GlsImage Class Reference

#include <gls_image.h>

Classes
class	ImageList
struct	InitParameters
struct	InlineImage

Public Types
enum	ImageCodec { IMAGE_CODEC_RAW, IMAGE_CODEC_RLE }
enum	InputPixelFormat { INPUT_PIXEL_FORMAT_RGB, INPUT_PIXEL_FORMAT_RGBA, INPUT_PIXEL_FORMAT_ALPHA }

Public Member Functions
void	BindTexture (GlsStateManager &gl) const
GlsBool	IsEqual (const InlineImage &inlineImage) const

Static Public Member Functions
static void	Initialize (const InitParameters &initParameters)
static GlsImage *	GetGlsImageFromInlineImage (const InlineImage &inlineImage, const GlsBool checkForDuplicate)

Protected Types
enum	{   PIXEL_GL_RED_COMPONENT = 0u, PIXEL_GL_GREEN_COMPONENT, PIXEL_GL_BLUE_COMPONENT, PIXEL_GL_ALPHA_COMPONENT,   NUM_BYTES_PER_PIXEL_GL }

Protected Member Functions
	GlsImage (const InlineImage &inlineImage)
void	DecodeImage (const InlineImage &inlineImage)
GlsUInt32	PixelSizeFromInputPixelFormat (const GlsImage::InputPixelFormat inputPixelFormat) const
virtual	~GlsImage ()

Protected Attributes
GLuint	_textureHandle
const InputPixelFormat	_inputPixelFormat
const GlsUInt32	_width
const GlsUInt32	_height
const GlsUInt32	_crcValue

Static Protected Attributes
static const GLuint	INVALID_TEXTURE_HANDLE = 0u
static const GlsUInt32	NUM_BYTES_PER_INPUT_PIXEL_FORMAT_RGB = 3u
static const GlsUInt32	NUM_BYTES_PER_INPUT_PIXEL_FORMAT_RGBA = 4u
static const GlsUInt32	NUM_BYTES_PER_INPUT_PIXEL_FORMAT_ALPHA = 1u
static ImageList *	_imageList
static GlsUChar *	_scanlineImageData

Detailed Description

Encapsulates a 2D image

Invariant

INVALID_TEXTURE_HANDLE != _textureHandle, GlsImageInputPixelFormatIsValid( _inputPixelFormat ), _pixelSize > 0, ( _height > 0 ) && IsPowerOf2( _height ), ( _width > 0 ) && IsPowerOf2( _width ), _imageList != GLS_NULL ( ( _maxImageWidth > 0u ) && IsPowerOf2( _maxImageWidth ) ), GlsAssert( GLS_NULL != _scanlineImageData != GLS_NULL

Member Enumeration Documentation

anonymous enum

protected

corresponds to layout of a GL_RGBA8 pixel

Enumerator
PIXEL_GL_RED_COMPONENT	GL_RGBA8 - red component
PIXEL_GL_GREEN_COMPONENT	GL_RGBA8 - green component
PIXEL_GL_BLUE_COMPONENT	GL_RGBA8 - blue component
PIXEL_GL_ALPHA_COMPONENT	GL_RGBA8 - alpha component
NUM_BYTES_PER_PIXEL_GL	number of bytes per pixel in GL texture data

enum GlsImage::ImageCodec

enumeration of possible image compression codecs

Enumerator
IMAGE_CODEC_RAW	Image data is not compressed
IMAGE_CODEC_RLE	Image data is compressed with RLE ( Run Length Encoded )

enum GlsImage::InputPixelFormat

enumeration of supported input pixel formats

Enumerator
INPUT_PIXEL_FORMAT_RGB	red, green, blue
INPUT_PIXEL_FORMAT_RGBA	red, green, blue, alpha
INPUT_PIXEL_FORMAT_ALPHA	alpha

Constructor & Destructor Documentation

GlsImage::GlsImage ( const InlineImage &  inlineImage )

protected

Constructor - create an image from the given inline image

Parameters

inlineImage

inline image in question

Precondition

inlineImage.IsValid(), the GlsImage subsystem has been initialized, inlineImage.width <= _maxImageWidth

Postcondition

image constructed

virtual GlsImage::~GlsImage ( )

protectedvirtual

Destructor - shall never be called

Precondition

none

Postcondition

none

Member Function Documentation

void GlsImage::BindTexture

(

GlsStateManager &

gl

)

const

Make this image the active GL texture.

