[Bf-blender-cvs] [3a1e6bc1d58] blender-v3.1-release: Fix T96430: new OBJ exporter wrong normals for non-uniform scale, and wrong face order for negative scale
Aras Pranckevicius
noreply at git.blender.org
Wed Mar 23 12:23:10 CET 2022
Commit: 3a1e6bc1d5807b732536c73170f11268fb398726
Author: Aras Pranckevicius
Date: Sat Mar 19 16:20:22 2022 -0400
Branches: blender-v3.1-release
https://developer.blender.org/rB3a1e6bc1d5807b732536c73170f11268fb398726
Fix T96430: new OBJ exporter wrong normals for non-uniform scale, and wrong face order for negative scale
The new 3.1+ OBJ exporter did not have correct logic when faced with
non-uniform & mirrored (negative on odd number of axes) object scale:
- Normals were not transformed correctly (should use inverse transpose of the matrix),
and were not normalized,
- Face order was not "flipped" when transform has negative scale on odd number of axes
(visible when using "face orientation" viewport overlay).
Cherry-picked from 8aa365745a78, with minor conflict fixes.
Reviewed By: Howard Trickey
Differential Revision: https://developer.blender.org/D14343
===================================================================
M source/blender/io/wavefront_obj/exporter/obj_export_file_writer.cc
M source/blender/io/wavefront_obj/exporter/obj_export_file_writer.hh
M source/blender/io/wavefront_obj/exporter/obj_export_mesh.cc
M source/blender/io/wavefront_obj/exporter/obj_export_mesh.hh
M source/blender/io/wavefront_obj/tests/obj_exporter_tests.cc
===================================================================
diff --git a/source/blender/io/wavefront_obj/exporter/obj_export_file_writer.cc b/source/blender/io/wavefront_obj/exporter/obj_export_file_writer.cc
index 38163af64b6..4eea2e51521 100644
--- a/source/blender/io/wavefront_obj/exporter/obj_export_file_writer.cc
+++ b/source/blender/io/wavefront_obj/exporter/obj_export_file_writer.cc
@@ -54,56 +54,109 @@ const char *MATERIAL_GROUP_DISABLED = "";
void OBJWriter::write_vert_uv_normal_indices(Span<int> vert_indices,
Span<int> uv_indices,
- Span<int> normal_indices) const
+ Span<int> normal_indices,
+ bool flip) const
{
BLI_assert(vert_indices.size() == uv_indices.size() &&
vert_indices.size() == normal_indices.size());
+ const int vertex_offset = index_offsets_.vertex_offset + 1;
+ const int uv_offset = index_offsets_.uv_vertex_offset + 1;
+ const int normal_offset = index_offsets_.normal_offset + 1;
+ const int n = vert_indices.size();
file_handler_->write<eOBJSyntaxElement::poly_element_begin>();
- for (int j = 0; j < vert_indices.size(); j++) {
- file_handler_->write<eOBJSyntaxElement::vertex_uv_normal_indices>(
- vert_indices[j] + index_offsets_.vertex_offset + 1,
- uv_indices[j] + index_offsets_.uv_vertex_offset + 1,
- normal_indices[j] + index_offsets_.normal_offset + 1);
+ if (!flip) {
+ for (int j = 0; j < n; ++j) {
+ file_handler_->write<eOBJSyntaxElement::vertex_uv_normal_indices>(
+ vert_indices[j] + vertex_offset,
+ uv_indices[j] + uv_offset,
+ normal_indices[j] + normal_offset);
+ }
+ }
+ else {
+ /* For a transform that is mirrored (negative scale on odd number of axes),
+ * we want to flip the face index order. Start from the same index, and
+ * then go backwards. Same logic in other write_*_indices functions below. */
