用程序显示自己的LOGO

static void DrawLogo_CB(vgChannel *chan, void *udata ) {
GLint matmode, mm;
GLfloat projmat[16];
GLboolean texstate;
GLboolean cullface;
int trans;
static int first = 1;
static unsigned char *texbuf;
static pfTexture *pftex;
static float alpha = 0.0f;
// 保存当前绘制状态
trans = pfGetTransparency();
glGetBooleanv( GL_CULL_FACE, &cullface);
pfPushState();
// 设置新的绘制状态
pfTransparency( PFTR_FAST );
glDisable( GL_CULL_FACE );
pfDisable( PFEN_LIGHTING );
glGetBooleanv( GL_TEXTURE_2D, &texstate );
if( !texstate ) {
  glEnable( GL_TEXTURE_2D );
}
pfEnable( PFEN_TEXTURE );
// 保存当前投影变换，为显示LOGO设置正交投影变换
pfPushIdentMatrix();
glDisable(GL_DEPTH_TEST);
glGetIntegerv(GL_MATRIX_MODE, &matmode);
glMatrixMode(GL_PROJECTION);
glGetFloatv(GL_PROJECTION_MATRIX, projmat);
glMatrixMode( matmode );
glGetIntegerv(GL_MATRIX_MODE, &mm);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluOrtho2D( 0.0f, 1.0f, 0.0f, 1.0f );
glMatrixMode(mm);
// 创建并加载LOGO纹理
if( first ) {
  char* buffer;
  int imgSize;
  first = 0;
  pftex = pfNewTex( vgGetSharedArena() );
  imgSize = logo_width * logo_height * logo_com * sizeof(char);
  buffer = (char*) pfMalloc(imgSize ,vgGetSharedArena());  //一定要从Vega内存共享区申请内存空间
  memcpy(buffer,logo_image_data,imgSize);   //将图像数据拷贝到申请的内存中
  pfTexImage( pftex, (unsigned int *)(buffer), logo_com, logo_width, logo_width,1 );  // 创建新的纹理备用
  pfTexFilter( pftex, PFTEX_MINFILTER, PFTEX_BILINEAR );
  pfTexFilter( pftex, PFTEX_MAGFILTER, PFTEX_BILINEAR );
  //其中：logo_width 为logo图像的宽度，logo_height为logo像素的高度 ，logo_com为图像的像素深度rgb=3 rgba=4
  //logo_image_data为指向logo图像数据的指针
}
// 将纹理映射到屏幕左下角的多边形上成为LOGO
else {
  pfApplyTex( pftex );  //将其邦定为OpenGl的当前纹理
  // LOGO渐渐出现
  alpha += 0.005f;
  if ( alpha > 0.98f )
   alpha = 1.0f;
  glBegin( GL_QUADS );
  glColor4f( 1.0f, 1.0f, 1.0f , alpha);
  glTexCoord2f( 0.0f, 0.0f);
  glVertex2f(  0.00f, 0.0f);
  glTexCoord2f( 1.00f, 0.00f);
  glVertex2f( 0.2f, 0.0f);
  glTexCoord2f( 1.00f, 1.00f);
  glVertex2f( 0.2f, 0.1f);
  glTexCoord2f( 0.00f, 1.00f);
  glVertex2f( 0.0f, 0.1f);
  glEnd( );
}
// 恢复原绘制状态
if( !texstate ) {
  glDisable( GL_TEXTURE_2D );
}
pfPopMatrix();
glMatrixMode(GL_PROJECTION);
glLoadMatrixf(projmat);
glMatrixMode( matmode );
glEnable(GL_DEPTH_TEST);
pfEnable(PFEN_LIGHTING);
pfTransparency( trans );
glEnable( cullface );
pfPopState ();
}

char* buffer;
  int imgSize;
  pftex = pfNewTex( vgGetSharedArena() );
  imgSize = logo_width * logo_height * logo_com * sizeof(char);
  buffer = (char*) pfMalloc(imgSize ,vgGetSharedArena());
  memcpy(buffer,logo_image_data,imgSize);  
  pfTexImage( pftex, (unsigned int *)(buffer), logo_com, logo_width, logo_width,1 );