public static void BuildDecalForObject(Decal decal, GameObject affectedObject)
{
Mesh affectedMesh = affectedObject.GetComponent<MeshFilter>().sharedMesh;
if(affectedMesh == null) return;
float maxAngle = decal.maxAngle;
Plane right = new Plane( Vector3.right, Vector3.right/2f );
Plane left = new Plane( -Vector3.right, -Vector3.right/2f );
Plane top = new Plane( Vector3.up, Vector3.up/2f );
Plane bottom = new Plane( -Vector3.up, -Vector3.up/2f );
Plane front = new Plane( Vector3.forward, Vector3.forward/2f );
Plane back = new Plane( -Vector3.forward, -Vector3.forward/2f );
Vector3[] vertices = affectedMesh.vertices;
int[] triangles = affectedMesh.triangles;
int startVertexCount = bufVertices.Count;
Matrix4x4 matrix = decal.transform.worldToLocalMatrix * affectedObject.transform.localToWorldMatrix;
for(int i=0; i<triangles.Length; i+=3) {
int i1 = triangles[i];
int i2 = triangles[i+1];
int i3 = triangles[i+2];
Vector3 v1 = matrix.MultiplyPoint( vertices[i1] );
Vector3 v2 = matrix.MultiplyPoint( vertices[i2] );
Vector3 v3 = matrix.MultiplyPoint( vertices[i3] );
Vector3 side1 = v2 - v1;
Vector3 side2 = v3 - v1;
Vector3 normal = Vector3.Cross(side1, side2).normalized;
if( Vector3.Angle(-Vector3.forward, normal) >= maxAngle ) continue;
DecalPolygonLegacy poly = new DecalPolygonLegacy( v1, v2, v3 );
poly = DecalPolygonLegacy.ClipPolygon(poly, right);
if(poly == null) continue;
poly = DecalPolygonLegacy.ClipPolygon(poly, left);
if(poly == null) continue;
poly = DecalPolygonLegacy.ClipPolygon(poly, top);
if(poly == null) continue;
poly = DecalPolygonLegacy.ClipPolygon(poly, bottom);
if(poly == null) continue;
poly = DecalPolygonLegacy.ClipPolygon(poly, front);
if(poly == null) continue;
poly = DecalPolygonLegacy.ClipPolygon(poly, back);
if(poly == null) continue;
AddPolygon( poly, normal );
}
GenerateTexCoords(startVertexCount, decal.sprite);
}
private static void AddPolygon(DecalPolygonLegacy poly, Vector3 normal)
{
int ind1 = AddVertex( poly.vertices[0], normal );
for(int i=1; i<poly.vertices.Count-1; i++) {
int ind2 = AddVertex( poly.vertices[i], normal );
int ind3 = AddVertex( poly.vertices[i+1], normal );
bufIndices.Add( ind1 );
bufIndices.Add( ind2 );
bufIndices.Add( ind3 );
}
}