FramebufferObject Class Reference

An implementation of framebuffer object (FBO). More...

#include <easy3d/renderer/framebuffer_object.h>

Public Member Functions
	FramebufferObject (int w, int h, int samples=0)
	Constructor.
virtual	~FramebufferObject ()
	Destructor.
bool	add_color_texture (GLenum internal_format=GL_RGBA8, GLenum format=GL_RGBA, GLenum type=GL_UNSIGNED_BYTE, GLenum filter=GL_NEAREST)
	Add a color texture render buffer.
bool	add_color_buffer (GLenum internal_format=GL_RGBA8, GLenum format=GL_RGBA, GLenum type=GL_UNSIGNED_BYTE)
	Add a color render buffer.
bool	add_depth_texture (GLenum internal_format=GL_DEPTH24_STENCIL8, GLenum filter=GL_NEAREST, GLenum compare_mode=GL_NONE, GLenum compare_func=GL_LEQUAL)
	Add a depth texture render buffer.
bool	add_depth_buffer (GLenum internal_format=GL_DEPTH24_STENCIL8)
	Add a depth render buffer.
bool	attach_color_texture (GLenum target, GLuint texture_id, GLenum attachment)
	Attach an existing color texture to the framebuffer.
bool	attach_depth_texture (GLenum target, GLuint texture_id, GLenum attachment)
	Attach an existing depth texture to the framebuffer.
void	ensure_size (int w, int h)
	Ensure the size of the buffers is (w, h). If its size matches the required size, i.e, (w, h), it does nothing. Otherwise, it resizes the buffers.
bool	bind (GLenum target=GL_FRAMEBUFFER)
	Bind FBO to FRAMEBUFFER, DRAW_FRAMEBUFFER, or READ_FRAMEBUFFER.
bool	release (GLenum target=GL_FRAMEBUFFER)
	Switches rendering back to the default framebuffer.
bool	is_valid () const
	Returns true if the framebuffer object is valid.
bool	is_bound (GLenum target=GL_FRAMEBUFFER) const
	Check if the framebuffer object is currently bound to the current context.
void	activate_draw_buffer (unsigned int index) const
	Choose the buffers to render into. This command lets you select which attachments are written to.
void	activate_draw_buffers (unsigned int num_buffers, const unsigned int indices[]) const
	Choose the buffers to render into.
void	activate_draw_buffers (unsigned int minId, unsigned int maxId) const
	Choose the buffers in the range [minId, ... maxId] to render into.
void	deactivate_draw_buffers () const
	Deactivate all draw buffers.
void	activate_read_buffer (unsigned int index) const
	Choose the buffers to read from. This command lets you select which attachment to read from.
void	deactivate_read_buffer () const
	Deactivates reading from the buffers.
GLuint	handle () const
	Returns the OpenGL framebuffer object handle for this framebuffer object. This handle can be used to attach new images or buffers to the framebuffer. If you attach images or buffers, you are responsible for cleaning up and destroying these objects.
int	width () const
	Returns the width of the render buffers.
int	height () const
	Returns the height of the render buffers.
int	samples () const
	Returns the number of samples per pixel.
int	num_color_attachments () const
	Returns the number of color attachments.
bool	has_color_attachment (unsigned int index) const
	Checks if the framebuffer object has a color attachment at the given index.
bool	has_depth_attachment () const
	Checks if the framebuffer object has a depth attachment.
int	depth_bits () const
	Returns the depth bits.
bool	has_stencil () const
	Checks if the framebuffer object has a stencil buffer.
GLenum	texture_target () const
	Returns the texture target.
GLuint	color_texture (unsigned int index=0, bool resolve=true) const
	Returns the texture ID attached to the color attachment at the given index.
bool	has_color_texture (unsigned int index) const
	Checks if the framebuffer object has a color texture at the given index.
GLuint	depth_texture (bool resolve=true) const
	Returns the texture ID for the texture attached to the depth attachment.
bool	has_depth_texture () const
	Checks if the framebuffer object has a depth texture.
bool	copy_color_to_texture (GLuint &texture_handle, unsigned int index=0, int internal_format=GL_RGBA8, GLenum format=GL_RGBA, GLenum type=GL_UNSIGNED_BYTE, GLenum filter=GL_NEAREST)
	Makes a copy of the current buffer into a texture (regardless the attachments already have textures).
bool	copy_depth_to_texture (GLuint &texture_handle, unsigned int internal_format=GL_DEPTH24_STENCIL8, GLenum filter=GL_NEAREST)
	Makes a copy of the current depth buffer into a texture.
void	print_attachments () const
	Print all the attachments of the current framebuffer object.
void	print_draw_buffers () const
	Print the draw buffers.
void	print_read_buffer () const
	Print the read buffer.
bool	read_color (unsigned int index, unsigned char *buffer, unsigned int format, bool flip_vertically=true) const
	Read the color render buffer attached to color attachment at the given index.
bool	read_color (unsigned int index, std::vector< unsigned char > &buffer, unsigned int format, bool flip_vertically=true) const
	Read the color render buffer attached to color attachment at the given index.
bool	read_depth (float *buffer, bool flip_vertically=true) const
	Read the depth render buffer into a specified buffer.
bool	read_depth (std::vector< float > &buffer, bool flip_vertically=true) const
	Read the depth render buffer into a specified buffer.
bool	read_color (unsigned char rgba[4], int x, int y, int index=0) const
	Reads the color at the given pixel coordinates from the color render buffer attached to color attachment at the given index.
bool	read_depth (float &depth, int x, int y) const
	Reads the depth at the given pixel coordinates.
bool	snapshot_color (unsigned int index, const std::string &file_name) const
	Snapshots the color render buffer attached to color attachment at the given index into an image file.
bool	snapshot_depth (const std::string &file_name) const
	Snapshots the depth render buffer into an image file.

