// dear imgui: Renderer for DirectX10
// This needs to be used along with a Platform Binding (e.g. Win32)

// Implemented features:
//  [X] Renderer: User texture binding. Use 'ID3D10ShaderResourceView*' as ImTextureID. Read the FAQ about ImTextureID in imgui.cpp.

// You can copy and use unmodified imgui_impl_* files in your project. See main.cpp for an example of using this.
// If you are new to dear imgui, read examples/README.txt and read the documentation at the top of imgui.cpp.
// https://github.com/ocornut/imgui

// CHANGELOG
// (minor and older changes stripped away, please see git history for details)
//  2018-12-03: Misc: Added #pragma comment statement to automatically link with d3dcompiler.lib when using D3DCompile().
//  2018-11-30: Misc: Setting up io.BackendRendererName so it can be displayed in the About Window.
//  2018-07-13: DirectX10: Fixed unreleased resources in Init and Shutdown functions.
//  2018-06-08: Misc: Extracted imgui_impl_dx10.cpp/.h away from the old combined DX10+Win32 example.
//  2018-06-08: DirectX10: Use draw_data->DisplayPos and draw_data->DisplaySize to setup projection matrix and clipping rectangle.
//  2018-04-09: Misc: Fixed erroneous call to io.Fonts->ClearInputData() + ClearTexData() that was left in DX10 example but removed in 1.47 (Nov 2015) on other back-ends.
//  2018-02-16: Misc: Obsoleted the io.RenderDrawListsFn callback and exposed ImGui_ImplDX10_RenderDrawData() in the .h file so you can call it yourself.
//  2018-02-06: Misc: Removed call to ImGui::Shutdown() which is not available from 1.60 WIP, user needs to call CreateContext/DestroyContext themselves.
//  2016-05-07: DirectX10: Disabling depth-write.

#include "imgui.h"
#include "imgui_impl_dx10.h"

// DirectX
#include <stdio.h>
#include <d3d10_1.h>
#include <d3d10.h>
#include <d3dcompiler.h>
#ifdef _MSC_VER
#pragma comment(lib, "d3dcompiler") // Automatically link with d3dcompiler.lib as we are using D3DCompile() below.
#endif

// DirectX data
static ID3D10Device*            g_pd3dDevice = NULL;
static IDXGIFactory*            g_pFactory = NULL;
static ID3D10Buffer*            g_pVB = NULL;
static ID3D10Buffer*            g_pIB = NULL;
static ID3D10Blob*              g_pVertexShaderBlob = NULL;
static ID3D10VertexShader*      g_pVertexShader = NULL;
static ID3D10InputLayout*       g_pInputLayout = NULL;
static ID3D10Buffer*            g_pVertexConstantBuffer = NULL;
static ID3D10Blob*              g_pPixelShaderBlob = NULL;
static ID3D10PixelShader*       g_pPixelShader = NULL;
static ID3D10SamplerState*      g_pFontSampler = NULL;
static ID3D10ShaderResourceView*g_pFontTextureView = NULL;
static ID3D10RasterizerState*   g_pRasterizerState = NULL;
static ID3D10BlendState*        g_pBlendState = NULL;
static ID3D10DepthStencilState* g_pDepthStencilState = NULL;
static int                      g_VertexBufferSize = 5000, g_IndexBufferSize = 10000;

struct VERTEX_CONSTANT_BUFFER
{
    float   mvp[4][4];
};

// Render function
// (this used to be set in io.RenderDrawListsFn and called by ImGui::Render(), but you can now call this directly from your main loop)
void ImGui_ImplDX10_RenderDrawData(ImDrawData* draw_data)
{
    ID3D10Device* ctx = g_pd3dDevice;

