// Adds a glTF attribute, as described by name, type, and semantic, to the given technique tech.
private static void AddAttribute(string name, GlTF_Technique.Type type,
GlTF_Technique.Semantic semantic, GlTF_Technique tech)
{
GlTF_Technique.Parameter tParam = new GlTF_Technique.Parameter();
tParam.name = name;
tParam.type = type;
tParam.semantic = semantic;
tech.parameters.Add(tParam);
GlTF_Technique.Attribute tAttr = new GlTF_Technique.Attribute();
tAttr.name = "a_" + name;
tAttr.param = tParam.name;
tech.attributes.Add(tAttr);
}
// Adds a glTF uniform, as described by name, type, and semantic, to the given technique tech. If
// node is non-null, that is also included (e.g. for lights).
private void AddUniform(
IExportableMaterial exportableMaterial,
string name, GlTF_Technique.Type type,
GlTF_Technique.Semantic semantic, GlTF_Node node = null)
{
//var techName = GlTF_Technique.GetNameFromObject(matObjName);
var tech = GlTF_Writer.GetTechnique(G, exportableMaterial);
GlTF_Technique.Parameter tParam = new GlTF_Technique.Parameter();
tParam.name = name;
tParam.type = type;
tParam.semantic = semantic;
if (node != null)
{
tParam.node = node;
}
tech.parameters.Add(tParam);
GlTF_Technique.Uniform tUniform = new GlTF_Technique.Uniform();
tUniform.name = "u_" + name;
tUniform.param = tParam.name;
tech.uniforms.Add(tUniform);
}
// 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);
}
}
}
