//returns the vertices for a billboard which has a custom vertex declaration
public static VertexBillboard[] GetVertexBillboard(int sidelength)
{
VertexBillboard[] vertices = new VertexBillboard[4];
float halfSideLength = sidelength / 2.0f;
Vector2 uvTopLeft = new Vector2(0, 0);
Vector2 uvTopRight = new Vector2(1, 0);
Vector2 uvBottomLeft = new Vector2(0, 1);
Vector2 uvBottomRight = new Vector2(1, 1);
//quad coplanar with the XY-plane (i.e. forward facing normal along UnitZ)
vertices[0] = new VertexBillboard(Vector3.Zero, new Vector4(uvTopLeft, -halfSideLength, halfSideLength));
vertices[1] = new VertexBillboard(Vector3.Zero, new Vector4(uvTopRight, halfSideLength, halfSideLength));
vertices[2] = new VertexBillboard(Vector3.Zero, new Vector4(uvBottomLeft, -halfSideLength, -halfSideLength));
vertices[3] = new VertexBillboard(Vector3.Zero, new Vector4(uvBottomRight, halfSideLength, -halfSideLength));
return(vertices);
}
/*************************************************************** Billboard (unlit) ***************************************************************/
//returns the vertices for a billboard which has a custom vertex declaration
public static VertexBillboard[] GetBillboard(out PrimitiveType primitiveType, out int primitiveCount)
{
primitiveType = PrimitiveType.TriangleStrip;
primitiveCount = 2;
VertexBillboard[] vertices = new VertexBillboard[4];
float halfSideLength = 0.5f;
Vector2 uvTopLeft = new Vector2(0, 0);
Vector2 uvTopRight = new Vector2(1, 0);
Vector2 uvBottomLeft = new Vector2(0, 1);
Vector2 uvBottomRight = new Vector2(1, 1);
//quad coplanar with the XY-plane (i.e. forward facing normal along UnitZ)
vertices[0] = new VertexBillboard(Vector3.Zero, new Vector4(uvTopLeft, -halfSideLength, halfSideLength));
vertices[1] = new VertexBillboard(Vector3.Zero, new Vector4(uvTopRight, halfSideLength, halfSideLength));
vertices[2] = new VertexBillboard(Vector3.Zero, new Vector4(uvBottomLeft, -halfSideLength, -halfSideLength));
vertices[3] = new VertexBillboard(Vector3.Zero, new Vector4(uvBottomRight, halfSideLength, -halfSideLength));
return(vertices);
}