    // 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;
        D3D10_BUFFER_DESC desc;
        memset(&desc, 0, sizeof(D3D10_BUFFER_DESC));
        desc.Usage = D3D10_USAGE_DYNAMIC;
        desc.ByteWidth = g_VertexBufferSize * sizeof(ImDrawVert);
        desc.BindFlags = D3D10_BIND_VERTEX_BUFFER;
        desc.CPUAccessFlags = D3D10_CPU_ACCESS_WRITE;
        desc.MiscFlags = 0;
        if (ctx->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;
        D3D10_BUFFER_DESC desc;
        memset(&desc, 0, sizeof(D3D10_BUFFER_DESC));
        desc.Usage = D3D10_USAGE_DYNAMIC;
        desc.ByteWidth = g_IndexBufferSize * sizeof(ImDrawIdx);
        desc.BindFlags = D3D10_BIND_INDEX_BUFFER;
        desc.CPUAccessFlags = D3D10_CPU_ACCESS_WRITE;
        if (ctx->CreateBuffer(&desc, NULL, &g_pIB) < 0)
            return;
    }

    // Copy and convert all vertices into a single contiguous buffer
    ImDrawVert* vtx_dst = NULL;
    ImDrawIdx* idx_dst = NULL;
    g_pVB->Map(D3D10_MAP_WRITE_DISCARD, 0, (void**)&vtx_dst);
    g_pIB->Map(D3D10_MAP_WRITE_DISCARD, 0, (void**)&idx_dst);
    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;
    }
    g_pVB->Unmap();
    g_pIB->Unmap();

    // 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).
    {
        void* mapped_resource;
        if (g_pVertexConstantBuffer->Map(D3D10_MAP_WRITE_DISCARD, 0, &mapped_resource) != S_OK)
            return;
        VERTEX_CONSTANT_BUFFER* constant_buffer = (VERTEX_CONSTANT_BUFFER*)mapped_resource;
        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));
        g_pVertexConstantBuffer->Unmap();
    }

    // Backup DX state that will be modified to restore it afterwards (unfortunately this is very ugly looking and verbose. Close your eyes!)
    struct BACKUP_DX10_STATE
    {
        UINT                        ScissorRectsCount, ViewportsCount;
        D3D10_RECT                  ScissorRects[D3D10_VIEWPORT_AND_SCISSORRECT_OBJECT_COUNT_PER_PIPELINE];
        D3D10_VIEWPORT              Viewports[D3D10_VIEWPORT_AND_SCISSORRECT_OBJECT_COUNT_PER_PIPELINE];
        ID3D10RasterizerState*      RS;
        ID3D10BlendState*           BlendState;
        FLOAT                       BlendFactor[4];
        UINT                        SampleMask;
        UINT                        StencilRef;
        ID3D10DepthStencilState*    DepthStencilState;
        ID3D10ShaderResourceView*   PSShaderResource;
        ID3D10SamplerState*         PSSampler;
        ID3D10PixelShader*          PS;
        ID3D10VertexShader*         VS;
        D3D10_PRIMITIVE_TOPOLOGY    PrimitiveTopology;
        ID3D10Buffer*               IndexBuffer, *VertexBuffer, *VSConstantBuffer;
        UINT                        IndexBufferOffset, VertexBufferStride, VertexBufferOffset;
        DXGI_FORMAT                 IndexBufferFormat;
        ID3D10InputLayout*          InputLayout;
    };
    BACKUP_DX10_STATE old;
    old.ScissorRectsCount = old.ViewportsCount = D3D10_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);
    ctx->PSGetShader(&old.PS);
    ctx->VSGetShader(&old.VS);
    ctx->VSGetConstantBuffers(0, 1, &old.VSConstantBuffer);
    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 viewport
    D3D10_VIEWPORT vp;
    memset(&vp, 0, sizeof(D3D10_VIEWPORT));
    vp.Width = (UINT)draw_data->DisplaySize.x;
    vp.Height = (UINT)draw_data->DisplaySize.y;
    vp.MinDepth = 0.0f;
    vp.MaxDepth = 1.0f;
    vp.TopLeftX = vp.TopLeftY = 0;
    ctx->RSSetViewports(1, &vp);

