Files
filament/third_party/meshoptimizer/gltf/mesh.cpp
2022-10-17 09:57:58 -07:00

1003 lines
27 KiB
C++

// This file is part of gltfpack; see gltfpack.h for version/license details
#include "gltfpack.h"
#include <algorithm>
#include <math.h>
#include <string.h>
#include "../src/meshoptimizer.h"
static float inverseTranspose(float* result, const float* transform)
{
float m[4][4] = {};
memcpy(m, transform, 16 * sizeof(float));
float det =
m[0][0] * (m[1][1] * m[2][2] - m[2][1] * m[1][2]) -
m[0][1] * (m[1][0] * m[2][2] - m[1][2] * m[2][0]) +
m[0][2] * (m[1][0] * m[2][1] - m[1][1] * m[2][0]);
float invdet = (det == 0.f) ? 0.f : 1.f / det;
float r[4][4] = {};
r[0][0] = (m[1][1] * m[2][2] - m[2][1] * m[1][2]) * invdet;
r[1][0] = (m[0][2] * m[2][1] - m[0][1] * m[2][2]) * invdet;
r[2][0] = (m[0][1] * m[1][2] - m[0][2] * m[1][1]) * invdet;
r[0][1] = (m[1][2] * m[2][0] - m[1][0] * m[2][2]) * invdet;
r[1][1] = (m[0][0] * m[2][2] - m[0][2] * m[2][0]) * invdet;
r[2][1] = (m[1][0] * m[0][2] - m[0][0] * m[1][2]) * invdet;
r[0][2] = (m[1][0] * m[2][1] - m[2][0] * m[1][1]) * invdet;
r[1][2] = (m[2][0] * m[0][1] - m[0][0] * m[2][1]) * invdet;
r[2][2] = (m[0][0] * m[1][1] - m[1][0] * m[0][1]) * invdet;
r[3][3] = 1.f;
memcpy(result, r, 16 * sizeof(float));
return det;
}
static void transformPosition(float* res, const float* ptr, const float* transform)
{
float x = ptr[0] * transform[0] + ptr[1] * transform[4] + ptr[2] * transform[8] + transform[12];
float y = ptr[0] * transform[1] + ptr[1] * transform[5] + ptr[2] * transform[9] + transform[13];
float z = ptr[0] * transform[2] + ptr[1] * transform[6] + ptr[2] * transform[10] + transform[14];
res[0] = x;
res[1] = y;
res[2] = z;
}
static void transformNormal(float* res, const float* ptr, const float* transform)
{
float x = ptr[0] * transform[0] + ptr[1] * transform[4] + ptr[2] * transform[8];
float y = ptr[0] * transform[1] + ptr[1] * transform[5] + ptr[2] * transform[9];
float z = ptr[0] * transform[2] + ptr[1] * transform[6] + ptr[2] * transform[10];
float l = sqrtf(x * x + y * y + z * z);
float s = (l == 0.f) ? 0.f : 1 / l;
res[0] = x * s;
res[1] = y * s;
res[2] = z * s;
}
// assumes mesh & target are structurally identical
static void transformMesh(Mesh& target, const Mesh& mesh, const cgltf_node* node)
{
assert(target.streams.size() == mesh.streams.size());
assert(target.indices.size() == mesh.indices.size());
float transform[16];
cgltf_node_transform_world(node, transform);
float transforminvt[16];
float det = inverseTranspose(transforminvt, transform);
for (size_t si = 0; si < mesh.streams.size(); ++si)
{
const Stream& source = mesh.streams[si];
Stream& stream = target.streams[si];
assert(source.type == stream.type);
assert(source.data.size() == stream.data.size());
if (stream.type == cgltf_attribute_type_position)
{
for (size_t i = 0; i < stream.data.size(); ++i)
transformPosition(stream.data[i].f, source.data[i].f, transform);
}
else if (stream.type == cgltf_attribute_type_normal)
{
for (size_t i = 0; i < stream.data.size(); ++i)
transformNormal(stream.data[i].f, source.data[i].f, transforminvt);
}
else if (stream.type == cgltf_attribute_type_tangent)
{
for (size_t i = 0; i < stream.data.size(); ++i)
transformNormal(stream.data[i].f, source.data[i].f, transform);
