordgamedev:textureproperties:reflectivity [2019/05/24 23:43] (current) – ↷ Links adapted because of a move operation dragonlord
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 +{{tag>graphic skin texture reflection}}
 <WRAP youarehere> <WRAP youarehere>
-[[:start|Start Page]] >> [[gamedev:main|Game Development with the Drag[en]gine]] >> [[gamedev:skinproperties|Skin Texture Properties]] >> [[gamedev:texturepropertylist|Texture Property Database]] >> **reflectivity**+[[:start|Start Page]] >> [[:gamedev|Game Development with the Drag[en]gine]] >> [[gamedev:skinproperties|Skin Texture Properties]] >> [[gamedev:texturepropertylist|Texture Property Database]] >> **reflectivity**
 </WRAP> </WRAP>
  
-<WRAP boxheader> +====== Skin Texture Property: reflectivity ====== 
-====== Summary ====== + 
-</WRAP> +Defines the per-color reflectivity/reflectance. 
-<WRAP boxcontent> +
-|Texture Property Name|reflectivity| +
-|Description|Defines the per-color reflectivity/reflectance|+
 |Excepted Data Source|3 component image| |Excepted Data Source|3 component image|
 |Data Range|0 to 1 for all image components| |Data Range|0 to 1 for all image components|
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 |Affected Modules|Graphic| |Affected Modules|Graphic|
 |Linked Properties|[[gamedev:textureproperties:reflectivity_gamma|reflectivity.gamma]]| |Linked Properties|[[gamedev:textureproperties:reflectivity_gamma|reflectivity.gamma]]|
-</WRAP> 
  
 ====== Description ====== ====== Description ======
 +
 The **reflectivity** texture property defines the per-color reflectivity or reflectance of a material at a **zero viewing angle**. This is more than the simple **specular reflectivity** parameter typically found in other game engines since the Drag[en]gine adepts a **[[gamedev:pbr|physically based rendering]]** approach. The zero angle reflectivity is often specified as the **F0 reflectance**. This is the value required to be used for this texture property. Important to note is the fact that this texture property is **gamma corrected** using the value of the **[[gamedev:textureproperties:reflectivity_gamma|reflectivity.gamma]]** texture property which is by default 2.2 . This is due to the fact that reflectivity can be an image. Using sRGB color space artists can work with shades of dark gray colors for the very low values of dielectric materials which is still well visible while editing the image. Hence if you use a static value or static color for this texture property the value has to be **raised to the power of 1.0/2.2** first to obtain the correct reflectivity value during rendering unless the **[[gamedev:textureproperties:reflectivity_gamma|reflectivity.gamma]]** is set to 1. For all values it is marked if they are in **linear space** or **sRGB** space. Use the sRGB values for this texture property if **[[gamedev:textureproperties:reflectivity_gamma|reflectivity.gamma]]** is not set to 1. The **reflectivity** texture property defines the per-color reflectivity or reflectance of a material at a **zero viewing angle**. This is more than the simple **specular reflectivity** parameter typically found in other game engines since the Drag[en]gine adepts a **[[gamedev:pbr|physically based rendering]]** approach. The zero angle reflectivity is often specified as the **F0 reflectance**. This is the value required to be used for this texture property. Important to note is the fact that this texture property is **gamma corrected** using the value of the **[[gamedev:textureproperties:reflectivity_gamma|reflectivity.gamma]]** texture property which is by default 2.2 . This is due to the fact that reflectivity can be an image. Using sRGB color space artists can work with shades of dark gray colors for the very low values of dielectric materials which is still well visible while editing the image. Hence if you use a static value or static color for this texture property the value has to be **raised to the power of 1.0/2.2** first to obtain the correct reflectivity value during rendering unless the **[[gamedev:textureproperties:reflectivity_gamma|reflectivity.gamma]]** is set to 1. For all values it is marked if they are in **linear space** or **sRGB** space. Use the sRGB values for this texture property if **[[gamedev:textureproperties:reflectivity_gamma|reflectivity.gamma]]** is not set to 1.
  
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 For most dielectric materials the reflectivity stays thus between 2% and 4%. The reflectivity image is thus not required to be of high resolution nor does it need that much of attention during authoring. If your material is not a metal use 3% (0.2 reflectivity in sRGB) and you are correct in most situations. If you have a metal pick the value from the table and you are all set too. Do not place **material imperfections and variations** in the reflectivity image as this is not going to help much. Use the **[[gamedev:textureproperties:roughness|roughness]]** texture property instead. This one adds a lot more subtle varitions to a material. Hence most of the time using just a static value or static color for this texture property is more than enough. Spend your time on the **[[gamedev:textureproperties:roughness|roughness]]** texture property instead. For most dielectric materials the reflectivity stays thus between 2% and 4%. The reflectivity image is thus not required to be of high resolution nor does it need that much of attention during authoring. If your material is not a metal use 3% (0.2 reflectivity in sRGB) and you are correct in most situations. If you have a metal pick the value from the table and you are all set too. Do not place **material imperfections and variations** in the reflectivity image as this is not going to help much. Use the **[[gamedev:textureproperties:roughness|roughness]]** texture property instead. This one adds a lot more subtle varitions to a material. Hence most of the time using just a static value or static color for this texture property is more than enough. Spend your time on the **[[gamedev:textureproperties:roughness|roughness]]** texture property instead.
 +
 +You can calculate this value also from the **index of refraction**(ior) for transparent objects. In this case the formula goes like this:
 +**reflectivity = (ior - 1)^2 / (ior + 1)^2**
  
 The source is typically an 8 bit image with 3 color components with the color components inside the range from 0 to 1. Most of the time though a static value or static color is enough. The source is typically an 8 bit image with 3 color components with the color components inside the range from 0 to 1. Most of the time though a static value or static color is enough.
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 ====== Examples ====== ====== Examples ======
 +
 <WRAP column 45%> <WRAP column 45%>
 <WRAP center box 450px> <WRAP center box 450px>
gamedev/textureproperties/reflectivity.1357241301.txt.gz · Last modified: 2013/01/03 19:28 by dragonlord

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