測試 MipmapCreate()

這次寫個程式來測試 Mipmap 建立函數 一文中的 MipmapCreate()，看看效果如何，而圖檔的讀取和儲存，採用 DevIL 這個知名的程式庫。

先看看 MipmapCreate() 建立的效果怎樣，此圖是將 Mipmap 各層的圖片疊加在一起：

看起來效果還不錯，這測試程式使用 vs2008 編寫，源碼下載：
https://www.dropbox.com/s/q3nlvb7qwkr4wg8/MipmapCreateTest.rar
http://pan.baidu.com/s/1i3BUiJ7

要編譯請先看一下內附的 ReadMe.txt 有關 DevIL 的說明。

以下列出程式碼：

#include <IL\il.h>
#include <io.h>
#include <stdio.h>
#include <sys/stat.h>
#include <iostream>
#include <sstream>
using namespace std;

// 以下兩個函數定義在 MipmapCreate.cpp

bool MipmapCreate(unsigned char ***Mipmap, unsigned int **WidthHeight, 
                  unsigned int *LevelNum,
                  const unsigned char *SrcMap, const unsigned int SrcWidth, 
                  const unsigned int SrcHeight, const unsigned int bpp);

void MipmapDelete(unsigned char **Mipmap, unsigned int *WidthHeight,
   unsigned int LevelNum);

bool dir_exists (char * dirName)
{
   struct stat buf;
   
   if ( stat ( dirName, &buf ) == 0 && buf.st_mode & _S_IFDIR)
     return true;
   
   return false;
}

bool file_exists (char * fileName)
{
  if( (_access( fileName, 0 )) != -1 )
    return true;

  return false;
}

string ults(unsigned int v)
{
  stringstream ss;
  ss << v;
  return ss.str();
}


int main(int argc, char* argv[])
{
  ILuint ImagesID;

  ilInit();
  ilEnable(IL_ORIGIN_SET);
  ilGenImages(1, &ImagesID);
  ilBindImage(ImagesID);

  char drive[_MAX_DRIVE];
  char dir[_MAX_DIR];
  char fname[_MAX_FNAME];
  char ext[_MAX_EXT];
  char input[_MAX_PATH];

  string SrcFileName;
  do
  {
    do
    {
      cout << "請輸入圖檔來源: ";
      cin.getline(input,_MAX_PATH);
    }while(file_exists(input) == false);

    SrcFileName = input;
  }while(ilLoadImage(SrcFileName.c_str()) == false);

  string TargetDirName;
  do
  {
    cout << "請輸入 Mipmap 圖檔存放目錄: ";
    cin.getline(input,_MAX_PATH);
  }while(dir_exists(input) == false);
  TargetDirName = input;


  //ILint format = ilGetInteger(IL_IMAGE_FORMAT);
  //ILint bpp = ilGetInteger(IL_IMAGE_BYTES_PER_PIXEL);
  ILint width = ilGetInteger(IL_IMAGE_WIDTH); // getting image width
  ILint height = ilGetInteger(IL_IMAGE_HEIGHT); // and height
  ILubyte *SrcMap = new ILubyte[width*height*4];
  ilCopyPixels(0, 0, 0, width, height, 1, IL_RGBA, IL_UNSIGNED_BYTE, SrcMap);
  
  unsigned char **Mipmap;
  unsigned int *WidthHeight;
  unsigned int LevelNum;
  MipmapCreate(&Mipmap, &WidthHeight, &LevelNum, SrcMap, width, height, 4);

  _splitpath( SrcFileName.c_str(), drive, dir, fname, ext );
  

  for(unsigned int n = 0; n < LevelNum; ++n)
  {
    string TargetFileName = TargetDirName + '\\' + fname + '_' + 
     ults(WidthHeight[n*2]) + 'x' + ults(WidthHeight[n*2+1]) + ".png";

    // 若用這個圖片會疊在一起
    // ilSetPixels(0, 0, 0, WidthHeight[n*2], WidthHeight[n*2+1], 1, 
    //  IL_RGBA, IL_UNSIGNED_BYTE, Mipmap[n]);

    ilTexImage(WidthHeight[n*2], WidthHeight[n*2+1], 0, 4, IL_RGBA, 
       IL_UNSIGNED_BYTE, Mipmap[n]);

    ilSaveImage(TargetFileName.c_str());   
  }

  MipmapDelete(Mipmap, WidthHeight, LevelNum);
  delete [] SrcMap;
  ilDeleteImages(1, &ImagesID);  

 return 0;
}