}
}
// copy indices so that we can modify them below
target.indices = mesh.indices;
if (det < 0 && mesh.type == cgltf_primitive_type_triangles)
{
// negative scale means we need to flip face winding
for (size_t i = 0; i < target.indices.size(); i += 3)
std::swap(target.indices[i + 0], target.indices[i + 1]);
}
}
bool compareMeshTargets(const Mesh& lhs, const Mesh& rhs)
{
if (lhs.targets != rhs.targets)
return false;
if (lhs.target_weights.size() != rhs.target_weights.size())
return false;
for (size_t i = 0; i < lhs.target_weights.size(); ++i)
if (lhs.target_weights[i] != rhs.target_weights[i])
return false;
if (lhs.target_names.size() != rhs.target_names.size())
return false;
for (size_t i = 0; i < lhs.target_names.size(); ++i)
if (strcmp(lhs.target_names[i], rhs.target_names[i]) != 0)
return false;
return true;
}
bool compareMeshVariants(const Mesh& lhs, const Mesh& rhs)
{
if (lhs.variants.size() != rhs.variants.size())
return false;
for (size_t i = 0; i < lhs.variants.size(); ++i)
{
if (lhs.variants[i].variant != rhs.variants[i].variant)
return false;
if (lhs.variants[i].material != rhs.variants[i].material)
return false;
}
return true;
}
bool compareMeshNodes(const Mesh& lhs, const Mesh& rhs)
{
if (lhs.nodes.size() != rhs.nodes.size())
return false;
for (size_t i = 0; i < lhs.nodes.size(); ++i)
if (lhs.nodes[i] != rhs.nodes[i])
return false;
return true;
}
static bool canMergeMeshNodes(cgltf_node* lhs, cgltf_node* rhs, const Settings& settings)
{
if (lhs == rhs)
return true;
if (lhs->parent != rhs->parent)
return false;
bool lhs_transform = lhs->has_translation | lhs->has_rotation | lhs->has_scale | lhs->has_matrix | (!!lhs->weights);
bool rhs_transform = rhs->has_translation | rhs->has_rotation | rhs->has_scale | rhs->has_matrix | (!!rhs->weights);
if (lhs_transform || rhs_transform)
return false;
if (settings.keep_nodes)
{
if (lhs->name && *lhs->name)
return false;
if (rhs->name && *rhs->name)
return false;
}
// we can merge nodes that don't have transforms of their own and have the same parent
// this is helpful when instead of splitting mesh into primitives, DCCs split mesh into mesh nodes
return true;
}
static bool canMergeMeshes(const Mesh& lhs, const Mesh& rhs, const Settings& settings)
{
if (lhs.scene != rhs.scene)
return false;
if (lhs.nodes.size() != rhs.nodes.size())
return false;
for (size_t i = 0; i < lhs.nodes.size(); ++i)
if (!canMergeMeshNodes(lhs.nodes[i], rhs.nodes[i], settings))
return false;
if (lhs.instances.size() || rhs.instances.size())
return false;
if (lhs.material != rhs.material)
return false;
if (lhs.skin != rhs.skin)
return false;
if (lhs.type != rhs.type)
return false;
if (!compareMeshTargets(lhs, rhs))
return false;
if (!compareMeshVariants(lhs, rhs))
return false;
if (lhs.indices.empty() != rhs.indices.empty())
return false;
if (lhs.streams.size() != rhs.streams.size())
return false;
for (size_t i = 0; i < lhs.streams.size(); ++i)
if (lhs.streams[i].type != rhs.streams[i].type || lhs.streams[i].index != rhs.streams[i].index || lhs.streams[i].target != rhs.streams[i].target)
return false;
return true;
}
static void mergeMeshes(Mesh& target, const Mesh& mesh)
{
assert(target.streams.size() == mesh.streams.size());
size_t vertex_offset = target.streams[0].data.size();
