//--------------------------------------------------------
void CRenderTextureLayer::update(float dt)
{
// 帧更新纹理偏移量
static float fOffsetLen = 0.0f;
fOffsetLen += MOVE_PIXELS_PER_SECOND * dt;
MoveTexture( fOffsetLen );
}
/**
* \brief Loads a texture from an image file and fits into a GL-compatible size.
* \param fileName The name of the image file.
* \param filtering True for linear filtering, false for nearest-neighbor.
* \param realW Returns the real width of the texture.
* \param realH Returns the real height of the texture.
* \return The OpenGL texture ID.
*/
long SDLGL_LoadTextureFromFileBestFit( std::string fileName, bool filtering, unsigned long &realW, unsigned long &realH ) {
GLuint theTexture;
SDL_Surface *loadSurface, *theSurface, *convertedSurface;
Uint32 rmask, gmask, bmask, amask;
loadSurface = IMG_Load( fileName.c_str() );
if ( loadSurface ) {
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
rmask = 0xff000000;
gmask = 0x00ff0000;
bmask = 0x0000ff00;
amask = 0x000000ff;
#else
rmask = 0x000000ff;
gmask = 0x0000ff00;
bmask = 0x00ff0000;
amask = 0xff000000;
#endif
theSurface = SDL_CreateRGBSurface( SDL_SWSURFACE | SDL_SRCALPHA, NextPowerOfTwo(loadSurface->w), NextPowerOfTwo(loadSurface->h), 32, rmask, gmask, bmask, amask );
SDL_FillRect( theSurface, NULL, SDL_MapRGBA( theSurface->format, 0,0,0,255 ) );
convertedSurface = SDL_ConvertSurface( loadSurface, theSurface->format, SDL_SWSURFACE | SDL_SRCALPHA );
MoveTexture( convertedSurface, theSurface );
}
else
theSurface = NULL;
if ( theSurface ) {
glGenTextures( 1, &theTexture);
glBindTexture( GL_TEXTURE_2D, theTexture );
if ( filtering ) {
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
} else {
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
}
realW = loadSurface->w;
realH = loadSurface->h;
glTexImage2D( GL_TEXTURE_2D, 0, 4, theSurface->w, theSurface->h, 0, GL_RGBA, GL_UNSIGNED_BYTE, theSurface->pixels );
SDL_FreeSurface( theSurface );
SDL_FreeSurface( loadSurface );
SDL_FreeSurface( convertedSurface );
return theTexture;
}
else
return 0; // GLspeak for "no texture"
}
