Question

我正在关注Youtube的2D DirectX图形编程教程。该项目包含3个文件。它包含一个main.cpp文件，用于创建窗口，图形类和图形标题。当代码尝试在图形类中创建D2D1工厂时，我收到Unhandled Exception错误。我在Windows Vista上使用Visual Studio 10。以下是Visual Studio 10中输出窗口的3个文件和输出：

main.cpp中：

includeKey

graphics.h中：

#include <Windows.h>
#include <d2d1.h>
#include "graphics.h"

Graphics *graphics;

LRESULT CALLBACK WindowProc(
    HWND hwnd,
    UINT uMsg,
    WPARAM wParam,
    LPARAM lParam
)
{
    if(uMsg == WM_DESTROY) { PostQuitMessage(0); return 0; }
    return DefWindowProc(hwnd, uMsg, wParam, lParam);


    if(uMsg == WM_PAINT)
    {
        graphics->BeginDraw();

        graphics->ClearScrean(0.0f, 0.0f, 0.5f);

        graphics->DrawCircle(100, 100, 50, 1.0f, 0.0, 0.0, 1.0);

        graphics->EndDraw();
    }
}

int WINAPI wWinMain(
    HINSTANCE hInstance,
    HINSTANCE precInstance,
    LPWSTR cmd,
    int nCmdShow)
{
    WNDCLASSEX windowclass;
    ZeroMemory(&windowclass, sizeof(WNDCLASSEX));
    windowclass.cbSize = sizeof(WNDCLASSEX);
    windowclass.hbrBackground = (HBRUSH) COLOR_WINDOW;
    windowclass.hInstance = hInstance;
    windowclass.lpfnWndProc = WindowProc;
    windowclass.lpszClassName = "MainWindow";
    windowclass.style = CS_HREDRAW | CS_VREDRAW;

    RegisterClassEx(&windowclass);

    RECT rect = { 0, 0, 800, 600 };
    AdjustWindowRectEx(&rect, WS_OVERLAPPEDWINDOW, false,
    WS

    HWND windowhandle = CreateWindowEx(
    WS_EX_OVERLAPPEDWINDOW,
    "MainWindow",
    "DirectX",
    WS_OVERLAPPEDWINDOW,
    100,
    100,
    rect.right - rect.left,
    rect.bottom - rect.top,
    NULL,
    NULL,
    hInstance,
    0);

    if(!windowhandle) { return -1; }


    if(!graphics->Init(windowhandle))
    {
         delete graphics;
         return -1;
    }

    ShowWindow(windowhandle, nCmdShow);

    MSG message;
    while(GetMessage(&message, NULL, 0, 0))
    {
        DispatchMessage(&message);
    }

    delete graphics;

    return 0;
 }

Graphics.cpp：

#pragma once
#include <Windows.h>
#include <d2d1.h>

class Graphics
{
    ID2D1Factory* factory;
    ID2D1HwndRenderTarget* renderTarget;

    public:
    Graphics();
    ~Graphics();

    bool Init(HWND windowhandle);

    void BeginDraw() { renderTarget->BeginDraw(); }
    void EndDraw() { renderTarget->EndDraw(); }

    void ClearScrean(float r, float g, float b);
    void DrawCircle(float x,
        float y, float radius, float r, floatg,float b, float a);
    };

调试输出：

#include "Graphics.h"

Graphics::Graphics()
{
    factory = NULL;
    renderTarget = NULL;
}

Graphics::~Graphics()
{
    if(factory) factory->Release();
    if(renderTarget) renderTarget->Release();
}

bool Graphics::Init(HWND windowHandle)
{
    HRESULT res = D2D1CreateFactory(
     D2D1_FACTORY_TYPE_SINGLE_THREADED,
     &factory);

    if(res != S_OK) { return false; }

    RECT rect;
    GetClientRect(windowHandle, &rect);

    res = factory->CreateHwndRenderTarget(
        D2D1::RenderTargetProperties(),
        D2D1::HwndRenderTargetProperties(
            windowHandle,
            D2D1::SizeU(rect.right, rect.bottom)),
        &renderTarget);

    if(res != S_OK) { return false; }

    return true;
}

void Graphics::ClearScrean(float r, float g, float b)
{
    renderTarget->Clear(D2D1::ColorF(r, g, b));
}

void Graphics::DrawCircle(float x, float y, float radius,
      float r, float g, float b, float a)
{
    ID2D1SolidColorBrush* brush;
   renderTarget->CreateSolidColorBrush(D2D1::ColorF(r, g, b, a), &brush);

    renderTarget->DrawEllipse(D2D1::Ellipse(D2D1::Point2F(x, y),
        radius, radius), brush, 3.0f);

    brush->Release();
}

Answer 1

您正在访问未初始化的指针：

Graphics *graphics;  
//...  
if(!graphics->Init(windowhandle))  // <-- CRASH  
{...}

要解决此问题，请使用new：

分配内存

Graphics *graphics;  
graphics = new Graphics;  
if(!graphics->Init(windowhandle))  
{...}

未处理的异常访问冲突2D DirectX渲染D2D1.dll

1 个答案: