I can't assign a texture to IMGUI because I can't create directx texture - c++

Question

I'm trying to add some images for using with IMGUI library. Basically, IMGUI can get directx or OpenGL raw texture data to draw. You can see example code from IMGUI for creating a texture ;
// Simple helper function to load an image into a DX11 texture with common settings
bool LoadTextureFromFile(const char* filename, ID3D11ShaderResourceView** out_srv, int* out_width, int* out_height)
{
// Load from disk into a raw RGBA buffer
int image_width = 0;
int image_height = 0;
unsigned char* image_data = stbi_load(filename, &image_width, &image_height, NULL, 4);
if (image_data == NULL)
return false;
// Create texture
D3D11_TEXTURE2D_DESC desc;
ZeroMemory(&desc, sizeof(desc));
desc.Width = image_width;
desc.Height = image_height;
desc.MipLevels = 1;
desc.ArraySize = 1;
desc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
desc.SampleDesc.Count = 1;
desc.Usage = D3D11_USAGE_DEFAULT;
desc.BindFlags = D3D11_BIND_SHADER_RESOURCE;
desc.CPUAccessFlags = 0;
ID3D11Texture2D *pTexture = NULL;
D3D11_SUBRESOURCE_DATA subResource;
subResource.pSysMem = image_data;
subResource.SysMemPitch = desc.Width * 4;
subResource.SysMemSlicePitch = 0;
g_pd3dDevice->CreateTexture2D(&desc, &subResource, &pTexture);
// Create texture view
D3D11_SHADER_RESOURCE_VIEW_DESC srvDesc;
ZeroMemory(&srvDesc, sizeof(srvDesc));
srvDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
srvDesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE2D;
srvDesc.Texture2D.MipLevels = desc.MipLevels;
srvDesc.Texture2D.MostDetailedMip = 0;
g_pd3dDevice->CreateShaderResourceView(pTexture, &srvDesc, out_srv);
pTexture->Release();
*out_width = image_width;
*out_height = image_height;
stbi_image_free(image_data);
return true;
}
Everything is ok except 'g_pd3dDevice->CreateTexture2D(&desc, &subResource, &pTexture);' line. Because as you can see g_pd3dDevice is undefined. That's why I put a line for this like : ID3D11Device* g_pd3dDevice = nullptr; but when I run code it hangs.. I guess I must create a 3ddevice before using this part. But I can't. Any suggestions? Thanks
Now I can get some image but it's wrong:
Now my code like this ;
bool LoadTextureFromBufferDX11(unsigned char* address, ID3D11ShaderResourceView** out_srv, int* out_width, int* out_height)
{
WNDCLASSEX wc = { sizeof(WNDCLASSEX), CS_CLASSDC, WndProc, 0L, 0L, GetModuleHandle(NULL), NULL, NULL, NULL, NULL, _T("ImGui Example"), NULL };
::RegisterClassEx(&wc);
//HWND hwnd = ::CreateWindow(wc.lpszClassName, _T("Dear ImGui DirectX11 Example"), WS_OVERLAPPEDWINDOW, 100, 100, 200, 200, NULL, NULL, wc.hInstance, NULL);
HWND hwnd = GetForegroundWindow();
CreateDeviceD3D(hwnd);
/*
if (!CreateDeviceD3D(hwnd))
{
CleanupDeviceD3D();
::UnregisterClass(wc.lpszClassName, wc.hInstance);
return 1;
}
*/
//ImGui_ImplDX11_Init(g_pd3dDevice, g_pd3dDeviceContext);
// Load from disk into a raw RGBA buffer
int image_width = 0;
int image_height = 0;
const char* filename = "e:\\obama.png";
unsigned char* image_data = stbi_load(filename, &image_width, &image_height, NULL, 4);
//unsigned char* image_data = address;
if (image_data == NULL)
return false;
// Create texture
D3D11_TEXTURE2D_DESC desc;
ZeroMemory(&desc, sizeof(desc));
desc.Width = image_width;
desc.Height = image_height;
desc.MipLevels = 1;
desc.ArraySize = 1;
desc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
desc.SampleDesc.Count = 1;
desc.Usage = D3D11_USAGE_DEFAULT;
desc.BindFlags = D3D11_BIND_SHADER_RESOURCE;
desc.CPUAccessFlags = 0;
ID3D11Texture2D *pTexture = NULL;
D3D11_SUBRESOURCE_DATA subResource;
subResource.pSysMem = image_data;
subResource.SysMemPitch = desc.Width * 4;
subResource.SysMemSlicePitch = 0;
g_pd3dDevice->CreateTexture2D(&desc, &subResource, &pTexture);
// Create texture view
D3D11_SHADER_RESOURCE_VIEW_DESC srvDesc;
ZeroMemory(&srvDesc, sizeof(srvDesc));
srvDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
srvDesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE2D;
srvDesc.Texture2D.MipLevels = desc.MipLevels;
srvDesc.Texture2D.MostDetailedMip = 0;
g_pd3dDevice->CreateShaderResourceView(pTexture, &srvDesc, out_srv);
pTexture->Release();
*out_width = image_width;
*out_height = image_height;
return true;
}
And I trigger this function from host app.
static ID3D11ShaderResourceView* my_texture = NULL;
int my_image_width = 0;
int my_image_height = 0;
fn_export double imgui_showimage(unsigned char* address) {
bool ret = LoadTextureFromBufferDX11(address, &my_texture, &my_image_width, &my_image_height);
//IM_ASSERT(ret);
//ImGui::Image((void*)my_texture, ImVec2(my_image_width, my_image_height));
return 1;
}
And I draw imgu image from host like ;
fn_export double imgui_image(char* address) {
ImGui::Image((void*)my_texture, ImVec2(my_image_width, my_image_height));
return 1;
}