static void WriteMesh(JsonWriter json, Mesh mesh, GeometryPool.VertexLayout layout) {
// Unity does not import .obj verbatim. It makes these changes:
// - flip x axis
// - reverse winding of triangles
// We undo these changes when exporting to obj.
// NOTE: It's currently unknown whether this also happens for fbx files.
int nVert = mesh.vertexCount;
WriteArray(json, "v", AsByte(mesh.vertices, nVert, flip: true));
if (layout.bUseNormals) {
WriteArray(json, "n", AsByte(mesh.normals, nVert, flip: true));
}
WriteUvChannel(json, 0, layout.texcoord0.size, mesh, nVert);
WriteUvChannel(json, 1, layout.texcoord1.size, mesh, nVert);
if (layout.bUseColors) {
WriteArray(json, "c", AsByte(mesh.colors32, nVert));
}
// NOTE(b/30710462): Bubble wand lies about its tangents, so check they are really there
if (layout.bUseTangents && mesh.tangents.Length > 0) {
WriteArray(json, "t", AsByte(mesh.tangents, nVert, flip: true));
}
var tris = mesh.GetTriangles(0);
// Reverse winding, per above
for (int i = 0; i < tris.Length; i += 3) {
var tmp = tris[i+1];
tris[i+1] = tris[i+2];
tris[i+2] = tmp;
}
WriteArray(json, "tri", AsByte(tris, tris.Length));
}
public override GeometryPool.VertexLayout GetVertexLayout(BrushDescriptor desc) {
// XXX: This doesn't work because blocks models may not always have the same vertex layout.
// It happens to work currently.
var layout = new GeometryPool.VertexLayout();
layout.bUseColors = true;
layout.bUseNormals = true;
layout.bUseTangents = false;
layout.bUseVertexIds = false;
return layout;
}
// Puts the passed timestamp data into pool.texcoord2.
// It's assumed that the pool does not already have anything in texcoord2.
private static void AugmentWithTimestamps(GeometryPool pool, ref List <Vector3> timestamps)
{
if (App.UserConfig.Export.ExportStrokeTimestamp)
{
GeometryPool.VertexLayout withTxc2 = pool.Layout;
if (withTxc2.texcoord2.size == 0 && timestamps.Count == pool.NumVerts)
{
withTxc2.texcoord2 = new TexcoordInfo {
size = 3, semantic = Semantic.Timestamp
};
pool.Layout = withTxc2;
pool.m_Texcoord2.v3 = timestamps;
timestamps = null; // don't let caller reuse the list
}
else
{
Debug.LogError("Internal error; cannot add timestamps");
}
}
}
/// Rewrite vertices and indices, welding together identical verts.
/// Input topology must be as documented at the top of QuadStripBrush.cs
/// Output topology is the same as FlatGeometryBrush
private static void WeldSingleSidedQuadStrip(
GeometryPool.VertexLayout layout,
MasterBrush geometry,
int numVerts,
out int newNumVerts,
out int newNumTris)
{
// Offsets to Front/Back Left/Right verts, QuadStrip-style (see ascii art at top of file)
// Because of duplication, there are sometimes multiple offsets.
// "S" is the stride, either 6 or 12 depending on usesDoubleSidedGeometry.
// In cases where there are multiple offsets to choose from, we choose the offset
// which makes it safe to reorder verts in-place. See the comment below re: overlaps
const int kBrOld = 2; // also -S+5, 3
const int kBlOld = 0; // also -S+1, -S+4
const int kFrOld = 5; // also S+2, S+3
const int kFlOld = 1; // also 4, S+0
// Offsets to Front/Back Left/Right verts, FlatGeometry-style
// See FlatGeometryBrush.cs:15
const int kBrNew = 0;
const int kBlNew = 1;
const int kFrNew = 2;
const int kFlNew = 3;
// End result:
// 0--1 4 keep 2, 0, 5, 1 0--1
// |,' ,'| -> ignore 3, 4 -> |,'|
// 2 3--5 2--5
int vertRead = 0; // vertex read index
int vertWrite = 0; // vertex write index
int triWrite = 0; // triangle write index
var vs = geometry.m_Vertices;
var ns = geometry.m_Normals;
var cs = geometry.m_Colors;
var ts = geometry.m_Tangents;
var tris = geometry.m_Tris;
var uv2s = geometry.m_UVs;
var uv3s = geometry.m_UVWs.GetBackingArray();
while (vertRead < numVerts)
{
// Compress a single connected strip.
// The first quad is treated differently from subsequent quads,
// because it doesn't have a previous quad to share its first two verts with.
// First quad
// We write to the same buffer being read from, which is a bit dangerous.
// Correctness requires we not copy from a location that's been written to.