size_t index_offset = target.indices.size();
for (size_t i = 0; i < target.streams.size(); ++i)
target.streams[i].data.insert(target.streams[i].data.end(), mesh.streams[i].data.begin(), mesh.streams[i].data.end());
target.indices.resize(target.indices.size() + mesh.indices.size());
size_t index_count = mesh.indices.size();
for (size_t i = 0; i < index_count; ++i)
target.indices[index_offset + i] = unsigned(vertex_offset + mesh.indices[i]);
}
void mergeMeshInstances(Mesh& mesh)
{
if (mesh.nodes.empty())
return;
// fast-path: for single instance meshes we transform in-place
if (mesh.nodes.size() == 1)
{
transformMesh(mesh, mesh, mesh.nodes[0]);
mesh.nodes.clear();
return;
}
Mesh base = mesh;
Mesh transformed = base;
for (size_t i = 0; i < mesh.streams.size(); ++i)
{
mesh.streams[i].data.clear();
mesh.streams[i].data.reserve(base.streams[i].data.size() * mesh.nodes.size());
}
mesh.indices.clear();
mesh.indices.reserve(base.indices.size() * mesh.nodes.size());
for (size_t i = 0; i < mesh.nodes.size(); ++i)
{
transformMesh(transformed, base, mesh.nodes[i]);
mergeMeshes(mesh, transformed);
}
mesh.nodes.clear();
}
void mergeMeshes(std::vector<Mesh>& meshes, const Settings& settings)
{
for (size_t i = 0; i < meshes.size(); ++i)
{
Mesh& target = meshes[i];
if (target.streams.empty())
continue;
size_t target_vertices = target.streams[0].data.size();
size_t target_indices = target.indices.size();
size_t last_merged = i;
for (size_t j = i + 1; j < meshes.size(); ++j)
{
Mesh& mesh = meshes[j];
if (!mesh.streams.empty() && canMergeMeshes(target, mesh, settings))
{
target_vertices += mesh.streams[0].data.size();
target_indices += mesh.indices.size();
last_merged = j;
}
}
for (size_t j = 0; j < target.streams.size(); ++j)
target.streams[j].data.reserve(target_vertices);
target.indices.reserve(target_indices);
for (size_t j = i + 1; j <= last_merged; ++j)
{
Mesh& mesh = meshes[j];
if (!mesh.streams.empty() && canMergeMeshes(target, mesh, settings))
{
mergeMeshes(target, mesh);
mesh.streams.clear();
mesh.indices.clear();
mesh.nodes.clear();
mesh.instances.clear();
}
}
assert(target.streams[0].data.size() == target_vertices);
assert(target.indices.size() == target_indices);
}
}
void filterEmptyMeshes(std::vector<Mesh>& meshes)
{
size_t write = 0;
for (size_t i = 0; i < meshes.size(); ++i)
{
Mesh& mesh = meshes[i];
if (mesh.streams.empty())
continue;
if (mesh.streams[0].data.empty())
continue;
if (mesh.type != cgltf_primitive_type_points && mesh.indices.empty())
continue;
// the following code is roughly equivalent to meshes[write] = std::move(mesh)
std::vector<Stream> streams;
streams.swap(mesh.streams);
std::vector<unsigned int> indices;
indices.swap(mesh.indices);
meshes[write] = mesh;
meshes[write].streams.swap(streams);
meshes[write].indices.swap(indices);
write++;
}
meshes.resize(write);
}
static bool hasColors(const std::vector<Attr>& data)
{
const float threshold = 0.99f;
for (size_t i = 0; i < data.size(); ++i)
{
const Attr& a = data[i];
if (a.f[0] < threshold || a.f[1] < threshold || a.f[2] < threshold || a.f[3] < threshold)
return true;
}
return false;
}
static bool hasDeltas(const std::vector<Attr>& data)
{
const float threshold = 0.01f;
for (size_t i = 0; i < data.size(); ++i)
{
