const float *vec, int width, int height,
int16_t us[4][4], int16_t vs[4][4], float *du, float *dv)
{
- const float phi = -atan2f(hypotf(vec[0], vec[1]), -vec[2]) / M_PI;
- const float theta = -atan2f(vec[0], vec[1]);
+ const float h = hypotf(vec[0], vec[1]);
+ const float lh = h > 0.f ? h : 1.f;
+ const float phi = atan2f(h, -vec[2]) / M_PI;
- float uf = sinf(theta) * phi * s->input_mirror_modifier[0] / s->iflat_range[0];
- float vf = cosf(theta) * phi * s->input_mirror_modifier[1] / s->iflat_range[1];
+ float uf = vec[0] / lh * phi * s->input_mirror_modifier[0] / s->iflat_range[0];
+ float vf = -vec[1] / lh * phi * s->input_mirror_modifier[1] / s->iflat_range[1];
const int visible = hypotf(uf, vf) <= 0.5f;
int ui, vi;