Windows API - Win32
A core set of Windows application programming interfaces (APIs) for desktop and server applications. Previously known as Win32 API.
2,418 questions
per-pixel transparent window using Windows Composition engine in C++
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(316.8, 82%, 40%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EVT%3C/text%3E%3C/svg%3E)
vincent torri
1
Reputation point
Hello
I want to display a raw BGRA data (so I have an unsigned int *, with width and height) on a window so that the alpha component is taken into account to have per-pixel transparency. The final purpose is to integrate this in a graphic toolkit.
after reading Kenny Kerr's article (https://learn.microsoft.com/en-us/archive/msdn-magazine/2014/june/windows-with-c-high-performance-window-layering-using-the-windows-composition-engine) I think that it can solve my problem.
I have already written a complete code that does what the article described : transparent window with a translucent disk
So, basically, what I am doing now is :
- get the buffer (a surface) from the swapchain
- get a bitmap with CreateBitmapFromDxgiSurface
- I allocate a BGRA test data
- use CopyFromMemory to copy my BGRA data onto the bitmap
- between BeginDraw and EndDraw, I call DrawBitmap
But whatever flag I use for the properties' bitmapOptions passed to CreateBitmapFromDxgiSurface, the app crashes and the D2D debug layer mentions an error like : "warning: D2D DEBUG ERROR - The bitmap options [0x1] must be a subset of the flags associated with the DXGI surface."
the complete code is here :
#include <iostream>
#ifdef _WIN32_WINNT
# undef _WIN32_WINNT
#endif
#define _WIN32_WINNT 0x0A00
#include <guiddef.h>
#include <d2d1_1.h>
#include <d3d11.h>
#include <dxgi1_3.h>
#include <dcomp.h>
static HINSTANCE instance = NULL;
static HWND win = NULL;
LRESULT CALLBACK _window_procedure(HWND window,
UINT message,
WPARAM window_param,
LPARAM data_param);
typedef struct
{
ID3D11Device *d3d_device;
IDXGIDevice *dxgi_device;
IDXGIFactory2 *dxgi_factory;
ID2D1Factory1 *d2d_factory;
ID2D1Device *d2d_device;
ID2D1DeviceContext *d2d_device_ctx;
IDCompositionDevice *dcomp_device;
IDCompositionVisual *dcomp_visual;
IDCompositionTarget *dcomp_target;
IDXGISwapChain1 *dxgi_swapchain;
} D2d;
int d2d_init(HWND window, D2d *d2d)
{
const D3D_FEATURE_LEVEL levels[] =
{
D3D_FEATURE_LEVEL_12_1,
D3D_FEATURE_LEVEL_12_0,
D3D_FEATURE_LEVEL_11_1,
D3D_FEATURE_LEVEL_11_0,
D3D_FEATURE_LEVEL_10_1,
D3D_FEATURE_LEVEL_10_0
};
D2D1_FACTORY_OPTIONS opt;
DXGI_SWAP_CHAIN_DESC1 desc;
RECT r;
HRESULT res;
/* direct3d device */
res = D3D11CreateDevice(NULL, D3D_DRIVER_TYPE_HARDWARE, NULL,
D3D11_CREATE_DEVICE_BGRA_SUPPORT |
D3D11_CREATE_DEVICE_DEBUG,
levels, sizeof(levels) / sizeof(D3D_FEATURE_LEVEL),
D3D11_SDK_VERSION, &d2d->d3d_device, NULL, NULL);
if (FAILED(res))
return 0;
/* dxgi device */
res = d2d->d3d_device->QueryInterface(&d2d->dxgi_device);
if (FAILED(res))
goto release_d3d_device;
/* dxgi factory */
res = CreateDXGIFactory2(DXGI_CREATE_FACTORY_DEBUG,
__uuidof(d2d->dxgi_factory),
(void **)&d2d->dxgi_factory);
if (FAILED(res))
goto release_dxgi_device;
/* d2d factory */
opt.debugLevel = D2D1_DEBUG_LEVEL_INFORMATION;
res = D2D1CreateFactory(D2D1_FACTORY_TYPE_SINGLE_THREADED,
__uuidof(d2d->d2d_factory), &opt,
(void **)&d2d->d2d_factory);
if (FAILED(res))
goto release_dxgi_factory;
/* d2d device */
res = d2d->d2d_factory->CreateDevice(d2d->dxgi_device, &d2d->d2d_device);
if (FAILED(res))
goto release_d2d_factory;
/* d2d device context */
// FIXME : D2D1_DEVICE_CONTEXT_OPTIONS_ENABLE_MULTITHREADED_OPTIMIZATIONS
res = d2d->d2d_device->CreateDeviceContext(D2D1_DEVICE_CONTEXT_OPTIONS_NONE,
&d2d->d2d_device_ctx);
if (FAILED(res))
goto release_d2d_device;
/* dcomp device */