const Attr& a = data[i];
if (fabsf(a.f[0]) > threshold || fabsf(a.f[1]) > threshold || fabsf(a.f[2]) > threshold)
return true;
}
return false;
}
void filterStreams(Mesh& mesh, const MaterialInfo& mi)
{
bool morph_normal = false;
bool morph_tangent = false;
int keep_texture_set = -1;
for (size_t i = 0; i < mesh.streams.size(); ++i)
{
Stream& stream = mesh.streams[i];
if (stream.target)
{
morph_normal = morph_normal || (stream.type == cgltf_attribute_type_normal && hasDeltas(stream.data));
morph_tangent = morph_tangent || (stream.type == cgltf_attribute_type_tangent && hasDeltas(stream.data));
}
if (stream.type == cgltf_attribute_type_texcoord && (mi.textureSetMask & (1u << stream.index)) != 0)
{
keep_texture_set = std::max(keep_texture_set, stream.index);
}
}
size_t write = 0;
for (size_t i = 0; i < mesh.streams.size(); ++i)
{
Stream& stream = mesh.streams[i];
if (stream.type == cgltf_attribute_type_texcoord && stream.index > keep_texture_set)
continue;
if (stream.type == cgltf_attribute_type_tangent && !mi.needsTangents)
continue;
if ((stream.type == cgltf_attribute_type_joints || stream.type == cgltf_attribute_type_weights) && !mesh.skin)
continue;
if (stream.type == cgltf_attribute_type_color && !hasColors(stream.data))
continue;
if (stream.target && stream.type == cgltf_attribute_type_normal && !morph_normal)
continue;
if (stream.target && stream.type == cgltf_attribute_type_tangent && !morph_tangent)
continue;
// the following code is roughly equivalent to streams[write] = std::move(stream)
std::vector<Attr> data;
data.swap(stream.data);
mesh.streams[write] = stream;
mesh.streams[write].data.swap(data);
write++;
}
mesh.streams.resize(write);
}
static void reindexMesh(Mesh& mesh)
{
size_t total_vertices = mesh.streams[0].data.size();
size_t total_indices = mesh.indices.size();
std::vector<meshopt_Stream> streams;
for (size_t i = 0; i < mesh.streams.size(); ++i)
{
if (mesh.streams[i].target)
continue;
assert(mesh.streams[i].data.size() == total_vertices);
meshopt_Stream stream = {&mesh.streams[i].data[0], sizeof(Attr), sizeof(Attr)};
streams.push_back(stream);
}
if (streams.empty())
return;
std::vector<unsigned int> remap(total_vertices);
size_t unique_vertices = meshopt_generateVertexRemapMulti(&remap[0], &mesh.indices[0], total_indices, total_vertices, &streams[0], streams.size());
assert(unique_vertices <= total_vertices);
meshopt_remapIndexBuffer(&mesh.indices[0], &mesh.indices[0], total_indices, &remap[0]);
for (size_t i = 0; i < mesh.streams.size(); ++i)
{
assert(mesh.streams[i].data.size() == total_vertices);
meshopt_remapVertexBuffer(&mesh.streams[i].data[0], &mesh.streams[i].data[0], total_vertices, sizeof(Attr), &remap[0]);
mesh.streams[i].data.resize(unique_vertices);
}
}
static void filterTriangles(Mesh& mesh)
{
assert(mesh.type == cgltf_primitive_type_triangles);
unsigned int* indices = &mesh.indices[0];
size_t total_indices = mesh.indices.size();
size_t write = 0;
for (size_t i = 0; i < total_indices; i += 3)
{
unsigned int a = indices[i + 0], b = indices[i + 1], c = indices[i + 2];
if (a != b && a != c && b != c)
{
indices[write + 0] = a;
indices[write + 1] = b;
indices[write + 2] = c;
write += 3;
}
}
mesh.indices.resize(write);
}
static Stream* getStream(Mesh& mesh, cgltf_attribute_type type, int index = 0)