    // Bind shader and vertex buffers
    unsigned int stride = sizeof(ImDrawVert);
    unsigned int offset = 0;
    ctx->IASetInputLayout(g_pInputLayout);
    ctx->IASetVertexBuffers(0, 1, &g_pVB, &stride, &offset);
    ctx->IASetIndexBuffer(g_pIB, sizeof(ImDrawIdx) == 2 ? DXGI_FORMAT_R16_UINT : DXGI_FORMAT_R32_UINT, 0);
    ctx->IASetPrimitiveTopology(D3D10_PRIMITIVE_TOPOLOGY_TRIANGLELIST);
    ctx->VSSetShader(g_pVertexShader);
    ctx->VSSetConstantBuffers(0, 1, &g_pVertexConstantBuffer);
    ctx->PSSetShader(g_pPixelShader);
    ctx->PSSetSamplers(0, 1, &g_pFontSampler);

    // Setup render state
    const float blend_factor[4] = { 0.f, 0.f, 0.f, 0.f };
    ctx->OMSetBlendState(g_pBlendState, blend_factor, 0xffffffff);
    ctx->OMSetDepthStencilState(g_pDepthStencilState, 0);
    ctx->RSSetState(g_pRasterizerState);

    // Render command lists
    int vtx_offset = 0;
    int idx_offset = 0;
    ImVec2 pos = 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)
            {
                // User callback (registered via ImDrawList::AddCallback)
                pcmd->UserCallback(cmd_list, pcmd);
            }
            else
            {
                // Apply scissor/clipping rectangle
                const D3D10_RECT r = { (LONG)(pcmd->ClipRect.x - pos.x), (LONG)(pcmd->ClipRect.y - pos.y), (LONG)(pcmd->ClipRect.z - pos.x), (LONG)(pcmd->ClipRect.w - pos.y)};
                ctx->RSSetScissorRects(1, &r);

                // Bind texture, Draw
                ID3D10ShaderResourceView* texture_srv = (ID3D10ShaderResourceView*)pcmd->TextureId;
                ctx->PSSetShaderResources(0, 1, &texture_srv);
                ctx->DrawIndexed(pcmd->ElemCount, idx_offset, vtx_offset);
            }
            idx_offset += pcmd->ElemCount;
        }
        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); if (old.PS) old.PS->Release();
    ctx->VSSetShader(old.VS); if (old.VS) old.VS->Release();
    ctx->VSSetConstantBuffers(0, 1, &old.VSConstantBuffer); if (old.VSConstantBuffer) old.VSConstantBuffer->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();
}

static void ImGui_ImplDX10_CreateFontsTexture()
{
    // Build texture atlas
    ImGuiIO& io = ImGui::GetIO();
    unsigned char* pixels;
    int width, height;
    io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height);

    // Upload texture to graphics system
    {
        D3D10_TEXTURE2D_DESC desc;
        ZeroMemory(&desc, sizeof(desc));
        desc.Width = width;
        desc.Height = height;
        desc.MipLevels = 1;
        desc.ArraySize = 1;
        desc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
        desc.SampleDesc.Count = 1;
        desc.Usage = D3D10_USAGE_DEFAULT;
        desc.BindFlags = D3D10_BIND_SHADER_RESOURCE;
        desc.CPUAccessFlags = 0;

        ID3D10Texture2D *pTexture = NULL;
        D3D10_SUBRESOURCE_DATA subResource;
        subResource.pSysMem = pixels;
        subResource.SysMemPitch = desc.Width * 4;
        subResource.SysMemSlicePitch = 0;
        g_pd3dDevice->CreateTexture2D(&desc, &subResource, &pTexture);

