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[OoT] Raise error on degenerate triangles #636

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[OoT] Raise error on degenerate triangles #636

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444c0df
skip and warn on degen wall tris
Yanis002 Dec 2, 2025
4c81191
error instead of warn
Yanis002 Dec 2, 2025
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23 changes: 20 additions & 3 deletions fast64_internal/z64/exporter/collision/__init__.py
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Original file line number Diff line number Diff line change
Expand Up @@ -103,6 +103,7 @@ def getCollisionData(dataHolder: Optional[Object], transform: Matrix, useMacros:
for i, face in enumerate(meshObj.data.loop_triangles):
material = meshObj.material_slots[face.material_index].material
colProp = material.ootCollisionProperty
raise_error = False

# get bounds and vertices data
planePoint = transform @ meshObj.data.vertices[face.vertices[0]].co
Expand All @@ -119,13 +120,29 @@ def getCollisionData(dataHolder: Optional[Object], transform: Matrix, useMacros:
)
distance = convertIntTo2sComplement(distance, 2, True)

def sq(val):
return val * val

nx = (y2 - y1) * (z3 - z2) - (z2 - z1) * (y3 - y2)
ny = (z2 - z1) * (x3 - x2) - (x2 - x1) * (z3 - z2)
nz = (x2 - x1) * (y3 - y2) - (y2 - y1) * (x3 - x2)
magSqr = nx * nx + ny * ny + nz * nz
magSqr = sq(nx) + sq(ny) + sq(nz)
if magSqr <= 0:
print("INFO: Ignore denormalized triangle.")
continue
raise_error = True

# for walls only, see https://github.com/zeldaret/oot/blob/eb5dac74d6435baf85ced9158d3ff915ba8872ca/src/code/z_bgcheck.c#L751
if normal[1] >= -0.8 and normal[1] <= 0.5:
normal_xz = math.sqrt(sq(normal[0]) + sq(normal[2]))
if math.fabs(normal_xz) < 0.008:
raise_error = True

if raise_error:
raise PluginError(
f"degenerate triangle detected on mesh object '{meshObj.name}' (material name is '{material.name}')"
)

if normal[0] == 0 and normal[2] == 0:
raise PluginError("unexpected degenerate triangle")

indices: list[int] = []
for pos in [(x1, y1, z1), (x2, y2, z2), (x3, y3, z3)]:
Expand Down