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/*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* The Original Code is Copyright (C) 2019 Blender Foundation.
* All rights reserved.
*/
#include "usd_writer_mesh.h"
#include "usd_hierarchy_iterator.h"
#include <pxr/usd/usdGeom/mesh.h>
#include <pxr/usd/usdShade/material.h>
#include <pxr/usd/usdShade/materialBindingAPI.h>
#include "BLI_assert.h"
#include "BLI_math_vector.h"
#include "BKE_customdata.h"
#include "BKE_lib_id.h"
#include "BKE_material.h"
#include "BKE_mesh.h"
#include "BKE_modifier.h"
#include "BKE_object.h"
#include "DEG_depsgraph.h"
#include "DNA_layer_types.h"
#include "DNA_mesh_types.h"
#include "DNA_meshdata_types.h"
#include "DNA_modifier_types.h"
#include "DNA_object_fluidsim_types.h"
#include "DNA_particle_types.h"
namespace blender {
namespace io {
namespace usd {
USDGenericMeshWriter::USDGenericMeshWriter(const USDExporterContext &ctx) : USDAbstractWriter(ctx)
{
}
bool USDGenericMeshWriter::is_supported(const HierarchyContext *context) const
{
Object *object = context->object;
bool is_dupli = context->duplicator != nullptr;
int base_flag;
if (is_dupli) {
/* Construct the object's base flags from its dupli-parent, just like is done in
* deg_objects_dupli_iterator_next(). Without this, the visibility check below will fail. Doing
* this here, instead of a more suitable location in AbstractHierarchyIterator, prevents
* copying the Object for every dupli. */
base_flag = object->base_flag;
object->base_flag = context->duplicator->base_flag | BASE_FROM_DUPLI;
}
int visibility = BKE_object_visibility(object,
usd_export_context_.export_params.evaluation_mode);
if (is_dupli) {
object->base_flag = base_flag;
}
return (visibility & OB_VISIBLE_SELF) != 0;
}
void USDGenericMeshWriter::do_write(HierarchyContext &context)
{
Object *object_eval = context.object;
bool needsfree = false;
Mesh *mesh = get_export_mesh(object_eval, needsfree);
if (mesh == nullptr) {
return;
}
try {
write_mesh(context, mesh);
if (needsfree) {
free_export_mesh(mesh);
}
}
catch (...) {
if (needsfree) {
free_export_mesh(mesh);
}
throw;
}
}
void USDGenericMeshWriter::free_export_mesh(Mesh *mesh)
{
BKE_id_free(nullptr, mesh);
}
struct USDMeshData {
pxr::VtArray<pxr::GfVec3f> points;
pxr::VtIntArray face_vertex_counts;
pxr::VtIntArray face_indices;
std::map<short, pxr::VtIntArray> face_groups;
/* The length of this array specifies the number of creases on the surface. Each element gives
* the number of (must be adjacent) vertices in each crease, whose indices are linearly laid out
* in the 'creaseIndices' attribute. Since each crease must be at least one edge long, each
* element of this array should be greater than one. */
pxr::VtIntArray crease_lengths;
/* The indices of all vertices forming creased edges. The size of this array must be equal to the
* sum of all elements of the 'creaseLengths' attribute. */
pxr::VtIntArray crease_vertex_indices;
/* The per-crease or per-edge sharpness for all creases (Usd.Mesh.SHARPNESS_INFINITE for a
* perfectly sharp crease). Since 'creaseLengths' encodes the number of vertices in each crease,
* the number of elements in this array will be either len(creaseLengths) or the sum over all X
* of (creaseLengths[X] - 1). Note that while the RI spec allows each crease to have either a
* single sharpness or a value per-edge, USD will encode either a single sharpness per crease on
* a mesh, or sharpnesses for all edges making up the creases on a mesh. */
pxr::VtFloatArray crease_sharpnesses;
};
void USDGenericMeshWriter::write_uv_maps(const Mesh *mesh, pxr::UsdGeomMesh usd_mesh)
{
pxr::UsdTimeCode timecode = get_export_time_code();
const CustomData *ldata = &mesh->ldata;
for (int layer_idx = 0; layer_idx < ldata->totlayer; layer_idx++) {
const CustomDataLayer *layer = &ldata->layers[layer_idx];
if (layer->type != CD_MLOOPUV) {
continue;
}
/* UV coordinates are stored in a Primvar on the Mesh, and can be referenced from materials.
