need to hook DX11 on a game to draw some rectangle.

To do it I have tried some source code but actually the only one that work in my case is ImGui:

https://github.com/ocornut/imgui

theoretically I can use it, but because in my case I need to draw only some line I like to consider other altarnative.

For this reason I have tried this example:

http://www.directxtutorial.com/Lesson.aspx?lessonid=11-4-5

that work on a test desktop project but not in my dll that hook the game.

My dll crash in this like:

pChain->Present(0, 0);

becouse I have already hook with detour this method:

HRESULT __stdcall IDXGISwapChain_Present(IDXGISwapChain* pChain, UINT SyncInterval, UINT Flags)
{
    // Get device and swapchain
    if (!bGraphicsInitialised)
    {
        // Init Direct X
        if (!InitDirectXAndInput(pChain)) return fnIDXGISwapChainPresent(pChain, SyncInterval, Flags);

        // Init ImGui
        ImGui::CreateContext();
        ImGuiIO& io = ImGui::GetIO(); (void)io;
        io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;

        // Setup rendering and IO
        ImGui_ImplWin32_Init(hWindow);
        ImGui_ImplDX11_Init(pDevice, pContext);
        ImGui::GetIO().ImeWindowHandle = hWindow;

        // Create render target view for rendering
        ID3D11Texture2D* pBackBuffer;
        pChain->GetBuffer(0, __uuidof(ID3D11Texture2D), (LPVOID*)&pBackBuffer);
        HRESULT hr = pDevice->CreateRenderTargetView(pBackBuffer, NULL, &pRenderTargetView);
        if (FAILED(hr))
        {
            std::cerr << "Failed to create render target view" << std::endl;
            return fnIDXGISwapChainPresent(pChain, SyncInterval, Flags);
        }
        pBackBuffer->Release();

        bGraphicsInitialised = true;
    }

    LF::Log_Update("IDXGISwapChain_Present");

    // Render ImGui
    ImGui_ImplDX11_NewFrame();
    ImGui_ImplWin32_NewFrame();
    ImGui::NewFrame();
    ImGui::ShowDemoWindowCustom(test);
    ImGui::EndFrame();
    ImGui::Render();

    pContext->OMSetRenderTargets(1, &pRenderTargetView, NULL);
    ImGui_ImplDX11_RenderDrawData(ImGui::GetDrawData());

    return fnIDXGISwapChainPresent(pChain, SyncInterval, Flags);
}

with this code my dll (that use ImuGui) work perfectly and not need "swapChain->Present".

Here my dll without ImuGui:

HRESULT __stdcall IDXGISwapChain_Present(IDXGISwapChain* pChain, UINT SyncInterval, UINT Flags)
{
    // Get device and swapchain
    if (!bGraphicsInitialised)
    {
        // Init Direct X
        if (!InitDirectXAndInput(pChain)) return fnIDXGISwapChainPresent(pChain, SyncInterval, Flags);

        // Init ImGui
        ////ImGui::CreateContext();
        ////ImGuiIO& io = ImGui::GetIO(); (void)io;
        ////io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;

        ////// Setup rendering and IO
        ////ImGui_ImplWin32_Init(hWindow);
        ////ImGui_ImplDX11_Init(pDevice, pContext);
        ////ImGui::GetIO().ImeWindowHandle = hWindow;
        // set up and initialize Direct3D
         InitD3D(hWindow, pDevice, pContext);

        // Create render target view for rendering
        ID3D11Texture2D* pBackBuffer;
        pChain->GetBuffer(0, __uuidof(ID3D11Texture2D), (LPVOID*)&pBackBuffer);
        HRESULT hr = pDevice->CreateRenderTargetView(pBackBuffer, NULL, &pRenderTargetView);
        if (FAILED(hr))
        {
            std::cerr << "Failed to create render target view" << std::endl;
            return fnIDXGISwapChainPresent(pChain, SyncInterval, Flags);
        }
        pBackBuffer->Release();

        bGraphicsInitialised = true;
    }

    RenderFrame();
    
    pChain->Present(0, 0);

    LF::Log_Update("pChain->Present(1, 0)");

    return fnIDXGISwapChainPresent(pChain, SyncInterval, Flags);
}

and here my renderframe:

// this is the function used to render a single frame
void RenderFrame(void)
{
    if (VectVertices.size() < 1)
        return;

