ObjLoader Debugging

The OBJ loader you are given loads a valid file, but but fails to provide feedback if the file format is incorrect

Assignment: make every format error explain itself and extend its capability.

1. Quick Start

cmake -S . -B build && cmake --build build
./build/objloader_tests

You should see 3 of 11 passing, and the run ends in a crash at case 10, missing_uv_data.

All of this is expected.

Two ways to run it:

./build/objloader_tests                                       # run everything
./build/objloader_tests --only test05_face_not_triangle.obj   # one case with full detail

--only <value> takes the exact .obj filename of one of the built-in cases.

2. Files

You should only edit src/objloader.cpp.

Assignment file and test case information
Path	Content
`src/objloader.cpp`	starter code
`include/objloader.hpp`	API and `ObjIssue` list
`src/diagnostics.cpp`	message formatting and report printing
`tests/test_objloader.cpp`	test runner
`tests/models/test01_...` - `test11_...`	test files (see table below)
`external/glm/`	glm headers

3. The 10 Cases

include/objloader.hpp defines 10 ObjIssue this loader can detect.

There are 11 test cases - one per condition, plus one baseline case (strict).

Every one of the 10 can be recognized, named correctly, and rejected cleanly.
Some of them can also be handled gracefully instead of rejected.

4. Test Files

4.1. Description

Assignment file and test case information
#	File	Test case	Issue	Outcome required
01	`test01_strict.obj`	`strict`	(none - baseline)	loads cleanly with 0 diagnostics
02	`test02_malformed_vertex.obj`	`malformed_vertex`	`MalformedVertex`	reject
03	`test03_malformed_texcoord.obj`	`malformed_texcoord`	`MalformedTexCoord`	reject
04	`test04_malformed_normal.obj`	`malformed_normal`	`MalformedNormal`	reject
05	`test05_face_not_triangle.obj`	`face_not_triangle`	`FaceNotTriangle`	reject
06	`test06_malformed_face_vertex.obj`	`malformed_face_vertex`	`MalformedFaceVertex`	reject
07	(no file - path doesn't exist)	`file_not_found`	`FileNotFound`	reject
08	`test08_missing_normal_data.obj`	`missing_normal_data`	`MissingNormalData`	accept, with warning
09	`test09_index_out_of_range.obj`	`index_out_of_range`	`IndexOutOfRange`	reject
10	`test10_missing_uv_data.obj`	`missing_uv_data`	`MissingUVData`	accept, with warning
11	`test11_negative_index_unsupported.obj`	`negative_index_unsupported`	`NegativeIndexUnsupported`	reject

4.2 Hints

Assignment file and test case information
File	What's inside
`test01_strict.obj`	Unit square in the XZ plane, two triangles, facing +Y, full `v/vt/vn` form.
`test02_malformed_vertex.obj`	A `v` line with only 2 numbers instead of 3, referenced by a face.
`test03_malformed_texcoord.obj`	A `vt` line with only 1 number instead of 2, referenced by a face (`v/vt` form).
`test04_malformed_normal.obj`	A `vn` line with only 2 numbers instead of 3, referenced by a face (`v//vn` form).
`test05_face_not_triangle.obj`	A square as one 4-vertex face instead of two triangles.
`test06_malformed_face_vertex.obj`	A face token with four slash-separated fields.
`test08_missing_normal_data.obj`	Bare position-only faces with no normal referenced.
`test09_index_out_of_range.obj`	The face cites position `99` in a file that only defines 4 positions.
`test10_missing_uv_data.obj`	A face references a uv slot, but the file defines zero `vt` lines anywhere.
`test11_negative_index_unsupported.obj`	Every face-vertex index is negative. Valid OBJ meaning "counted backward from the most recently defined element," is not implemented here.

The suite checks the ObjIssue value, never your message wording, so phrase detail however you like.