DIRECTX9 中 CustomVertex 的虚拟析构函数
Virtual destructor for CustomVertex in DIRECTX9
这是我关于 Whosebug 的第一个问题，如果我的问题很愚蠢，请原谅我。
我试图在 Visual Studio 2012 中简单地在 DirectX9 中渲染一个三角形，如下所示：www.directxtutorial.com/Lesson.aspx?lessonid=9-4-4。
当我使用非虚拟析构函数创建 CUSTOMVERTEX class 时，它可以毫无问题地渲染三角形。而如果我将析构函数设为虚拟，则不会渲染三角形。
这是带有虚拟析构函数的代码：
// include the basic windows header files and the Direct3D header file
#include <windows.h>
#include <windowsx.h>
#include <d3d9.h>
// define the screen resolution
#define SCREEN_WIDTH 800
#define SCREEN_HEIGHT 600
// include the Direct3D Library file
#pragma comment (lib, "d3d9.lib")
#define CUSTOMFVF (D3DFVF_XYZRHW | D3DFVF_DIFFUSE)
// global declarations
LPDIRECT3D9 d3d; // the pointer to our Direct3D interface
LPDIRECT3DDEVICE9 d3ddev; // the pointer to the device class
LPDIRECT3DVERTEXBUFFER9 v_buffer = NULL; // the pointer to the vertex buffer
// function prototypes
void initD3D(HWND hWnd); // sets up and initializes Direct3D
void render_frame(void); // renders a single frame
void cleanD3D(void); // closes Direct3D and releases memory
void init_graphics(void); // 3D declarations
// the WindowProc function prototype
LRESULT CALLBACK WindowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);
//************CUSTOMVERTEX CLASS**********/
class CUSTOMVERTEX {
public:
CUSTOMVERTEX( float _X, float _Y, float _Z, float _RHW, DWORD _COLOR )
: X(_X), Y(_Y), Z(_Z), RHW(_RHW), COLOR(_COLOR)
{}
virtual ~CUSTOMVERTEX(){
OutputDebugString("Destructed!!!\n");
}
float X, Y, Z, RHW;
DWORD COLOR;
};
// the entry point for any Windows program
int WINAPI WinMain(HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPSTR lpCmdLine,
int nCmdShow)
{
HWND hWnd;
WNDCLASSEX wc;
ZeroMemory(&wc, sizeof(WNDCLASSEX));
wc.cbSize = sizeof(WNDCLASSEX);
wc.style = CS_HREDRAW | CS_VREDRAW;
wc.lpfnWndProc = WindowProc;
wc.hInstance = hInstance;
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.lpszClassName = "WindowClass";
RegisterClassEx(&wc);
hWnd = CreateWindowEx(NULL,
"WindowClass",
"Our Direct3D Program",
WS_OVERLAPPEDWINDOW,
0, 0,
SCREEN_WIDTH, SCREEN_HEIGHT,
NULL,
NULL,
hInstance,
NULL);
ShowWindow(hWnd, nCmdShow);
// set up and initialize Direct3D
initD3D(hWnd);
// enter the main loop:
MSG msg;
while(TRUE)
{
while(PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
if(msg.message == WM_QUIT)
break;
render_frame();
}
// clean up DirectX and COM
cleanD3D();
return msg.wParam;
}
// this is the main message handler for the program
LRESULT CALLBACK WindowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch(message)
{
case WM_DESTROY:
{
PostQuitMessage(0);
return 0;
} break;
}
return DefWindowProc (hWnd, message, wParam, lParam);
}
// this function initializes and prepares Direct3D for use
void initD3D(HWND hWnd)
{
d3d = Direct3DCreate9(D3D_SDK_VERSION);
D3DPRESENT_PARAMETERS d3dpp;
ZeroMemory(&d3dpp, sizeof(d3dpp));
d3dpp.Windowed = TRUE;
d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;
d3dpp.hDeviceWindow = hWnd;
d3dpp.BackBufferFormat = D3DFMT_X8R8G8B8;
d3dpp.BackBufferWidth = SCREEN_WIDTH;
