vk-book/shared/Scene/Scene.cpp
2025-05-23 21:13:53 -04:00

493 lines
16 KiB
C++

#include "shared/Scene/Scene.h"
#include "shared/Utils.h"
#include <algorithm>
#include <numeric>
int addNode(Scene &scene, int parent, int level) {
const int node = (int)scene.hierarchy.size();
{
// TODO: resize aux arrays (local/global etc.)
scene.localTransform.push_back(glm::mat4(1.0f));
scene.globalTransform.push_back(glm::mat4(1.0f));
}
scene.hierarchy.push_back({.parent = parent, .lastSibling = -1});
if (parent > -1) {
// find first item (sibling)
const int s = scene.hierarchy[parent].firstChild;
if (s == -1) {
scene.hierarchy[parent].firstChild = node;
scene.hierarchy[node].lastSibling = node;
} else {
int dest = scene.hierarchy[s].lastSibling;
if (dest <= -1) {
// no cached lastSibling, iterate nextSibling indices
for (dest = s; scene.hierarchy[dest].nextSibling != -1;
dest = scene.hierarchy[dest].nextSibling)
;
}
scene.hierarchy[dest].nextSibling = node;
scene.hierarchy[s].lastSibling = node;
}
}
scene.hierarchy[node].level = level;
scene.hierarchy[node].nextSibling = -1;
scene.hierarchy[node].firstChild = -1;
return node;
}
void markAsChanged(Scene &scene, int node) {
const int level = scene.hierarchy[node].level;
scene.changedAtThisFrame[level].push_back(node);
// TODO: use non-recursive iteration with aux stack
for (int s = scene.hierarchy[node].firstChild; s != -1;
s = scene.hierarchy[s].nextSibling) {
markAsChanged(scene, s);
}
}
int findNodeByName(const Scene &scene, const std::string &name) {
// Extremely simple linear search without any hierarchy reference
// To support DFS/BFS searches separate traversal routines are needed
for (size_t i = 0; i < scene.localTransform.size(); i++)
if (scene.nameForNode.contains(i)) {
int strID = scene.nameForNode.at(i);
if (strID > -1)
if (scene.nodeNames[strID] == name)
return (int)i;
}
return -1;
}
bool mat4IsIdentity(const glm::mat4 &m);
void fprintfMat4(FILE *f, const glm::mat4 &m);
// CPU version of global transform update []
bool recalculateGlobalTransforms(Scene &scene) {
bool wasUpdated = false;
if (!scene.changedAtThisFrame[0].empty()) {
const int c = scene.changedAtThisFrame[0][0];
scene.globalTransform[c] = scene.localTransform[c];
scene.changedAtThisFrame[0].clear();
wasUpdated = true;
}
for (int i = 1; i < MAX_NODE_LEVEL; i++) {
for (int c : scene.changedAtThisFrame[i]) {
const int p = scene.hierarchy[c].parent;
scene.globalTransform[c] =
scene.globalTransform[p] * scene.localTransform[c];
}
wasUpdated |= !scene.changedAtThisFrame[i].empty();
scene.changedAtThisFrame[i].clear();
}
return wasUpdated;
}
void loadMap(FILE *f, std::unordered_map<uint32_t, uint32_t> &map) {
std::vector<uint32_t> ms;
uint32_t sz = 0;
fread(&sz, 1, sizeof(sz), f);
ms.resize(sz);
fread(ms.data(), sizeof(uint32_t), sz, f);
for (size_t i = 0; i < (sz / 2); i++)
map[ms[i * 2 + 0]] = ms[i * 2 + 1];
}
void loadScene(const char *fileName, Scene &scene) {
FILE *f = fopen(fileName, "rb");
if (!f) {
printf("Cannot open scene file '%s'. Please run SceneConverter from "
"Chapter7 and/or MergeMeshes from Chapter 9",
fileName);
return;
}
uint32_t sz = 0;
fread(&sz, sizeof(sz), 1, f);
scene.hierarchy.resize(sz);
scene.globalTransform.resize(sz);
scene.localTransform.resize(sz);
// TODO: check > -1
// TODO: recalculate changedAtThisLevel() - find max depth of a node [or save
// scene.maxLevel]
fread(scene.localTransform.data(), sizeof(glm::mat4), sz, f);
fread(scene.globalTransform.data(), sizeof(glm::mat4), sz, f);
fread(scene.hierarchy.data(), sizeof(Hierarchy), sz, f);
// Mesh for node [index to some list of buffers]
loadMap(f, scene.materialForNode);
loadMap(f, scene.meshForNode);
if (!feof(f)) {
loadMap(f, scene.nameForNode);
loadStringList(f, scene.nodeNames);
loadStringList(f, scene.materialNames);
}
fclose(f);
markAsChanged(scene, 0);
recalculateGlobalTransforms(scene);
}