res = DCompositionCreateDevice(d2d->dxgi_device,
__uuidof(d2d->dcomp_device),
(void **)&d2d->dcomp_device);
if (FAILED(res))
goto release_d2d_device_ctx;
/* dcomp visual */
res = d2d->dcomp_device->CreateVisual(&d2d->dcomp_visual);
if (FAILED(res))
goto release_dcomp_device;
/* dcomp target */
res = d2d->dcomp_device->CreateTargetForHwnd(window, TRUE,
&d2d->dcomp_target);
if (FAILED(res))
goto release_dcomp_visual;
/* dxgi swapchain */
if (!GetClientRect(window, &r))
goto release_dcomp_target;
desc.Width = r.right - r.left; /* width of client area */
desc.Height = r.bottom - r.top; /* height of client area */
desc.Format = DXGI_FORMAT_B8G8R8A8_UNORM;
desc.Stereo = FALSE;
desc.SampleDesc.Count = 1;
desc.SampleDesc.Quality = 0;
desc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
desc.BufferCount = 2;
desc.Scaling = DXGI_SCALING_STRETCH;
desc.SwapEffect= DXGI_SWAP_EFFECT_FLIP_SEQUENTIAL;
desc.AlphaMode = DXGI_ALPHA_MODE_PREMULTIPLIED;
desc.Flags = 0;
res = d2d->dxgi_factory->CreateSwapChainForComposition(d2d->dxgi_device,
&desc,
NULL,
&d2d->dxgi_swapchain);
if (FAILED(res))
goto release_dcomp_target;
return 1;
release_dcomp_target:
d2d->dcomp_target->Release();
release_dcomp_visual:
d2d->dcomp_visual->Release();
release_dcomp_device:
d2d->dcomp_device->Release();
release_d2d_device_ctx:
d2d->d2d_device_ctx->Release();
release_d2d_device:
d2d->d2d_device->Release();
release_d2d_factory:
d2d->d2d_factory->Release();
release_dxgi_factory:
d2d->dxgi_factory->Release();
release_dxgi_device:
d2d->dxgi_device->Release();
release_d3d_device:
d2d->d3d_device->Release();
return 0;
}
void d2d_shutdown(D2d *d2d)
{
d2d->dxgi_swapchain->Release();
d2d->dcomp_target->Release();
d2d->dcomp_visual->Release();
d2d->dcomp_device->Release();
d2d->d2d_device_ctx->Release();
d2d->d2d_device->Release();
d2d->d2d_factory->Release();
d2d->dxgi_factory->Release();
d2d->dxgi_device->Release();
d2d->d3d_device->Release();
}
void render(D2d *d2d)
{
IDXGISurface *surface;
ID2D1Bitmap1 *bitmap;
D2D1_BITMAP_PROPERTIES1 properties;
D2D1_COLOR_F c;
HRESULT res;
std::cout << "render" << std::endl;
/* swapchain buffer in a IDXGISurface */
res = d2d->dxgi_swapchain->GetBuffer(0, __uuidof(surface),
(void **)&surface);
if (FAILED(res))
return;
std::cout << "render 1" << std::endl;
properties.pixelFormat.alphaMode = D2D1_ALPHA_MODE_PREMULTIPLIED;
properties.pixelFormat.format = DXGI_FORMAT_B8G8R8A8_UNORM;
properties.dpiX = 96;
properties.dpiY = 96;
// which value to set here ??
properties.bitmapOptions = D2D1_BITMAP_OPTIONS_TARGET;
properties.colorContext = NULL;
res = d2d->d2d_device_ctx->CreateBitmapFromDxgiSurface(surface,
&properties,
&bitmap);
if (FAILED(res))
goto release_surface;
std::cout << "render 2" << std::endl;
d2d->d2d_device_ctx->SetTarget(bitmap);
std::cout << "render 3" << std::endl;
unsigned int *data, *iter;
unsigned int i, j;
D2D1_SIZE_U s;
D2D1_RECT_U r;
// BGRA test data
s = bitmap->GetPixelSize();
data = (unsigned int *)malloc(s.width * s.height * sizeof(unsigned int));
if (!data)
{
std::cout << "malloc fails" << std::endl;
goto bitmap_release;
}
iter = data;
for (i = 0; i < s.height; i++)
{
for (j = 0; j < s.width; j++, iter++)
{
if (i >= 50 && j>= 50)
*iter = 0xff0000ff;
else
*iter = 0xffff0000;
}
}
r.left = 0;
r.top = 0;
r.right = s.width;
r.bottom = s.height;
std::cout << "render 4" << std::endl;
res = bitmap->CopyFromMemory(&r, data, 4 * s.width);
if (FAILED(res))
{
std::cout << "copy failed" << std::endl;
goto data_free;
}
std::cout << "render 5" << std::endl;
d2d->d2d_device_ctx->BeginDraw();
// c.r = 0.18f;
// c.g = 0.55f;
// c.b = 0.34f;
// c.a = 0.75f;
c.r = 0.0f;
c.g = 0.0f;
c.b = 0.0f;
c.a = 0.0f;
d2d->d2d_device_ctx->Clear(&c);
std::cout << "render 6" << std::endl;
D2D1_RECT_F rect;
rect.left = 0.0f;
rect.top = 0.0f;