d3dpp.BackBufferHeight = SCREEN_HEIGHT;
// create a device class using this information and the info from the d3dpp struct
d3d->CreateDevice(D3DADAPTER_DEFAULT,
D3DDEVTYPE_HAL,
hWnd,
D3DCREATE_SOFTWARE_VERTEXPROCESSING,
&d3dpp,
&d3ddev);
init_graphics(); // call the function to initialize the triangle
}
// this is the function used to render a single frame
void render_frame(void)
{
d3ddev->Clear(0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(0, 0, 0), 1.0f, 0);
d3ddev->BeginScene();
// select which vertex format we are using
d3ddev->SetFVF(CUSTOMFVF);
// select the vertex buffer to display
d3ddev->SetStreamSource(0, v_buffer, 0, sizeof(CUSTOMVERTEX));
// copy the vertex buffer to the back buffer
d3ddev->DrawPrimitive(D3DPT_TRIANGLELIST, 0, 1);
d3ddev->EndScene();
d3ddev->Present(NULL, NULL, NULL, NULL);
}
// this is the function that cleans up Direct3D and COM
void cleanD3D(void)
{
v_buffer->Release(); // close and release the vertex buffer
d3ddev->Release(); // close and release the 3D device
d3d->Release(); // close and release Direct3D
}
// this is the function that puts the 3D models into video RAM
void init_graphics(void)
{
// create the vertices using the CUSTOMVERTEX class
CUSTOMVERTEX vertices[] =
{
CUSTOMVERTEX(400.0f, 62.5f, 0.5f, 1.0f, D3DCOLOR_XRGB(0, 0, 255)),
CUSTOMVERTEX(650.0f, 500.0f, 0.5f, 1.0f, D3DCOLOR_XRGB(0, 255, 0)),
CUSTOMVERTEX(150.0f, 500.0f, 0.5f, 1.0f, D3DCOLOR_XRGB(255, 0, 0)),
};
// create a vertex buffer interface called v_buffer
d3ddev->CreateVertexBuffer(3*sizeof(CUSTOMVERTEX),
0,
CUSTOMFVF,
D3DPOOL_MANAGED,
&v_buffer,
NULL);
VOID* pVoid; // a void pointer
// lock v_buffer and load the vertices into it
v_buffer->Lock(0, 0, (void**)&pVoid, 0);
memcpy(pVoid, vertices, sizeof(vertices));
v_buffer->Unlock();
}
渲染三角形：Rendered Triangle
没有虚析构函数的代码：
// include the basic windows header files and the Direct3D header file
#include <windows.h>
#include <windowsx.h>
#include <d3d9.h>
// define the screen resolution
#define SCREEN_WIDTH 800
#define SCREEN_HEIGHT 600
// include the Direct3D Library file
#pragma comment (lib, "d3d9.lib")
#define CUSTOMFVF (D3DFVF_XYZRHW | D3DFVF_DIFFUSE)
// global declarations
LPDIRECT3D9 d3d; // the pointer to our Direct3D interface
LPDIRECT3DDEVICE9 d3ddev; // the pointer to the device class
LPDIRECT3DVERTEXBUFFER9 v_buffer = NULL; // the pointer to the vertex buffer
// function prototypes
void initD3D(HWND hWnd); // sets up and initializes Direct3D
void render_frame(void); // renders a single frame
void cleanD3D(void); // closes Direct3D and releases memory
void init_graphics(void); // 3D declarations
// the WindowProc function prototype
LRESULT CALLBACK WindowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);
//************CUSTOMVERTEX CLASS**********/
class CUSTOMVERTEX {
public:
CUSTOMVERTEX( float _X, float _Y, float _Z, float _RHW, DWORD _COLOR )
: X(_X), Y(_Y), Z(_Z), RHW(_RHW), COLOR(_COLOR)
{}
~CUSTOMVERTEX(){
OutputDebugString("Destructed!!!\n");
}
float X, Y, Z, RHW;
DWORD COLOR;
};
