Presorted

function TFL3dCobject.Init:Boolean;
var
I      : Integer;
J      : Integer;
K      : Integer;
M      : Integer;
N      : Integer;
Num    : UINT;
Mat    : UINT;
Vms    : PVms;
Idx    : array of UINT;
begin
for I := 0 to High(F3dbs) do
  with F3dbs[I] do
    for J := 0 to High(Levels) do
      with Levels[J] do
      begin
        Vms := Lib.Data;
        if (Ref.MeshCount > 0) and
          (Ref.IndexStart < Vms.Data.IndexCount) and
          (Ref.VertexStart < Vms.Data.VertexCount) and
          (UINT(Ref.MeshStart) + UINT(Ref.MeshCount) <= UINT(Vms.Data.MeshesCount)) then
          begin
            Num := 0;
            if Length(Idx) < Ref.MeshCount then SetLength(Idx, Ref.MeshCount);
            for M := 0 to Ref.MeshCount-1 do
              with Vms.Meshes[Ref.MeshStart + M] do
              begin
                Idx[M] := Ref.IndexStart + Num;
                Inc(Num,VNum);
              end;
            if Num > 0 then
            begin
              N := 0;
              Num := 0;
              SetLength(_3d, Ref.MeshCount);
              for K := 0 to High(Vms.Mats) do
              begin
                Mat := Vms.Mats[K];
                for M := 0 to Ref.MeshCount-1 do
                  if Mat = Vms.Meshes[Ref.MeshStart + M].MaterialID then
                  begin
                    for N := M to Ref.MeshCount-1 do
                      with Vms.Meshes[Ref.MeshStart + N] do
                        if Mat = MaterialID then
                        begin
                          _3d[Num].IStart := Idx[N] + Vms.Buffer.IB;
                          _3d[Num].ICount := VNum;
                          _3d[Num].VStart := Ref.VertexStart + VStart + Vms.Buffer.VB;
                          _3d[Num].VCount := VEnd - VStart;
                          _3d[Num].Material := MaterialID;
                          Inc(Num);
                        end;
                    Break;
                  end;
              end;
            end;
          end;
      end;
Result := True;
end;


//Shader expects that matrices buffer is bound at slot #7.
//Precalculated matrices of all instances (typical static geometry) gives +25% boost VS updating matrices each frame.
procedure TFL3dCobject.DrawInstanced(const Context:ID3D11DeviceContext;const Count,Start:UINT;const Level:Byte=0);
var
DC    : ID3D11DeviceContext;
P     : Integer;
C     : TD3DXColor;
Cnt   : UINT;
Clr   : Single;
Add   : Single;
M     : Integer;
MatID : UINT;
Buff  : ID3DX11Buffer;
//  Z: Integer;
begin
if not Eval or (Count = 0) then Exit;
if Context = nil then
  FL.Device.GetImmediateContext(DC) else
  DC := Context;
DC.IASetInputLayout(FL.Layout);
DC.IASetPrimitiveTopology(D3D_PRIMITIVE_TOPOLOGY_TRIANGLELIST);
MatID := 0;
for P := 0 to High(FParts) do
  with FParts[P] do
    if Model >= 0 then
      with F3dbs[Model] do
        if UINT(Level) < UINT(Length(Levels)) then
          with Levels[Level], Lib.Data^, Buffer do
            if Value <> nil then
            begin
              if Buff <> Value then
              begin
                Buff := Value;
                if Failed(Buff.Pipeline(nil,Map)) then
                  Exit;
              end;
              FL.Effect.GetVariableByName('Model').AsMatrix.SetMatrix(@Mat);
              for M := 0 to High(_3d) do
                with _3d[M] do
                begin
                  if MatID <> Material then
                  begin
                    MatID := Material;
                    Clr := Clr + Add;
                    C := D3DXColorToUINT(MIHSV2RGB(DWORD(Round(Clr) shl 16) or $0000FFFF));
                    FL.Effect.GetVariableByName('Dc').AsVector.SetFloatVector(@C);

                    //This should called as less as possible. It kills performance.
                    FL.Effect.GetTechniqueByIndex(0).GetPassByIndex(0).Apply(0,DC);
                  end;
                  //6000 meshes: fps ~2000-2700
                  //for Z := 0 to 100 do //6000 meshes x100 (~600000 calls) fps ~43
                  DC.DrawIndexedInstanced(ICount, Count, IStart, VStart, Start);
                end;
            end;
end;