Files
workinf_Blender_Wasm/blender-5.2.0/intern/cycles/scene/mesh_displace.cpp
2026-08-12 04:47:48 -04:00

459 lines
16 KiB
C++

/* SPDX-FileCopyrightText: 2011-2022 Blender Foundation
*
* SPDX-License-Identifier: Apache-2.0 */
#include "device/device.h"
#include "integrator/shader_eval.h"
#include "scene/mesh.h"
#include "scene/object.h"
#include "scene/scene.h"
#include "scene/shader.h"
#include "util/progress.h"
CCL_NAMESPACE_BEGIN
/* Fill in coordinates for mesh displacement shader evaluation on device. */
static int fill_shader_input(const Scene *scene,
const Mesh *mesh,
const size_t object_index,
device_vector<KernelShaderEvalInput> &d_input)
{
int d_input_size = 0;
KernelShaderEvalInput *d_input_data = d_input.data();
const array<int> &mesh_shaders = mesh->get_shader();
const array<Node *> &mesh_used_shaders = mesh->get_used_shaders();
const int num_verts = mesh->num_verts();
vector<bool> done(num_verts, false);
const int num_triangles = mesh->num_triangles();
for (int i = 0; i < num_triangles; i++) {
const Mesh::Triangle t = mesh->get_triangle(i);
const int shader_index = mesh_shaders[i];
Shader *shader = (shader_index < mesh_used_shaders.size()) ?
static_cast<Shader *>(mesh_used_shaders[shader_index]) :
scene->default_surface;
if (!shader->has_displacement || shader->get_displacement_method() == DISPLACE_BUMP) {
continue;
}
for (int j = 0; j < 3; j++) {
if (done[t.v[j]]) {
continue;
}
done[t.v[j]] = true;
/* set up object, primitive and barycentric coordinates */
const int object = object_index;
const int prim = mesh->prim_offset + i;
float u;
float v;
switch (j) {
case 0:
u = 0.0f;
v = 0.0f;
break;
case 1:
u = 1.0f;
v = 0.0f;
break;
default:
u = 0.0f;
v = 1.0f;
break;
}
/* back */
KernelShaderEvalInput in;
in.object = object;
in.prim = prim;
in.u = u;
in.v = v;
d_input_data[d_input_size++] = in;
}
}
return d_input_size;
}
/* Read back mesh displacement shader output. */
static void read_shader_output(const Scene *scene,
Mesh *mesh,
const device_vector<float> &d_output)
{
const array<int> &mesh_shaders = mesh->get_shader();
const array<Node *> &mesh_used_shaders = mesh->get_used_shaders();
packed_float3 *mesh_verts = mesh->get_position_for_write();
const int num_verts = mesh->num_verts();
const int num_motion_steps = mesh->get_motion_steps();
vector<bool> done(num_verts, false);
const float *d_output_data = d_output.data();
int d_output_index = 0;
Attribute *attr_P = mesh->attributes.find(ATTR_STD_POSITION);
if (!attr_P->has_motion()) {
attr_P = nullptr;
}
const int num_triangles = mesh->num_triangles();
for (int i = 0; i < num_triangles; i++) {
const Mesh::Triangle t = mesh->get_triangle(i);
const int shader_index = mesh_shaders[i];
Shader *shader = (shader_index < mesh_used_shaders.size()) ?
static_cast<Shader *>(mesh_used_shaders[shader_index]) :
scene->default_surface;
if (!shader->has_displacement || shader->get_displacement_method() == DISPLACE_BUMP) {
continue;
}
for (int j = 0; j < 3; j++) {
if (!done[t.v[j]]) {
done[t.v[j]] = true;
float3 off = make_float3(d_output_data[d_output_index + 0],
d_output_data[d_output_index + 1],
d_output_data[d_output_index + 2]);
d_output_index += 3;
/* Avoid illegal vertex coordinates. */
off = ensure_finite(off);
mesh_verts[t.v[j]] = float3(mesh_verts[t.v[j]]) + off;
if (attr_P != nullptr) {
for (int step = 1; step < num_motion_steps; step++) {
packed_float3 *mP = attr_P->data_for_write<packed_float3>(step);
mP[t.v[j]] = float3(mP[t.v[j]]) + off;
}
}
}
}
}
}
/* Compute unnormalized vertex normals by accumulating face normals from the
* specified triangles. Vertices not touched by any included triangle are left
* at zero. */
static void compute_vertex_normals(const Mesh *mesh,
const packed_float3 *verts_data,
const vector<bool> &tri_recompute,
vector<float3> &vN)
{
const size_t num_triangles = mesh->num_triangles();
for (size_t i = 0; i < num_triangles; i++) {
if (tri_recompute[i]) {
const Mesh::Triangle triangle = mesh->get_triangle(i);
for (size_t j = 0; j < 3; j++) {
vN[triangle.v[j]] = zero_float3();
}
}
}
for (size_t i = 0; i < num_triangles; i++) {
if (tri_recompute[i]) {
const Mesh::Triangle triangle = mesh->get_triangle(i);
const float3 fN = triangle.compute_normal(verts_data);
for (size_t j = 0; j < 3; j++) {
vN[triangle.v[j]] += fN;
}
}
}
}
/* Store normalized vertex normals into a packed_normal attribute, applying
* flip for negative-scaled transforms. Only vertices of included triangles
* are written. */
static void store_vertex_normals(const Mesh *mesh,
const vector<float3> &vN_float,
const vector<bool> &tri_recompute,
const bool flip,
packed_normal *vN)
{
const size_t num_verts = mesh->num_verts();
vector<bool> done(num_verts, false);
for (size_t i = 0; i < mesh->num_triangles(); i++) {
if (tri_recompute[i]) {
const Mesh::Triangle triangle = mesh->get_triangle(i);
for (size_t j = 0; j < 3; j++) {
const int vert = triangle.v[j];
if (done[vert]) {
continue;
}
float3 N = safe_normalize(vN_float[vert]);
if (flip) {
N = -N;
}
vN[vert] = packed_normal(N);
done[vert] = true;
}
}
}
}
/* Apply vertex normal delta from displacement to a set of corner normals.