    // Set transparent color
    float color[4] = { 0.0f, 0.0f, 0.0f, 0.0f };

    // clear the back buffer
    devcon->ClearRenderTargetView(backbuffer, color);

    // select which vertex buffer to display
    UINT stride = sizeof(VERTEX);
    UINT offset = 0;

    devcon->IASetVertexBuffers(0, 1, &pVBuffer, &stride, &offset);

    // select which primtive type we are using
    //  draw the vertex buffer to the back buffer
    devcon->IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_LINELIST);
    devcon->Draw(VectVertices.size(), 0);

   // swapchain->Present(0, 0);

}

in short my code not work becouse shouldn't use swapchain->Present that is hooked.

The here the working rendering method of imuGUI:

// Render function
void ImGui_ImplDX11_RenderDrawData(ImDrawData* draw_data)
{
    // Avoid rendering when minimized
    if (draw_data->DisplaySize.x <= 0.0f || draw_data->DisplaySize.y <= 0.0f)
        return;

    ID3D11DeviceContext* ctx = g_pd3dDeviceContext;

    // Create and grow vertex/index buffers if needed
    if (!g_pVB || g_VertexBufferSize < draw_data->TotalVtxCount)
    {
        if (g_pVB) { g_pVB->Release(); g_pVB = NULL; }
        g_VertexBufferSize = draw_data->TotalVtxCount + 5000;
        D3D11_BUFFER_DESC desc;
        memset(&desc, 0, sizeof(D3D11_BUFFER_DESC));
        desc.Usage = D3D11_USAGE_DYNAMIC;
        desc.ByteWidth = g_VertexBufferSize * sizeof(ImDrawVert);
        desc.BindFlags = D3D11_BIND_VERTEX_BUFFER;
        desc.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;
        desc.MiscFlags = 0;
        if (g_pd3dDevice->CreateBuffer(&desc, NULL, &g_pVB) < 0)
            return;
    }
    if (!g_pIB || g_IndexBufferSize < draw_data->TotalIdxCount)
    {
        if (g_pIB) { g_pIB->Release(); g_pIB = NULL; }
        g_IndexBufferSize = draw_data->TotalIdxCount + 10000;
        D3D11_BUFFER_DESC desc;
        memset(&desc, 0, sizeof(D3D11_BUFFER_DESC));
        desc.Usage = D3D11_USAGE_DYNAMIC;
        desc.ByteWidth = g_IndexBufferSize * sizeof(ImDrawIdx);
        desc.BindFlags = D3D11_BIND_INDEX_BUFFER;
        desc.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;
        if (g_pd3dDevice->CreateBuffer(&desc, NULL, &g_pIB) < 0)
            return;
    }

    // Upload vertex/index data into a single contiguous GPU buffer
    D3D11_MAPPED_SUBRESOURCE vtx_resource, idx_resource;
    if (ctx->Map(g_pVB, 0, D3D11_MAP_WRITE_DISCARD, 0, &vtx_resource) != S_OK)
        return;
    if (ctx->Map(g_pIB, 0, D3D11_MAP_WRITE_DISCARD, 0, &idx_resource) != S_OK)
        return;
    ImDrawVert* vtx_dst = (ImDrawVert*)vtx_resource.pData;
    ImDrawIdx* idx_dst = (ImDrawIdx*)idx_resource.pData;
    for (int n = 0; n < draw_data->CmdListsCount; n++)
    {
        const ImDrawList* cmd_list = draw_data->CmdLists[n];
        memcpy(vtx_dst, cmd_list->VtxBuffer.Data, cmd_list->VtxBuffer.Size * sizeof(ImDrawVert));
        memcpy(idx_dst, cmd_list->IdxBuffer.Data, cmd_list->IdxBuffer.Size * sizeof(ImDrawIdx));
        vtx_dst += cmd_list->VtxBuffer.Size;
        idx_dst += cmd_list->IdxBuffer.Size;
    }
    ctx->Unmap(g_pVB, 0);
    ctx->Unmap(g_pIB, 0);

