Extend ShaderParam system to support loading different shader languages

[iche033]

🎉 New feature

Summary

Implemented proposed idea from: #1275 (comment)

The idea is to let users specify different shader files to use. The <shader> sdf element now takes an optional language attribute. On macOS, the system will use metal shaders over glsl if specified.

The deformable_sphere and waves models on Fuel have been updated to include metal shaders.

Test it

Remove the deformable_sphere and waves models in your fuel cache (~/.ignition/fuel/fuel.ignitionrobotics.org/openrobotics/models/) then run ign-gazebo with shaders_param.sdf world. You should get the same output as the screenshot shown in #1310

Checklist

• Signed all commits for DCO
• Added tests
• Added example and/or tutorial
• Updated documentation (as needed)
• Updated migration guide (as needed)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• While waiting for a review on your PR, please help review another open pull request to support the maintainers

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by messages.

[iche033]

@srmainwaring, I integrated your shaders into the existing models. Hope I didn't mess anything up.

[codecov]

Codecov Report

Merging #1335 (fc02517) into ign-gazebo6 (e0d88f7) will increase coverage by 0.06%.
The diff coverage is 100.00%.

❗ Current head fc02517 differs from pull request most recent head 95b1817. Consider uploading reports for the commit 95b1817 to get more accurate results

@@               Coverage Diff               @@
##           ign-gazebo6    #1335      +/-   ##
===============================================
+ Coverage        62.91%   62.97%   +0.06%     
===============================================
  Files              299      301       +2     
  Lines            24151    24208      +57     
===============================================
+ Hits             15194    15245      +51     
- Misses            8957     8963       +6     

Impacted Files	Coverage Δ
include/ignition/gazebo/Link.hh	100.00% <ø> (ø)
src/SimulationRunner.hh	100.00% <ø> (ø)
src/systems/physics/Physics.hh	100.00% <ø> (ø)
src/systems/pose_publisher/PosePublisher.hh	100.00% <ø> (ø)
src/Link.cc	94.77% <100.00%> (+0.28%)	⬆️
src/SimulationRunner.cc	91.12% <100.00%> (-1.26%)	⬇️
src/SystemInternal.hh	100.00% <100.00%> (ø)
src/SystemManager.cc	100.00% <100.00%> (ø)
src/systems/lift_drag/LiftDrag.cc	62.85% <100.00%> (ø)
src/systems/physics/Physics.cc	71.75% <100.00%> (+0.19%)	⬆️
... and 2 more

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[srmainwaring]

I integrated your shaders into the existing models. Hope I didn't mess anything up.

Thanks @iche033! - I'm sure you haven't. I'll give them a test and let you know.

Working on porting my more general wave model to Ignition at present - not quite straightforward as it updates the Ogre::v1::Mesh and that route is no longer available. I looked at the Ogre2DynamicRenderable but don't think it quite does what I need - also no support for tangent vectors which are needed for bump mapping. I'm looking at the Ogre2 DynamicGeometry example with a view to using the approach suggested there.

A couple of things I noticed when trying to map shader materials onto a custom mesh:

• the ShaderParams doesn't seem to supply the normals to the vertex shader (just the positions and uv0 texture coords). I can add a VES_NORMAL param to the inputs but it is zeroed.
• it doesn't look like you can use the material defined by ShaderParams in another system plugin declared in the same visual.

I'll post an issue with some simplified examples to illustrate.

[nkoenig]

Looks good to me. Not sure if srmainwaring has additional comments.

[iche033]

@srmainwaring oops I missed your comment

• the ShaderParams doesn't seem to supply the normals to the vertex shader (just the positions and uv0 texture coords). I can add a VES_NORMAL param to the inputs but it is zeroed.

yep that sounds good to me.

• it doesn't look like you can use the material defined by ShaderParams in another system plugin declared in the same visual.

hmm like the entire ogre material or specific texture? I would have expected ogre to add the texture to its resource path so that it would be available to others but that also depends on the order in which the systems are loaded.

[srmainwaring]

it doesn't look like you can use the material defined by ShaderParams in another system plugin declared in the same visual.

On this second point it turns out that only one plugin per visual is processed at present, and that is which ever one is declared last is loaded and the preceding ones are ignored. The protobuf Visual message allows for multiple plugins, but the server dispatching the message does not, and there may also be an assumption of one plugin on the GUI side as well.

I can work around this for the moment by replicating the ShaderParam plugin logic in my plugin, so it's probably best to submit support for multiple plugins as a feature request.

On the first point, addition of normals and tangent attributes, I have some more work to get that working for my example, so again that would best be included as a follow up.

[iche033]

On this second point it turns out that only one plugin per visual is processed at present, and that is which ever one is declared last is loaded and the preceding ones are ignored. The protobuf Visual message allows for multiple plugins, but the server dispatching the message does not, and there may also be an assumption of one plugin on the GUI side as well.

ok you're right. I've ticketed an issue for this. #1363

[iche033]

I'll merge this first. We can address other issues as they come up.

[osrf-triage]

This pull request has been mentioned on Gazebo Community. There might be relevant details there:

https://community.gazebosim.org/t/new-ignition-releases-2022-03-25-fortress-edifice-citadel/1343/1