Precondition

glIsTexture( _textureHandle ) == GL_TRUE

Postcondition

image is bound to GL

void GlsImage::DecodeImage ( const InlineImage &  inlineImage )

protected

decode the given inline image and upload to GL

Parameters

inlineImage

inline image in question

Precondition

inlineImage.IsValid(), inlineImage.codec is either IMAGE_CODEC_RLE or IMAGE_CODEC_RAW, inlineImage.width <= _maxImageWidth, inlineImage.inputPixelFormat must be either INPUT_PIXEL_FORMAT_ALPHA, INPUT_PIXEL_FORMAT_RGB, or INPUT_PIXEL_FORMAT_RGBA empty texture of appropriate size is created and bound to GL, the GlsImage subsystem has been initialized

Postcondition

image is decoded and uploaded to GL

static GlsImage* GlsImage::GetGlsImageFromInlineImage ( const InlineImage &  inlineImage, const GlsBool  checkForDuplicate  )

static

Get an Image object with the given GlsInlineImage data. If checkForDuplicate is GLS_TRUE, this method checks to see if an image has already been constructed for the GlsInlineImage and if found, returns the previously constructed image.

Parameters

inlineImage	GlsInlineImage in question
checkForDuplicate	GLS_TRUE to check if this inline image is a duplicate of an existing image else GLS_FALSE

Returns

image corresponding to given inline image

Precondition

inlineImage.IsValid(), a GlsStateManager instance does not yet exist, the GlsImage subsytem has been initialized, inlineImage.width <= _maxImageWidth

Postcondition

new image constructed as needed

static void GlsImage::Initialize ( const InitParameters &  initParameters )

static

Initialize the GlsImage subsystem. This is a one time call that must be made before the image subsystem can be used.

Parameters

initParameters

initialization parameters for GlsImage subsystem

Precondition

GlsImage subsystem has not already been initialized, initParameters.IsValid()

Postcondition

GlsImage subsystem intermediate image buffers and image list are allocated

GlsBool GlsImage::IsEqual

(

const InlineImage &

inlineImage

)

const

Determine if this image matches the given inline image

Parameters

inlineImage

inline image in question

Returns

GLS_TRUE if matches inline image else GLS_FALSE

Precondition

inlineImage.IsValid()

Postcondition

none

GlsUInt32 GlsImage::PixelSizeFromInputPixelFormat ( const GlsImage::InputPixelFormat  inputPixelFormat ) const

protected

Get the number of bytes required per pixel for the given format

Parameters

inputPixelFormat

format in question

Returns

number of bytes required per pixel for format

Precondition

GlsImageInputPixelFormatIsValid( inputPixelFormat )

Postcondition

none

Member Data Documentation

const GlsUInt32 GlsImage::_crcValue

protected

CRC value used to determine if two images are the same

const GlsUInt32 GlsImage::_height

protected

height of image in pixels. must be a power of 2

ImageList* GlsImage::_imageList

staticprotected

singleton image list

const InputPixelFormat GlsImage::_inputPixelFormat

protected

Input pixel format of image

GlsUChar* GlsImage::_scanlineImageData

staticprotected

intermediate image buffer for RGBA image data scanline, number of bytes = ( NUM_BYTES_PER_PIXEL_GL * _maxWidth

GLuint GlsImage::_textureHandle

protected

The texture handle of the image, else INVALID_TEXTURE_HANDLE

const GlsUInt32 GlsImage::_width

protected

width of image in pixels. must be a power of 2

const GLuint GlsImage::INVALID_TEXTURE_HANDLE = 0u

staticprotected

value indicating invalid texture handle

const GlsUInt32 GlsImage::NUM_BYTES_PER_INPUT_PIXEL_FORMAT_ALPHA = 1u

staticprotected

number of bytes per input pixel for INPUT_PIXEL_FORMAT_ALPHA

const GlsUInt32 GlsImage::NUM_BYTES_PER_INPUT_PIXEL_FORMAT_RGB = 3u

staticprotected

number of bytes per input pixel for INPUT_PIXEL_FORMAT_RGB

const GlsUInt32 GlsImage::NUM_BYTES_PER_INPUT_PIXEL_FORMAT_RGBA = 4u

staticprotected

number of bytes per input pixel for INPUT_PIXEL_FORMAT_RGBA