GG::Texture Class Reference

This class encapsulates OpenGL texture objects. More...

#include <Texture.h>

List of all members.

Structors
	Texture ()
virtual	~Texture ()
Accessors
std::string	Filename () const
GLenum	WrapS () const
GLenum	WrapT () const
GLenum	MinFilter () const
GLenum	MagFilter () const
int	BytesPP () const
GLint	Width () const
GLint	Height () const
bool	MipMapped () const
GLuint	OpenGLId () const
const GLfloat *	DefaultTexCoords () const
GLint	DefaultWidth () const
GLint	DefaultHeight () const
void	OrthoBlit (const Pt &pt1, const Pt &pt2, const GLfloat *tex_coords=0) const
void	OrthoBlit (const Pt &pt) const
Mutators
void	Load (const std::string &filename, bool mipmap=false)
void	Init (int width, int height, const unsigned char *image, GLenum format, GLenum type, int bytes_per_pixel, bool mipmap=false)
void	Init (int x, int y, int width, int height, int image_width, const unsigned char *image, GLenum format, GLenum type, int bytes_per_pixel, bool mipmap=false)
void	SetWrap (GLenum s, GLenum t)
void	SetFilters (GLenum min, GLenum mag)
void	Clear ()
Exceptions
	GG_ABSTRACT_EXCEPTION (Exception)
	GG_CONCRETE_EXCEPTION (BadFile, GG::Texture, Exception)
	GG_CONCRETE_EXCEPTION (InvalidColorChannels, GG::Texture, Exception)
	GG_CONCRETE_EXCEPTION (InsufficientResources, GG::Texture, Exception)

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Detailed Description

This class encapsulates OpenGL texture objects.

If the dimensions of the image used to initialize the texture are not both powers of two, the texture is created with dimensions of the next largest (or equal) powers of two. The original image occupies the region near the texture's origin, and the rest is zero-initialized. This is done to prevent the image from being scaled, since textures used in a GUI almost always must maintain pixel accuracy. The original image size and corresponding texture coords are saved, and can be accessed through DefaultWidth(), DefaultHeight(), and DefaultTexCoords(), respectively. These are kept so that only the originally-loaded-image part of the texture can be used, if desired. All initialization functions first free the OpenGL texture currently in use by the texture (if any) and create a new one. When the load filename is "" or the image parameter is 0, all initialization functions fail silently, performing no initialization and allocating no memory or OpenGL texture. Serialized Textures save the filename associated with the texture when available, so the originally loaded file can be reloaded again later. If no such file exists, such as when a Texture is created from in-memory image data, the contents of the Texture are read from video memory and saved as binary data. A default-constructed Texture will have niether a filename nor raw image data.

Definition at line 55 of file Texture.h.

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Constructor & Destructor Documentation

GG::Texture::Texture

(

)

ctor

virtual GG::Texture::~Texture

(

)

[virtual]

virtual dtor

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Member Function Documentation

std::string GG::Texture::Filename

(

)

const

returns the filename from which this texture was loaded ("" if this texture was not loaded from a file)

GLenum GG::Texture::WrapS

(

)

const

returns S-wrap mode associated with this opengl texture

GLenum GG::Texture::WrapT

(

)

const

returns T-wrap mode associated with this opengl texture

GLenum GG::Texture::MinFilter

(

)

const

returns minimization filter modes associated with this opengl texture

GLenum GG::Texture::MagFilter

(

)

const

returns maximization filter modes associated with this opengl texture

int GG::Texture::BytesPP

(

)

const

returns the image's color depth in bytes

GLint GG::Texture::Width

(

)

const

returns width of entire texture

GLint GG::Texture::Height

(

)

const

returns height of entire texture

bool GG::Texture::MipMapped

(

)

const

returns true if the texture has mipmaps

GLuint GG::Texture::OpenGLId

(

)

const

GLuint "name" of the opengl texture object associated with this object.

const GLfloat* GG::Texture::DefaultTexCoords

(

)

const

texture coordinates to use by default when blitting this texture

GLint GG::Texture::DefaultWidth

(

)

const

returns width in pixels, based on initial image (0 if texture was not loaded)

GLint GG::Texture::DefaultHeight

(

)

const

returns height in pixels, based on initial image (0 if texture was not loaded)

void GG::Texture::OrthoBlit	(	const Pt &	pt1,
		const Pt &	pt2,
		const GLfloat *	tex_coords = 0
	)			const

blit any portion of texture to any place on screen, scaling as necessary

void GG::Texture::OrthoBlit

(

const Pt &

pt

)

const

blit default portion of texture unscaled to pt (upper left corner)

void GG::Texture::Load	(	const std::string &	filename,
		bool	mipmap = false
	)

frees any currently-held memory and loads a texture from file filename.

Exceptions:

GG::Texture::BadFile

Throws if the texture creation fails.

void GG::Texture::Init	(	int	width,
		int	height,
		const unsigned char *	image,
		GLenum	format,
		GLenum	type,
		int	bytes_per_pixel,
		bool	mipmap = false
	)

frees any currently-held memory and creates a texture from supplied array image.

Exceptions:

GG::Texture::Exception

Throws applicable subclass if the texture creation fails in one of the specified ways.

void GG::Texture::Init	(	int	x,
		int	y,
		int	width,
		int	height,
		int	image_width,
		const unsigned char *	image,
		GLenum	format,
		GLenum	type,
		int	bytes_per_pixel,
		bool	mipmap = false
	)

frees any currently-held memory and creates a texture from subarea of supplied array image.

Exceptions:

GG::Texture::Exception

Throws applicable subclass if the texture creation fails in one of the specified ways.

void GG::Texture::SetWrap	(	GLenum	s,
		GLenum	t
	)

sets the opengl texture wrap modes associated with opengl texture m_opengl_id

void GG::Texture::SetFilters	(	GLenum	min,
		GLenum	mag
	)

sets the opengl min/mag filter modes associated with opengl texture m_opengl_id

void GG::Texture::Clear

(

)

frees the opengl texture object associated with this object

GG::Texture::GG_ABSTRACT_EXCEPTION

(

Exception

)

The base class for Texture exceptions.

GG::Texture::GG_CONCRETE_EXCEPTION	(	BadFile	,
		GG::Texture	,
		Exception
	)

Thrown when valid texture data cannot be read from a file.

GG::Texture::GG_CONCRETE_EXCEPTION	(	InvalidColorChannels	,
		GG::Texture	,
		Exception
	)

Thrown when an unsupported number of color channels is requested.

GG::Texture::GG_CONCRETE_EXCEPTION	(	InsufficientResources	,
		GG::Texture	,
		Exception
	)

Thrown when GL fails to provide a requested texture object.

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The documentation for this class was generated from the following file:

• Texture.h

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