我正在尝试使窗口透明，以便只有部分内容可见，我尝试使用 SetLayeredWindowAttributes 来实现这一点，这使窗口如我所愿地透明，但是只有当 Windows 图片的一部分超出我桌面的可见区域时，它才会这样工作。出于某种原因，每当窗口完全显示在屏幕上时，它都会重新绘制其黑色背景(我用于透明的颜色是不可见的。)Here是问题的视频示例。我不确定到底是什么导致了这种情况，为了安全起见，我发布了完整的代码。
#define _WIN32_WINNT 0x501
#include "C:\Program Files\Microsoft DirectX SDK (August 2008)\Include\D3dx9core.h"
#include "C:\Documents and Settings\Death\My Documents\Downloads\DXSprite\DXSprite\resource.h"
#include <windows.h>
#include <string>
#include <stdio.h>
//-----------------------------------------------------------------------------
// GLOBALS
//-----------------------------------------------------------------------------
HWND g_hWnd = NULL;
LPDIRECT3D9 g_pD3D = NULL;
LPDIRECT3DDEVICE9 g_pD3DDevice = NULL;
ID3DXSprite * g_pD3DXSprite = NULL;
LPDIRECT3DTEXTURE9 g_pTexture = NULL;
const int SCREEN_WIDTH = 800;
const int SCREEN_HEIGHT = 600;
//-----------------------------------------------------------------------------
// PROTOTYPES
//-----------------------------------------------------------------------------
LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam);
HRESULT InitializeD3D ( );
void RenderFrame ( );
//-----------------------------------------------------------------------------
// Name: WinMain()
// Desc: The application's entry point
//-----------------------------------------------------------------------------
int WINAPI WinMain( HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPSTR lpCmdLine,
int nCmdShow )
{
WNDCLASSEX winClass;
MSG uMsg;
HRESULT hr;
memset(&uMsg,0,sizeof(uMsg));
winClass.lpszClassName = "MY_WINDOWS_CLASS";
winClass.cbSize = sizeof(WNDCLASSEX);
winClass.style = CS_HREDRAW | CS_VREDRAW;
winClass.lpfnWndProc = WindowProc;
winClass.hInstance = hInstance;
winClass.hIcon = LoadIcon(hInstance, (LPCTSTR)IDC_DXSPRITE);
winClass.hIconSm = LoadIcon(hInstance, (LPCTSTR)IDC_DXSPRITE);
winClass.hCursor = LoadCursor(NULL, IDC_ARROW);
winClass.hbrBackground = (HBRUSH)GetStockObject(BLACK_BRUSH);
winClass.lpszMenuName = NULL;
winClass.cbClsExtra = 0;
winClass.cbWndExtra = 0;
if( !RegisterClassEx(&winClass) )
return E_FAIL;
g_hWnd = CreateWindowEx( WS_EX_LAYERED, "MY_WINDOWS_CLASS",
"Direct3D 9 - ID3DXSprite Example",
WS_OVERLAPPEDWINDOW | WS_VISIBLE ,
0, 0, SCREEN_WIDTH, SCREEN_HEIGHT, NULL, NULL, hInstance, NULL );
if( g_hWnd == NULL )
return E_FAIL;
SetLayeredWindowAttributes(g_hWnd, RGB(0x00,0x00,0x00), 0, LWA_COLORKEY});
ShowWindow( g_hWnd, nCmdShow );
//----------------------------------------------------------------
// Create the DirectX device
//----------------------------------------------------------------
if (FAILED( InitializeD3D()))
return 0;
//----------------------------------------------------------------
// CREATE THE ID3DXSprite
//----------------------------------------------------------------
// Create the ID3DXSprite interface object
hr = D3DXCreateSprite(g_pD3DDevice, &g_pD3DXSprite );
if( FAILED(hr) )
return hr;
//----------------------------------------------------------------
// LOAD THE TEXTURE FOR THE SPRITE
//----------------------------------------------------------------
// --------------------------------------------------------
// Load the texture. I decided to use the extended
// version of the texture loading function just to show what
// it would look like.
// The texture was created with Photoshop with a transparent
// background to start with. Then line cross hairs were added.
