Loading Bitmap Files
o DirectDrawby Kieren Johnstone
载入位图文件到 DirectDraw
译:sea_bug
Introduction
介绍
In this article I will briefly describe the process of using Windows\' functions to load a bitmap (.bmp) file of any type, and place it _disibledevent=>在这篇文章里
我将简要叙述
下使用Windows
来载入任何类型
BMP图象文件数据并将数据存放到
个新建立DirectDraw表面中
在这以后篇幅里我们将使用DirectX 7.0 SDKDirectDraw Surface Creation
创建DirectDraw表面
Creating a
DirectDraw surface is very easy, and this function will create a surface of any size. This can also be used as a general-purpose surface creation function, and 
you were writing an engine 
you\'d probably put it in there somewhere. 创建
个DirectDraw表面是非常容易这个将根据大小来创建个表面这同样能用于多种多样
表面创建如果你要制作个引擎类你也许会把这个放在引擎某处Listing 1
代码列表 1
void CreateSurface(LPDIRECTDRAWSURFACE7 *lpSource,
xs, ys){
DDSURFACEDESC2 ddsd;
ZeroMemory(&ddsd,
(ddsd));ddsd.dwSize =
(ddsd);ddsd.dwFlags = DDSD_CAPS | DDSD_WIDTH | DDSD_HEIGHT;
ddsd.ddsCaps.dwCaps = DDSCAPS_OFFSCREENPLAIN;
ddsd.dwWidth = xs;
ddsd.dwHeight = ys;
lpdd->CreateSurface(&ddsd, lpSource, NULL);
}
All this code does is create a DDSURFACEDESC2 structure that describes the dimensions of the surface, and tells DirectDraw that it\'s an off-screen surface. Then, the call to DirectDraw (in this
, DirectDraw is the lpdd poer) just creates the surface. 所有
这些代码是为表面建立个DDSURFACEDESC2数据结构来记录大小尺度并且告诉DirectDraw那是
个离屏表面然后呼叫DirectDraw(在这部分DirectDraw是lpdd指针)真正创建这个表面Bitmap Loading
位图载入
To load .bmp files we will use the standard Windows graphics library (GDI). This is best because
we\'re in a mode with a palette then Windows will automatically re-map the bitmap colours to the nearest in the palette. Here is the code that blits a loaded bitmap to a surface…. 要载入.BMP图形文件
我们将使用标准Windows图形库(GDI)这个是最好思路方法
如果我们是在
个调色板视频模式那么Windows将自动将位图映射到最接近调色板颜色以下代码是绘制
个位图数据到表面……Listing 2
代码列表 2
void DrawHBitmap(IDirectDrawSurface7 *lpSurface, HBITMAP hBitmap,
x, y, width, height){
HDC hdcImage;
HDC hdc;
BITMAP bm;
(lpSurface 
NULL || hBitmap NULL)
;lpSurface->Restore
;hdcImage = CreateCompatibleDC(NULL);
SelectObject(hdcImage, hBitmap);
GetObject(hBitmap,
(bm), &bm);width = width
0 ? bm.bmWidth : width;height = height
0 ? bm.bmHeight : height;lpSurface->GetDC(&hdc);
BitBlt(hdc, x, y, width, height, hdcImage, 0, 0, SRCCOPY);
lpSurface->ReleaseDC(hdc);
DeleteDC(hdcImage);
}
and here is the code that loads, blits, then unloads the bitmap:
以下
代码是把位图载入、绘制、到数据释放:Listing 3
代码列表 3
void CreateBitmapSurface(LPDIRECTDRAWSURFACE7 lpSurface, char *fname,
xs, ys){
HBITMAP hBitmap;
CreateSurface(&lpSurface, xs, ys);
hBitmap = LoadImage(NULL, fname, IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
DrawHBitmap(lpSurface, hBitmap, 0, 0, xs, ys);
DeleteObject(hBitmap);
}
Quick Example
快速例程
And to round it all up, here\'s some example code that loads the file \"test.bmp\" (width = 128, height = 128)
o the lpddsTest surface, and then releases it again: 围绕着以下部分
我们将结束此章节这里是些例程代码它载入\"test.bmp\"文件(宽=128高=128)到lpddTest表面中
并且将其释放:Listing 4
代码列表 4
void Example(void)
{
/*
* Declare the surface object
* 声名表面对象
*/
LPDIRECTDRAWSURFACE7 lpddsTest;
/*
* Load the bitmap file
o it* 载入位图文件
*/
CreateBitmapSurface(lpddsTest, “test.bmp”, 128, 128);
/*
* The lpddsTest surface now contains the “test.bmp” file
* lpddsTest表面已经包含了\"test.bmp\"文件数据
*/
/*
* Release the surface
* 释放表面
*/
lpddsTest->Release
;}
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