32-bit float image preview broken in OpenGL

[Bicyclops]

Hello

32-bit floating-point images (from RawTherapee) load and are previewed correctly using the "Preview panorama" button, but the preview is broken using "OpenGL Fast panorama preview" - some images are completely black, others completely overexposed.

Sample files and screenshots:
https://filebin.net/3cp8rzg4e1t84vk2

Please download these, as the link will expire 2 months from now.

Operating System: Linux 4.17.0-sabayon x86_64
Architecture: 64 bit
Free memory: 2246320 kiB

Hugin
Version: 2018.0.0.5abfb4de7961
Path to resources: /usr/share/hugin/xrc/
Path to data: /usr/share/hugin/data/
Hugins camera and lens database: /home/morgan/.hugindata/camlens.db
Multi-threading using C++11 std::thread and OpenMP
Monitor profile: B133HAN02.1 #1 2016-10-19 21-46 D6500 2.2 F-S XYZLUT+MTX

Libraries
wxWidgets: wxWidgets 3.0.4
wxWidgets Library (wxGTK port)
Version 3.0.4 (Unicode: wchar_t, debug level: 1),
compiled at Jun 14 2018 19:21:01

Runtime version of toolkit used is 2.24.
Compile-time GTK+ version is 2.24.31.

libpano13: 2.9.19
Boost: 1.65.0
Exiv2: 0.26
SQLite3: 3.23.1
Vigra: 1.11.0
LittleCMS2: 2.9

[Bicyclops (bugs-8)]

Are you sure this is a duplicate of that issue from 2011? I'm not requesting preview tonemapping (which would be nice, but is a separate topic). Some of the images do preview correctly in OpenGL, but others are completely black - that behavior resembles a bug.