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DSTexCompress/FreeImage/Examples/OpenGL/TextureManager/TextureManager.cpp

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+//**********************************************
+//Singleton Texture Manager class
+//Written by Ben English
+//benjamin.english@oit.edu
+//
+//For use with OpenGL and the FreeImage library
+//**********************************************
+
+#include "TextureManager.h"
+
+TextureManager* TextureManager::m_inst(0);
+
+TextureManager* TextureManager::Inst()
+{
+	if(!m_inst)
+		m_inst = new TextureManager();
+
+	return m_inst;
+}
+
+TextureManager::TextureManager()
+{
+	// call this ONLY when linking with FreeImage as a static library
+	#ifdef FREEIMAGE_LIB
+		FreeImage_Initialise();
+	#endif
+}
+
+//these should never be called
+//TextureManager::TextureManager(const TextureManager& tm){}
+//TextureManager& TextureManager::operator=(const TextureManager& tm){}
+	
+TextureManager::~TextureManager()
+{
+	// call this ONLY when linking with FreeImage as a static library
+	#ifdef FREEIMAGE_LIB
+		FreeImage_DeInitialise();
+	#endif
+
+	UnloadAllTextures();
+	m_inst = 0;
+}
+
+bool TextureManager::LoadTexture(const char* filename, const unsigned int texID, 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 false;
+
+	//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 false;
+
+	//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 false;
+	
+	//if this texture ID is in use, unload the current texture
+	if(m_texID.find(texID) != m_texID.end())
+		glDeleteTextures(1, &(m_texID[texID]));
+
+	//generate an OpenGL texture ID for this texture
+	glGenTextures(1, &gl_texID);
+	//store the texture ID mapping
+	m_texID[texID] = gl_texID;
+	//bind to the new texture ID
+	glBindTexture(GL_TEXTURE_2D, gl_texID);
+	//store the texture data for OpenGL use
+	glTexImage2D(GL_TEXTURE_2D, level, internal_format, width, height,
+		border, image_format, GL_UNSIGNED_BYTE, bits);
+
+	//Free FreeImage's copy of the data
+	FreeImage_Unload(dib);
+
+	//return success
+	return true;
+}
+
+bool TextureManager::UnloadTexture(const unsigned int texID)
+{
+	bool result(true);
+	//if this texture ID mapped, unload it's texture, and remove it from the map
+	if(m_texID.find(texID) != m_texID.end())
+	{
+		glDeleteTextures(1, &(m_texID[texID]));
+		m_texID.erase(texID);
+	}
+	//otherwise, unload failed
+	else
+	{
+		result = false;
+	}
+
+	return result;
+}
+
+bool TextureManager::BindTexture(const unsigned int texID)
+{
+	bool result(true);
+	//if this texture ID mapped, bind it's texture as current
+	if(m_texID.find(texID) != m_texID.end())
+		glBindTexture(GL_TEXTURE_2D, m_texID[texID]);
+	//otherwise, binding failed
+	else
+		result = false;
+
+	return result;
+}
+
+void TextureManager::UnloadAllTextures()
+{
+	//start at the begginning of the texture map
+	std::map<unsigned int, GLuint>::iterator i = m_texID.begin();
+
+	//Unload the textures untill the end of the texture map is found
+	while(i != m_texID.end())
+		UnloadTexture(i->first);
+
+	//clear the texture map
+	m_texID.clear();
+}