ALS technical notes: Difference between revisions

 

ALS supports a grain texture for models. This is a semi-transparent overlay texture that works just as [[Procedural_Texturing#The_grain_texture | its equivalent]] for terrain texturing and provides the option of generating cm-scale details such as rust or discoloration on a surface without having to use huge textures. An example of a surface rendered with grain texture is the Vinson flightdeck below:

<?xml version="1.0" encoding="utf-8"?>

    <name>flightdeck</name>

    <inherits-from>Effects/model-combined-deferred</inherits-from>

    <parameters>

        <grain-texture-enabled type="int">2</grain-texture-enabled>

        <grain-magnification type="float">0.1</grain-magnification>

        <rain-enabled type="int">2</rain-enabled>

        <texture n="7">

            <image>Models/Geometry/Nimitz/rust_texture.png</image>

            <type>2d</type>

            <filter>linear-mipmap-linear</filter>  

            <wrap-s>repeat</wrap-s>

            <wrap-t>repeat</wrap-t>

            <internal-format>normalized</internal-format>

        </texture>

    </parameters>

If the number is < 0, the grain resolution is lower than the base layer, if the parameter is > 0, it is higher (note that in the above case, the grain is mapped to (xy) rather than (uv), hence the base size is 1 m, so the grain texture is mapped on a 10x10 m patch on the flightdeck), for which a 1024x1024 pixel texture provides ~1 cm sized details).