{
for (size_t i = 0; i < mesh.streams.size(); ++i)
if (mesh.streams[i].type == type && mesh.streams[i].index == index)
return &mesh.streams[i];
return 0;
}
static void simplifyMesh(Mesh& mesh, float threshold, bool aggressive)
{
assert(mesh.type == cgltf_primitive_type_triangles);
if (mesh.indices.empty())
return;
const Stream* positions = getStream(mesh, cgltf_attribute_type_position);
if (!positions)
return;
size_t vertex_count = mesh.streams[0].data.size();
size_t target_index_count = size_t(double(mesh.indices.size() / 3) * threshold) * 3;
float target_error = 1e-2f;
float target_error_aggressive = 1e-1f;
if (target_index_count < 1)
return;
std::vector<unsigned int> indices(mesh.indices.size());
indices.resize(meshopt_simplify(&indices[0], &mesh.indices[0], mesh.indices.size(), positions->data[0].f, vertex_count, sizeof(Attr), target_index_count, target_error));
mesh.indices.swap(indices);
// Note: if the simplifier got stuck, we can try to reindex without normals/tangents and retry
// For now we simply fall back to aggressive simplifier instead
// if the precise simplifier got "stuck", we'll try to simplify using the sloppy simplifier; this is only used when aggressive simplification is enabled as it breaks attribute discontinuities
if (aggressive && mesh.indices.size() > target_index_count)
{
indices.resize(meshopt_simplifySloppy(&indices[0], &mesh.indices[0], mesh.indices.size(), positions->data[0].f, vertex_count, sizeof(Attr), target_index_count, target_error_aggressive));
mesh.indices.swap(indices);
}
}
static void optimizeMesh(Mesh& mesh, bool compressmore)
{
assert(mesh.type == cgltf_primitive_type_triangles);
if (mesh.indices.empty())
return;
size_t vertex_count = mesh.streams[0].data.size();
if (compressmore)
meshopt_optimizeVertexCacheStrip(&mesh.indices[0], &mesh.indices[0], mesh.indices.size(), vertex_count);
else
meshopt_optimizeVertexCache(&mesh.indices[0], &mesh.indices[0], mesh.indices.size(), vertex_count);
std::vector<unsigned int> remap(vertex_count);
size_t unique_vertices = meshopt_optimizeVertexFetchRemap(&remap[0], &mesh.indices[0], mesh.indices.size(), vertex_count);
assert(unique_vertices <= vertex_count);
meshopt_remapIndexBuffer(&mesh.indices[0], &mesh.indices[0], mesh.indices.size(), &remap[0]);
for (size_t i = 0; i < mesh.streams.size(); ++i)
{
assert(mesh.streams[i].data.size() == vertex_count);
meshopt_remapVertexBuffer(&mesh.streams[i].data[0], &mesh.streams[i].data[0], vertex_count, sizeof(Attr), &remap[0]);
mesh.streams[i].data.resize(unique_vertices);
}
}
struct BoneInfluence
{
float i;
float w;
};
struct BoneInfluenceWeightPredicate
{
bool operator()(const BoneInfluence& lhs, const BoneInfluence& rhs) const
{
return lhs.w > rhs.w;
}
};
static void filterBones(Mesh& mesh)
{
const int kMaxGroups = 8;
std::pair<Stream*, Stream*> groups[kMaxGroups];
int group_count = 0;
// gather all joint/weight groups; each group contains 4 bone influences
for (int i = 0; i < kMaxGroups; ++i)
{
Stream* jg = getStream(mesh, cgltf_attribute_type_joints, int(i));
Stream* wg = getStream(mesh, cgltf_attribute_type_weights, int(i));
if (!jg || !wg)
break;
groups[group_count++] = std::make_pair(jg, wg);
}
if (group_count == 0)
return;
