[bugfix] Spline path perspective

[3Dickulus]

Description After transition to GLM camera and target spline paths perspective is wrong.

To Reproduce Steps to demonstrate the behavior:

1. Load tutorial 30
2. Click on 'Progressive'
3. Click on 'Stop'
4. Goto the 'Camera' tab
5. Adjust FOV

Expected behavior Paths are rendered with the proper scale and orientation relative to the 3D scene with occlusion when 'Depth to Alpha' is not enabled.

Desktop

• OS: SuSE Leap 15.1 linux x86_64
• Gfx card: nVidia GTX 760
• Driver version: nVidia 418.87

Additional context Fix will be in next push/merge cycle

in void DisplayWidget::setPerspective() change double vertAngle = 180.0 * ( 2.0 * atan2 ( 1.0, ( 1.0/fov ) ) / M_PI ); to double vertAngle = 2.0 * atan2 ( 1.0, ( 1.0/fov ) );

edit: this also requires testing for GL version for use of glLoadMatrixd()

[claudeha]

depends on GLM version - ancient used degrees, modern uses radians, forgot which version changed it