+ for (int k = 0; k < n; ++k) {
+ int j = k == 0 ? 0 : n - k;
+ file_handler_->write<eOBJSyntaxElement::vertex_uv_normal_indices>(
+ vert_indices[j] + vertex_offset,
+ uv_indices[j] + uv_offset,
+ normal_indices[j] + normal_offset);
+ }
}
file_handler_->write<eOBJSyntaxElement::poly_element_end>();
}
void OBJWriter::write_vert_normal_indices(Span<int> vert_indices,
Span<int> /*uv_indices*/,
- Span<int> normal_indices) const
+ Span<int> normal_indices,
+ bool flip) const
{
BLI_assert(vert_indices.size() == normal_indices.size());
+ const int vertex_offset = index_offsets_.vertex_offset + 1;
+ const int normal_offset = index_offsets_.normal_offset + 1;
+ const int n = vert_indices.size();
file_handler_->write<eOBJSyntaxElement::poly_element_begin>();
- for (int j = 0; j < vert_indices.size(); j++) {
- file_handler_->write<eOBJSyntaxElement::vertex_normal_indices>(
- vert_indices[j] + index_offsets_.vertex_offset + 1,
- normal_indices[j] + index_offsets_.normal_offset + 1);
+ if (!flip) {
+ for (int j = 0; j < n; ++j) {
+ file_handler_->write<eOBJSyntaxElement::vertex_normal_indices>(
+ vert_indices[j] + vertex_offset, normal_indices[j] + normal_offset);
+ }
+ }
+ else {
+ for (int k = 0; k < n; ++k) {
+ int j = k == 0 ? 0 : n - k;
+ file_handler_->write<eOBJSyntaxElement::vertex_normal_indices>(
+ vert_indices[j] + vertex_offset, normal_indices[j] + normal_offset);
+ }
}
file_handler_->write<eOBJSyntaxElement::poly_element_end>();
}
void OBJWriter::write_vert_uv_indices(Span<int> vert_indices,
Span<int> uv_indices,
- Span<int> /*normal_indices*/) const
+ Span<int> /*normal_indices*/,
+ bool flip) const
{
BLI_assert(vert_indices.size() == uv_indices.size());
+ const int vertex_offset = index_offsets_.vertex_offset + 1;
+ const int uv_offset = index_offsets_.uv_vertex_offset + 1;
+ const int n = vert_indices.size();
file_handler_->write<eOBJSyntaxElement::poly_element_begin>();
- for (int j = 0; j < vert_indices.size(); j++) {
- file_handler_->write<eOBJSyntaxElement::vertex_uv_indices>(
- vert_indices[j] + index_offsets_.vertex_offset + 1,
- uv_indices[j] + index_offsets_.uv_vertex_offset + 1);
+ if (!flip) {
+ for (int j = 0; j < n; ++j) {
+ file_handler_->write<eOBJSyntaxElement::vertex_uv_indices>(vert_indices[j] + vertex_offset,
+ uv_indices[j] + uv_offset);
+ }
+ }
+ else {
+ for (int k = 0; k < n; ++k) {
+ int j = k == 0 ? 0 : n - k;
+ file_handler_->write<eOBJSyntaxElement::vertex_uv_indices>(vert_indices[j] + vertex_offset,
+ uv_indices[j] + uv_offset);
+ }
}
file_handler_->write<eOBJSyntaxElement::poly_element_end>();
}
void OBJWriter::write_vert_indices(Span<int> vert_indices,
Span<int> /*uv_indices*/,
- Span<int> /*normal_indices*/) const
+ Span<int> /*normal_indices*/,
+ bool flip) const
{
+ const int vertex_offset = index_offsets_.vertex_offset + 1;
+ const int n = vert_indices.size();
file_handler_->write<eOBJSyntaxElement::poly_element_begin>();
- for (const int vert_index : vert_indices) {
- file_handler_->write<eOBJSyntaxElement::vertex_indices>(vert_index +
- index_offsets_.vertex_offset + 1);
+ if (!flip) {
+ for (int j = 0; j < n; ++j) {
+ file_handler_->write<eOBJSyntaxElement::vertex_indices>(vert_indices[j] + vertex_offset);
+ }
+ }
+ else {
+ for (int k = 0; k < n; ++k) {
+ int j = k == 0 ? 0 : n - k;