// the entry point for any Windows program
int WINAPI WinMain(HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPSTR lpCmdLine,
int nCmdShow)
{
HWND hWnd;
WNDCLASSEX wc;
ZeroMemory(&wc, sizeof(WNDCLASSEX));
wc.cbSize = sizeof(WNDCLASSEX);
wc.style = CS_HREDRAW | CS_VREDRAW;
wc.lpfnWndProc = WindowProc;
wc.hInstance = hInstance;
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.lpszClassName = "WindowClass";
RegisterClassEx(&wc);
hWnd = CreateWindowEx(NULL,
"WindowClass",
"Our Direct3D Program",
WS_OVERLAPPEDWINDOW,
0, 0,
SCREEN_WIDTH, SCREEN_HEIGHT,
NULL,
NULL,
hInstance,
NULL);
ShowWindow(hWnd, nCmdShow);
// set up and initialize Direct3D
initD3D(hWnd);
// enter the main loop:
MSG msg;
while(TRUE)
{
while(PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
if(msg.message == WM_QUIT)
break;
render_frame();
}
// clean up DirectX and COM
cleanD3D();
return msg.wParam;
}
// this is the main message handler for the program
LRESULT CALLBACK WindowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch(message)
{
case WM_DESTROY:
{
PostQuitMessage(0);
return 0;
} break;
}
return DefWindowProc (hWnd, message, wParam, lParam);
}
// this function initializes and prepares Direct3D for use
void initD3D(HWND hWnd)
{
d3d = Direct3DCreate9(D3D_SDK_VERSION);
D3DPRESENT_PARAMETERS d3dpp;
ZeroMemory(&d3dpp, sizeof(d3dpp));
d3dpp.Windowed = TRUE;
d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;
d3dpp.hDeviceWindow = hWnd;
d3dpp.BackBufferFormat = D3DFMT_X8R8G8B8;
d3dpp.BackBufferWidth = SCREEN_WIDTH;
d3dpp.BackBufferHeight = SCREEN_HEIGHT;
// create a device class using this information and the info from the d3dpp struct
d3d->CreateDevice(D3DADAPTER_DEFAULT,
D3DDEVTYPE_HAL,
hWnd,
D3DCREATE_SOFTWARE_VERTEXPROCESSING,
&d3dpp,
&d3ddev);
init_graphics(); // call the function to initialize the triangle
}
// this is the function used to render a single frame
void render_frame(void)
{
d3ddev->Clear(0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(0, 0, 0), 1.0f, 0);
d3ddev->BeginScene();
// select which vertex format we are using
d3ddev->SetFVF(CUSTOMFVF);
// select the vertex buffer to display
d3ddev->SetStreamSource(0, v_buffer, 0, sizeof(CUSTOMVERTEX));
// copy the vertex buffer to the back buffer
d3ddev->DrawPrimitive(D3DPT_TRIANGLELIST, 0, 1);
d3ddev->EndScene();
d3ddev->Present(NULL, NULL, NULL, NULL);
}
// this is the function that cleans up Direct3D and COM
void cleanD3D(void)
{
v_buffer->Release(); // close and release the vertex buffer
d3ddev->Release(); // close and release the 3D device
d3d->Release(); // close and release Direct3D
}
// this is the function that puts the 3D models into video RAM
void init_graphics(void)
{
// create the vertices using the CUSTOMVERTEX class
CUSTOMVERTEX vertices[] =
{
CUSTOMVERTEX(400.0f, 62.5f, 0.5f, 1.0f, D3DCOLOR_XRGB(0, 0, 255)),
CUSTOMVERTEX(650.0f, 500.0f, 0.5f, 1.0f, D3DCOLOR_XRGB(0, 255, 0)),
CUSTOMVERTEX(150.0f, 500.0f, 0.5f, 1.0f, D3DCOLOR_XRGB(255, 0, 0)),
};
// create a vertex buffer interface called v_buffer
