diff options
| -rw-r--r-- | modules/gltf/gltf_document.cpp | 25 |
1 files changed, 14 insertions, 11 deletions
diff --git a/modules/gltf/gltf_document.cpp b/modules/gltf/gltf_document.cpp index 32fe37d9af..e0bdd4cf33 100644 --- a/modules/gltf/gltf_document.cpp +++ b/modules/gltf/gltf_document.cpp @@ -5785,15 +5785,17 @@ struct SceneFormatImporterGLTFInterpolate { return 0.5f * ((2.0f * p1) + (-p0 + p2) * t + (2.0f * p0 - 5.0f * p1 + 4.0f * p2 - p3) * t2 + (-p0 + 3.0f * p1 - 3.0f * p2 + p3) * t3); } - T bezier(T start, T control_1, T control_2, T end, float t) { - /* Formula from Wikipedia article on Bezier curves. */ - const real_t omt = (1.0 - t); - const real_t omt2 = omt * omt; - const real_t omt3 = omt2 * omt; + T hermite(T start, T tan_start, T end, T tan_end, float t) { + /* Formula from the glTF 2.0 specification. */ const real_t t2 = t * t; const real_t t3 = t2 * t; - return start * omt3 + control_1 * omt2 * t * 3.0 + control_2 * omt * t2 * 3.0 + end * t3; + const real_t h00 = 2.0 * t3 - 3.0 * t2 + 1.0; + const real_t h10 = t3 - 2.0 * t2 + t; + const real_t h01 = -2.0 * t3 + 3.0 * t2; + const real_t h11 = t3 - t2; + + return start * h00 + tan_start * h10 + end * h01 + tan_end * h11; } }; @@ -5814,7 +5816,7 @@ struct SceneFormatImporterGLTFInterpolate<Quaternion> { return p1.slerp(p2, c).normalized(); } - Quaternion bezier(const Quaternion start, const Quaternion control_1, const Quaternion control_2, const Quaternion end, const float t) { + Quaternion hermite(const Quaternion start, const Quaternion tan_start, const Quaternion end, const Quaternion tan_end, const float t) { ERR_FAIL_COND_V_MSG(!start.is_normalized(), Quaternion(), vformat("The start quaternion %s must be normalized.", start)); ERR_FAIL_COND_V_MSG(!end.is_normalized(), Quaternion(), vformat("The end quaternion %s must be normalized.", end)); @@ -5879,14 +5881,15 @@ T GLTFDocument::_interpolate_track(const Vector<real_t> &p_times, const Vector<T return p_values[(p_times.size() - 1) * 3 + 1]; } - const float c = (p_time - p_times[idx]) / (p_times[idx + 1] - p_times[idx]); + const float td = (p_times[idx + 1] - p_times[idx]); + const float c = (p_time - p_times[idx]) / td; const T &from = p_values[idx * 3 + 1]; - const T c1 = from + p_values[idx * 3 + 2]; + const T tan_from = td * p_values[idx * 3 + 2]; const T &to = p_values[idx * 3 + 4]; - const T c2 = to + p_values[idx * 3 + 3]; + const T tan_to = td * p_values[idx * 3 + 3]; - return interp.bezier(from, c1, c2, to, c); + return interp.hermite(from, tan_from, to, tan_to, c); } break; } |