* The primvar name is the same as the UV Map name. This is to allow the standard name "st"
* for texture coordinates by naming the UV Map as such, without having to guess which UV Map
* is the "standard" one. */
pxr::TfToken primvar_name(pxr::TfMakeValidIdentifier(layer->name));
pxr::UsdGeomPrimvar uv_coords_primvar = usd_mesh.CreatePrimvar(
primvar_name, pxr::SdfValueTypeNames->TexCoord2fArray, pxr::UsdGeomTokens->faceVarying);
MLoopUV *mloopuv = static_cast<MLoopUV *>(layer->data);
pxr::VtArray<pxr::GfVec2f> uv_coords;
for (int loop_idx = 0; loop_idx < mesh->totloop; loop_idx++) {
uv_coords.push_back(pxr::GfVec2f(mloopuv[loop_idx].uv));
}
if (!uv_coords_primvar.HasValue()) {
uv_coords_primvar.Set(uv_coords, pxr::UsdTimeCode::Default());
}
const pxr::UsdAttribute &uv_coords_attr = uv_coords_primvar.GetAttr();
usd_value_writer_.SetAttribute(uv_coords_attr, pxr::VtValue(uv_coords), timecode);
}
}
void USDGenericMeshWriter::write_mesh(HierarchyContext &context, Mesh *mesh)
{
pxr::UsdTimeCode timecode = get_export_time_code();
pxr::UsdTimeCode defaultTime = pxr::UsdTimeCode::Default();
pxr::UsdStageRefPtr stage = usd_export_context_.stage;
const pxr::SdfPath &usd_path = usd_export_context_.usd_path;
pxr::UsdGeomMesh usd_mesh = pxr::UsdGeomMesh::Define(stage, usd_path);
USDMeshData usd_mesh_data;
get_geometry_data(mesh, usd_mesh_data);
if (usd_export_context_.export_params.use_instancing && context.is_instance()) {
// This object data is instanced, just reference the original instead of writing a copy.
if (context.export_path == context.original_export_path) {
printf("USD ref error: export path is reference path: %s\n", context.export_path.c_str());
BLI_assert(!"USD reference error");
return;
}
pxr::SdfPath ref_path(context.original_export_path);
if (!usd_mesh.GetPrim().GetReferences().AddInternalReference(ref_path)) {
/* See this URL for a description fo why referencing may fail"
* https://graphics.pixar.com/usd/docs/api/class_usd_references.html#Usd_Failing_References
*/
printf("USD Export warning: unable to add reference from %s to %s, not instancing object\n",
context.export_path.c_str(),
context.original_export_path.c_str());
return;
}
/* The material path will be of the form </_materials/{material name}>, which is outside the
subtree pointed to by ref_path. As a result, the referenced data is not allowed to point out
of its own subtree. It does work when we override the material with exactly the same path,
though.*/
if (usd_export_context_.export_params.export_materials) {
assign_materials(context, usd_mesh, usd_mesh_data.face_groups);
}
return;
}
pxr::UsdAttribute attr_points = usd_mesh.CreatePointsAttr(pxr::VtValue(), true);
pxr::UsdAttribute attr_face_vertex_counts = usd_mesh.CreateFaceVertexCountsAttr(pxr::VtValue(),
true);
pxr::UsdAttribute attr_face_vertex_indices = usd_mesh.CreateFaceVertexIndicesAttr(pxr::VtValue(),
true);
if (!attr_points.HasValue()) {
// Provide the initial value as default. This makes USD write the value as constant if they
// don't change over time.