d3ddev->CreateVertexBuffer(3*sizeof(CUSTOMVERTEX),
0,
CUSTOMFVF,
D3DPOOL_MANAGED,
&v_buffer,
NULL);
VOID* pVoid; // a void pointer
// lock v_buffer and load the vertices into it
v_buffer->Lock(0, 0, (void**)&pVoid, 0);
memcpy(pVoid, vertices, sizeof(vertices));
v_buffer->Unlock();
}
渲染时没有任何三角形：without any triangle
任何人都可以向我解释为什么会这样吗？
简而言之：添加 virtual 会更改结构的内存布局，这意味着您的数据不再位于您提供的顶点声明的正确位置：
struct CUSTOMVERTEX {
CUSTOMVERTEX( float _X, float _Y, float _Z, float _RHW, DWORD _COLOR )
: X(_X), Y(_Y), Z(_Z), RHW(_RHW), COLOR(_COLOR)
{}
float X, Y, Z, RHW;
DWORD COLOR;
};
这个结构的大小是 20 个字节。
class CUSTOMVERTEX {
public:
CUSTOMVERTEX( float _X, float _Y, float _Z, float _RHW, DWORD _COLOR )
: X(_X), Y(_Y), Z(_Z), RHW(_RHW), COLOR(_COLOR)
{}
virtual ~CUSTOMVERTEX(){
OutputDebugString("Destructed!!!\n");
}
float X, Y, Z, RHW;
DWORD COLOR;
};
此结构的大小对于 x86 (Win32) 为 24 字节，对于 x64 本机为 32 字节。这是因为在结构的开头添加了一个指向 vtable 的指针（在 x64 上，额外的填充将其推出略多于 8 个字节）。
此外，由于您是通过 Direct3D 顶点缓冲区使用该类型，因此它永远不会执行其构造函数或析构函数。它只是作为 "plain old data type" 从堆中分配的。为堆分配的内存调用构造函数或析构函数的唯一时间是通过 new、new []、delete、and/or delete []。在内部 Direct3D 顶点缓冲区正在做一些更类似于 malloc.
的事情
当您创建初始化数组 vertices 时，C++ 编译器会调用您的构造函数，当 vertices 超出范围时会调用析构函数。
换句话说：这并不像您想象的那样。不要在顶点数据结构中使用 virtual。
Note that you should consider making using of a smart pointer like Microsoft::WRL::ComPtr for managing the lifetime of your Direct3D COM objects. This takes advantage of the C++ scoping rules for ctors/destructors to properly call Release automatically. Of course, you should also not be spending a lot of time learning legacy Direc3D 9 either.
这是我关于 Whosebug 的第一个问题，如果我的问题很愚蠢，请原谅我。 我试图在 Visual Studio 2012 中简单地在 DirectX9 中渲染一个三角形，如下所示：www.directxtutorial.com/Lesson.aspx?lessonid=9-4-4。
当我使用非虚拟析构函数创建 CUSTOMVERTEX class 时，它可以毫无问题地渲染三角形。而如果我将析构函数设为虚拟，则不会渲染三角形。
这是带有虚拟析构函数的代码：
// include the basic windows header files and the Direct3D header file
#include <windows.h>
#include <windowsx.h>
#include <d3d9.h>
// define the screen resolution
#define SCREEN_WIDTH 800
#define SCREEN_HEIGHT 600
// include the Direct3D Library file
#pragma comment (lib, "d3d9.lib")
#define CUSTOMFVF (D3DFVF_XYZRHW | D3DFVF_DIFFUSE)
// global declarations
LPDIRECT3D9 d3d; // the pointer to our Direct3D interface
LPDIRECT3DDEVICE9 d3ddev; // the pointer to the device class
LPDIRECT3DVERTEXBUFFER9 v_buffer = NULL; // the pointer to the vertex buffer
// function prototypes
void initD3D(HWND hWnd); // sets up and initializes Direct3D
void render_frame(void); // renders a single frame
void cleanD3D(void); // closes Direct3D and releases memory
void init_graphics(void); // 3D declarations
// the WindowProc function prototype
LRESULT CALLBACK WindowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);
//************CUSTOMVERTEX CLASS**********/
class CUSTOMVERTEX {
public:
CUSTOMVERTEX( float _X, float _Y, float _Z, float _RHW, DWORD _COLOR )
: X(_X), Y(_Y), Z(_Z), RHW(_RHW), COLOR(_COLOR)
{}
virtual ~CUSTOMVERTEX(){
OutputDebugString("Destructed!!!\n");
}
float X, Y, Z, RHW;
DWORD COLOR;
};
// the entry point for any Windows program
