public GlTF_Attributes(
GlTF_Globals G, ObjectName meshName, GlTF_VertexLayout layout)
{
// This prefix should be used with possibly-nonconforming gltf data:
// - texcoords that are not 2-element or that don't contain texture coordinates
// - made-up / mythical semantics like VERTEXID
string nonconformingPrefix = (G.GltfCompatibilityMode) ? "_TB_UNITY_" : "";
m_layout = layout;
{
AttributeInfo positionInfo = layout.PositionInfo;
positionAccessor = G.CreateAccessor(
GlTF_Accessor.GetNameFromObject(meshName, "position"),
positionInfo.accessorType, positionInfo.accessorComponentType);
m_accessors.Add("POSITION", positionAccessor);
}
{ if (layout.NormalInfo is AttributeInfo normalInfo)
{
normalAccessor = G.CreateAccessor(
GlTF_Accessor.GetNameFromObject(meshName, "normal"),
normalInfo.accessorType, normalInfo.accessorComponentType);
// Genius particles put things that don't look like normals into the normal attribute.
bool isNonconforming = (layout.m_tbLayout.normalSemantic == Semantic.Position);
string prefix = isNonconforming ? nonconformingPrefix : "";
m_accessors.Add(prefix + "NORMAL", normalAccessor);
}
}
{ if (layout.ColorInfo is AttributeInfo cInfo)
{
colorAccessor = G.CreateAccessor(
GlTF_Accessor.GetNameFromObject(meshName, "color"),
cInfo.accessorType, cInfo.accessorComponentType,
normalized: true);
m_accessors.Add(G.Gltf2 ? "COLOR_0" : "COLOR", colorAccessor);
}
}
{ if (layout.TangentInfo is AttributeInfo tangentInfo)
{
tangentAccessor = G.CreateAccessor(
GlTF_Accessor.GetNameFromObject(meshName, "tangent"),
tangentInfo.accessorType, tangentInfo.accessorComponentType);
m_accessors.Add("TANGENT", tangentAccessor);
}
}
if (layout.PackVertexIdIntoTexcoord1W)
{
// The vertexid hack modifies the gl layout to extend texcoord1 so the vertexid
// can be stuffed into it
Debug.Assert(layout.m_tbLayout.GetTexcoordInfo(1).size == 3);
Debug.Assert(layout.GetTexcoordSize(1) == 4);
}
GlTF_Accessor MakeAccessorFor(int texcoord)
{
var txcInfo = layout.GetTexcoordInfo(texcoord);
if (txcInfo == null)
{
return(null);
}
Semantic tbSemantic = layout.m_tbLayout.GetTexcoordInfo(texcoord).semantic;
string attrName = $"{nonconformingPrefix}TEXCOORD_{texcoord}";
// Timestamps are tunneled into us via a texcoord because there's not really a better way
// due to GeometryPool limitations. But that's an internal implementation detail. I'd like
// them to have a better attribute name in the gltf.
if (tbSemantic == Semantic.Timestamp)
{
// For b/141876882; Poly doesn't like _TB_TIMESTAMP
if (!G.Gltf2)
{
return(null);
}
attrName = "_TB_TIMESTAMP";
}
var ret = G.CreateAccessor(
GlTF_Accessor.GetNameFromObject(meshName, $"uv{texcoord}"),
txcInfo.Value.accessorType, txcInfo.Value.accessorComponentType);
m_accessors.Add(attrName, ret);
return(ret);
}
texCoord0Accessor = MakeAccessorFor(0);
texCoord1Accessor = MakeAccessorFor(1);
texCoord2Accessor = MakeAccessorFor(2);
texCoord3Accessor = MakeAccessorFor(3);
if (G.GltfCompatibilityMode)
{
TiltBrush.GeometryPool.VertexLayout tbLayout = layout.m_tbLayout;
switch (tbLayout.texcoord0.semantic)
{
case Semantic.Unspecified when tbLayout.texcoord0.size == 2:
case Semantic.XyIsUv:
case Semantic.XyIsUvZIsDistance: {
GlTF_Accessor accessor = GlTF_Accessor.CloneWithDifferentType(
G, texCoord0Accessor, GlTF_Accessor.Type.VEC2);
m_accessors.Add("TEXCOORD_0", accessor);
break;
}
}
// No need to check the other texcoords because TB only ever puts texture coordinates
// in texcoord0
}
}
private void PopulateUv(
int channel, TiltBrush.GeometryPool pool, GlTF_Accessor accessor,
Semantic semantic)
{
bool packVertId = m_layout.PackVertexIdIntoTexcoord1W && channel == 1;
if (packVertId)
{
// Guaranteed by GlTF_VertexLayout
Debug.Assert(m_layout.m_tbLayout.GetTexcoordInfo(channel).size == 3);
Debug.Assert(m_layout.GetTexcoordSize(channel) == 4);
}
if (accessor == null)
{
return;
}
if (channel < 0 || channel > 3)
{
throw new ArgumentException("Invalid channel");
}
TiltBrush.GeometryPool.TexcoordData texcoordData = pool.GetTexcoordData(channel);
if (semantic == Semantic.XyIsUvZIsDistance && accessor.type != GlTF_Accessor.Type.VEC3)
{
throw new ArgumentException("XyIsUvZIsDistance semantic can only be applied to VEC3");
}
bool flipY;
if (semantic == Semantic.Unspecified && channel == 0 &&
accessor.type == GlTF_Accessor.Type.VEC2)
{
Debug.LogWarning("Assuming Semantic.XyIsUv");
semantic = Semantic.XyIsUv;
}
switch (semantic)
{
case Semantic.Position:
case Semantic.Vector:
case Semantic.Timestamp:
flipY = false;
break;
case Semantic.XyIsUvZIsDistance:
case Semantic.XyIsUv:
flipY = true;
break;
default:
throw new ArgumentException("semantic");
}
switch (accessor.type)
{
case GlTF_Accessor.Type.SCALAR:
throw new NotImplementedException();
case GlTF_Accessor.Type.VEC2:
accessor.Populate(texcoordData.v2, flipY: flipY, calculateMinMax: false);
break;
case GlTF_Accessor.Type.VEC3:
accessor.Populate(texcoordData.v3, flipY: flipY, calculateMinMax: false);
break;
case GlTF_Accessor.Type.VEC4:
if (packVertId)
{
// In the vertexId case, we actually have a vec3, which needs to be augmented to a vec4.
// TODO: this should happen at some higher level.
int i = 0;
var v4 = texcoordData.v3.ConvertAll <Vector4>((v => new Vector4(v.x, v.y, v.z, i++)));
accessor.Populate(v4, flipY: flipY, calculateMinMax: false);
}
else
{
accessor.Populate(texcoordData.v4, flipY: flipY, calculateMinMax: false);
}
break;
default:
throw new ArgumentException("Unexpected accessor.type");
}
}
