environment_map.mtlx

<?xml version="1.0"?>
<materialx version="1.39" colorspace="lin_rec709">

  <nodegraph name="envMap">

    <!-- Get view direction -->
    <viewdirection name="viewDir" type="vector3" />

    <!-- Compute longitude coordinate -->
    <separate3 name="viewDirChannels" type="multioutput">
      <input name="in" type="vector3" nodename="viewDir" />
    </separate3>
    <atan2 name="angleXZ" type="float">
      <input name="iny" type="float" nodename="viewDirChannels" output="outx" />
      <input name="inx" type="float" nodename="viewDirChannels" output="outz" />
    </atan2>
    <multiply name="scaleXZ" type="float">
      <input name="in1" type="float" nodename="angleXZ" />
      <input name="in2" type="float" value="-0.15915494" />
    </multiply>
    <add name="longitude" type="float">
      <input name="in1" type="float" nodename="scaleXZ" />
      <input name="in2" type="float" value="0.5" />
    </add>

    <!-- Compute latitude coordinate -->
    <asin name="angleY" type="float">
      <input name="in" type="float" nodename="viewDirChannels" output="outy" />
    </asin>
    <multiply name="scaleY" type="float">
      <input name="in1" type="float" nodename="angleY" />
      <input name="in2" type="float" value="0.31830989" />
    </multiply>
    <add name="latitude" type="float">
      <input name="in1" type="float" nodename="scaleY" />
      <input name="in2" type="float" value="0.5" />
    </add>

    <!-- Sample the latitude-longitude map -->
    <combine2 name="mapUvs" type="vector2">
      <input name="in1" type="float" nodename="longitude" />
      <input name="in2" type="float" nodename="latitude" />
    </combine2>
    <image name="envImage" type="color3">
      <input name="file" type="filename" value="resources/Lights/san_giuseppe_bridge.hdr" />
      <input name="texcoord" type="vector2" nodename="mapUvs" />
      <input name="uaddressmode" type="string" value="periodic" />
      <input name="vaddressmode" type="string" value="clamp" />
      <input name="filtertype" type="string" value="linear" />
    </image>

    <multiply name="envImageAdjusted" type="color3">
      <input name="in1" type="color3" nodename="envImage" />
      <input name="in2" type="float" value="1.0" />
    </multiply>

    <!-- Return the resulting color -->
    <output name="out" type="color3" nodename="envImageAdjusted" />
  </nodegraph>
</materialx>