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minor change to resolution slider, added backface culling and normal preprocessing

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yggdrasil75
2026-02-14 10:06:55 -05:00
parent a1e4a852be
commit d6d638cb01
2 changed files with 59 additions and 7 deletions
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8
tests/g3etest.cpp
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@@ -37,7 +37,7 @@ struct defaults {
float lodDropoff = 0.1;
PNoise2 noise = PNoise2(42);
int meshResolution = 128;
int meshResolution = 16;
float meshIsoLevel = 0.4f;
};
@@ -190,8 +190,8 @@ void livePreview(Octree<int>& grid, defaults& config, const Camera& cam) {
if (meshNeedsUpdate) {
scene.clear();
std::shared_ptr<Mesh> planetMesh = grid.generateMesh(1, config.meshIsoLevel, config.meshResolution);
std::shared_ptr<Mesh> starMesh = grid.generateMesh(2, config.meshIsoLevel, config.meshResolution / 4);
std::shared_ptr<Mesh> planetMesh = grid.generateMesh(1, config.meshIsoLevel, pow(config.meshResolution, 2));
std::shared_ptr<Mesh> starMesh = grid.generateMesh(2, config.meshIsoLevel, config.meshResolution);
scene.addMesh(planetMesh);
scene.addMesh(starMesh);
@@ -506,7 +506,7 @@ int main() {
ImGui::Separator();
ImGui::Text("Marching Cubes Config");
if (ImGui::SliderInt("Mesh Resolution", &config.meshResolution, 16, 128)) {
if (ImGui::SliderInt("Mesh Resolution", &config.meshResolution, 1, 64)) {
meshNeedsUpdate = true;
}
if (ImGui::SliderFloat("Iso Level", &config.meshIsoLevel, 0.01f, 1.0f)) {

58
util/grid/mesh.hpp
View File

@@ -39,14 +39,19 @@ private:
std::vector<std::vector<int>> _polys;
std::vector<Color> _colors;
mutable std::vector<Eigen::Vector3i> _tris;
mutable std::vector<Vector3f> _triNormals;
mutable bool _needs_triangulation = true;
mutable bool _needs_norm_calc = true;
inline static float edgeFunction(const Vector2f& a, const Vector2f& b, const Vector2f& c) {
return (c.x() - a.x()) * (b.y() - a.y()) - (c.y() - a.y()) * (b.x() - a.x());
}
public:
Mesh(int id, const std::vector<Vector3f>& verts, const std::vector<std::vector<int>>& polys, const std::vector<Color>& colors)
: id(id), _vertices(verts), _polys(polys), _colors(colors) {}
: id(id), _vertices(verts), _polys(polys), _colors(colors) {
_needs_triangulation = true;
_needs_norm_calc = true;
}
std::vector<Vector3f> vertices() {
return _vertices;
@@ -56,11 +61,13 @@ public:
if (verts.size() != _colors.size()) {
if (_colors.size() == 1) {
_vertices = verts;
_needs_norm_calc = true;
return true;
}
return false;
} else {
_vertices = verts;
_needs_norm_calc = true;
return true;
}
}
@@ -72,6 +79,7 @@ public:
void triangulate() {
if (!_needs_triangulation) return;
std::vector<Eigen::Vector3i> newPols;
newPols.reserve(_polys.size() * 2);
for (auto& pol : _polys) {
if (pol.size() > 3) {
auto v0 = pol[0];
@@ -84,7 +92,33 @@ public:
}
}
_tris = newPols;
_polys.clear();
_polys.shrink_to_fit();
_needs_triangulation = false;
_needs_norm_calc = true;
}
void calculateNormals() {
if (!_needs_norm_calc) return;
_triNormals.clear();
_triNormals.reserve(_tris.size());
for (const auto& tri : _tris) {
Vector3f v0 = _vertices[tri.x()];
Vector3f v1 = _vertices[tri.y()];
Vector3f v2 = _vertices[tri.z()];
Vector3f edge1 = v1 - v0;
Vector3f edge2 = v2 - v0;
// Normalized cross product gives the face normal
Vector3f normal = edge1.cross(edge2).normalized();
_triNormals.push_back(normal);
}
_needs_norm_calc = false;
}
std::vector<Color> colors() {
@@ -101,8 +135,10 @@ public:
std::vector<Triangle2D> project_2d(Camera cam, int height, int width, float near, float far) {
triangulate();
calculateNormals();
std::vector<Triangle2D> renderList;
renderList.reserve(_tris.size());
Vector3f forward = cam.forward();
Vector3f right = cam.right();
@@ -160,7 +196,19 @@ public:
validVerts[i] = true;
}
for (const auto& triIdx : _tris) {
Vector3f camPos = cam.origin;
size_t triCount = _tris.size();
for (size_t t = 0; t < triCount; ++t) {
const auto& triIdx = _tris[t];
Vector3f p0 = _vertices[triIdx.x()];
Vector3f viewDir = (p0 - camPos).normalized();
if (viewDir.dot(_triNormals[t]) >= 0.0f) {
continue;
}
int i0 = triIdx.x();
int i1 = triIdx.y();
int i2 = triIdx.z();
@@ -250,7 +298,9 @@ public:
os << "Structure:\n";
os << " Total Vertices : " << _vertices.size() << "\n";
os << " Total Tris : " << _tris.size() << "\n";
os << " Total Polys : " << _polys.size() << "\n";
os << " Tri Normals : " << _triNormals.size() << "\n";
if (_needs_triangulation) os << " Total Polys : " << _polys.size() << "\n";
else os << " Polys (Cleared) : " << 0 << "\n";
os << " colors : " << _colors.size() << "\n";
}
};
@@ -267,10 +317,12 @@ public:
void addMesh(std::shared_ptr<Mesh> mesh) {
_meshes.push_back(mesh);
updateStats();
}
void clear() {
_meshes.clear();
updateStats();
}
frame render(Camera cam, int height, int width, float near, float far, frame::colormap colorformat = frame::colormap::RGB) {