//
// Note - If you don't use a texture image that has a power of
// 2 size for the width or height then the image may not load
// properly. This image is 256x256.
//
D3DXCreateTextureFromFileEx(
g_pD3DDevice,
"C:\\Documents and Settings\\Death\\My Documents\\45handold2.tga", // Our texture image!
D3DX_DEFAULT, // width
D3DX_DEFAULT, // height
D3DX_DEFAULT, // MIP levels
0, // usage
D3DFMT_DXT1, // texture format
D3DPOOL_MANAGED, // mem pool
D3DX_DEFAULT, // filter
D3DX_DEFAULT, // MIP filter
0, // transparent color key
NULL, // image info struct
NULL, // palette
&g_pTexture); // the returned texture, if success
if ( FAILED(hr) )
return hr;
// ---------
// Main Loop
// ---------
while( uMsg.message != WM_QUIT )
{
if( PeekMessage( &uMsg, NULL, 0, 0, PM_REMOVE ) )
{
TranslateMessage( &uMsg );
DispatchMessage( &uMsg );
}
}
// -------------------------
// Release directx resources
// -------------------------
if (g_pD3DXSprite)
{
g_pD3DXSprite->Release();
g_pD3DXSprite = NULL;
}
if (g_pTexture)
{
g_pTexture->Release();
g_pTexture = NULL;
}
if (g_pD3DDevice)
{
g_pD3DDevice->Release();
g_pD3DDevice = NULL;
}
UnregisterClass( "MY_WINDOWS_CLASS", winClass.hInstance );
return (int)uMsg.wParam;
}
//-----------------------------------------------------------------------------
// Name: WindowProc()
// Desc: The window's message handler
//-----------------------------------------------------------------------------
LRESULT CALLBACK WindowProc( HWND hWnd,
UINT msg,
WPARAM wParam,
LPARAM lParam )
{
switch( msg )
{
case WM_KEYDOWN:
{
switch( wParam )
{
case VK_ESCAPE:
PostQuitMessage(0);
break;
}
}
break;
case WM_CLOSE:
{
PostQuitMessage(0);
}
case WM_DESTROY:
{
PostQuitMessage(0);
}
break;
default:
{
RenderFrame();
return DefWindowProc( hWnd, msg, wParam, lParam );
}
break;
}
return 0;
}
//-----------------------------------------------------------------------------
// Name: InitializeD3D()
// Desc: Create DirectX interface objects
// Initialize the view matrix.
// Setup render states that will not need changing throughout
// the life of the application.
//-----------------------------------------------------------------------------
HRESULT InitializeD3D( )
{
HRESULT hr;
// Create a direct 3D interface object
g_pD3D = Direct3DCreate9( D3D_SDK_VERSION );
if( g_pD3D == NULL )
{
// TO DO: Respond to failure of Direct3DCreate9
return E_FAIL;
}
D3DDISPLAYMODE d3ddm;
if( FAILED( hr = g_pD3D->GetAdapterDisplayMode( D3DADAPTER_DEFAULT, &d3ddm ) ) )
{
// TO DO: Respond to failure of GetAdapterDisplayMode
return hr;
}
//
if( FAILED( hr = g_pD3D->CheckDeviceFormat( D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL,
d3ddm.Format, D3DUSAGE_DEPTHSTENCIL,
D3DRTYPE_SURFACE, D3DFMT_D16 ) ) )
{
if( hr == D3DERR_NOTAVAILABLE )
// POTENTIAL PROBLEM: We need at least a 16-bit z-buffer!
return hr;
}
//
// Do we support hardware vertex processing? If so, use it.
// If not, downgrade to software.
//
D3DCAPS9 d3dCaps;
if( FAILED( hr = g_pD3D->GetDeviceCaps( D3DADAPTER_DEFAULT,
D3DDEVTYPE_HAL, &d3dCaps ) ) )
{
// TO DO: Respond to failure of GetDeviceCaps
return hr;
}
DWORD dwBehaviorFlags = 0;
if( d3dCaps.VertexProcessingCaps != 0 )
dwBehaviorFlags |= D3DCREATE_HARDWARE_VERTEXPROCESSING;
else
dwBehaviorFlags |= D3DCREATE_SOFTWARE_VERTEXPROCESSING;
//
// Everything checks out - create a simple, windowed device.