attr_points.Set(usd_mesh_data.points, defaultTime);
attr_face_vertex_counts.Set(usd_mesh_data.face_vertex_counts, defaultTime);
attr_face_vertex_indices.Set(usd_mesh_data.face_indices, defaultTime);
}
usd_value_writer_.SetAttribute(attr_points, pxr::VtValue(usd_mesh_data.points), timecode);
usd_value_writer_.SetAttribute(
attr_face_vertex_counts, pxr::VtValue(usd_mesh_data.face_vertex_counts), timecode);
usd_value_writer_.SetAttribute(
attr_face_vertex_indices, pxr::VtValue(usd_mesh_data.face_indices), timecode);
if (!usd_mesh_data.crease_lengths.empty()) {
pxr::UsdAttribute attr_crease_lengths = usd_mesh.CreateCreaseLengthsAttr(pxr::VtValue(), true);
pxr::UsdAttribute attr_crease_indices = usd_mesh.CreateCreaseIndicesAttr(pxr::VtValue(), true);
pxr::UsdAttribute attr_crease_sharpness = usd_mesh.CreateCreaseSharpnessesAttr(pxr::VtValue(),
true);
if (!attr_crease_lengths.HasValue()) {
attr_crease_lengths.Set(usd_mesh_data.crease_lengths, defaultTime);
attr_crease_indices.Set(usd_mesh_data.crease_vertex_indices, defaultTime);
attr_crease_sharpness.Set(usd_mesh_data.crease_sharpnesses, defaultTime);
}
usd_value_writer_.SetAttribute(
attr_crease_lengths, pxr::VtValue(usd_mesh_data.crease_lengths), timecode);
usd_value_writer_.SetAttribute(
attr_crease_indices, pxr::VtValue(usd_mesh_data.crease_vertex_indices), timecode);
usd_value_writer_.SetAttribute(
attr_crease_sharpness, pxr::VtValue(usd_mesh_data.crease_sharpnesses), timecode);
}
if (usd_export_context_.export_params.export_uvmaps) {
write_uv_maps(mesh, usd_mesh);
}
if (usd_export_context_.export_params.export_normals) {
write_normals(mesh, usd_mesh);
}
write_surface_velocity(context.object, mesh, usd_mesh);
// TODO(Sybren): figure out what happens when the face groups change.
if (frame_has_been_written_) {
return;
}
usd_mesh.CreateSubdivisionSchemeAttr().Set(pxr::UsdGeomTokens->none);
if (usd_export_context_.export_params.export_materials) {
assign_materials(context, usd_mesh, usd_mesh_data.face_groups);
}
}
static void get_vertices(const Mesh *mesh, USDMeshData &usd_mesh_data)
{
usd_mesh_data.points.reserve(mesh->totvert);
const MVert *verts = mesh->mvert;
for (int i = 0; i < mesh->totvert; ++i) {
usd_mesh_data.points.push_back(pxr::GfVec3f(verts[i].co));
}
}
static void get_loops_polys(const Mesh *mesh, USDMeshData &usd_mesh_data)
{
/* Only construct face groups (a.k.a. geometry subsets) when we need them for material
* assignments. */
bool construct_face_groups = mesh->totcol > 1;
usd_mesh_data.face_vertex_counts.reserve(mesh->totpoly);
usd_mesh_data.face_indices.reserve(mesh->totloop);
MLoop *mloop = mesh->mloop;
MPoly *mpoly = mesh->mpoly;
for (int i = 0; i < mesh->totpoly; ++i, ++mpoly) {
MLoop *loop = mloop + mpoly->loopstart;
usd_mesh_data.face_vertex_counts.push_back(mpoly->totloop);
for (int j = 0; j < mpoly->totloop; ++j, ++loop) {
usd_mesh_data.face_indices.push_back(loop->v);
}
if (construct_face_groups) {
usd_mesh_data.face_groups[mpoly->mat_nr].push_back(i);
}
}
}
static void get_creases(const Mesh *mesh, USDMeshData &usd_mesh_data)
{
const float factor = 1.0f / 255.0f;
MEdge *edge = mesh->medge;
float sharpness;
for (int edge_idx = 0, totedge = mesh->totedge; edge_idx < totedge; ++edge_idx, ++edge) {