    // Setup orthographic projection matrix into our constant buffer
    // Our visible imgui space lies from draw_data->DisplayPos (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right). DisplayPos is (0,0) for single viewport apps.
    {
        D3D11_MAPPED_SUBRESOURCE mapped_resource;
        if (ctx->Map(g_pVertexConstantBuffer, 0, D3D11_MAP_WRITE_DISCARD, 0, &mapped_resource) != S_OK)
            return;
        VERTEX_CONSTANT_BUFFER* constant_buffer = (VERTEX_CONSTANT_BUFFER*)mapped_resource.pData;
        float L = draw_data->DisplayPos.x;
        float R = draw_data->DisplayPos.x + draw_data->DisplaySize.x;
        float T = draw_data->DisplayPos.y;
        float B = draw_data->DisplayPos.y + draw_data->DisplaySize.y;
        float mvp[4][4] =
        {
            { 2.0f/(R-L),   0.0f,           0.0f,       0.0f },
            { 0.0f,         2.0f/(T-B),     0.0f,       0.0f },
            { 0.0f,         0.0f,           0.5f,       0.0f },
            { (R+L)/(L-R),  (T+B)/(B-T),    0.5f,       1.0f },
        };
        memcpy(&constant_buffer->mvp, mvp, sizeof(mvp));
        ctx->Unmap(g_pVertexConstantBuffer, 0);
    }

    // Backup DX state that will be modified to restore it afterwards (unfortunately this is very ugly looking and verbose. Close your eyes!)
    struct BACKUP_DX11_STATE
    {
        UINT                        ScissorRectsCount, ViewportsCount;
        D3D11_RECT                  ScissorRects[D3D11_VIEWPORT_AND_SCISSORRECT_OBJECT_COUNT_PER_PIPELINE];
        D3D11_VIEWPORT              Viewports[D3D11_VIEWPORT_AND_SCISSORRECT_OBJECT_COUNT_PER_PIPELINE];
        ID3D11RasterizerState*      RS;
        ID3D11BlendState*           BlendState;
        FLOAT                       BlendFactor[4];
        UINT                        SampleMask;
        UINT                        StencilRef;
        ID3D11DepthStencilState*    DepthStencilState;
        ID3D11ShaderResourceView*   PSShaderResource;
        ID3D11SamplerState*         PSSampler;
        ID3D11PixelShader*          PS;
        ID3D11VertexShader*         VS;
        ID3D11GeometryShader*       GS;
        UINT                        PSInstancesCount, VSInstancesCount, GSInstancesCount;
        ID3D11ClassInstance         *PSInstances[256], *VSInstances[256], *GSInstances[256];   // 256 is max according to PSSetShader documentation
        D3D11_PRIMITIVE_TOPOLOGY    PrimitiveTopology;
        ID3D11Buffer*               IndexBuffer, *VertexBuffer, *VSConstantBuffer;
        UINT                        IndexBufferOffset, VertexBufferStride, VertexBufferOffset;
        DXGI_FORMAT                 IndexBufferFormat;
        ID3D11InputLayout*          InputLayout;
    };
    BACKUP_DX11_STATE old;
    old.ScissorRectsCount = old.ViewportsCount = D3D11_VIEWPORT_AND_SCISSORRECT_OBJECT_COUNT_PER_PIPELINE;
    ctx->RSGetScissorRects(&old.ScissorRectsCount, old.ScissorRects);
    ctx->RSGetViewports(&old.ViewportsCount, old.Viewports);
    ctx->RSGetState(&old.RS);
    ctx->OMGetBlendState(&old.BlendState, old.BlendFactor, &old.SampleMask);
    ctx->OMGetDepthStencilState(&old.DepthStencilState, &old.StencilRef);
    ctx->PSGetShaderResources(0, 1, &old.PSShaderResource);
    ctx->PSGetSamplers(0, 1, &old.PSSampler);
    old.PSInstancesCount = old.VSInstancesCount = old.GSInstancesCount = 256;
    ctx->PSGetShader(&old.PS, old.PSInstances, &old.PSInstancesCount);
    ctx->VSGetShader(&old.VS, old.VSInstances, &old.VSInstancesCount);
    ctx->VSGetConstantBuffers(0, 1, &old.VSConstantBuffer);
    ctx->GSGetShader(&old.GS, old.GSInstances, &old.GSInstancesCount);

    ctx->IAGetPrimitiveTopology(&old.PrimitiveTopology);
    ctx->IAGetIndexBuffer(&old.IndexBuffer, &old.IndexBufferFormat, &old.IndexBufferOffset);
    ctx->IAGetVertexBuffers(0, 1, &old.VertexBuffer, &old.VertexBufferStride, &old.VertexBufferOffset);
    ctx->IAGetInputLayout(&old.InputLayout);