* For flat shaded triangles, use the new face normal directly. */
static void apply_corner_normal_delta(const Mesh *mesh,
const packed_float3 *verts_data,
const vector<float3> &post_vN,
const float3 *pre_vN,
const vector<bool> &tri_recompute,
const bool flip,
packed_normal *cN)
{
const bool *smooth = mesh->get_smooth().data();
for (size_t i = 0; i < mesh->num_triangles(); i++) {
if (!tri_recompute[i]) {
continue;
}
const Mesh::Triangle triangle = mesh->get_triangle(i);
if (smooth && smooth[i]) {
for (size_t j = 0; j < 3; j++) {
const int vert = triangle.v[j];
float3 post = safe_normalize(post_vN[vert]);
if (flip) {
post = -post;
}
const float3 delta = post - pre_vN[vert];
cN[i * 3 + j] = packed_normal(safe_normalize(cN[i * 3 + j].decode() + delta));
}
}
else {
float3 post_fN = triangle.compute_normal(verts_data);
if (flip) {
post_fN = -post_fN;
}
for (size_t j = 0; j < 3; j++) {
cN[i * 3 + j] = packed_normal(post_fN);
}
}
}
}
/* Save pre-displacement vertex normals so we can compute the delta after
* displacement and apply it to corner normals. Also saves per motion step. */
static void save_pre_displacement_normals(const Mesh *mesh,
array<float3> &pre_displace_vN,
vector<array<float3>> &pre_displace_motion_vN)
{
const size_t num_verts = mesh->num_verts();
const size_t num_triangles = mesh->num_triangles();
const bool flip = mesh->transform_negative_scaled;
const vector<bool> all_tris(num_triangles, true);
auto compute_normals = [&](const packed_float3 *verts_data) {
array<float3> result;
result.resize(num_verts, zero_float3());
vector<float3> vN(num_verts, zero_float3());
compute_vertex_normals(mesh, verts_data, all_tris, vN);
for (size_t i = 0; i < num_verts; i++) {
float3 N = safe_normalize(vN[i]);
if (flip) {
N = -N;
}
result[i] = N;
}
return result;
};
pre_displace_vN = compute_normals(mesh->get_position());
const Attribute *attr_P = mesh->attributes.find(ATTR_STD_POSITION);
const Attribute *attr_cN = mesh->attributes.find(ATTR_STD_CORNER_NORMAL);
if (mesh->has_motion_blur() && attr_P->has_motion() && attr_cN && attr_cN->has_motion()) {
const int num_steps = mesh->get_motion_steps() - 1;
pre_displace_motion_vN.resize(num_steps);
for (int attr_step = 1; attr_step <= num_steps; attr_step++) {
const packed_float3 *mP = attr_P->data<packed_float3>(attr_step);
pre_displace_motion_vN[attr_step - 1] = compute_normals(mP);
}
}
}
/* Update corner normals after displacement, including motion blur steps. */
static void recompute_displaced_corner_normals(Mesh *mesh,
const vector<float3> &vN_float,
const array<float3> &pre_displace_vN,
const vector<array<float3>> &pre_displace_motion_vN,
const vector<bool> &tri_recompute,
const bool flip)
{
/* Static corner normals. */
Attribute *attr_cN = mesh->attributes.find(ATTR_STD_CORNER_NORMAL);
apply_corner_normal_delta(mesh,
mesh->get_position(),
vN_float,
pre_displace_vN.data(),
tri_recompute,
flip,
attr_cN->data_for_write<packed_normal>());
/* Motion corner normals. */
Attribute *attr_P = mesh->attributes.find(ATTR_STD_POSITION);
if (mesh->has_motion_blur() && attr_P->has_motion() && attr_cN && attr_cN->has_motion()) {
const size_t num_verts = mesh->num_verts();
for (int attr_step = 1; attr_step < mesh->get_motion_steps(); attr_step++) {
const packed_float3 *mP = attr_P->data<packed_float3>(attr_step);
packed_normal *mcN = attr_cN->data_for_write<packed_normal>(attr_step);
vector<float3> mN_float(num_verts, zero_float3());
compute_vertex_normals(mesh, mP, tri_recompute, mN_float);
apply_corner_normal_delta(mesh,
mP,
mN_float,
pre_displace_motion_vN[attr_step - 1].data(),
tri_recompute,
flip,
mcN);
}
}
}
/* Update vertex normals after displacement, including motion blur steps. */
static void recompute_displaced_vertex_normals(Mesh *mesh,
const vector<float3> &vN_float,
const vector<bool> &tri_recompute,
const bool flip)
{
const size_t num_verts = mesh->num_verts();
/* Static vertex normals. */
Attribute *attr_vN = mesh->attributes.find(ATTR_STD_VERTEX_NORMAL);
store_vertex_normals(