int WINAPI WinMain(HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPSTR lpCmdLine,
int nCmdShow)
{
HWND hWnd;
WNDCLASSEX wc;
ZeroMemory(&wc, sizeof(WNDCLASSEX));
wc.cbSize = sizeof(WNDCLASSEX);
wc.style = CS_HREDRAW | CS_VREDRAW;
wc.lpfnWndProc = WindowProc;
wc.hInstance = hInstance;
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.lpszClassName = "WindowClass";
RegisterClassEx(&wc);
hWnd = CreateWindowEx(NULL,
"WindowClass",
"Our Direct3D Program",
WS_OVERLAPPEDWINDOW,
0, 0,
SCREEN_WIDTH, SCREEN_HEIGHT,
NULL,
NULL,
hInstance,
NULL);
ShowWindow(hWnd, nCmdShow);
// set up and initialize Direct3D
initD3D(hWnd);
// enter the main loop:
MSG msg;
while(TRUE)
{
while(PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
if(msg.message == WM_QUIT)
break;
render_frame();
}
// clean up DirectX and COM
cleanD3D();
return msg.wParam;
}
// this is the main message handler for the program
LRESULT CALLBACK WindowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch(message)
{
case WM_DESTROY:
{
PostQuitMessage(0);
return 0;
} break;
}
return DefWindowProc (hWnd, message, wParam, lParam);
}
// this function initializes and prepares Direct3D for use
void initD3D(HWND hWnd)
{
d3d = Direct3DCreate9(D3D_SDK_VERSION);
D3DPRESENT_PARAMETERS d3dpp;
ZeroMemory(&d3dpp, sizeof(d3dpp));
d3dpp.Windowed = TRUE;
d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;
d3dpp.hDeviceWindow = hWnd;
d3dpp.BackBufferFormat = D3DFMT_X8R8G8B8;
d3dpp.BackBufferWidth = SCREEN_WIDTH;
d3dpp.BackBufferHeight = SCREEN_HEIGHT;
// create a device class using this information and the info from the d3dpp struct
d3d->CreateDevice(D3DADAPTER_DEFAULT,
D3DDEVTYPE_HAL,
hWnd,
D3DCREATE_SOFTWARE_VERTEXPROCESSING,
&d3dpp,
&d3ddev);
init_graphics(); // call the function to initialize the triangle
}
// this is the function used to render a single frame
void render_frame(void)
{
d3ddev->Clear(0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(0, 0, 0), 1.0f, 0);
d3ddev->BeginScene();
// select which vertex format we are using
d3ddev->SetFVF(CUSTOMFVF);
// select the vertex buffer to display
d3ddev->SetStreamSource(0, v_buffer, 0, sizeof(CUSTOMVERTEX));
// copy the vertex buffer to the back buffer
d3ddev->DrawPrimitive(D3DPT_TRIANGLELIST, 0, 1);
d3ddev->EndScene();
d3ddev->Present(NULL, NULL, NULL, NULL);
}
// this is the function that cleans up Direct3D and COM
void cleanD3D(void)
{
v_buffer->Release(); // close and release the vertex buffer
d3ddev->Release(); // close and release the 3D device
d3d->Release(); // close and release Direct3D
}
// this is the function that puts the 3D models into video RAM
void init_graphics(void)
{
// create the vertices using the CUSTOMVERTEX class
CUSTOMVERTEX vertices[] =
{
CUSTOMVERTEX(400.0f, 62.5f, 0.5f, 1.0f, D3DCOLOR_XRGB(0, 0, 255)),
CUSTOMVERTEX(650.0f, 500.0f, 0.5f, 1.0f, D3DCOLOR_XRGB(0, 255, 0)),
CUSTOMVERTEX(150.0f, 500.0f, 0.5f, 1.0f, D3DCOLOR_XRGB(255, 0, 0)),
};
// create a vertex buffer interface called v_buffer
d3ddev->CreateVertexBuffer(3*sizeof(CUSTOMVERTEX),
