* avoid undefined behavior from UNREACHABLE on reachable code paths
UNREACHABLE expands to __assume(false) / __builtin_unreachable() in
release builds, which is undefined behavior if the code is ever actually
reached. Many UNREACHABLE sites only guard against unexpected-but-
possible runtime states (values from tables, mission/save files, network
packets, scripting, or user input), so reaching them should degrade
gracefully rather than invoke UB.
Replace UNREACHABLE with Assertion(false, ...) at all such sites. It
still pops an error in debug builds, but in release it is a harmless
no-op that simply falls through to the following code. Sites that are
genuinely unreachable by local invariants (e.g. a switch over a bounded
random number) are left as UNREACHABLE.
A few converted sites had no safe fall-through -- an uninitialized read,
null dereference, or null call would have followed -- so they also get a
minimal recovery: initialize the value, guard the dereference, return
early, or skip the offending item.
Where the converted site was a simple guard of the form
if (x) { Assertion(false, ...); return; }
hoist the check onto the invariant instead:
Assertion(!x, ...);
if (x) { return; }
This states the expectation directly and shows the offending value in
the debug popup, while keeping the same graceful runtime degradation.
Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
* addendum
After consultation with Lafiel, use UNREACHABLE in situations that are effectively impossible even if not provably impossible. UNREACHABLE = "this shouldn't ever happen"; Assertion = "if this ever happens, it's a coding error". Also fix a few other sites and change a couple to Warnings.
---------
Co-authored-by: Claude Opus 4.8 (1M context) <[email protected]>
* initial changes
* add GLAD_ES loader
* Implement basic es compatibility header
* re-add accidentally deleted break
* Add GLES BC7 extension to glad and improve extension support report
* fix some enum mappings
* Use the ARB name for geo shader check
* Add es espand shader includes
* Fix glbufferstorage mapping
* fix some gl errors on opengl es
* Enable GL_CLIP_DISTANCE
* Add format conversions
* add bgba 8888 to rgba 8888 converter
* disable GLAD_GL_ARB_timer_query
* Properly handle wgl + opengl es on windows
* initial enable imgui gles
* add GL_BGR to GL_RGBA conversion
* inform opengl es on menu
* small corrections to the es header
* small refactor of glTexSubImage3D
* remove expandincludes, existing code already did that better
* change default graphic values for opengl es
* compile imgui with opengl es 3 on linux
* allow qtfred to run on opengl es
* improve es compatibility header and remove shader precision quantification
* add compiler hints
* remove unused structs
* Fix imgui crashing on windows with gles, use angle lib
* Do not use MSAA under OpenGL ES, at least for now
MSAA will need an alternative path for GL ES using GL_EXT_multisampled_render_to_texture and GL_EXT_multisampled_render_to_texture2
* add missing profile handler
* cleanup
* revert color_attachment_4/5 fbo workarounds
* Adjustments to log output and enable GL_BLEND
* Implement glGetQueryObjectui64v on es layer
* Fix deferred and decals support
Also added glGetTexImage(), glQueryCounter() and some additional comments
* Revert changes to default values of graphics options
* Minor improvements to glTexSubImage3D()
This can be used for mark parts of the code which should be unreachable
in normal execution. In debug mode, if such a statement is reached an
Error dialog is shown which aborts the execution. In release mode the
macro is replaced with a compiler specific expression that lets the
compiler know that this part is unreachable which allows it to optimize
the code better.
Since our target version is only OpenGL 3.2 all additional functionality
should only be used through their respective extensions to avoid
accidentially using a function not available in our minimum target
environment.