if (edge->crease == 0) {
continue;
}
if (edge->crease == 255) {
sharpness = pxr::UsdGeomMesh::SHARPNESS_INFINITE;
}
else {
sharpness = static_cast<float>(edge->crease) * factor;
}
usd_mesh_data.crease_vertex_indices.push_back(edge->v1);
usd_mesh_data.crease_vertex_indices.push_back(edge->v2);
usd_mesh_data.crease_lengths.push_back(2);
usd_mesh_data.crease_sharpnesses.push_back(sharpness);
}
}
void USDGenericMeshWriter::get_geometry_data(const Mesh *mesh, USDMeshData &usd_mesh_data)
{
get_vertices(mesh, usd_mesh_data);
get_loops_polys(mesh, usd_mesh_data);
get_creases(mesh, usd_mesh_data);
}
void USDGenericMeshWriter::assign_materials(const HierarchyContext &context,
pxr::UsdGeomMesh usd_mesh,
const MaterialFaceGroups &usd_face_groups)
{
if (context.object->totcol == 0) {
return;
}
/* Binding a material to a geometry subset isn't supported by the Hydra GL viewport yet,
* which is why we always bind the first material to the entire mesh. See
* https://github.com/PixarAnimationStudios/USD/issues/542 for more info. */
bool mesh_material_bound = false;
pxr::UsdShadeMaterialBindingAPI material_binding_api(usd_mesh.GetPrim());
for (short mat_num = 0; mat_num < context.object->totcol; mat_num++) {
Material *material = BKE_object_material_get(context.object, mat_num + 1);
if (material == nullptr) {
continue;
}
pxr::UsdShadeMaterial usd_material = ensure_usd_material(material);
material_binding_api.Bind(usd_material);
/* USD seems to support neither per-material nor per-face-group double-sidedness, so we just
* use the flag from the first non-empty material slot. */
usd_mesh.CreateDoubleSidedAttr(
pxr::VtValue((material->blend_flag & MA_BL_CULL_BACKFACE) == 0));
mesh_material_bound = true;
break;
}
if (!mesh_material_bound) {
/* Blender defaults to double-sided, but USD to single-sided. */
usd_mesh.CreateDoubleSidedAttr(pxr::VtValue(true));
}
if (!mesh_material_bound || usd_face_groups.size() < 2) {
/* Either all material slots were empty or there is only one material in use. As geometry
* subsets are only written when actually used to assign a material, and the mesh already has
* the material assigned, there is no need to continue. */
return;
}
// Define a geometry subset per material.
for (const MaterialFaceGroups::value_type &face_group : usd_face_groups) {
short material_number = face_group.first;
const pxr::VtIntArray &face_indices = face_group.second;
Material *material = BKE_object_material_get(context.object, material_number + 1);
if (material == nullptr) {
continue;
}
pxr::UsdShadeMaterial usd_material = ensure_usd_material(material);
pxr::TfToken material_name = usd_material.GetPath().GetNameToken();
pxr::UsdGeomSubset usd_face_subset = material_binding_api.CreateMaterialBindSubset(
material_name, face_indices);
pxr::UsdShadeMaterialBindingAPI(usd_face_subset.GetPrim()).Bind(usd_material);
}
}
void USDGenericMeshWriter::write_normals(const Mesh *mesh, pxr::UsdGeomMesh usd_mesh)
{
pxr::UsdTimeCode timecode = get_export_time_code();
const float(*lnors)[3] = static_cast<float(*)[3]>(CustomData_get_layer(&mesh->ldata, CD_NORMAL));
pxr::VtVec3fArray loop_normals;
loop_normals.reserve(mesh->totloop);
if (lnors != nullptr) {
