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https://github.com/islamhaqq/marchingcubestables.h
Converted from JS to C++ from https://gist.githubusercontent.com/dwilliamson/c041e3454a713e58baf6e4f8e5fffecd/raw/3c761fa2dfc4333749626ed3d1a0ff25d708089c/MarchingCubes.js
https://github.com/islamhaqq/marchingcubestables.h
Last synced: 5 days ago
JSON representation
Converted from JS to C++ from https://gist.githubusercontent.com/dwilliamson/c041e3454a713e58baf6e4f8e5fffecd/raw/3c761fa2dfc4333749626ed3d1a0ff25d708089c/MarchingCubes.js
- Host: GitHub
- URL: https://github.com/islamhaqq/marchingcubestables.h
- Owner: islamhaqq
- Created: 2024-07-01T11:46:35.000Z (5 months ago)
- Default Branch: main
- Last Pushed: 2024-07-01T11:52:34.000Z (5 months ago)
- Last Synced: 2024-09-13T15:42:38.723Z (2 months ago)
- Language: C
- Size: 16.6 KB
- Stars: 1
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# MarchingCubesTables.h
This is taken from user https://gist.github.com/dwilliamson who had a JavaScript file for the marching cubes tables. I needed it for C++, so there you go.
Converted from JS to C++ from the following gist: https://gist.githubusercontent.com/dwilliamson/c041e3454a713e58baf6e4f8e5fffecd/raw/3c761fa2dfc4333749626ed3d1a0ff25d708089c/MarchingCubes.js
## Example usage
Create a procedural terrain by convert volumetric (density) data into a triangle mesh using the marching cubes algorithm.
```c++
#include
#include
#include "MarchingCubesTables.h"
struct Triangle {
glm::vec3 vertices[3];
glm::vec3 normal;
};
std::vector GenerateMarchingCubesTriangles(const VoxelChunkComponent& chunk, float isoLevel) {
std::vector triangles;
for (int x = 0; x < chunk.width - 1; x++) {
for (int y = 0; y < chunk.height - 1; y++) {
for (int z = 0; z < chunk.depth - 1; z++) {
float cube[8];
glm::vec3 normals[8];
glm::vec3 positions[8];
// Sample the 8 corners of the cube
for (int i = 0; i < 8; i++) {
int dx = i & 1;
int dy = (i & 2) >> 1;
int dz = (i & 4) >> 2;
cube[i] = VoxelHelpers::GetVoxel(chunk, x + dx, y + dy, z + dz);
normals[i] = VoxelHelpers::GetNormal(chunk, x + dx, y + dy, z + dz);
positions[i] = glm::vec3(x + dx, y + dy, z + dz);
}
// Determine the index in the edge table
int cubeIndex = 0;
if (cube[0] < isoLevel) cubeIndex |= 1;
if (cube[1] < isoLevel) cubeIndex |= 2;
if (cube[2] < isoLevel) cubeIndex |= 4;
if (cube[3] < isoLevel) cubeIndex |= 8;
if (cube[4] < isoLevel) cubeIndex |= 16;
if (cube[5] < isoLevel) cubeIndex |= 32;
if (cube[6] < isoLevel) cubeIndex |= 64;
if (cube[7] < isoLevel) cubeIndex |= 128;
// Skip this cube if it's entirely inside or outside the isosurface
if (EdgeMasks[cubeIndex] == 0) continue;
glm::vec3 vertlist[12];
glm::vec3 normlist[12];
// Find the vertices where the surface intersects the cube
for (int i = 0; i < 12; i++) {
if (EdgeMasks[cubeIndex] & (1 << i)) {
int v1 = EdgeVertexIndices[i][0];
int v2 = EdgeVertexIndices[i][1];
float t = (isoLevel - cube[v1]) / (cube[v2] - cube[v1]);
vertlist[i] = positions[v1] + t * (positions[v2] - positions[v1]);
normlist[i] = glm::normalize(normals[v1] + t * (normals[v2] - normals[v1]));
}
}
// Create the triangles
for (int i = 0; TriangleTable[cubeIndex][i] != -1; i += 3) {
Triangle tri;
tri.vertices[0] = vertlist[TriangleTable[cubeIndex][i]];
tri.vertices[1] = vertlist[TriangleTable[cubeIndex][i+1]];
tri.vertices[2] = vertlist[TriangleTable[cubeIndex][i+2]];
tri.normal = glm::normalize(normlist[TriangleTable[cubeIndex][i]] +
normlist[TriangleTable[cubeIndex][i+1]] +
normlist[TriangleTable[cubeIndex][i+2]]);
triangles.push_back(tri);
}
}
}
}
return triangles;
}
```