void saveMap(FILE *f, const std::unordered_map<uint32_t, uint32_t> &map) {
std::vector<uint32_t> ms;
ms.reserve(map.size() * 2);
for (const auto &m : map) {
ms.push_back(m.first);
ms.push_back(m.second);
}
const uint32_t sz = static_cast<uint32_t>(ms.size());
fwrite(&sz, sizeof(sz), 1, f);
fwrite(ms.data(), sizeof(uint32_t), ms.size(), f);
}
void saveScene(const char *fileName, const Scene &scene) {
FILE *f = fopen(fileName, "wb");
const uint32_t sz = (uint32_t)scene.hierarchy.size();
fwrite(&sz, sizeof(sz), 1, f);
fwrite(scene.localTransform.data(), sizeof(glm::mat4), sz, f);
fwrite(scene.globalTransform.data(), sizeof(glm::mat4), sz, f);
fwrite(scene.hierarchy.data(), sizeof(Hierarchy), sz, f);
// Mesh for node [index to some list of buffers]
saveMap(f, scene.materialForNode);
saveMap(f, scene.meshForNode);
if (!scene.nodeNames.empty() && !scene.nameForNode.empty()) {
saveMap(f, scene.nameForNode);
saveStringList(f, scene.nodeNames);
saveStringList(f, scene.materialNames);
}
fclose(f);
}
bool mat4IsIdentity(const glm::mat4 &m) {
return (m[0][0] == 1 && m[0][1] == 0 && m[0][2] == 0 && m[0][3] == 0 &&
m[1][0] == 0 && m[1][1] == 1 && m[1][2] == 0 && m[1][3] == 0 &&
m[2][0] == 0 && m[2][1] == 0 && m[2][2] == 1 && m[2][3] == 0 &&
m[3][0] == 0 && m[3][1] == 0 && m[3][2] == 0 && m[3][3] == 1);
}
void fprintfMat4(FILE *f, const glm::mat4 &m) {
if (mat4IsIdentity(m)) {
fprintf(f, "Identity\n");
} else {
fprintf(f, "\n");
for (int i = 0; i < 4; i++) {
for (int j = 0; j < 4; j++)
fprintf(f, "%f ;", m[i][j]);
fprintf(f, "\n");
}
}
}
void dumpTransforms(const char *fileName, const Scene &scene) {
FILE *f = fopen(fileName, "a+");
for (size_t i = 0; i < scene.localTransform.size(); i++) {
fprintf(f, "Node[%d].localTransform: ", (int)i);
fprintfMat4(f, scene.localTransform[i]);
fprintf(f, "Node[%d].globalTransform: ", (int)i);
fprintfMat4(f, scene.globalTransform[i]);
fprintf(f, "Node[%d].globalDet = %f; localDet = %f\n", (int)i,
glm::determinant(scene.globalTransform[i]),
glm::determinant(scene.localTransform[i]));
}
fclose(f);
}
void printChangedNodes(const Scene &scene) {
for (int i = 0; i < MAX_NODE_LEVEL && (!scene.changedAtThisFrame[i].empty());
i++) {
printf("Changed at level(%d):\n", i);
for (const int &c : scene.changedAtThisFrame[i]) {
int p = scene.hierarchy[c].parent;
// scene.globalTransform_[c] = scene.globalTransform_[p] *
// scene.localTransform_[c];
printf(" Node %d. Parent = %d; LocalTransform: ", c, p);
fprintfMat4(stdout, scene.localTransform[i]);
if (p > -1) {
printf(" ParentGlobalTransform: ");
fprintfMat4(stdout, scene.globalTransform[p]);
}
}
}
}
// Shift all hierarchy components in the nodes
void shiftNodes(Scene &scene, int startOffset, int nodeCount, int shiftAmount) {
auto shiftNode = [shiftAmount](Hierarchy &node) {
if (node.parent > -1)
node.parent += shiftAmount;
if (node.firstChild > -1)
node.firstChild += shiftAmount;
if (node.nextSibling > -1)
node.nextSibling += shiftAmount;
if (node.lastSibling > -1)
node.lastSibling += shiftAmount;
// node->level does not require to be shifted
};
// If there are too many nodes, we can use std::execution::par with
// std::transform:
// std::transform(scene.hierarchy_.begin() + startOffset,
// scene.hierarchy_.begin() + nodeCount,
// scene.hierarchy_.begin() + startOffset,
// shiftNode);
// for (auto i = scene.hierarchy_.begin() + startOffset ; i !=
// scene.hierarchy_.begin() + nodeCount ; i++) shiftNode(*i);
for (int i = 0; i < nodeCount; i++)
shiftNode(scene.hierarchy[i + startOffset]);
}
using ItemMap = std::unordered_map<uint32_t, uint32_t>;
// Add the items from otherMap shifting indices and values along the way
void mergeMaps(ItemMap &m, const ItemMap &otherMap, int indexOffset,
int itemOffset) {
for (const auto &i : otherMap)
m[i.first + indexOffset] = i.second + itemOffset;
}
/**
There are different use cases for scene merging.