rect.right = (float)s.width;
rect.bottom = (float)s.height;
d2d->d2d_device_ctx->DrawBitmap(bitmap, rect, 1.0f, D2D1_BITMAP_INTERPOLATION_MODE_LINEAR, rect);
std::cout << "render 7" << std::endl;
d2d->d2d_device_ctx->EndDraw(NULL, NULL);
d2d->dxgi_swapchain->Present(1, 0);
d2d->dcomp_visual->SetContent(d2d->dxgi_swapchain);
d2d->dcomp_target->SetRoot(d2d->dcomp_visual);
d2d->dcomp_device->Commit();
data_free:
free(data);
bitmap_release:
bitmap->Release();
release_surface:
surface->Release();
}
LRESULT CALLBACK
_window_procedure(HWND window,
UINT message,
WPARAM window_param,
LPARAM data_param)
{
switch (message)
{
case WM_CLOSE:
PostQuitMessage(0);
return 0;
case WM_KEYUP:
if (window_param == 'Q')
{
PostQuitMessage(0);
}
if (window_param == 'T')
{
std::cout << "transp" << std::endl;
}
return 0;
/* GDI notifications */
case WM_CREATE:
return 0;
case WM_PAINT:
{
RECT rect;
D2d *d2d;
d2d = (D2d *)GetWindowLongPtr(window, GWLP_USERDATA);
std::cout << "paint" << std::endl;
if (GetUpdateRect(window, &rect, FALSE))
{
PAINTSTRUCT ps;
BeginPaint(window, &ps);
render(d2d);
EndPaint(window, &ps);
}
return 0;
}
default:
return DefWindowProc(window, message, window_param, data_param);
}
}
int main()
{
/* class */
WNDCLASS wc;
instance = GetModuleHandle(NULL);
if (!instance)
return 1;
memset (&wc, 0, sizeof (WNDCLASS));
wc.style = CS_HREDRAW | CS_VREDRAW;
wc.lpfnWndProc = _window_procedure;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = instance;
wc.hIcon = LoadIcon (NULL, IDI_APPLICATION);
wc.hCursor = LoadCursor (NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)(1 + COLOR_BTNFACE);
wc.lpszMenuName = NULL;
wc.lpszClassName = "D2D";
if(!RegisterClass(&wc))
goto free_library;
/* Window */
int w;
int h;
RECT r;
DWORD style;
DWORD exstyle;
w = 640;
h = 480;
style = WS_OVERLAPPEDWINDOW | WS_SIZEBOX;
exstyle = WS_EX_NOREDIRECTIONBITMAP;
r.left = 0;
r.top = 0;
r.right = w;
r.bottom = h;
if (!AdjustWindowRectEx(&r, style, FALSE, exstyle))
goto unregister_class;
win = CreateWindowEx(exstyle,
"D2D", "Test",
style,
100, 100,
r.right - r.left,
r.bottom - r.top,
NULL,
NULL, instance, NULL);
if (!win)
goto unregister_class;
/* d2d init */
D2d d2d;
if (!d2d_init(win, &d2d))
{
std::cout << "d2d init failed" << std::endl;
goto destroy_win;
}
SetWindowLongPtr(win, GWLP_USERDATA, (LONG_PTR)&d2d);
ShowWindow(win, SW_SHOWNORMAL);
UpdateWindow(win);
/* msg loop */
while(1)
{
MSG msg;
BOOL ret;
ret = PeekMessage(&msg, NULL, 0, 0, PM_REMOVE);
if (ret)
{
do
{
if (msg.message == WM_QUIT)
goto beach;
TranslateMessage(&msg);
DispatchMessageW(&msg);
} while (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE));
}
}
beach:
d2d_shutdown(&d2d);
DestroyWindow(win);
UnregisterClass("D2D", instance);
FreeLibrary(instance);
std::cout << "exiting..." << std::endl;
return 0;
destroy_win:
DestroyWindow(win);
unregister_class:
UnregisterClass("D2D", instance);
free_library:
FreeLibrary(instance);
std::cout << "exiting 2..." << std::endl;
return 1;
}
if I add the flag D2D1_BITMAP_OPTIONS_CANNOT_DRAW as in Kerr's article, i get this error : warning: D2D DEBUG ERROR - An operation failed because the bitmap has the D2D1_BITMAP_OPTIONS_CANNOT_DRAW option
after 1 week of search on internet, especially on msdn, i couldn't found a solution. I have tried several combination of flags, but always a crash of this program.
Does someone know what is wrong ?
thank you
Windows API - Win32
C++
C++
A high-level, general-purpose programming language, created as an extension of the C programming language, that has object-oriented, generic, and functional features in addition to facilities for low-level memory manipulation.
3,526 questions
{count} votes
-
vincent torri 1 Reputation point
2020-12-09T19:35:22.67+00:00 no idea at all ?
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