yggdrasil75/stupidsimcpp
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pushing a star

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Yggdrasil75
2026-03-04 14:07:05 -05:00
parent 83989e955e
commit 4478bc1845
3 changed files with 133 additions and 9 deletions
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66
util/sim/planet.hpp
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@@ -26,7 +26,7 @@
#include "../stb/stb_image.h"
using v3 = Eigen::Vector3f;
using v3half = Eigen::Matrix<Eigen::half, 3, 1>; // 16-bit vector alias
using v3half = Eigen::Matrix<Eigen::half, 3, 1>;
const float Φ = M_PI * (3.0f - std::sqrt(5.0f));
enum class PlateType {
@@ -149,7 +149,7 @@ struct planetConfig {
float maxElevationRatio = 0.25f;
float gridSizeCube = 65536; //absolute max size for all nodes
float gridSizeCubeMin = 16384; //max size, if something leaves this, then it probably needs to be purged before it leaves the grid and becomes lost
float gridSizeCubeMin = 4096; //max size, if something leaves this, then it probably needs to be purged before it leaves the grid and becomes lost
float SMOOTHING_RADIUS = 1024.0f;
float REST_DENSITY = 0.00005f;
float TIMESTEP = 0.016f;
@@ -184,7 +184,7 @@ public:
planetsim() {
config = planetConfig();
grid = Octree<Particle>(v3(-config.gridSizeCube,-config.gridSizeCube,-config.gridSizeCube),v3(config.gridSizeCube,config.gridSizeCube,config.gridSizeCube), 16, 32);
grid = Octree<Particle>(v3(-config.gridSizeCubeMin,-config.gridSizeCubeMin,-config.gridSizeCubeMin),v3(config.gridSizeCubeMin,config.gridSizeCubeMin,config.gridSizeCubeMin), 16, 32);
}
float evaluate2DStack(const Eigen::Vector2f& point, const NoisePreviewState& state, PNoise2& gen) {
@@ -255,7 +255,7 @@ public:
}
config.currentStep = 1;
std::cout << "Step 1 done. base sphere generated" << std::endl;
grid.save("output/fibSphere");
grid.save("output/fibSphere.yggs");
}
inline void _applyNoise(std::function<float(const Eigen::Vector3f&)> noiseFunc) {
@@ -776,10 +776,66 @@ public:
}
grid.optimize();
std::cout << "Finalize apply results completed." << std::endl;
grid.save("output/plateworld.yggs");
}
void addStar() {
///TODO: add a star at roughly earth distance scaled based on planet radius.
TIME_FUNCTION;
const float realEarthRadiusKm = 6371.0f;
const float realSunRadiusKm = 696340.0f;
const float realAuKm = 149597870.0f;
float simScale = config.radius / realEarthRadiusKm;
float starRadius = realSunRadiusKm * simScale;
float orbitDistance = realAuKm * simScale;
std::cout << "--- STAR GENERATION ---" << std::endl;
std::cout << "Sim Scale: " << simScale << " units/km" << std::endl;
std::cout << "Star Radius: " << starRadius << " units" << std::endl;
std::cout << "Orbit Distance: " << orbitDistance << " units" << std::endl;
if (orbitDistance > config.gridSizeCube) {
std::cout << "[WARNING] Star distance (" << orbitDistance
<< ") exceeds octree bounds (" << config.gridSizeCube
<< "). Please increase gridSizeCube or the star will be outside the grid!" << std::endl;
}
v3 starCenter = config.center + v3(orbitDistance, 0.0f, 0.0f);
v3 starColor = v3(1.0f, 0.95f, 0.8f);
int starPoints = config.surfacePoints * 10;
for (int i = 0; i < starPoints; i++) {
float y = 1.0f - (i * 2.0f) / (starPoints - 1);
float radiusY = std::sqrt(1.0f - y * y);
float Θ = Φ * i;
float x = std::cos(Θ) * radiusY;
float z = std::sin(Θ) * radiusY;
v3 dir(x, y, z);
v3 pos = starCenter + dir * starRadius;
Particle pt;
pt.altPos = std::make_unique<AltPositions>();
pt.altPos->originalPos = pos.cast<Eigen::half>();
pt.altPos->noisePos = pos.cast<Eigen::half>();
pt.altPos->tectonicPos = pos.cast<Eigen::half>();
pt.currentPos = pos;
pt.originColor = starColor.cast<Eigen::half>();
pt.noiseDisplacement = 0.0f;
pt.surface = true;
pt.plateID = -2;
config.surfaceNodes.emplace_back(pt);
grid.set(pt, pt.currentPos, true, pt.originColor.cast<float>(), config.voxelSize, true, 2, 0, 1.0, 0.0f, 0.0f, 1.0f);
}
grid.optimize();
config.currentStep = 1;
std::cout << "Star generation complete. Placed " << starPoints << " nodes." << std::endl;
}
void addMoon() {