Static Public Member Functions
static bool	is_supported ()
	Queries if FramebufferObject is supported.
static void	blit_framebuffer (FramebufferObject *target, const FramebufferObject *source, GLbitfield buffers, GLenum filter=GL_NEAREST)
	Blit the whole sized buffer.
static void	blit_framebuffer (FramebufferObject *target, const FramebufferObject *source, int target_color_attachment_index, int source_color_attachment_index, GLbitfield buffers, GLenum filter=GL_NEAREST)
	Blit the whole sized buffer of a specific color attachment.
static void	blit_framebuffer (FramebufferObject *target, int tx0, int ty0, int tx1, int ty1, const FramebufferObject *source, int sx0, int sy0, int sx1, int sy1, GLbitfield buffers, GLenum filter=GL_NEAREST)
	Blit a specified region.
static void	blit_framebuffer (FramebufferObject *target, int tx0, int ty0, int tx1, int ty1, const FramebufferObject *source, int sx0, int sy0, int sx1, int sy1, int target_color_attachment_index, int source_color_attachment_index, GLbitfield buffers, GLenum filter=GL_NEAREST)
	Blit a specified region of a specific color attachment.

Detailed Description

An implementation of framebuffer object (FBO).

A framebuffer object is conceptually a structure containing pointers to GPU memory. The memory pointed to is either an OpenGL texture or an OpenGL RenderBuffer. FBOs can be used to render to one or more textures, share depth buffers between multiple sets of color buffers/textures. http://oss.sgi.com/projects/ogl-sample/registry/EXT/framebuffer_object.txt for details.

Note that you need to create a FramebufferObject with more than one sample per pixel for primitives to be antialiased. To create a multisample framebuffer object you should set the sample property to a non-zero value. The default sample count of 0 represents a regular non-multisample framebuffer object. If the desired amount of samples per pixel is not supported by the hardware then the maximum number of samples per pixel will be used. The GL_EXT_framebuffer_multisample extension is required to create a framebuffer with more than one sample per pixel.

Note

• A valid OpenGL context must be present when creating a FramebufferObject, otherwise initialization will fail.
• GL_TEXTURE_2D textures must have a power of 2 width and height(e.g. 256x512), unless you are using OpenGL 2.0 or higher.
• To create a multisample framebuffer object you should set the sample property to a non-zero value.
• If you want to use a multisample framebuffer object as texture, you need to blit it to a regular framebuffer object using blit_framebuffer().
• It is more efficient(but not required) to call bind() on an FBO before making multiple method calls. For example :

  FramebufferObject fbo;
  fbo.bind();
  fbo.add_color_buffer();
  fbo.add_color_buffer();
  fbo.print_attachments();

  To provide a complete encapsulation, the following usage pattern works correctly but is less efficient :

  FramebufferObject fbo;
  // NOTE: No bind() call
  fbo.add_color_buffer();
  fbo.add_color_buffer();
  fbo.print_attachments();

  The first usage pattern binds the FBO only once, whereas the second usage binds/unbinds the FBO for each method call.