        // Create texture view
        D3D10_SHADER_RESOURCE_VIEW_DESC srv_desc;
        ZeroMemory(&srv_desc, sizeof(srv_desc));
        srv_desc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
        srv_desc.ViewDimension = D3D10_SRV_DIMENSION_TEXTURE2D;
        srv_desc.Texture2D.MipLevels = desc.MipLevels;
        srv_desc.Texture2D.MostDetailedMip = 0;
        g_pd3dDevice->CreateShaderResourceView(pTexture, &srv_desc, &g_pFontTextureView);
        pTexture->Release();
    }

    // Store our identifier
    io.Fonts->TexID = (ImTextureID)g_pFontTextureView;

    // Create texture sampler
    {
        D3D10_SAMPLER_DESC desc;
        ZeroMemory(&desc, sizeof(desc));
        desc.Filter = D3D10_FILTER_MIN_MAG_MIP_LINEAR;
        desc.AddressU = D3D10_TEXTURE_ADDRESS_WRAP;
        desc.AddressV = D3D10_TEXTURE_ADDRESS_WRAP;
        desc.AddressW = D3D10_TEXTURE_ADDRESS_WRAP;
        desc.MipLODBias = 0.f;
        desc.ComparisonFunc = D3D10_COMPARISON_ALWAYS;
        desc.MinLOD = 0.f;
        desc.MaxLOD = 0.f;
        g_pd3dDevice->CreateSamplerState(&desc, &g_pFontSampler);
    }
}

bool    ImGui_ImplDX10_CreateDeviceObjects()
{
    if (!g_pd3dDevice)
        return false;
    if (g_pFontSampler)
        ImGui_ImplDX10_InvalidateDeviceObjects();

    // By using D3DCompile() from <d3dcompiler.h> / d3dcompiler.lib, we introduce a dependency to a given version of d3dcompiler_XX.dll (see D3DCOMPILER_DLL_A)
    // If you would like to use this DX10 sample code but remove this dependency you can:
    //  1) compile once, save the compiled shader blobs into a file or source code and pass them to CreateVertexShader()/CreatePixelShader() [preferred solution]
    //  2) use code to detect any version of the DLL and grab a pointer to D3DCompile from the DLL.
    // See https://github.com/ocornut/imgui/pull/638 for sources and details.

    // Create the vertex shader
    {
        static const char* vertexShader =
            "cbuffer vertexBuffer : register(b0) \
            {\
            float4x4 ProjectionMatrix; \
            };\
            struct VS_INPUT\
            {\
            float2 pos : POSITION;\
            float4 col : COLOR0;\
            float2 uv  : TEXCOORD0;\
            };\
            \
            struct PS_INPUT\
            {\
            float4 pos : SV_POSITION;\
            float4 col : COLOR0;\
            float2 uv  : TEXCOORD0;\
            };\
            \
            PS_INPUT main(VS_INPUT input)\
            {\
            PS_INPUT output;\
            output.pos = mul( ProjectionMatrix, float4(input.pos.xy, 0.f, 1.f));\
            output.col = input.col;\
            output.uv  = input.uv;\
            return output;\
            }";

        D3DCompile(vertexShader, strlen(vertexShader), NULL, NULL, NULL, "main", "vs_4_0", 0, 0, &g_pVertexShaderBlob, NULL);
        if (g_pVertexShaderBlob == NULL) // NB: Pass ID3D10Blob* pErrorBlob to D3DCompile() to get error showing in (const char*)pErrorBlob->GetBufferPointer(). Make sure to Release() the blob!
            return false;
        if (g_pd3dDevice->CreateVertexShader((DWORD*)g_pVertexShaderBlob->GetBufferPointer(), g_pVertexShaderBlob->GetBufferSize(), &g_pVertexShader) != S_OK)
            return false;