The simplest one is the direct "gluing" of multiple scenes into one [all the
material lists and mesh lists are merged and indices in all scene nodes are
shifted appropriately] The second one is creating a "grid" of objects (or
scenes) with the same material and mesh sets. For the second use case we need
two flags: 'mergeMeshes' and 'mergeMaterials' to avoid shifting mesh indices
*/
void mergeScenes(Scene &scene, const std::vector<Scene *> &scenes,
const std::vector<glm::mat4> &rootTransforms,
const std::vector<uint32_t> &meshCounts, bool mergeMeshes,
bool mergeMaterials) {
// Create new root node
scene.hierarchy = {{
.parent = -1,
.firstChild = 1,
.nextSibling = -1,
.lastSibling = -1,
.level = 0,
}};
scene.nameForNode[0] = 0;
scene.nodeNames = {"NewRoot"};
scene.localTransform.push_back(glm::mat4(1.f));
scene.globalTransform.push_back(glm::mat4(1.f));
if (scenes.empty())
return;
int offs = 1;
int meshOffs = 0;
int nameOffs = (int)scene.nodeNames.size();
int materialOfs = 0;
auto meshCount = meshCounts.begin();
if (!mergeMaterials)
scene.materialNames = scenes[0]->materialNames;
// FIXME: too much logic (for all the components in a scene, though mesh data
// and materials go separately - they're dedicated data lists)
for (const Scene *s : scenes) {
mergeVectors(scene.localTransform, s->localTransform);
mergeVectors(scene.globalTransform, s->globalTransform);
mergeVectors(scene.hierarchy, s->hierarchy);
mergeVectors(scene.nodeNames, s->nodeNames);
if (mergeMaterials)
mergeVectors(scene.materialNames, s->materialNames);
const int nodeCount = (int)s->hierarchy.size();
shiftNodes(scene, offs, nodeCount, offs);
mergeMaps(scene.meshForNode, s->meshForNode, offs,
mergeMeshes ? meshOffs : 0);
mergeMaps(scene.materialForNode, s->materialForNode, offs,
mergeMaterials ? materialOfs : 0);
mergeMaps(scene.nameForNode, s->nameForNode, offs, nameOffs);
offs += nodeCount;
materialOfs += (int)s->materialNames.size();
nameOffs += (int)s->nodeNames.size();
if (mergeMeshes) {
meshOffs += *meshCount;
meshCount++;
}
}
// fixing 'nextSibling' fields in the old roots (zero-index in all the scenes)
offs = 1;
int idx = 0;
for (const Scene *s : scenes) {
const int nodeCount = (int)s->hierarchy.size();
const bool isLast = (idx == scenes.size() - 1);
// calculate new next sibling for the old scene roots
const int next = isLast ? -1 : offs + nodeCount;
scene.hierarchy[offs].nextSibling = next;
// attach to new root
scene.hierarchy[offs].parent = 0;
// transform old root nodes, if the transforms are given
if (!rootTransforms.empty())
scene.localTransform[offs] =
rootTransforms[idx] * scene.localTransform[offs];
offs += nodeCount;
idx++;
}
// now, shift levels of all nodes below the root
for (auto i = scene.hierarchy.begin() + 1; i != scene.hierarchy.end(); i++)
i->level++;
}
void dumpSceneToDot(const char *fileName, const Scene &scene, int *visited) {
FILE *f = fopen(fileName, "w");
fprintf(f, "digraph G\n{\n");
for (size_t i = 0; i < scene.globalTransform.size(); i++) {
std::string name = "";
std::string extra = "";
if (scene.nameForNode.contains(i)) {
int strID = scene.nameForNode.at(i);
name = scene.nodeNames[strID];
}
if (visited) {
if (visited[i])
extra = ", color = red";
}
fprintf(f, "n%d [label=\"%s\" %s]\n", (int)i, name.c_str(), extra.c_str());
}
for (size_t i = 0; i < scene.hierarchy.size(); i++) {
int p = scene.hierarchy[i].parent;
if (p > -1)
fprintf(f, "\t n%d -> n%d\n", p, (int)i);
}
fprintf(f, "}\n");
fclose(f);
}
// A rather long algorithm (and the auxiliary routines) to delete a number of
// scene nodes from the hierarchy
// Add an index to a sorted index array
static void addUniqueIdx(std::vector<uint32_t> &v, uint32_t index) {
if (!std::binary_search(v.begin(), v.end(), index))
v.push_back(index);
}
// Recurse down from a node and collect all nodes which are already marked for
// deletion
static void collectNodesToDelete(const Scene &scene, int node,
std::vector<uint32_t> &nodes) {
for (int n = scene.hierarchy[node].firstChild; n != -1;
n = scene.hierarchy[n].nextSibling) {
addUniqueIdx(nodes, n);
collectNodesToDelete(scene, n, nodes);
}
}
int findLastNonDeletedItem(const Scene &scene,
const std::vector<int> &newIndices, int node) {
// we have to be more subtle:
// if the (newIndices[firstChild_] == -1), we should follow the link and
// extract the last non-removed item
// ..
