Gazebo/White and other Materials that have a light pass appear very different from Gazebo classic's rendering

[azeey]

Environment

• OS Version: Ubuntu 22.04
• Source or binary build? gz-sim8

Description

• Expected behavior: Materials, especially commonly used ones, such as Gazebo/White to look reasonably close to Gazebo classic's rendering
• Actual behavior:

Gazebo classic

gz-sim8

Steps to reproduce

1. Run the following world

Details

<?xml version="1.0" ?>
<sdf version="1.6">
  <world name="shapes">
    <scene>
      <ambient>0.2 0.2 0.2</ambient>
      <background>0.8 0.8 0.8</background>
    </scene>

    <light type="directional" name="sun">
      <cast_shadows>true</cast_shadows>
      <pose>0 0 10 0 0 0</pose>
      <diffuse>0.8 0.8 0.8 1</diffuse>
      <specular>0.2 0.2 0.2 1</specular>
      <attenuation>
        <range>1000</range>
        <constant>0.9</constant>
        <linear>0.01</linear>
        <quadratic>0.001</quadratic>
      </attenuation>
      <direction>-0.5 0.1 -0.9</direction>
    </light>

    <model name="ground_plane">
      <static>true</static>
      <link name="link">
        <collision name="collision">
          <geometry>
            <plane>
              <normal>0 0 1</normal>
              <size>100 100</size>
            </plane>
          </geometry>
        </collision>
        <visual name="visual">
          <geometry>
            <plane>
              <normal>0 0 1</normal>
              <size>100 100</size>
            </plane>
          </geometry>
          <material>
            <ambient>0.8 0.8 0.8 1</ambient>
            <diffuse>0.8 0.8 0.8 1</diffuse>
            <specular>0.8 0.8 0.8 1</specular>
          </material>
        </visual>
      </link>
    </model>

    <model name="box">
      <pose>0 0 0.5 0 0 0</pose>
      <link name="box_link">
        <inertial>
          <inertia>
            <ixx>0.16666</ixx>
            <ixy>0</ixy>
            <ixz>0</ixz>
            <iyy>0.16666</iyy>
            <iyz>0</iyz>
            <izz>0.16666</izz>
          </inertia>
          <mass>1.0</mass>
        </inertial>
        <collision name="box_collision">
          <geometry>
            <box>
              <size>1 1 1</size>
            </box>
          </geometry>
        </collision>

        <visual name="box_visual">
          <geometry>
            <box>
              <size>1 1 1</size>
            </box>
          </geometry>
          <material>
            <script>
              <uri>file://media/materials/scripts/gazebo.material</uri>
              <name>Gazebo/White</name>
            </script>
          </material>
        </visual>
      </link>
    </model>
  </world>
</sdf>

[iche033]

I think the current material parser just reads value from the 1st pass only and ignores other passes.

Gazebo/White has 2 passes:

material Gazebo/White
{
  technique
  {
    pass ambient
    {
      ambient 1 1 1 1
    }

    pass light
    {
      diffuse 1 1 1 1
      specular .1 .1 .1 128
    }
  }
}

I actually don't see a reason to use 2 passes for this material. We could just combine them into one:

material Gazebo/White
{
  technique
  {
    pass ambient
    {
      ambient 1 1 1 1
      diffuse 1 1 1 1
      specular .1 .1 .1 128
    }
  }
}

[iche033]

I think most materials with multiple passes could also be merged into a single pass. There are others, e.g. Gazebo/TurquoiseGlowOutline, that do seem like multiple passes are intended and may be more difficult to port.

[azeey]

Yes, I think combining them manually in the gazebo.material file is probably the best way to go.

[quarkytale]

I had the same thought, and since we're shipping a new file we can modify it however it fits best I guess. I don't mind taking this up and editing gazebo.material manually.

[quarkytale]

material Gazebo/White
{
. . .
specular .1 .1 .1 128
}

This 128 or any value > 1 should be divided by 256 right?

[azeey]

Yes, I believe so: https://github.com/gazebosim/gz-math/blob/ec655a9260c1b1c5d3765c160999fd6e4d625788/include/gz/math/Color.hh#L281-L284