0,
CUSTOMFVF,
D3DPOOL_MANAGED,
&v_buffer,
NULL);
VOID* pVoid; // a void pointer
// lock v_buffer and load the vertices into it
v_buffer->Lock(0, 0, (void**)&pVoid, 0);
memcpy(pVoid, vertices, sizeof(vertices));
v_buffer->Unlock();
}
渲染三角形：Rendered Triangle
没有虚析构函数的代码：
// include the basic windows header files and the Direct3D header file
#include <windows.h>
#include <windowsx.h>
#include <d3d9.h>
// define the screen resolution
#define SCREEN_WIDTH 800
#define SCREEN_HEIGHT 600
// include the Direct3D Library file
#pragma comment (lib, "d3d9.lib")
#define CUSTOMFVF (D3DFVF_XYZRHW | D3DFVF_DIFFUSE)
// global declarations
LPDIRECT3D9 d3d; // the pointer to our Direct3D interface
LPDIRECT3DDEVICE9 d3ddev; // the pointer to the device class
LPDIRECT3DVERTEXBUFFER9 v_buffer = NULL; // the pointer to the vertex buffer
// function prototypes
void initD3D(HWND hWnd); // sets up and initializes Direct3D
void render_frame(void); // renders a single frame
void cleanD3D(void); // closes Direct3D and releases memory
void init_graphics(void); // 3D declarations
// the WindowProc function prototype
LRESULT CALLBACK WindowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);
//************CUSTOMVERTEX CLASS**********/
class CUSTOMVERTEX {
public:
CUSTOMVERTEX( float _X, float _Y, float _Z, float _RHW, DWORD _COLOR )
: X(_X), Y(_Y), Z(_Z), RHW(_RHW), COLOR(_COLOR)
{}
~CUSTOMVERTEX(){
OutputDebugString("Destructed!!!\n");
}
float X, Y, Z, RHW;
DWORD COLOR;
};
// the entry point for any Windows program
int WINAPI WinMain(HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPSTR lpCmdLine,
int nCmdShow)
{
HWND hWnd;
WNDCLASSEX wc;
ZeroMemory(&wc, sizeof(WNDCLASSEX));
wc.cbSize = sizeof(WNDCLASSEX);
wc.style = CS_HREDRAW | CS_VREDRAW;
wc.lpfnWndProc = WindowProc;
wc.hInstance = hInstance;
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.lpszClassName = "WindowClass";
RegisterClassEx(&wc);
hWnd = CreateWindowEx(NULL,
"WindowClass",
"Our Direct3D Program",
WS_OVERLAPPEDWINDOW,
0, 0,
SCREEN_WIDTH, SCREEN_HEIGHT,
NULL,
NULL,
hInstance,
NULL);
ShowWindow(hWnd, nCmdShow);
// set up and initialize Direct3D
initD3D(hWnd);
// enter the main loop:
MSG msg;
while(TRUE)
{
while(PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
if(msg.message == WM_QUIT)
break;
render_frame();
}
// clean up DirectX and COM
cleanD3D();
return msg.wParam;
}
// this is the main message handler for the program
LRESULT CALLBACK WindowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch(message)
{
case WM_DESTROY:
{
PostQuitMessage(0);
return 0;
} break;
}
return DefWindowProc (hWnd, message, wParam, lParam);
}
// this function initializes and prepares Direct3D for use
void initD3D(HWND hWnd)
{
d3d = Direct3DCreate9(D3D_SDK_VERSION);
D3DPRESENT_PARAMETERS d3dpp;
ZeroMemory(&d3dpp, sizeof(d3dpp));
d3dpp.Windowed = TRUE;
d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;
d3dpp.hDeviceWindow = hWnd;
d3dpp.BackBufferFormat = D3DFMT_X8R8G8B8;
d3dpp.BackBufferWidth = SCREEN_WIDTH;
d3dpp.BackBufferHeight = SCREEN_HEIGHT;