//
D3DPRESENT_PARAMETERS d3dpp;
memset(&d3dpp, 0, sizeof(d3dpp));
d3dpp.BackBufferFormat = d3ddm.Format;
d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;
d3dpp.Windowed = TRUE;
d3dpp.EnableAutoDepthStencil = TRUE;
d3dpp.AutoDepthStencilFormat = D3DFMT_D16;
d3dpp.PresentationInterval = D3DPRESENT_INTERVAL_IMMEDIATE;
// Attempt to create a HAL device, end app on failure just to keep things
// simple. In other words we are not trying to create a REF device if the
// HAL fails.
if( FAILED( hr = g_pD3D->CreateDevice( D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, g_hWnd,
dwBehaviorFlags, &d3dpp, &g_pD3DDevice ) ) )
{
// char blah[100];
// snprintf (blah, 1000, "%d", hr);
//MessageBox (NULL,blah,NULL,NULL);
}
// If we get here everything worked!
return S_OK;
}
//-----------------------------------------------------------------------------
// Name: RenderFrame()
// Desc: Draw the image to the framebuffer.
//-----------------------------------------------------------------------------
void RenderFrame( )
{
if (!g_pD3DDevice && !g_pD3DXSprite && !g_pTexture)
return;
// Clear the frame & depth buffer ready for drawing (Black color)
g_pD3DDevice->Clear( 0, NULL, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER, 0x00000000, 1.0f, 0 );
g_pD3DDevice->BeginScene();
{
//-------------------------
// Render the sprite
//
D3DXVECTOR3 vecPos = D3DXVECTOR3(0,0,0);
if (g_pD3DXSprite && g_pTexture)
{
g_pD3DXSprite->Begin( D3DXSPRITE_ALPHABLEND );
g_pD3DXSprite->Draw(g_pTexture, NULL, NULL, &vecPos, 0xffffffff);
g_pD3DXSprite->End();
}
}
g_pD3DDevice->EndScene();
// Frame buffer to Front buffer
g_pD3DDevice->Present( NULL, NULL, NULL, NULL );
}
最佳答案
您遇到的问题基本上是 Windows 中曾经有两个完全独立的渲染堆栈:GDI 和 Direct3D。它们根本没有真正相互交谈，因此标准窗口和 GDI API 对 Direct3D 并不真正了解。当 Vista 出现时，他们统一了两个驱动程序堆栈，但 GDI 代码(一般来说)仍然对 Direct3D 一无所知，即使它在幕后内部使用了一些 Direct3D(用于桌面组合)。
简而言之，SetLayeredWindowAttributes 和 UpdateLayeredWindow 不能也不知道您的 Direct3D 交换链。如果您在 Windows XP 或 2000 上尝试过此操作，我希望您会得到一些非常时髦的视觉效果。这有一些非常好的理由，我应该补充一下。例如，在 GDI 世界中，使用 UpdateLayeredWindow 设置具有每像素 alpha 的位图实际上会导致 alpha 值为零的地方被视为不是窗口的一部分。换句话说，点击会传递到下面的窗口。为了使用 Direct3D 实现这一点，系统必须将 Direct3D 纹理从 GPU 读回到 CPU 内存，这是非常昂贵的，然后执行 HitTest 。
当然，一种解决方案是使用 GDI 来渲染窗口，包括颜色键。我假设您出于性能原因排除了这种可能性。
我不完全确定您期望的视觉效果，但如果您想在具有完整硬件加速且没有窗口边框的窗口中呈现任意 alpha 混合内容，您可以创建一个无边框窗口(例如，仅 WS_POPUP其窗口样式)并调用 DwmExtendFrameIntoClientArea为所有边距传递 -1。然后，使用 D3DFMT_A8R8G8B8 像素格式或 Direct3D 10/11 的 DXGI 等效格式(这是 DWM 用于渲染窗口的 native 格式)创建交换链并渲染到其中。您现在有一个窗口，其中仅包含叠加在桌面上的 alpha 混合内容。有一个 older article on CodeProject关于这个话题。
关于c++ - SetLayeredWindowAttributes 使窗口透明仅在部分时间有效，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/18383681/