static unsafe void GetVoxelsInternal(ref GetVoxelsContext context, int indexStart)
{
int i0 = context.indices[indexStart];
int i1 = context.indices[indexStart + 1];
int i2 = context.indices[indexStart + 2];
SimpleMesh.Vertex v0 = context.verts[i0];
SimpleMesh.Vertex v1 = context.verts[i1];
SimpleMesh.Vertex v2 = context.verts[i2];
float3 a = v0.Position;
float3 b = v1.Position;
float3 c = v2.Position;
float3 normalTri;
{
float3 normalCross = cross(b - a, c - a);
float normalCrossLengthSqrd = dot(normalCross, normalCross);
if (normalCrossLengthSqrd == 0f)
{
return;
}
normalTri = normalCross * rcp(sqrt(normalCrossLengthSqrd));
}
// extend every tri by half a voxel by just extending it along the corner-middle dir.
// it's a naive attempt to get a conservative rasterizer - works good enough in general
float3 middle = (a + b + c) / 3f;
a += normalize(a - middle) * 0.5f;
b += normalize(b - middle) * 0.5f;
c += normalize(c - middle) * 0.5f;
// get the AABB
float3 minf = min(a, min(b, c));
float3 maxf = max(a, max(b, c));
int3 maxDimensions = context.maxDimensions;
int3 mini = clamp(int3(floor(minf)), 0, maxDimensions);
int3 maxi = clamp(int3(ceil(maxf)), 0, maxDimensions);
int written = 0;
VoxelizedPosition *positions = context.positions;
int positionsLength = context.positionLength;
Color color0 = v0.Color;
Color color1 = v1.Color;
Color color2 = v2.Color;
for (int x = mini.x; x <= maxi.x; x++)
{
for (int z = mini.z; z <= maxi.z; z++)
{
for (int y = mini.y; y <= maxi.y; y++)
{
float3 voxel = float3(x, y, z) + 0.5f;
float normalDistToTriangle = dot(voxel - a, normalTri);
if (abs(normalDistToTriangle) > 0.5f)
{
continue; // distance to the triangle plane is over half a voxel -> the other side will have a voxel instead if we're at 0.5-1.0 dist
}
// set up barycentric coordinates
float3 p = voxel - normalTri * normalDistToTriangle;
float3 p0 = b - a;
float3 p1 = c - a;
float3 p2 = p - a;
float d00 = dot(p0, p0);
float d01 = dot(p0, p1);
float d11 = dot(p1, p1);
float d20 = dot(p2, p0);
float d21 = dot(p2, p1);
float denom = 1f / (d00 * d11 - d01 * d01);
float3 barry;
barry.y = (d11 * d20 - d01 * d21) * denom; // v1
barry.z = (d00 * d21 - d01 * d20) * denom; // v2
barry.x = 1.0f - barry.y - barry.z; // v0
if (any(barry < 0 | barry > 1))
{
continue; // we're on the triangle plane, but outside the triangle
}
// interpolate vertex colors with the barycentric coordinates
Color color;
color.r = (color0.r * barry.x + color1.r * barry.y + color2.r * barry.z);
color.g = (color0.g * barry.x + color1.g * barry.y + color2.g * barry.z);
color.b = (color0.b * barry.x + color1.b * barry.y + color2.b * barry.z);
color.a = 1f;
float2 uv;
uv.x = (v0.UV.x * barry.x + v1.UV.x * barry.y + v2.UV.x * barry.z);
uv.y = (v0.UV.y * barry.x + v1.UV.y * barry.y + v2.UV.y * barry.z);
int idx = x * (maxDimensions.z + 1) + z;
positions[written++] = new VoxelizedPosition
{
XZIndex = idx,
Y = (short)y,
Color = color,
MaterialIndex = (sbyte)v0.MaterialIndex,
UV = uv
};
if (written == positionsLength)
{
goto END; // buffer full, our triangle must've been huge
}
}
}
}
END:
context.writtenVoxelCount = written;
}
public static SimpleMesh Import(string path, bool swapYZ)
{
long fileByteSize = new System.IO.FileInfo(path).Length;
// would use Allocator.Temp, but that doesn't clean up on re-allocation; so total RAM balloons
NativeArrayList <float3> positionsLUT = new NativeArrayList <float3>(1024 * 64, Allocator.Persistent);
NativeArrayList <Color32> colorsLUT = new NativeArrayList <Color32>(1024 * 64, Allocator.Persistent);
NativeArrayList <float2> uvLookupTable = new NativeArrayList <float2>(1024 * 64, Allocator.Persistent);
NativeArrayList <SimpleMesh.Vertex> vertexResult = new NativeArrayList <SimpleMesh.Vertex>(1024 * 64, Allocator.Persistent);
