PBR file paths cannot be relative

[nkoenig]

Material maps within an SDF file require model://. For example:

          <pbr>
            <metal>
              <albedo_map>model://UnderwaterWorld/materials/textures/Rock_Albedo.png</albedo_map>
              <normal_map>model://UnderwaterWorld/materials/textures/Rock_Normal.png</normal_map>
              <roughness_map>model://UnderwaterWorld/materials/textures/Rock_Roughness.png</roughness_map>
            </metal>
          </pbr>

It would be nice if these paths could be relative like <mesh><uri>.

[iche033]

This is the place in code that parses these sdf params:
https://github.com/ignitionrobotics/ign-gazebo/blob/master/src/rendering/SceneManager.cc#L428

looks like common::findFile is not sufficient. I noticed that other places use asFullPath, e.g. for parsing mesh path, so may be that'll help

[nkoenig]

See #328.

[chapulina]

Reopening this issue because the fix only affected the client, but not the server. To reproduce the remaining issue, use a world that has rendering sensors, for example:

1. ign gazebo -v 1 -r sensors_demo.sdf
2. Drag this model into simulation: https://app.ignitionrobotics.org/chapulina/fuel/models/Rescue%20Randy%20-%20relative%20paths
3. The model will look good on the GUI but not for the sensors. And you'll also see these errors:

[Err] [SceneManager.cc:450] Unable to find file [materials/textures/rescue_randy_roughness.png]
[Err] [SystemPaths.cc:453] Could not resolve file [materials/textures/rescue_randy_metalness.png]
[Err] [SceneManager.cc:461] Unable to find file [materials/textures/rescue_randy_metalness.png]
[Err] [SystemPaths.cc:453] Could not resolve file [materials/textures/rescue_randy_albedo.png]
[Err] [SceneManager.cc:483] Unable to find file [materials/textures/rescue_randy_albedo.png]
[Err] [SystemPaths.cc:453] Could not resolve file [materials/textures/rescue_randy_normal.png]
[Err] [SceneManager.cc:494] Unable to find file [materials/textures/rescue_randy_normal.png]

[chapulina]

Sounds like it's fixed