gizmo drawn incorrectly at direction (-1, 0, 0)

[koala999cn]

Hello!
When entering the following code, incorrect result appears

vgm::Vec3 dir(-1, 0, 0);
ImGui::gizmo3D("Direction", dir);

It means, I wanna (-1, 0, 0), but get (1, 0, 0).

[BrutPitt]

Hi @koala999cn, and sorry for the (very!) late reply.

I tried your example, but the problem does not happen.
On picture, below, there is my debug session (tested with both gcc 14.2.1 and clang 18.1. 8):

A value (1.0, 0.0, 0.0) is a condition that can occur/be returmed only if the length of vector "dir" < FLT_EPSILON (alias: NULL vector): and this would not be the case!
Below the code relative, used to avoid a NULL vector and consequentially a division by ZERO

        float len = length(dir);

        if(len<1.0 && len>= FLT_EPSILON) { normalize(dir); len = 1.0; }
        else if(len< FLT_EPSILON) { dir = vec3(1.f, 0.f, 0.f); len = 1.0; }

        q = angleAxis(acosf(dir.x/len), normalize(vec3(FLT_EPSILON, -dir.z, dir.y)));

On the basis of this I can assume that dir is initialized to (0.0, 0.0, 0.0) instead of (-1.0, 0.0, 0.0)

For this reason, please, tell me more about your C/C++ compiler (brand, version and used compiler flags) and your OS