// Scan for MeshRenderers that overlap the projector, and collect all of their triangles to be clipped
// into the projector
int GatherTriangles(NativeArray <Triangle> sourceTriangleArray)
{
TRS meshTRS = new TRS();
int sourceTriangles = 0;
float4 up = new float4(0f, 1f, 0f, 0f);
foreach (var meshFilter in FindObjectsOfType <MeshFilter>())
{
// Filter out object by layer mask
int mask = 1 << meshFilter.gameObject.layer;
if ((mask & m_layerMask) != mask)
{
continue;
}
// Filter out objects that are themselves decal projectors
if (meshFilter.GetComponent <DecalProjector>() != null)
{
continue;
}
// Filter out objects by render bounds
Renderer r = meshFilter.GetComponent <Renderer>();
if (!r.bounds.Intersects(m_bounds))
{
continue;
}
// Filter out objects with no mesh
Mesh m = meshFilter.sharedMesh;
if (m == null)
{
continue;
}
Transform meshTransform = meshFilter.transform;
meshTRS.Update(meshTransform.worldToLocalMatrix, meshTransform.localToWorldMatrix, meshTransform.position.ToFloat4());
Vector3[] meshVertices = m.vertices;
// Iterate over the submeshes
for (int submeshIndex = 0; submeshIndex < m.subMeshCount; submeshIndex++)
{
// Iterate over every group of 3 indices that form triangles
int[] meshIndices = m.GetIndices(submeshIndex);
for (int meshIndex = 0; meshIndex < meshIndices.Length; meshIndex += 3)
{
// TODO, make triangle Transform modify the triangle instead of making a new one
Triangle tInMeshLocal = Triangle.zero;
tInMeshLocal.SetFrom(
meshVertices[meshIndices[meshIndex]].ToFloat4(),
meshVertices[meshIndices[meshIndex + 1]].ToFloat4(),
meshVertices[meshIndices[meshIndex + 2]].ToFloat4());
Triangle tInWorld = tInMeshLocal.LocalToWorld(meshTRS);
if (m_cullBackfaces)
{
if (math.dot(tInWorld.Normal, up) < 0f)
{
continue;
}
}
// If the bounds of the individual triangle don't intersect with the unit cube bounds, we can
// ignore it
Bounds triangleBounds = BoundsFromTriangle(tInWorld);
if (!triangleBounds.Intersects(m_bounds))
{
continue;
}
Triangle tInProjectorLocal = tInWorld.WorldToLocal(m_TRS);
sourceTriangleArray[sourceTriangles++] = tInProjectorLocal;
if (sourceTriangles >= MaxDecalTriangles)
{
Debug.LogError($"Decal triangles exceeds max trianges {MaxDecalTriangles}.");
return(sourceTriangles);
}
}
}
}
return(sourceTriangles);
}
void UpdateSelfTRS()
{
m_TRS.Update(transform.worldToLocalMatrix, transform.localToWorldMatrix, transform.position.ToFloat4());
}