yggdrasil75/stupidsimcpp
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added fluidsim to main

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yggdrasil75
2026-02-07 08:58:54 -05:00
parent 02361effc5
commit ca226d8c02
5 changed files with 186 additions and 88 deletions
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33
util/sim/fluidsim.hpp
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@@ -11,6 +11,7 @@
#include <cmath>
#include <random>
#include <algorithm>
#include <unordered_map>
#include "../util/grid/grid3eigen.hpp"
#include "../util/output/frame.hpp"
@@ -30,10 +31,10 @@ struct fluidParticle {
struct gridConfig {
float gridSizeCube = 8192;
const float SMOOTHING_RADIUS = 1024.0f;
const float REST_DENSITY = 0.00005f;
const float TIMESTEP = 0.016f;
const float G_ATTRACTION = 50.0f;
float SMOOTHING_RADIUS = 1024.0f;
float REST_DENSITY = 0.00005f;
float TIMESTEP = 0.016f;
float G_ATTRACTION = 50.0f;
};
Eigen::Matrix<float, 3, 1> posGen() {
@@ -170,20 +171,27 @@ private:
std::map<float, Eigen::Vector3f> gradientmap;
public:
gridConfig config;
float closeThresh = 0.01f * config.SMOOTHING_RADIUS;
float closeThresh;
Octree<fluidParticle> grid;
fluidSim() : grid({-config.gridSizeCube, -config.gridSizeCube, -config.gridSizeCube}, {config.gridSizeCube, config.gridSizeCube, config.gridSizeCube}) {
closeThresh = 0.01f * config.SMOOTHING_RADIUS;
grid.setBackgroundColor({0.1f, 0.1f, 0.2f});
gradientmap.emplace(0.0, Eigen::Vector3f(1, 0, 0));
gradientmap.emplace(0.5, Eigen::Vector3f(0, 1, 0));
gradientmap.emplace(1.0, Eigen::Vector3f(0, 0, 1));
}
void reset() {
grid.clear();
idposMap.clear();
nextObjectId = 0;
newMass = 1000;
}
void spawnParticles(fluidParticle toSpawn, int count, bool resize = true) {
TIME_FUNCTION;
toSpawn.mass = newMass;
//float size = toSpawn.mass / 10;
Eigen::Vector3f color = buildGradient(toSpawn.mass / 1000, gradientmap);
for (int i = 0; i < count; i++) {
Eigen::Matrix<float, 3, 1> pos = posGen();
@@ -219,7 +227,6 @@ public:
}
void applyPressure() {
size_t pointcounter = 0;
for (auto& point : idposMap) {
auto node = grid.find(point.second);
if (!node) {
@@ -311,10 +318,11 @@ public:
void replaceLost() {
std::vector<size_t> idsToRemove;
int gridHalfSize = config.gridSizeCube / 2;
for (auto& point : idposMap) {
if (config.gridSizeCube / 2 > point.second[0] > config.gridSizeCube / 2 ||
config.gridSizeCube / 2 > point.second[1] > config.gridSizeCube / 2 ||
config.gridSizeCube / 2 > point.second[2] > config.gridSizeCube / 2) {
if (std::abs(point.second[0]) > gridHalfSize ||
std::abs(point.second[1]) > gridHalfSize ||
std::abs(point.second[2]) > gridHalfSize) {
idsToRemove.push_back(point.first);
}
}
@@ -331,7 +339,6 @@ public:
}
void applyPhysics() {
TIME_FUNCTION;
computeDensities();
applyPressure();
applyViscosity();
@@ -345,13 +352,13 @@ public:
Eigen::Matrix<float, 3, 1> newPos = point.second + (node->data.velocity);
Eigen::Vector3f oldPos = point.second;
if (grid.move(oldPos, newPos)) {
auto newpoint = grid.find(newPos);
idposMap[point.first] = newPos;
}
}
replaceLost();
}
size_t getParticleCount() const { return idposMap.size(); }
};
#endif