如何在 GLUT 上加载 bmp 以将其用作纹理? [英] How to load a bmp on GLUT to use it as a texture?

问题描述

我一直在四处寻找一个简单的解决方案，以在 C++ 中为我的 OpenGl GLUT 简单月球着陆器游戏添加精灵，看来我必须使用 bmp，因为它们最容易加载并用作矩形上的纹理.

I've been searching all around for a simple solution to add sprites to my OpenGl GLUT simple moon lander game in c++ and it appears I must use bmp's since they're easiest to load and use them as textures on a rectangle.

我究竟如何将 bmp 加载为纹理?

How exactly can I load the bmp's as textures though?

推荐答案

看我简单的c实现函数加载纹理.

Look my simple c implementation function to load texture.

GLuint LoadTexture( const char * filename )
{
  GLuint texture;
  int width, height;
  unsigned char * data;

  FILE * file;
  file = fopen( filename, "rb" );

  if ( file == NULL ) return 0;
  width = 1024;
  height = 512;
  data = (unsigned char *)malloc( width * height * 3 );
  //int size = fseek(file,);
  fread( data, width * height * 3, 1, file );
  fclose( file );

  for(int i = 0; i < width * height ; ++i)
  {
    int index = i*3;
    unsigned char B,R;
    B = data[index];
    R = data[index+2];

    data[index] = R;
    data[index+2] = B;
  }

  glGenTextures( 1, &texture );
  glBindTexture( GL_TEXTURE_2D, texture );
  glTexEnvf( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE,GL_MODULATE );
  glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,GL_LINEAR_MIPMAP_NEAREST );

  glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,GL_LINEAR );
  glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S,GL_REPEAT );
  glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T,GL_REPEAT );
  gluBuild2DMipmaps( GL_TEXTURE_2D, 3, width, height,GL_RGB, GL_UNSIGNED_BYTE, data );
  free( data );

  return texture;
}

以上函数返回纹理数据.将纹理数据存储在变量中

Above function returns the texture data. Store the texture data in variable

GLuint texture;
texture= LoadTexture( "your_image_name.bmp" );

现在您可以使用 glBindTexture 绑定纹理

Now you can bind the texture using glBindTexture

glBindTexture (GL_TEXTURE_2D, texture);

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