        // Create the input layout
        D3D10_INPUT_ELEMENT_DESC local_layout[] =
        {
            { "POSITION", 0, DXGI_FORMAT_R32G32_FLOAT,   0, (size_t)(&((ImDrawVert*)0)->pos), D3D10_INPUT_PER_VERTEX_DATA, 0 },
            { "TEXCOORD", 0, DXGI_FORMAT_R32G32_FLOAT,   0, (size_t)(&((ImDrawVert*)0)->uv),  D3D10_INPUT_PER_VERTEX_DATA, 0 },
            { "COLOR",    0, DXGI_FORMAT_R8G8B8A8_UNORM, 0, (size_t)(&((ImDrawVert*)0)->col), D3D10_INPUT_PER_VERTEX_DATA, 0 },
        };
        if (g_pd3dDevice->CreateInputLayout(local_layout, 3, g_pVertexShaderBlob->GetBufferPointer(), g_pVertexShaderBlob->GetBufferSize(), &g_pInputLayout) != S_OK)
            return false;

        // Create the constant buffer
        {
            D3D10_BUFFER_DESC desc;
            desc.ByteWidth = sizeof(VERTEX_CONSTANT_BUFFER);
            desc.Usage = D3D10_USAGE_DYNAMIC;
            desc.BindFlags = D3D10_BIND_CONSTANT_BUFFER;
            desc.CPUAccessFlags = D3D10_CPU_ACCESS_WRITE;
            desc.MiscFlags = 0;
            g_pd3dDevice->CreateBuffer(&desc, NULL, &g_pVertexConstantBuffer);
        }
    }

    // Create the pixel shader
    {
        static const char* pixelShader =
            "struct PS_INPUT\
            {\
            float4 pos : SV_POSITION;\
            float4 col : COLOR0;\
            float2 uv  : TEXCOORD0;\
            };\
            sampler sampler0;\
            Texture2D texture0;\
            \
            float4 main(PS_INPUT input) : SV_Target\
            {\
            float4 out_col = input.col * texture0.Sample(sampler0, input.uv); \
            return out_col; \
            }";

        D3DCompile(pixelShader, strlen(pixelShader), NULL, NULL, NULL, "main", "ps_4_0", 0, 0, &g_pPixelShaderBlob, NULL);
        if (g_pPixelShaderBlob == NULL)  // NB: Pass ID3D10Blob* pErrorBlob to D3DCompile() to get error showing in (const char*)pErrorBlob->GetBufferPointer(). Make sure to Release() the blob!
            return false;
        if (g_pd3dDevice->CreatePixelShader((DWORD*)g_pPixelShaderBlob->GetBufferPointer(), g_pPixelShaderBlob->GetBufferSize(), &g_pPixelShader) != S_OK)
            return false;
    }

    // Create the blending setup
    {
        D3D10_BLEND_DESC desc;
        ZeroMemory(&desc, sizeof(desc));
        desc.AlphaToCoverageEnable = false;
        desc.BlendEnable[0] = true;
        desc.SrcBlend = D3D10_BLEND_SRC_ALPHA;
        desc.DestBlend = D3D10_BLEND_INV_SRC_ALPHA;
        desc.BlendOp = D3D10_BLEND_OP_ADD;
        desc.SrcBlendAlpha = D3D10_BLEND_INV_SRC_ALPHA;
        desc.DestBlendAlpha = D3D10_BLEND_ZERO;
        desc.BlendOpAlpha = D3D10_BLEND_OP_ADD;
        desc.RenderTargetWriteMask[0] = D3D10_COLOR_WRITE_ENABLE_ALL;
        g_pd3dDevice->CreateBlendState(&desc, &g_pBlendState);
    }

    // Create the rasterizer state
    {
        D3D10_RASTERIZER_DESC desc;
        ZeroMemory(&desc, sizeof(desc));
        desc.FillMode = D3D10_FILL_SOLID;
        desc.CullMode = D3D10_CULL_NONE;
        desc.ScissorEnable = true;
        desc.DepthClipEnable = true;
        g_pd3dDevice->CreateRasterizerState(&desc, &g_pRasterizerState);
    }

