[VolumetricRendering] Fix the compilation

[alxbilger]

But scenes crash

Before going further with #4395, it is wiser to first fix the compilation of the plugin. We can even wonder if we keep this plugin since it has not been maintained for a while.

Note that this plugin is not compiled on the CI. See sofa-framework/ci#32

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Reviewers will merge this pull-request only if

• it builds with SUCCESS for all platforms on the CI.
• it does not generate new warnings.
• it does not generate new unit test failures.
• it does not generate new scene test failures.
• it does not break API compatibility.
• it is more than 1 week old (or has fast-merge label).

[alxbilger]

@fredroy thanks for the PR but I still crash in applications/plugins/VolumetricRendering/examples/OglTetrahedralModel.scn and applications/plugins/VolumetricRendering/examples/OglVolumetricModel_hexa.scn.

[alxbilger]

@fredroy Yeah! The scene no longer crashes! But I have the following errors:

[ERROR]   [GLSLShader] ERROR: Compilation of Fragment shader failed:
[ERROR]   [GLSLShader] From File: C:\Users\Alex\Dev\sofa1\src\applications\plugins\VolumetricRendering\examples/share/shaders/tetra.frag
[ERROR]   [GLSLShader] 0(8) : warning C7555: 'varying' is deprecated, use 'in/out' instead
0(16) : error C7616: global variable gl_Color is removed after version 140
0(35) : warning C7533: global variable gl_FragColor is deprecated after version 120

[ERROR]   [GLSLShader] ERROR: Compilation of Vertex shader failed:
[ERROR]   [GLSLShader] From File: C:\Users\Alex\Dev\sofa1\src\applications\plugins\VolumetricRendering\examples/share/shaders/tetra.vert
[ERROR]   [GLSLShader] 0(20) : error C7616: global variable gl_ModelViewProjectionMatrix is removed after version 140
0(23) : error C7616: global variable gl_ClipVertex is removed after version 140
0(23) : error C7616: global variable gl_ModelViewMatrix is removed after version 140
0(23) : error C7616: global variable gl_Vertex is removed after version 140

[ERROR]   [GLSLShader] ERROR: Compilation of Geometry shader failed:
[ERROR]   [GLSLShader] From File: C:\Users\Alex\Dev\sofa1\src\applications\plugins\VolumetricRendering\examples/share/shaders/tetra_triangles.geo
[ERROR]   [GLSLShader] 0(45) : warning C7533: global variable gl_FrontColor is deprecated after version 120
0(46) : error C7616: global variable gl_ClipVertex is removed after version 140

[ERROR]   [GLSLShader] SHADER compilation failed.
[ERROR]   [OglFloat4Attribute(OglFloat4Attribute1)] Variable "a_vertexColor" NOT FOUND in shader "[ 'share/shaders/tetra.vert' ]"
[ERROR]   [Node()] Object 'OglFloat4Attribute1' already has a node (/OglFloat4Attribute1). Please remove it from this node before adding it to a new one.
[ERROR]   [OglFloat4Attribute(OglFloat4Attribute1)] TopologyData: value already has a TopologyDataHandler. createTopologyHandler should only be called once at init of the TopologyData.
[ERROR]   [OglFloat4Attribute(OglFloat4Attribute1)] Variable "a_vertexColor" NOT FOUND in shader "[ 'share/shaders/tetra.vert' ]"

I guess the shaders needs to be updated for version >= 140