mesh, vN_float, tri_recompute, flip, attr_vN->data_for_write<packed_normal>());
/* Motion vertex normals. */
Attribute *attr_P = mesh->attributes.find(ATTR_STD_POSITION);
if (mesh->has_motion_blur() && attr_P->has_motion() && attr_vN && attr_vN->has_motion()) {
for (int attr_step = 1; attr_step < mesh->get_motion_steps(); attr_step++) {
const packed_float3 *mP = attr_P->data<packed_float3>(attr_step);
packed_normal *mN = attr_vN->data_for_write<packed_normal>(attr_step);
vector<float3> mN_float(num_verts, zero_float3());
compute_vertex_normals(mesh, mP, tri_recompute, mN_float);
store_vertex_normals(mesh, mN_float, tri_recompute, flip, mN);
}
}
}
bool GeometryManager::displace(Device *device, Scene *scene, Mesh *mesh, Progress &progress)
{
/* verify if we have a displacement shader */
if (!mesh->has_true_displacement()) {
return false;
}
const size_t num_verts = mesh->num_verts();
const size_t num_triangles = mesh->num_triangles();
if (num_triangles == 0) {
return false;
}
/* Corner normals for sharp edges and faces should be preserved, but we can not
* individually displace corners as the mesh would break apart. Instead we
* compute the delta between vertex normals before and after displacement and
* apply the delta to corner normals. */
bool need_recompute_vertex_normals = false;
bool need_recompute_all_vertex_normals = false;
const bool has_corner_normals = mesh->attributes.find(ATTR_STD_CORNER_NORMAL) != nullptr;
array<float3> pre_displace_vN;
vector<array<float3>> pre_displace_motion_vN;
if (has_corner_normals) {
need_recompute_vertex_normals = true;
need_recompute_all_vertex_normals = true;
save_pre_displacement_normals(mesh, pre_displace_vN, pre_displace_motion_vN);
}
/* Add undisplaced attributes right before doing displacement. */
mesh->add_undisplaced(scene);
const string msg = string_printf("Computing Displacement %s", mesh->name.c_str());
progress.set_status("Updating Mesh", msg);
/* find object index. todo: is arbitrary */
size_t object_index = OBJECT_NONE;
for (size_t i = 0; i < scene->objects.size(); i++) {
if (scene->objects[i]->get_geometry() == mesh) {
object_index = i;
break;
}
}
/* Evaluate shader on device. */
ShaderEval shader_eval(device, progress);
if (!shader_eval.eval(
SHADER_EVAL_DISPLACE,
num_verts,
3,
[scene, mesh, object_index](device_vector<KernelShaderEvalInput> &d_input) {
return fill_shader_input(scene, mesh, object_index, d_input);
},
[scene, mesh](const device_vector<float> &d_output) {
read_shader_output(scene, mesh, d_output);
}))
{
return false;
}
/* For displacement method both, we don't need to recompute the vertex normals
* as bump mapping in the shader will already alter the vertex normal, so we start
* from the non-displaced vertex normals to avoid applying the perturbation twice. */
for (Node *node : mesh->get_used_shaders()) {
Shader *shader = static_cast<Shader *>(node);
if (shader->has_displacement && shader->get_displacement_method() == DISPLACE_TRUE) {
need_recompute_vertex_normals = true;
break;
}
}
if (need_recompute_vertex_normals) {
const bool flip = mesh->transform_negative_scaled;
vector<bool> tri_recompute(num_triangles, need_recompute_all_vertex_normals);
if (!need_recompute_all_vertex_normals) {
for (size_t i = 0; i < num_triangles; i++) {
const int shader_index = mesh->shader[i];
Shader *shader = (shader_index < mesh->used_shaders.size()) ?
static_cast<Shader *>(mesh->used_shaders[shader_index]) :
scene->default_surface;
tri_recompute[i] = shader->has_displacement &&
shader->get_displacement_method() == DISPLACE_TRUE;
}
}
vector<float3> vN_float(num_verts, zero_float3());
compute_vertex_normals(mesh, mesh->get_position(), tri_recompute, vN_float);
if (has_corner_normals) {
recompute_displaced_corner_normals(
mesh, vN_float, pre_displace_vN, pre_displace_motion_vN, tri_recompute, flip);
}
else {
recompute_displaced_vertex_normals(mesh, vN_float, tri_recompute, flip);
}
}
mesh->update_tangents(scene, false);
return true;
}
CCL_NAMESPACE_END