Feature: Support Wavefront OBJ files with TGA Textures

[gapry]

Related Issue:

This work addresses the Issue: #1281

Current Progress

I download the free assets, DarkSider Mercy Gun 3D Model, as the input data to work the Issue: #1281

$ ./build/bin/f3d assets/DarkSiderGun/GUN_OBJ.obj

For now, I've written some tracing code to find out where to add the supported code. Here is the current tracing output.

[gapry][issues][1281][int F3DStarter::Start(int, char**)] assets/DarkSiderGun/GUN_OBJ.obj
[gapry][issues][1281][void F3DStarter::LoadFileGroup(int, bool, bool)] 000
[gapry][issues][1281][void F3DStarter::LoadFileGroup(const std::vector<std::filesystem::__cxx11::path>&, bool, const std::string&)] /home/gapry/Workspaces/f3d/assets/DarkSiderGun/GUN_OBJ.obj1(1/1)
[gapry][issues][1281][void F3DStarter::LoadFileGroup(const std::vector<std::filesystem::__cxx11::path>&, bool, const std::string&)] /home/gapry/Workspaces/f3d/assets/DarkSiderGun/GUN_OBJ.obj
[gapry][issues][1281][virtual f3d::scene& f3d::detail::scene_impl::add(const std::vector<std::filesystem::__cxx11::path>&)] /home/gapry/Workspaces/f3d/assets/DarkSiderGun/GUN_OBJ.obj
[gapry][issues][1281][void f3d::detail::scene_impl::internals::Load(const std::vector<vtkSmartPointer<vtkImporter> >&)]
[gapry][issues][1281][void vtkF3DMetaImporter::AddImporter(const vtkSmartPointer<vtkImporter>&)]

I'm sorry, I haven't finished yet. I will keep trying, I think the key is this->Pimpl->Importers. I think I need to know who used it.

void vtkF3DMetaImporter::AddImporter(const vtkSmartPointer<vtkImporter>& importer)
{
  F3DLog::Print(F3DLog::Severity::Info, std::string("[gapry][issues][1281][") + __PRETTY_FUNCTION__ + "] ");

  this->Pimpl->Importers.emplace_back(vtkF3DMetaImporter::Internals::ImporterPair {importer, false}); // [gapry][issues][1281]
  
  ... 
}  

[mwestphal]

To fix this you need to make changes in VTK first though.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.97%. Comparing base (ca4a69f) to head (1874f16).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1719   +/-   ##
=======================================
  Coverage   96.97%   96.97%           
=======================================
  Files         106      106           
  Lines        8754     8763    +9     
=======================================
+ Hits         8489     8498    +9     
  Misses        265      265           

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[gapry]

Got it

I have read the document, https://gitlab.kitware.com/vtk/vtk/-/blob/master/CONTRIBUTING.md

and using the example as a starting point, https://examples.vtk.org/site/Cxx/IO/OBJImporter/

I find take a look at the testing data in vtk-example, it doesn't seem to have any TGA files.

So I will also to contribute an obj model with TGA textures to testing data in vtk-example

[mwestphal]

Ok!

[mwestphal]

Do you need help moving forward @gapry ?

[gapry]

Current Progress

1. I have created an account on https://gitlab.kitware.com/ with the username gapry
2. I have forked the VTK project, https://gitlab.kitware.com/vtk, to my repository, https://gitlab.kitware.com/gapry/vtk
3. I created a new branch WavefrontOBJ-TGA to address the issue Obj's with tga textures don't get their textures displayed #1281
4. I made the commit, https://gitlab.kitware.com/gapry/vtk/-/commit/119506e45f699d0ed74d5b7850cec406ab1a0d87, to add support for TGA images in Wavefront Obj files.
5. I use the example, OBJImporter and the free assets DarkSider Mercy Gun to verify my implement, https://github.com/gapry/code-for-blog/tree/main/2024/OBJImporter.
   For now, it will output the following messages in the console

$ ./VTK_App.out GUN_OBJ.obj GUN_OBJ.mtl textures
There are 2 actors
data output 0 with material named blinn1SG texture file none diffuse color (0, 0, 0) ambient color (0, 0, 0) specular color (0, 0, 0) specular power 18 opacity 1
data output 1 with material named blinn1SG texture file none diffuse color (0, 0, 0) ambient color (0, 0, 0) specular color (0, 0, 0) specular power 18 opacity 1

and the rendered result does not display the GUN_OBJ.obj model with the TGA images located in the textures folder.

The current rendered result

The correct rendered result

Any idea? Thanks

[mwestphal]

Can you open a VTK MR with your branch ? It will be easier to discuss there.

In any case, does the code enter the if (bIsReadableTGA) ?

[gapry]

Just to confirm: does MR mean Merge requests ? If yes, I can do it.

[mwestphal]

Yes, a MR means a Merge Request

[gapry]

Done: https://gitlab.kitware.com/vtk/vtk/-/merge_requests/11759