    // Create depth-stencil State
    {
        D3D10_DEPTH_STENCIL_DESC desc;
        ZeroMemory(&desc, sizeof(desc));
        desc.DepthEnable = false;
        desc.DepthWriteMask = D3D10_DEPTH_WRITE_MASK_ALL;
        desc.DepthFunc = D3D10_COMPARISON_ALWAYS;
        desc.StencilEnable = false;
        desc.FrontFace.StencilFailOp = desc.FrontFace.StencilDepthFailOp = desc.FrontFace.StencilPassOp = D3D10_STENCIL_OP_KEEP;
        desc.FrontFace.StencilFunc = D3D10_COMPARISON_ALWAYS;
        desc.BackFace = desc.FrontFace;
        g_pd3dDevice->CreateDepthStencilState(&desc, &g_pDepthStencilState);
    }

    ImGui_ImplDX10_CreateFontsTexture();

    return true;
}

void    ImGui_ImplDX10_InvalidateDeviceObjects()
{
    if (!g_pd3dDevice)
        return;

    if (g_pFontSampler) { g_pFontSampler->Release(); g_pFontSampler = NULL; }
    if (g_pFontTextureView) { g_pFontTextureView->Release(); g_pFontTextureView = NULL; ImGui::GetIO().Fonts->TexID = NULL; } // We copied g_pFontTextureView to io.Fonts->TexID so let's clear that as well.
    if (g_pIB) { g_pIB->Release(); g_pIB = NULL; }
    if (g_pVB) { g_pVB->Release(); g_pVB = NULL; }

    if (g_pBlendState) { g_pBlendState->Release(); g_pBlendState = NULL; }
    if (g_pDepthStencilState) { g_pDepthStencilState->Release(); g_pDepthStencilState = NULL; }
    if (g_pRasterizerState) { g_pRasterizerState->Release(); g_pRasterizerState = NULL; }
    if (g_pPixelShader) { g_pPixelShader->Release(); g_pPixelShader = NULL; }
    if (g_pPixelShaderBlob) { g_pPixelShaderBlob->Release(); g_pPixelShaderBlob = NULL; }
    if (g_pVertexConstantBuffer) { g_pVertexConstantBuffer->Release(); g_pVertexConstantBuffer = NULL; }
    if (g_pInputLayout) { g_pInputLayout->Release(); g_pInputLayout = NULL; }
    if (g_pVertexShader) { g_pVertexShader->Release(); g_pVertexShader = NULL; }
    if (g_pVertexShaderBlob) { g_pVertexShaderBlob->Release(); g_pVertexShaderBlob = NULL; }
}

bool    ImGui_ImplDX10_Init(ID3D10Device* device)
{
    ImGuiIO& io = ImGui::GetIO();
    io.BackendRendererName = "imgui_impl_dx10";

    // Get factory from device
    IDXGIDevice* pDXGIDevice = NULL;
    IDXGIAdapter* pDXGIAdapter = NULL;
    IDXGIFactory* pFactory = NULL;

    if (device->QueryInterface(IID_PPV_ARGS(&pDXGIDevice)) == S_OK)
        if (pDXGIDevice->GetParent(IID_PPV_ARGS(&pDXGIAdapter)) == S_OK)
            if (pDXGIAdapter->GetParent(IID_PPV_ARGS(&pFactory)) == S_OK)
            {
                g_pd3dDevice = device;
                g_pFactory = pFactory;
            }
    if (pDXGIDevice) pDXGIDevice->Release();
    if (pDXGIAdapter) pDXGIAdapter->Release();

    return true;
}

void ImGui_ImplDX10_Shutdown()
{
    ImGui_ImplDX10_InvalidateDeviceObjects();
    if (g_pFactory) { g_pFactory->Release(); g_pFactory = NULL; }
    g_pd3dDevice = NULL;
}

void ImGui_ImplDX10_NewFrame()
{
    if (!g_pFontSampler)
        ImGui_ImplDX10_CreateDeviceObjects();
}