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Catch unsupported transforms on armature #72

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Catch unsupported transforms on armature #72

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b4bb71e
add check to catch unsupported transforms on armature (or any skin an…
mullermarian Feb 25, 2026
590b768
compare transforms to an epsilon to avoid false positives
mullermarian Mar 1, 2026
8455e3e
fix matrix order
mullermarian Mar 2, 2026
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47 changes: 47 additions & 0 deletions tools/gltf_importer/src/parser.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -71,6 +71,53 @@ T3DM::T3DMData T3DM::parseGLTF(const char *gltfPath)
continue;
}

constexpr auto EPSILON = 0.0001;
bool ancestorHasTransforms = false;
cgltf_node* p = bone->parent;
while (p != nullptr) {
if (p->has_translation || p->has_rotation || p->has_scale || p->has_matrix) {
if(config.verbose) printf("Ancestor '%s' of skin armature/root bone '%s' has transforms: t:%d r:%d s:%d m:%d\n", p->name, bone->name, p->has_translation, p->has_rotation, p->has_scale, p->has_matrix);
if (p->has_translation) {
if (fabs(p->translation[0]) > EPSILON || fabs(p->translation[1]) > EPSILON || fabs(p->translation[2]) > EPSILON) {
ancestorHasTransforms = true;
}
if(config.verbose) printf("t: %f %f %f\n", p->translation[0], p->translation[1], p->translation[2]);
}
if (p->has_rotation) {
if (fabs(p->rotation[0]) > EPSILON || fabs(p->rotation[1]) > EPSILON || fabs(p->rotation[2]) > EPSILON || fabs(p->rotation[3] - 1) > EPSILON) {
ancestorHasTransforms = true;
}
if(config.verbose) printf("r: %f %f %f %f\n", p->rotation[0], p->rotation[1], p->rotation[2], p->rotation[3]);
}
if (p->has_scale) {
if (fabs(p->scale[0] - 1) > EPSILON || fabs(p->scale[1] - 1) > EPSILON || fabs(p->scale[2] - 1) > EPSILON) {
ancestorHasTransforms = true;
}
if(config.verbose) printf("s: %f %f %f\n", p->scale[0], p->scale[1], p->scale[2]);
}
if (p->has_matrix) {
for (int y=0; y<4; y++) {
for (int x=0; x<4; x++) {
float reference = x==y ? 1 : 0;
if (fabs(p->matrix[y+x*4] - reference) > EPSILON) {
ancestorHasTransforms = true;
}
}
}
if(config.verbose) printf("m: %f %f %f %f\n %f %f %f %f\n %f %f %f %f\n %f %f %f %f\n",
p->matrix[0], p->matrix[4], p->matrix[8], p->matrix[12],
p->matrix[1], p->matrix[5], p->matrix[9], p->matrix[13],
p->matrix[2], p->matrix[6], p->matrix[10], p->matrix[14],
p->matrix[3], p->matrix[7], p->matrix[11], p->matrix[15]
);
}
}
p = p->parent;
}
if (ancestorHasTransforms) {
throw std::runtime_error("At least one ancestor of armature/skin root bone has significant transforms! (in file: " + std::string(gltfPath) + ")");
}

Bone armature = parseBoneTree(bone, nullptr, boneCount);

//printBoneTree(armature, 0);
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