/* Export custom loop normals. */
for (int loop_idx = 0, totloop = mesh->totloop; loop_idx < totloop; ++loop_idx) {
loop_normals.push_back(pxr::GfVec3f(lnors[loop_idx]));
}
}
else {
/* Compute the loop normals based on the 'smooth' flag. */
float normal[3];
MPoly *mpoly = mesh->mpoly;
const MVert *mvert = mesh->mvert;
for (int poly_idx = 0, totpoly = mesh->totpoly; poly_idx < totpoly; ++poly_idx, ++mpoly) {
MLoop *mloop = mesh->mloop + mpoly->loopstart;
if ((mpoly->flag & ME_SMOOTH) == 0) {
/* Flat shaded, use common normal for all verts. */
BKE_mesh_calc_poly_normal(mpoly, mloop, mvert, normal);
pxr::GfVec3f pxr_normal(normal);
for (int loop_idx = 0; loop_idx < mpoly->totloop; ++loop_idx) {
loop_normals.push_back(pxr_normal);
}
}
else {
/* Smooth shaded, use individual vert normals. */
for (int loop_idx = 0; loop_idx < mpoly->totloop; ++loop_idx, ++mloop) {
normal_short_to_float_v3(normal, mvert[mloop->v].no);
loop_normals.push_back(pxr::GfVec3f(normal));
}
}
}
}
pxr::UsdAttribute attr_normals = usd_mesh.CreateNormalsAttr(pxr::VtValue(), true);
if (!attr_normals.HasValue()) {
attr_normals.Set(loop_normals, pxr::UsdTimeCode::Default());
}
usd_value_writer_.SetAttribute(attr_normals, pxr::VtValue(loop_normals), timecode);
usd_mesh.SetNormalsInterpolation(pxr::UsdGeomTokens->faceVarying);
}
void USDGenericMeshWriter::write_surface_velocity(Object *object,
const Mesh *mesh,
pxr::UsdGeomMesh usd_mesh)
{
/* Only velocities from the fluid simulation are exported. This is the most important case,
* though, as the baked mesh changes topology all the time, and thus computing the velocities
* at import time in a post-processing step is hard. */
ModifierData *md = BKE_modifiers_findby_type(object, eModifierType_Fluidsim);
if (md == nullptr) {
return;
}
/* Check that the fluid sim modifier is enabled and has useful data. */
const bool use_render = (DEG_get_mode(usd_export_context_.depsgraph) == DAG_EVAL_RENDER);
const ModifierMode required_mode = use_render ? eModifierMode_Render : eModifierMode_Realtime;
const Scene *scene = DEG_get_evaluated_scene(usd_export_context_.depsgraph);
if (!BKE_modifier_is_enabled(scene, md, required_mode)) {
return;
}
FluidsimModifierData *fsmd = reinterpret_cast<FluidsimModifierData *>(md);
if (!fsmd->fss || fsmd->fss->type != OB_FLUIDSIM_DOMAIN) {
return;
}
FluidsimSettings *fss = fsmd->fss;
if (!fss->meshVelocities) {
return;
}
/* Export per-vertex velocity vectors. */
pxr::VtVec3fArray usd_velocities;
usd_velocities.reserve(mesh->totvert);
FluidVertexVelocity *mesh_velocities = fss->meshVelocities;
for (int vertex_idx = 0, totvert = mesh->totvert; vertex_idx < totvert;
++vertex_idx, ++mesh_velocities) {
usd_velocities.push_back(pxr::GfVec3f(mesh_velocities->vel));
}
pxr::UsdTimeCode timecode = get_export_time_code();
usd_mesh.CreateVelocitiesAttr().Set(usd_velocities, timecode);
}
USDMeshWriter::USDMeshWriter(const USDExporterContext &ctx) : USDGenericMeshWriter(ctx)
{
}
Mesh *USDMeshWriter::get_export_mesh(Object *object_eval, bool & /*r_needsfree*/)
{
return BKE_object_get_evaluated_mesh(object_eval);
}
} // namespace usd
} // namespace io
} // namespace blender
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