// create a device class using this information and the info from the d3dpp struct
d3d->CreateDevice(D3DADAPTER_DEFAULT,
D3DDEVTYPE_HAL,
hWnd,
D3DCREATE_SOFTWARE_VERTEXPROCESSING,
&d3dpp,
&d3ddev);
init_graphics(); // call the function to initialize the triangle
}
// this is the function used to render a single frame
void render_frame(void)
{
d3ddev->Clear(0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(0, 0, 0), 1.0f, 0);
d3ddev->BeginScene();
// select which vertex format we are using
d3ddev->SetFVF(CUSTOMFVF);
// select the vertex buffer to display
d3ddev->SetStreamSource(0, v_buffer, 0, sizeof(CUSTOMVERTEX));
// copy the vertex buffer to the back buffer
d3ddev->DrawPrimitive(D3DPT_TRIANGLELIST, 0, 1);
d3ddev->EndScene();
d3ddev->Present(NULL, NULL, NULL, NULL);
}
// this is the function that cleans up Direct3D and COM
void cleanD3D(void)
{
v_buffer->Release(); // close and release the vertex buffer
d3ddev->Release(); // close and release the 3D device
d3d->Release(); // close and release Direct3D
}
// this is the function that puts the 3D models into video RAM
void init_graphics(void)
{
// create the vertices using the CUSTOMVERTEX class
CUSTOMVERTEX vertices[] =
{
CUSTOMVERTEX(400.0f, 62.5f, 0.5f, 1.0f, D3DCOLOR_XRGB(0, 0, 255)),
CUSTOMVERTEX(650.0f, 500.0f, 0.5f, 1.0f, D3DCOLOR_XRGB(0, 255, 0)),
CUSTOMVERTEX(150.0f, 500.0f, 0.5f, 1.0f, D3DCOLOR_XRGB(255, 0, 0)),
};
// create a vertex buffer interface called v_buffer
d3ddev->CreateVertexBuffer(3*sizeof(CUSTOMVERTEX),
0,
CUSTOMFVF,
D3DPOOL_MANAGED,
&v_buffer,
NULL);
VOID* pVoid; // a void pointer
// lock v_buffer and load the vertices into it
v_buffer->Lock(0, 0, (void**)&pVoid, 0);
memcpy(pVoid, vertices, sizeof(vertices));
v_buffer->Unlock();
}
渲染时没有任何三角形：without any triangle
任何人都可以向我解释为什么会这样吗？
简而言之：添加 virtual 会更改结构的内存布局，这意味着您的数据不再位于您提供的顶点声明的正确位置：
struct CUSTOMVERTEX {
CUSTOMVERTEX( float _X, float _Y, float _Z, float _RHW, DWORD _COLOR )
: X(_X), Y(_Y), Z(_Z), RHW(_RHW), COLOR(_COLOR)
{}
float X, Y, Z, RHW;
DWORD COLOR;
};
这个结构的大小是 20 个字节。
class CUSTOMVERTEX {
public:
CUSTOMVERTEX( float _X, float _Y, float _Z, float _RHW, DWORD _COLOR )
: X(_X), Y(_Y), Z(_Z), RHW(_RHW), COLOR(_COLOR)
{}
virtual ~CUSTOMVERTEX(){
OutputDebugString("Destructed!!!\n");
}
float X, Y, Z, RHW;
DWORD COLOR;
};
此结构的大小对于 x86 (Win32) 为 24 字节，对于 x64 本机为 32 字节。这是因为在结构的开头添加了一个指向 vtable 的指针（在 x64 上，额外的填充将其推出略多于 8 个字节）。
此外，由于您是通过 Direct3D 顶点缓冲区使用该类型，因此它永远不会执行其构造函数或析构函数。它只是作为 "plain old data type" 从堆中分配的。为堆分配的内存调用构造函数或析构函数的唯一时间是通过 new、new []、delete、and/or delete []。在内部 Direct3D 顶点缓冲区正在做一些更类似于 malloc.
当您创建初始化数组 vertices 时，C++ 编译器会调用您的构造函数，当 vertices 超出范围时会调用析构函数。
换句话说：这并不像您想象的那样。不要在顶点数据结构中使用 virtual。
Note that you should consider making using of a smart pointer like
Microsoft::WRL::ComPtrfor managing the lifetime of your Direct3D COM objects. This takes advantage of the C++ scoping rules for ctors/destructors to properly callReleaseautomatically. Of course, you should also not be spending a lot of time learning legacy Direc3D 9 either.