+ file_handler_->write<eOBJSyntaxElement::vertex_indices>(vert_indices[j] + vertex_offset);
+ }
}
file_handler_->write<eOBJSyntaxElement::poly_element_end>();
}
@@ -297,7 +350,10 @@ void OBJWriter::write_poly_elements(const OBJMesh &obj_mesh_data,
last_poly_smooth_group = write_smooth_group(obj_mesh_data, i, last_poly_smooth_group);
last_poly_vertex_group = write_vertex_group(obj_mesh_data, i, last_poly_vertex_group);
last_poly_mat_nr = write_poly_material(obj_mesh_data, i, last_poly_mat_nr, matname_fn);
- (this->*poly_element_writer)(poly_vertex_indices, poly_uv_indices, poly_normal_indices);
+ (this->*poly_element_writer)(poly_vertex_indices,
+ poly_uv_indices,
+ poly_normal_indices,
+ obj_mesh_data.is_mirrored_transform());
}
}
diff --git a/source/blender/io/wavefront_obj/exporter/obj_export_file_writer.hh b/source/blender/io/wavefront_obj/exporter/obj_export_file_writer.hh
index 7385d9fabe2..1bbdb7a848c 100644
--- a/source/blender/io/wavefront_obj/exporter/obj_export_file_writer.hh
+++ b/source/blender/io/wavefront_obj/exporter/obj_export_file_writer.hh
@@ -135,7 +135,8 @@ class OBJWriter : NonMovable, NonCopyable {
private:
using func_vert_uv_normal_indices = void (OBJWriter::*)(Span<int> vert_indices,
Span<int> uv_indices,
- Span<int> normal_indices) const;
+ Span<int> normal_indices,
+ bool flip) const;
/**
* \return Writer function with appropriate polygon-element syntax.
*/
@@ -146,25 +147,29 @@ class OBJWriter : NonMovable, NonCopyable {
*/
void write_vert_uv_normal_indices(Span<int> vert_indices,
Span<int> uv_indices,
- Span<int> normal_indices) const;
+ Span<int> normal_indices,
+ bool flip) const;
/**
* Write one line of polygon indices as "f v1//vn1 v2//vn2 ...".
*/
void write_vert_normal_indices(Span<int> vert_indices,
Span<int> /*uv_indices*/,
- Span<int> normal_indices) const;
+ Span<int> normal_indices,
+ bool flip) const;
/**
* Write one line of polygon indices as "f v1/vt1 v2/vt2 ...".
*/
void write_vert_uv_indices(Span<int> vert_indices,
Span<int> uv_indices,
- Span<int> /*normal_indices*/) const;
+ Span<int> /*normal_indices*/,
+ bool flip) const;
/**
* Write one line of polygon indices as "f v1 v2 ...".
*/
void write_vert_indices(Span<int> vert_indices,
Span<int> /*uv_indices*/,
- Span<int> /*normal_indices*/) const;
+ Span<int> /*normal_indices*/,
+ bool flip) const;
};
/**
diff --git a/source/blender/io/wavefront_obj/exporter/obj_export_mesh.cc b/source/blender/io/wavefront_obj/exporter/obj_export_mesh.cc
index 66f10009875..c1b9b0a8ccf 100644
--- a/source/blender/io/wavefront_obj/exporter/obj_export_mesh.cc
+++ b/source/blender/io/wavefront_obj/exporter/obj_export_mesh.cc
@@ -125,6 +125,13 @@ void OBJMesh::set_world_axes_transform(const eTransformAxisForward forward,
/* mul_m4_m3m4 does not transform last row of obmat, i.e. location data. */
mul_v3_m3v3(world_and_axes_transform_[3], axes_transform, export_object_eval_.obmat[3]);
world_and_axes_transform_[3][3] = export_object_eval_.obmat[3][3];
+
+ /* Normals need inverse transpose of the regular matrix to handle non-uniform scale. */
+ float normal_matrix[3][3];
+ copy_m3_m4(normal_matrix, world_and_axes_transform_);
+
@@ Diff output truncated at 10240 characters. @@
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