// Updates glTF technique tech by adding all relevant attributes.
// Pass:
// mesh - (optional) the attributes of some mesh that uses this material, for sanity-checking.
private void AddAllAttributes(
GlTF_Technique tech, IExportableMaterial exportableMaterial, GlTF_Attributes mesh)
{
GlTF_VertexLayout layout = new GlTF_VertexLayout(G, exportableMaterial.VertexLayout);
if (mesh != null)
{
GlTF_VertexLayout meshLayout = mesh.m_layout;
if (layout != meshLayout)
{
if (meshLayout.GetTexcoordSize(2) > 0)
{
// We funnel timestamps in through GeometryPool.texcoord2 and write them out as
// _TB_TIMESTAMP. Thus, the Pool's layout has a texcoord2 but the material's layout does
// not. This is a mismatch between the mesh data and the material props, but:
// 1. Timestamp isn't intended to be funneled to the material, so it's correct that the
// material layoutdoesn't have texcoord2
// 2. It's fine if material attrs are a subset of the mesh attrs
// 3. This only affects gltf1; only materials with techniques need to enum their attrs.
// Maybe this check should be layout.IsSubset(meshLayout).
/* ignore this mismatch */
}
else
{
Debug.LogWarning($"Layout for {exportableMaterial.DurableName} doesn't match mesh's");
}
}
}
// Materials are things that are shared across multiple meshes.
// Material creation shouldn't depend on data specific to a particular mesh.
// But it does. It's a hack.
// Rather than do something reasonable like this:
//
// Create material's technique's attributes based on layout
// Create mesh and its accessors based on layout
//
// We do this:
//
// Create mesh and its accessors based on layout
// Lazily create the material used by the mesh
// Create material's technique's attributes based on the accessors
// of the last mesh we created
AddAttribute("position", layout.PositionInfo.techniqueType,
GlTF_Technique.Semantic.POSITION, tech);
if (layout.NormalInfo != null)
{
AddAttribute("normal", layout.NormalInfo.Value.techniqueType,
GlTF_Technique.Semantic.NORMAL, tech);
}
if (layout.ColorInfo != null)
{
AddAttribute("color", layout.ColorInfo.Value.techniqueType,
GlTF_Technique.Semantic.COLOR, tech);
}
if (layout.TangentInfo != null)
{
AddAttribute("tangent", layout.TangentInfo.Value.techniqueType,
GlTF_Technique.Semantic.TANGENT, tech);
}
// TODO: remove; this accessor isn't used. Instead, shaders use texcoord1.w
if (layout.PackVertexIdIntoTexcoord1W)
{
AddAttribute("vertexId", GlTF_Technique.Type.FLOAT /* hardcoded, but this is gong away */,
GlTF_Technique.Semantic.UNKNOWN, tech);
}
for (int i = 0; i < 4; ++i)
{
var texcoordInfo = layout.GetTexcoordInfo(i);
if (texcoordInfo != null)
{
GlTF_Technique.Semantic semantic = GlTF_Technique.Semantic.TEXCOORD_0 + i;
AddAttribute($"texcoord{i}", texcoordInfo.Value.techniqueType, semantic, tech);
}
}
}
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
}
}