if (node == -1)
return -1;
return (newIndices[node] == -1)
? findLastNonDeletedItem(scene, newIndices,
scene.hierarchy[node].nextSibling)
: newIndices[node];
}
void shiftMapIndices(std::unordered_map<uint32_t, uint32_t> &items,
const std::vector<int> &newIndices) {
std::unordered_map<uint32_t, uint32_t> newItems;
for (const auto &m : items) {
int newIndex = newIndices[m.first];
if (newIndex != -1)
newItems[newIndex] = m.second;
}
items = newItems;
}
// Approximately an O ( N * Log(N) * Log(M)) algorithm (N = scene.size, M =
// nodesToDelete.size) to delete a collection of nodes from scene graph
void deleteSceneNodes(Scene &scene,
const std::vector<uint32_t> &nodesToDelete) {
// 0) Add all the nodes down below in the hierarchy
auto indicesToDelete = nodesToDelete;
for (uint32_t i : indicesToDelete)
collectNodesToDelete(scene, i, indicesToDelete);
// aux array with node indices to keep track of the moved ones [moved =
// [](node) { return (node != nodes[node]); ]
std::vector<int> nodes(scene.hierarchy.size());
std::iota(nodes.begin(), nodes.end(), 0);
// 1.a) Move all the indicesToDelete to the end of 'nodes' array (and cut them
// off, a variation of swap'n'pop for multiple elements)
const size_t oldSize = nodes.size();
eraseSelected(nodes, indicesToDelete);
// 1.b) Make a newIndices[oldIndex] mapping table
std::vector<int> newIndices(oldSize, -1);
for (int i = 0; i < nodes.size(); i++)
newIndices[nodes[i]] = i;
// 2) Replace all non-null parent/firstChild/nextSibling pointers in all the
// nodes by new positions
auto nodeMover = [&scene, &newIndices](Hierarchy &h) {
return Hierarchy{
.parent = (h.parent != -1) ? newIndices[h.parent] : -1,
.firstChild = findLastNonDeletedItem(scene, newIndices, h.firstChild),
.nextSibling = findLastNonDeletedItem(scene, newIndices, h.nextSibling),
.lastSibling = findLastNonDeletedItem(scene, newIndices, h.lastSibling),
};
};
std::transform(scene.hierarchy.begin(), scene.hierarchy.end(),
scene.hierarchy.begin(), nodeMover);
// 3) Finally throw away the hierarchy items
eraseSelected(scene.hierarchy, indicesToDelete);
// 4) As in mergeScenes() routine we also have to adjust all the "components"
// (i.e., meshes, materials, names and transformations)
// 4a) Transformations are stored in arrays, so we just erase the items as we
// did with the scene.hierarchy_
eraseSelected(scene.localTransform, indicesToDelete);
eraseSelected(scene.globalTransform, indicesToDelete);
// 4b) All the maps should change the key values with the newIndices[] array
shiftMapIndices(scene.meshForNode, newIndices);
shiftMapIndices(scene.materialForNode, newIndices);
shiftMapIndices(scene.nameForNode, newIndices);
// 5) scene node names list is not modified, but in principle it can be
// (remove all non-used items and adjust the nameForNode_ map) 6) Material
// names list is not modified also, but if some materials fell out of use
}