// weights below cutoff can't be represented in quantized 8-bit storage
const float weight_cutoff = 0.5f / 255.f;
size_t vertex_count = mesh.streams[0].data.size();
BoneInfluence inf[kMaxGroups * 4] = {};
for (size_t i = 0; i < vertex_count; ++i)
{
int count = 0;
// gather all bone influences for this vertex
for (int j = 0; j < group_count; ++j)
{
const Attr& ja = groups[j].first->data[i];
const Attr& wa = groups[j].second->data[i];
for (int k = 0; k < 4; ++k)
if (wa.f[k] > weight_cutoff)
{
inf[count].i = ja.f[k];
inf[count].w = wa.f[k];
count++;
}
}
// pick top 4 influences; this also sorts resulting influences by weight which helps renderers that use influence subset in shader LODs
std::sort(inf, inf + count, BoneInfluenceWeightPredicate());
// copy the top 4 influences back into stream 0 - we will remove other streams at the end
Attr& ja = groups[0].first->data[i];
Attr& wa = groups[0].second->data[i];
for (int k = 0; k < 4; ++k)
{
if (k < count)
{
ja.f[k] = inf[k].i;
wa.f[k] = inf[k].w;
}
else
{
ja.f[k] = 0.f;
wa.f[k] = 0.f;
}
}
}
// remove redundant weight/joint streams
for (size_t i = 0; i < mesh.streams.size();)
{
Stream& s = mesh.streams[i];
if ((s.type == cgltf_attribute_type_joints || s.type == cgltf_attribute_type_weights) && s.index > 0)
mesh.streams.erase(mesh.streams.begin() + i);
else
++i;
}
}
static void simplifyPointMesh(Mesh& mesh, float threshold)
{
assert(mesh.type == cgltf_primitive_type_points);
if (threshold >= 1)
return;
const Stream* positions = getStream(mesh, cgltf_attribute_type_position);
if (!positions)
return;
size_t vertex_count = mesh.streams[0].data.size();
size_t target_vertex_count = size_t(double(vertex_count) * threshold);
if (target_vertex_count < 1)
return;
std::vector<unsigned int> indices(target_vertex_count);
indices.resize(meshopt_simplifyPoints(&indices[0], positions->data[0].f, vertex_count, sizeof(Attr), target_vertex_count));
std::vector<Attr> scratch(indices.size());
for (size_t i = 0; i < mesh.streams.size(); ++i)
{
std::vector<Attr>& data = mesh.streams[i].data;
assert(data.size() == vertex_count);
for (size_t j = 0; j < indices.size(); ++j)
scratch[j] = data[indices[j]];
data = scratch;
}
}
static void sortPointMesh(Mesh& mesh)
{
assert(mesh.type == cgltf_primitive_type_points);
const Stream* positions = getStream(mesh, cgltf_attribute_type_position);
if (!positions)
return;
size_t vertex_count = mesh.streams[0].data.size();
std::vector<unsigned int> remap(vertex_count);
meshopt_spatialSortRemap(&remap[0], positions->data[0].f, vertex_count, sizeof(Attr));
for (size_t i = 0; i < mesh.streams.size(); ++i)
{
assert(mesh.streams[i].data.size() == vertex_count);
meshopt_remapVertexBuffer(&mesh.streams[i].data[0], &mesh.streams[i].data[0], vertex_count, sizeof(Attr), &remap[0]);
}
}
void processMesh(Mesh& mesh, const Settings& settings)
{
switch (mesh.type)
{
case cgltf_primitive_type_points:
assert(mesh.indices.empty());
simplifyPointMesh(mesh, settings.simplify_threshold);
sortPointMesh(mesh);
break;
case cgltf_primitive_type_lines:
break;
case cgltf_primitive_type_triangles:
filterBones(mesh);
reindexMesh(mesh);
filterTriangles(mesh);
if (settings.simplify_threshold < 1)
simplifyMesh(mesh, settings.simplify_threshold, settings.simplify_aggressive);