// The potential problem cases where the read area overlaps the write area are:
// Quad #0: write [0, 4) read [0, 6)
// Quad #1: write [4, 8) read [6, 12)
// For subsequent quads the read area is ahead of, and does not overlap, the write area.
vs[vertWrite + kFlNew] = vs[vertRead + kFlOld]; // 3 <- 1 7 <- 7
ns[vertWrite + kFlNew] = ns[vertRead + kFlOld];
cs[vertWrite + kFlNew] = cs[vertRead + kFlOld];
ts[vertWrite + kFlNew] = ts[vertRead + kFlOld];
vs[vertWrite + kBlNew] = vs[vertRead + kBlOld]; // 1 <- 0 5 <- 6
ns[vertWrite + kBlNew] = ns[vertRead + kBlOld];
cs[vertWrite + kBlNew] = cs[vertRead + kBlOld];
ts[vertWrite + kBlNew] = ts[vertRead + kBlOld];
vs[vertWrite + kBrNew] = vs[vertRead + kBrOld]; // 0 <- 2 4 <- 8
ns[vertWrite + kBrNew] = ns[vertRead + kBrOld];
cs[vertWrite + kBrNew] = cs[vertRead + kBrOld];
ts[vertWrite + kBrNew] = ts[vertRead + kBrOld];
vs[vertWrite + kFrNew] = vs[vertRead + kFrOld]; // 2 <- 5 6 <- 11
ns[vertWrite + kFrNew] = ns[vertRead + kFrOld];
cs[vertWrite + kFrNew] = cs[vertRead + kFrOld];
ts[vertWrite + kFrNew] = ts[vertRead + kFrOld];
if (layout.texcoord0.size == 2)
{
uv2s[vertWrite + kFlNew] = uv2s[vertRead + kFlOld];
uv2s[vertWrite + kBlNew] = uv2s[vertRead + kBlOld];
uv2s[vertWrite + kBrNew] = uv2s[vertRead + kBrOld];
uv2s[vertWrite + kFrNew] = uv2s[vertRead + kFrOld];
}
else
{
uv3s[vertWrite + kFlNew] = uv3s[vertRead + kFlOld];
uv3s[vertWrite + kBlNew] = uv3s[vertRead + kBlOld];
uv3s[vertWrite + kBrNew] = uv3s[vertRead + kBrOld];
uv3s[vertWrite + kFrNew] = uv3s[vertRead + kFrOld];
}
// See FlatGeometryBrush.cs:240
// SetTri(cur.iTri, cur.iVert, 0, BR, BL, FL);
// SetTri(cur.iTri, cur.iVert, 1, BR, FL, FR);
tris[triWrite + 0] = vertWrite + kBrNew;
tris[triWrite + 1] = vertWrite + kBlNew;
tris[triWrite + 2] = vertWrite + kFlNew;
tris[triWrite + 3] = vertWrite + kBrNew;
tris[triWrite + 4] = vertWrite + kFlNew;
tris[triWrite + 5] = vertWrite + kFrNew;
vertWrite += 4; // we wrote to a range of 4 verts
vertRead += 6; // we read from a range of 6 verts
triWrite += 6; // we wrote 6 indices
// Remaining quads.
// Detect strip continuation by checking a single vertex position.
// To be fully correct, we should check both the left and right verts, and all the
// attributes. However, as of M16 this simpler version suffices for all shipping
// QuadStripBrushes.
while (vertRead < numVerts && vs[vertRead + kBrOld] == vs[vertWrite - 4 + kFrNew])
{
vertWrite -= 2; // Share 2 verts with the previous quad
// The read range will provably never overlap with the write range. Note that
// this cannot be quad 0 since there exists a previous quad.
// Therefore, the closest the ranges get is:
// Quad #1: write [2, 6) read [6, 12)
vs[vertWrite + kFlNew] = vs[vertRead + kFlOld];
ns[vertWrite + kFlNew] = ns[vertRead + kFlOld];
cs[vertWrite + kFlNew] = cs[vertRead + kFlOld];
ts[vertWrite + kFlNew] = ts[vertRead + kFlOld];
vs[vertWrite + kFrNew] = vs[vertRead + kFrOld];
ns[vertWrite + kFrNew] = ns[vertRead + kFrOld];
cs[vertWrite + kFrNew] = cs[vertRead + kFrOld];
ts[vertWrite + kFrNew] = ts[vertRead + kFrOld];
if (layout.texcoord0.size == 2)
{
uv2s[vertWrite + kFlNew] = uv2s[vertRead + kFlOld];
uv2s[vertWrite + kFrNew] = uv2s[vertRead + kFrOld];
}
else
{
uv3s[vertWrite + kFlNew] = uv3s[vertRead + kFlOld];
uv3s[vertWrite + kFrNew] = uv3s[vertRead + kFrOld];
}
tris[triWrite + 0] = vertWrite + kBrNew;
tris[triWrite + 1] = vertWrite + kBlNew;
tris[triWrite + 2] = vertWrite + kFlNew;
tris[triWrite + 3] = vertWrite + kBrNew;
tris[triWrite + 4] = vertWrite + kFlNew;
tris[triWrite + 5] = vertWrite + kFrNew;
vertWrite += 4;
vertRead += 6;
triWrite += 6;
}
}
newNumVerts = vertWrite;
newNumTris = triWrite;
}