    // Setup desired DX state
    ImGui_ImplDX11_SetupRenderState(draw_data, ctx);

    // Render command lists
    // (Because we merged all buffers into a single one, we maintain our own offset into them)
    int global_idx_offset = 0;
    int global_vtx_offset = 0;
    ImVec2 clip_off = draw_data->DisplayPos;
    for (int n = 0; n < draw_data->CmdListsCount; n++)
    {
        const ImDrawList* cmd_list = draw_data->CmdLists[n];
        for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.Size; cmd_i++)
        {
            const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
            if (pcmd->UserCallback != NULL)
            {
                // User callback, registered via ImDrawList::AddCallback()
                // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
                if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
                    ImGui_ImplDX11_SetupRenderState(draw_data, ctx);
                else
                    pcmd->UserCallback(cmd_list, pcmd);
            }
            else
            {
                // Apply scissor/clipping rectangle
                const D3D11_RECT r = { (LONG)(pcmd->ClipRect.x - clip_off.x), (LONG)(pcmd->ClipRect.y - clip_off.y), (LONG)(pcmd->ClipRect.z - clip_off.x), (LONG)(pcmd->ClipRect.w - clip_off.y) };
                ctx->RSSetScissorRects(1, &r);

                // Bind texture, Draw
                ID3D11ShaderResourceView* texture_srv = (ID3D11ShaderResourceView*)pcmd->TextureId;
                ctx->PSSetShaderResources(0, 1, &texture_srv);
                ctx->DrawIndexed(pcmd->ElemCount, pcmd->IdxOffset + global_idx_offset, pcmd->VtxOffset + global_vtx_offset);
            }
        }
        global_idx_offset += cmd_list->IdxBuffer.Size;
        global_vtx_offset += cmd_list->VtxBuffer.Size;
    }

    // Restore modified DX state
    ctx->RSSetScissorRects(old.ScissorRectsCount, old.ScissorRects);
    ctx->RSSetViewports(old.ViewportsCount, old.Viewports);
    ctx->RSSetState(old.RS); if (old.RS) old.RS->Release();
    ctx->OMSetBlendState(old.BlendState, old.BlendFactor, old.SampleMask); if (old.BlendState) old.BlendState->Release();
    ctx->OMSetDepthStencilState(old.DepthStencilState, old.StencilRef); if (old.DepthStencilState) old.DepthStencilState->Release();
    ctx->PSSetShaderResources(0, 1, &old.PSShaderResource); if (old.PSShaderResource) old.PSShaderResource->Release();
    ctx->PSSetSamplers(0, 1, &old.PSSampler); if (old.PSSampler) old.PSSampler->Release();
    ctx->PSSetShader(old.PS, old.PSInstances, old.PSInstancesCount); if (old.PS) old.PS->Release();
    for (UINT i = 0; i < old.PSInstancesCount; i++) if (old.PSInstances[i]) old.PSInstances[i]->Release();
    ctx->VSSetShader(old.VS, old.VSInstances, old.VSInstancesCount); if (old.VS) old.VS->Release();
    ctx->VSSetConstantBuffers(0, 1, &old.VSConstantBuffer); if (old.VSConstantBuffer) old.VSConstantBuffer->Release();
    ctx->GSSetShader(old.GS, old.GSInstances, old.GSInstancesCount); if (old.GS) old.GS->Release();
    for (UINT i = 0; i < old.VSInstancesCount; i++) if (old.VSInstances[i]) old.VSInstances[i]->Release();
    ctx->IASetPrimitiveTopology(old.PrimitiveTopology);
    ctx->IASetIndexBuffer(old.IndexBuffer, old.IndexBufferFormat, old.IndexBufferOffset); if (old.IndexBuffer) old.IndexBuffer->Release();
    ctx->IASetVertexBuffers(0, 1, &old.VertexBuffer, &old.VertexBufferStride, &old.VertexBufferOffset); if (old.VertexBuffer) old.VertexBuffer->Release();
    ctx->IASetInputLayout(old.InputLayout); if (old.InputLayout) old.InputLayout->Release();
}

Can you please suggest me a way to avoid to use pChain->Present(0, 0) ?

Thank you !