optimizeMesh(mesh, settings.compressmore);
break;
default:
assert(!"Unknown primitive type");
}
}
#ifndef NDEBUG
extern MESHOPTIMIZER_API unsigned char* meshopt_simplifyDebugKind;
extern MESHOPTIMIZER_API unsigned int* meshopt_simplifyDebugLoop;
extern MESHOPTIMIZER_API unsigned int* meshopt_simplifyDebugLoopBack;
void debugSimplify(const Mesh& source, Mesh& kinds, Mesh& loops, float ratio)
{
Mesh mesh = source;
assert(mesh.type == cgltf_primitive_type_triangles);
// note: it's important to follow the same pipeline as processMesh
// otherwise the result won't match
filterBones(mesh);
reindexMesh(mesh);
filterTriangles(mesh);
// before simplification we need to setup target kind/loop arrays
size_t vertex_count = mesh.streams[0].data.size();
std::vector<unsigned char> kind(vertex_count);
std::vector<unsigned int> loop(vertex_count);
std::vector<unsigned int> loopback(vertex_count);
std::vector<unsigned char> live(vertex_count);
meshopt_simplifyDebugKind = &kind[0];
meshopt_simplifyDebugLoop = &loop[0];
meshopt_simplifyDebugLoopBack = &loopback[0];
simplifyMesh(mesh, ratio, /* aggressive= */ false);
meshopt_simplifyDebugKind = 0;
meshopt_simplifyDebugLoop = 0;
meshopt_simplifyDebugLoopBack = 0;
// fill out live info
for (size_t i = 0; i < mesh.indices.size(); ++i)
live[mesh.indices[i]] = true;
// color palette for display
static const Attr kPalette[] = {
{0.5f, 0.5f, 0.5f, 1.f}, // manifold
{0.f, 0.f, 1.f, 1.f}, // border
{0.f, 1.f, 0.f, 1.f}, // seam
{0.f, 1.f, 1.f, 1.f}, // complex
{1.f, 0.f, 0.f, 1.f}, // locked
};
// prepare meshes
kinds.nodes = mesh.nodes;
kinds.skin = mesh.skin;
loops.nodes = mesh.nodes;
loops.skin = mesh.skin;
for (size_t i = 0; i < mesh.streams.size(); ++i)
{
const Stream& stream = mesh.streams[i];
if (stream.target == 0 && (stream.type == cgltf_attribute_type_position || stream.type == cgltf_attribute_type_joints || stream.type == cgltf_attribute_type_weights))
{
kinds.streams.push_back(stream);
loops.streams.push_back(stream);
}
}
// transform kind/loop data into lines & points
Stream colors = {cgltf_attribute_type_color};
colors.data.resize(vertex_count);
for (size_t i = 0; i < vertex_count; ++i)
colors.data[i] = kPalette[kind[i]];
kinds.type = cgltf_primitive_type_points;
kinds.streams.push_back(colors);
for (size_t i = 0; i < vertex_count; ++i)
if (live[i] && kind[i] != 0)
kinds.indices.push_back(unsigned(i));
loops.type = cgltf_primitive_type_lines;
loops.streams.push_back(colors);
for (size_t i = 0; i < vertex_count; ++i)
if (live[i] && (kind[i] == 1 || kind[i] == 2))
{
if (loop[i] != ~0u && live[loop[i]])
{
loops.indices.push_back(unsigned(i));
loops.indices.push_back(loop[i]);
}
if (loopback[i] != ~0u && live[loopback[i]])
{
loops.indices.push_back(loopback[i]);
loops.indices.push_back(unsigned(i));
}
}
}
void debugMeshlets(const Mesh& source, Mesh& meshlets, Mesh& bounds, int max_vertices, bool scan)
{
Mesh mesh = source;
assert(mesh.type == cgltf_primitive_type_triangles);
reindexMesh(mesh);
if (scan)
optimizeMesh(mesh, false);
const Stream* positions = getStream(mesh, cgltf_attribute_type_position);
assert(positions);
const float cone_weight = 0.f;
size_t max_triangles = (max_vertices * 2 + 3) & ~3;
size_t max_meshlets = meshopt_buildMeshletsBound(mesh.indices.size(), max_vertices, max_triangles);
