gistfile1.cpp

BPTextureInfo *flua_loadTexture(
		const char* filename,
		GLenum image_format,
		GLint internal_format,
		GLint level,
		GLint border
) {
	//image format
	FREE_IMAGE_FORMAT fif = FIF_UNKNOWN;
	
	//pointer to the image, once loaded
	FIBITMAP* dib(0);
	
	//pointer to the image data
	BYTE* bits(0);
	
	//image width and height
	unsigned int width(0), height(0);
	
	//OpenGL's image ID to map to
	GLuint gl_texID;
	
	//check the file signature and deduce its format
	fif = FreeImage_GetFileType(filename, 0);
	
	//if still unknown, try to guess the file format from the file extension
	if(fif == FIF_UNKNOWN) 
		fif = FreeImage_GetFIFFromFilename(filename);
	
	//if still unkown, return failure
	if(fif == FIF_UNKNOWN)
		return NULL;

	//check that the plugin has reading capabilities and load the file
	if(FreeImage_FIFSupportsReading(fif))
		dib = FreeImage_Load(fif, filename);
	
	//if the image failed to load, return failure
	if(!dib)
		return NULL;
	
	//retrieve the image data
	bits = FreeImage_GetBits(dib);
	
	//get the image width and height
	width = FreeImage_GetWidth(dib);
	height = FreeImage_GetHeight(dib);
	
	//if this somehow one of these failed (they shouldn't), return failure
	if((bits == 0) || (width == 0) || (height == 0))
		return NULL;
	
	//generate an OpenGL texture ID for this texture
	glGenTextures(1, &gl_texID);
	
	//bind to the new texture ID
	glBindTexture(GL_TEXTURE_2D, gl_texID);
	
	//store the texture data for OpenGL use
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	
	glTexImage2D(GL_TEXTURE_2D, level, internal_format, width, height, border, image_format, GL_UNSIGNED_BYTE, bits);
	
	gluBuild2DMipmaps(GL_TEXTURE_2D, internal_format, width, height, image_format, GL_UNSIGNED_BYTE, bits);
	
	//Free FreeImage's copy of the data
	// TODO: This should not lead to a segfault
	FreeImage_Unload(dib);
	
	//return success
	return new (UseGC) BPTextureInfo(gl_texID, width, height);
}