uint16_t us[4][4], uint16_t vs[4][4], float *du, float *dv)
{
const float l = hypotf(vec[0], vec[1]);
- const float r = sinf(acosf(-vec[2]) * 0.5f);
+ const float r = sqrtf(1.f + vec[2]) / M_SQRT2;
float uf, vf;
int ui, vi;
- uf = (1.f - r * vec[0] * s->input_mirror_modifier[0] / l) * width / 2.f;
- vf = (1.f + r * vec[1] * s->input_mirror_modifier[1] / l) * height / 2.f;
+ uf = (1.f + r * vec[0] * s->input_mirror_modifier[0] / (l > 0.f ? l : 1.f)) * width * 0.5f;
+ vf = (1.f - r * vec[1] * s->input_mirror_modifier[1] / (l > 0.f ? l : 1.f)) * height * 0.5f;
+
ui = floorf(uf);
vi = floorf(vf);