SimpleMesh.MaterialLib activeMaterialLib = default;
SimpleMesh.Material activeMaterial = default;
char[] splits = new char[] { ' ' };
Profiler.BeginSample("Read file");
using (var file = new System.IO.FileStream(path, System.IO.FileMode.Open, System.IO.FileAccess.Read)) {
using (var text = new System.IO.StreamReader(file)) {
while (true)
{
if (text.EndOfStream)
{
break;
}
string line = text.ReadLine();
if (line == null || line.Length == 0)
{
continue;
}
// start of a line
if (line.StartsWith("v "))
{
ParsePositionLine();
}
else if (line.StartsWith("f "))
{
ParseFaceLine();
}
else if (line.StartsWith("vt "))
{
ParseUVLine();
}
else if (line.StartsWith("vn "))
{
//
}
else if (line.StartsWith("mtllib "))
{
activeMaterialLib = SimpleMesh.MaterialLib.ParseFromObj(path, line.Substring("mtllib ".Length));
}
else if (line.StartsWith("o "))
{
//
}
else if (line.StartsWith("usemtl "))
{
activeMaterial = activeMaterialLib.GetByName(line.Substring("usemtl ".Length));
}
continue;
void ParseUVLine()
{
string[] subs = line.Split(splits, System.StringSplitOptions.RemoveEmptyEntries);
float2 uv = new float2(ParseFloat(subs[1]), ParseFloat(subs[2]));
uvLookupTable.Add(uv);
}
void ParsePositionLine()
{
string[] subs = line.Split(splits, System.StringSplitOptions.RemoveEmptyEntries);
float3 pos = new float3(ParseFloat(subs[1]), ParseFloat(subs[2]), ParseFloat(subs[3]));
if (swapYZ)
{
float t = pos.z;
pos.z = pos.y;
pos.y = t;
}
positionsLUT.Add(pos);
Color color;
if (subs.Length > 6)
{
color.r = ParseFloat(subs[4]);
color.g = ParseFloat(subs[5]);
color.b = ParseFloat(subs[6]);
color.a = 1f;
}
else
{
color = Color.white;
}
colorsLUT.Add(color);
}
float ParseFloat(string str)
{
return(float.Parse(str, System.Globalization.CultureInfo.InvariantCulture));
}
void ParseFaceLine()
{
int index = 2;
int entriesPerIndex = 1;
for (int i = index; i < line.Length && line[i] != ' '; i++)
{
if (line[i] == '/')
{
entriesPerIndex++;
}
}
switch (entriesPerIndex)
{
case 1: // f v1 v2 v3
for (int i = 0; i < 3; i++)
{
vertexResult.Add(GatherVertex(ParseFaceIndex(line, ref index), -1, -1));
index++;
}
break;
case 2: // f v1/vt1 v2/vt2 v3/vt3
for (int i = 0; i < 3; i++)
{
int v = ParseFaceIndex(line, ref index);
index++; // skip /
int vt = ParseFaceIndex(line, ref index);
index++; // skip space between the 3 indices
vertexResult.Add(GatherVertex(v, vt, -1));
}
break;
case 3:
// f v1/vt1/vn1 ..
// f v1//vn1 ..
for (int i = 0; i < 3; i++)
{
int v = ParseFaceIndex(line, ref index);
index++; // skip /
int vt = -1;
if (line[index] != '/')
{
// vt1
vt = ParseFaceIndex(line, ref index);
}
index++; // skip second /
int vn = ParseFaceIndex(line, ref index);
index++; // skip space between the 3 indices
vertexResult.Add(GatherVertex(v, vt, vn));
}
break;
}
}
SimpleMesh.Vertex GatherVertex(int positionIndex, int textureIndex, int normalIndex)
{
SimpleMesh.Vertex vertex = default;
vertex.Color = colorsLUT[positionIndex];
vertex.Position = positionsLUT[positionIndex];
if (textureIndex >= 0)
{
vertex.UV = uvLookupTable[textureIndex];
}
vertex.MaterialIndex = activeMaterial?.MaterialIndex ?? -1;
return(vertex);
}
}
}
}
positionsLUT.Dispose();
uvLookupTable.Dispose();
colorsLUT.Dispose();
Profiler.EndSample();
int vertexCount = vertexResult.Count;
unsafe {
SimpleMesh.Vertex *vertices = (SimpleMesh.Vertex *)SimpleMesh.MallocHelper <SimpleMesh.Vertex>(vertexCount);
UnsafeUtility.MemCpy(vertices, vertexResult.Array.GetUnsafePtr(), UnsafeUtility.SizeOf <SimpleMesh.Vertex>() * vertexCount);
vertexResult.Dispose();
int *indices = (int *)SimpleMesh.MallocHelper <int>(vertexCount);
for (int i = 0; i < vertexCount; i++)
{
indices[i] = i;
}
return(new SimpleMesh(activeMaterialLib, vertices, indices, vertexCount, vertexCount));
}
}