std::vector<meshopt_Meshlet> ml(max_meshlets);
std::vector<unsigned int> mlv(max_meshlets * max_vertices);
std::vector<unsigned char> mlt(max_meshlets * max_triangles * 3);
if (scan)
ml.resize(meshopt_buildMeshletsScan(&ml[0], &mlv[0], &mlt[0], &mesh.indices[0], mesh.indices.size(), positions->data.size(), max_vertices, max_triangles));
else
ml.resize(meshopt_buildMeshlets(&ml[0], &mlv[0], &mlt[0], &mesh.indices[0], mesh.indices.size(), positions->data[0].f, positions->data.size(), sizeof(Attr), max_vertices, max_triangles, cone_weight));
// generate meshlet meshes, using unique colors
meshlets.nodes = mesh.nodes;
Stream mv = {cgltf_attribute_type_position};
Stream mc = {cgltf_attribute_type_color};
for (size_t i = 0; i < ml.size(); ++i)
{
const meshopt_Meshlet& m = ml[i];
unsigned int h = unsigned(i);
h ^= h >> 13;
h *= 0x5bd1e995;
h ^= h >> 15;
Attr c = {{float(h & 0xff) / 255.f, float((h >> 8) & 0xff) / 255.f, float((h >> 16) & 0xff) / 255.f, 1.f}};
unsigned int offset = unsigned(mv.data.size());
for (size_t j = 0; j < m.vertex_count; ++j)
{
mv.data.push_back(positions->data[mlv[m.vertex_offset + j]]);
mc.data.push_back(c);
}
for (size_t j = 0; j < m.triangle_count; ++j)
{
meshlets.indices.push_back(offset + mlt[m.triangle_offset + j * 3 + 0]);
meshlets.indices.push_back(offset + mlt[m.triangle_offset + j * 3 + 1]);
meshlets.indices.push_back(offset + mlt[m.triangle_offset + j * 3 + 2]);
}
}
meshlets.type = cgltf_primitive_type_triangles;
meshlets.streams.push_back(mv);
meshlets.streams.push_back(mc);
// generate bounds meshes, using a sphere per meshlet
bounds.nodes = mesh.nodes;
Stream bv = {cgltf_attribute_type_position};
Stream bc = {cgltf_attribute_type_color};
for (size_t i = 0; i < ml.size(); ++i)
{
const meshopt_Meshlet& m = ml[i];
meshopt_Bounds mb = meshopt_computeMeshletBounds(&mlv[m.vertex_offset], &mlt[m.triangle_offset], m.triangle_count, positions->data[0].f, positions->data.size(), sizeof(Attr));
unsigned int h = unsigned(i);
h ^= h >> 13;
h *= 0x5bd1e995;
h ^= h >> 15;
Attr c = {{float(h & 0xff) / 255.f, float((h >> 8) & 0xff) / 255.f, float((h >> 16) & 0xff) / 255.f, 0.1f}};
unsigned int offset = unsigned(bv.data.size());
const int N = 10;
for (int y = 0; y <= N; ++y)
{
float u = (y == N) ? 0 : float(y) / N * 2 * 3.1415926f;
float sinu = sinf(u), cosu = cosf(u);
for (int x = 0; x <= N; ++x)
{
float v = float(x) / N * 3.1415926f;
float sinv = sinf(v), cosv = cosf(v);
float fx = sinv * cosu;
float fy = sinv * sinu;
float fz = cosv;
Attr p = {{mb.center[0] + mb.radius * fx, mb.center[1] + mb.radius * fy, mb.center[2] + mb.radius * fz, 1.f}};
bv.data.push_back(p);
bc.data.push_back(c);
}
}
for (int y = 0; y < N; ++y)
for (int x = 0; x < N; ++x)
{
bounds.indices.push_back(offset + (N + 1) * (y + 0) + (x + 0));
bounds.indices.push_back(offset + (N + 1) * (y + 0) + (x + 1));
bounds.indices.push_back(offset + (N + 1) * (y + 1) + (x + 0));
bounds.indices.push_back(offset + (N + 1) * (y + 1) + (x + 0));
bounds.indices.push_back(offset + (N + 1) * (y + 0) + (x + 1));
bounds.indices.push_back(offset + (N + 1) * (y + 1) + (x + 1));
}
}
bounds.type = cgltf_primitive_type_triangles;
bounds.streams.push_back(bv);
bounds.streams.push_back(bc);
}
#endif