【发布时间】：2016-10-31 14:29:23
【问题描述】：
我一直在关注“什么是纱架？”的直接 2d 教程。我到了教程 8：“加载图像”。我没有 spritesheet 对象保存指向 Graphics 对象的指针，因为这会导致此版本的 Visual Studio 出现问题，因此每次调用需要它的东西时都会通过。要点：当我尝试使用wicfactory->CreateDecoderFromFile() 方法创建IWICBitmapDecoder 时，出现以下错误：
在 Project8.exe 中的 0x008C70A7 处引发异常：0xC0000005：访问冲突读取位置 0x00000000。
在我得到的汽车中：
hr | E_NOINTERFACE No such interface supported.
this | 0x00c1a5c8 {bmp=0x00000000 <NULL> } spritesheet *
wicfactory | 0x00000000<NULL>
wicdecoder | 0xcccccccc{...}
代码是这样的：
#pragma once
#include <wincodec.h> //include windowscodecs.lib in the linker input
#include "Graphics.h"
#include <d2d1.h>
#include<string>
class spritesheet {
public:
ID2D1Bitmap* bmp;
spritesheet() {}
spritesheet(LPCWSTR file, graphics* gfx) {
//this->gfx = gfx;
//bmp = NULL;
HRESULT hr;
//create an image factory
IWICImagingFactory *wicFactory;
hr = CoCreateInstance(
CLSID_WICImagingFactory,
NULL,
CLSCTX_INPROC_SERVER,
CLSID_WICImagingFactory,
(LPVOID*)&wicFactory
);
//create a decoder
IWICBitmapDecoder *wicdecoder;
hr = wicFactory->CreateDecoderFromFilename(
file,
NULL,
GENERIC_READ,
WICDecodeMetadataCacheOnLoad,
&wicdecoder
);
IWICBitmapFrameDecode* wicframe = NULL;
hr = wicdecoder->GetFrame(0, &wicframe);
IWICFormatConverter *wicconverter = NULL;
hr = wicFactory->CreateFormatConverter(&wicconverter);
hr = wicconverter->Initialize(
wicframe,
GUID_WICPixelFormat32bppPBGRA,
WICBitmapDitherTypeNone,
NULL,
0.0,
WICBitmapPaletteTypeCustom
);
gfx->gettarget()->CreateBitmapFromWicBitmap(
wicconverter,
NULL,
&bmp
);
if (wicdecoder) wicdecoder->Release();
if (wicFactory) wicFactory->Release();
if (wicconverter) wicconverter->Release();
if (wicframe) wicframe->Release();
}
void init(wchar_t * file, graphics * gfx) {
//this->gfx = gfx;
//bmp = NULL;
HRESULT hr;
//create an image factory
IWICImagingFactory* wicFactory;
hr = CoCreateInstance(
CLSID_WICImagingFactory,
NULL,
CLSCTX_INPROC_SERVER,
CLSID_WICImagingFactory,
(LPVOID*)&wicFactory
);
//create a decoder
IWICBitmapDecoder* wicdecoder;
hr = wicFactory->CreateDecoderFromFilename(
file,
NULL,
GENERIC_READ,
WICDecodeMetadataCacheOnLoad,
&wicdecoder
);
IWICBitmapFrameDecode* wicframe = NULL;
hr = wicdecoder->GetFrame(0, &wicframe);
IWICFormatConverter *wicconverter = NULL;
hr = wicFactory->CreateFormatConverter(&wicconverter);
hr = wicconverter->Initialize(
wicframe,
GUID_WICPixelFormat32bppPBGRA,
WICBitmapDitherTypeNone,
NULL,
0.0,
WICBitmapPaletteTypeCustom
);
gfx->rendertarget->CreateBitmapFromWicBitmap(
wicconverter,
NULL,
&bmp
);
if (wicdecoder) wicdecoder->Release();
if (wicFactory) wicFactory->Release();
if (wicconverter) wicconverter->Release();
if (wicframe) wicframe->Release();
gfx->rendertarget->DrawBitmap(
bmp,
D2D1::RectF(0.0f, 0.0f, 10, 10), //dest rect
1.0f,
D2D1_BITMAP_INTERPOLATION_MODE::D2D1_BITMAP_INTERPOLATION_MODE_NEAREST_NEIGHBOR, //effect for scaling
D2D1::RectF(0, 0, 10, 10)); //scource rect
}
void draw(graphics *gfx) {
gfx->rendertarget->DrawBitmap(
bmp,
D2D1::RectF(0.0f, 0.0f, 10, 10), //dest rect
1.0f,
D2D1_BITMAP_INTERPOLATION_MODE::D2D1_BITMAP_INTERPOLATION_MODE_NEAREST_NEIGHBOR, //effect for scaling
D2D1::RectF(0, 0, 10, 10)); //scource rect
}
};
现在，只是为了测试一下，我确实在每个方法的开头放了一个 ID2D1Bitmap* bmp; 只是为了看看事情发生在哪里，但是 wicdecoder 错误消息只是更改为内存中的一个随机位置。
【问题讨论】：
-
您没有正确使用 CoCreateInstance()。使用正确的接口 guid，IID_IWICImagingFactory。并添加错误检查，这样您就不会一直耕作，直到它因随机异常而崩溃。
-
你能举例说明我在这种情况下如何使用 CoCreateInstance() 吗？我对此有点陌生，我想知道老手将如何实施它
标签： c++ visual-studio-2015 direct2d wic