Example usage 1: draw to a fbo:

   FramebufferObject fbo(w, h, 0);
   fbo.add_color_texture();
   fbo.add_depth_buffer();
   fbo.bind();
   fbo.activate_draw_buffer(0);
   glClearDepth(1.0f);                             // optional, done by default
   glClearColor(1.0f, 1.0f, 1.0f, 1.0f);               // optional, done by default
   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // optional, done by default
   you draw code here...
   fbo.release();
//... Now you can use fbo.color_texture() for other purposes.

Example usage 2: draw the depth map of an object or a scene:

   FramebufferObject fbo(w, h, 0);
   fbo.add_depth_texture();
   fbo.bind();
   glClearDepth(1.0f);             // optional, done by default
   glClear(GL_DEPTH_BUFFER_BIT);       // optional, done by default
   you draw code here...
   fbo.release();
//... Now you can use the fbo.depth_texture().

For both the above examples, it's easy to enable MSAA by creating a multisample FBO and render to it. But do remember to blit to a normal FBO before using the texture.

Current implement support only GL_TEXTURE_2D (see the texture_target_ variable), and it does not manage externally created textures.

Todo

• add a class TextureFormat for flexible format specification and add related functions using the TextureFormat class.
• modify the attach_color_texture() and attach_depth_texture() to use TextureFormat.
• replace ColorAttachment by TextureFormat.

Examples

Tutorial_404_VirtualScanner/main.cpp, and Tutorial_506_DepthMap/main.cpp.

Constructor & Destructor Documentation

FramebufferObject()

FramebufferObject	(	int	w,
		int	h,
		int	samples = 0 )

Constructor.

Parameters

w	The width of the framebuffer.
h	The height of the framebuffer.
samples	The number of samples per pixel.

Member Function Documentation

activate_draw_buffer()

void activate_draw_buffer

(

unsigned int

index

)

const

Choose the buffers to render into. This command lets you select which attachments are written to.

Parameters

index

The index of the buffer.

Note

The default buffer is the 0. In such a case calling to this function is optional.

activate_draw_buffers() [1/2]

void activate_draw_buffers	(	unsigned int	minId,
		unsigned int	maxId ) const

Choose the buffers in the range [minId, ... maxId] to render into.

Parameters

minId	The minimum index of the buffer.
maxId	The maximum index of the buffer.

activate_draw_buffers() [2/2]

void activate_draw_buffers	(	unsigned int	num_buffers,
		const unsigned int	indices[] ) const

Choose the buffers to render into.

Parameters

num_buffers	The number of buffers.
indices	The indices of the buffers.

activate_read_buffer()

void activate_read_buffer

(

unsigned int

index

)

const

Choose the buffers to read from. This command lets you select which attachment to read from.

Parameters

index

The index of the buffer.

Note

The default buffer is the 0. In such a case calling to this function is optional.

add_color_buffer()

bool add_color_buffer	(	GLenum	internal_format = GL_RGBA8,
		GLenum	format = GL_RGBA,
		GLenum	type = GL_UNSIGNED_BYTE )

Add a color render buffer.

Parameters

internal_format	The internal format of the buffer. It looks like GL_[components][size][type], e.g., GL_RG8, GL_RGBA16, GL_R16F, GL_RG16, GL_RGBA32F.
format	The format of the pixel data, e.g., GL_RED, GL_RG, GL_RGB, GL_BGR, GL_BGRA.
type	The data type of the pixel data, e.g., GL_BYTE, GL_SHORT, GL_UNSIGNED_INT, GL_INT, GL_FLOAT.

Returns

True if successful, false otherwise.

add_color_texture()

bool add_color_texture	(	GLenum	internal_format = GL_RGBA8,
		GLenum	format = GL_RGBA,
		GLenum	type = GL_UNSIGNED_BYTE,
		GLenum	filter = GL_NEAREST )

Add a color texture render buffer.

Parameters

internal_format	The internal format of the texture. It looks like GL_[components][size][type], e.g., GL_RG8, GL_RGBA16, GL_R16F, GL_RG16, GL_RGBA32F.
format	The format of the pixel data, e.g., GL_RED, GL_RG, GL_RGB, GL_BGR, GL_BGRA.
type	The data type of the pixel data, e.g., GL_BYTE, GL_SHORT, GL_UNSIGNED_INT, GL_INT, GL_FLOAT.
filter	The texture minifying/magnification functions, e.g., GL_NEAREST, GL_LINEAR.

Returns

True if successful, false otherwise.

add_depth_buffer()

bool add_depth_buffer

(

GLenum

internal_format = GL_DEPTH24_STENCIL8

)

Add a depth render buffer.

Parameters

internal_format

The internal format of the buffer, e.g., GL_DEPTH_COMPONENT32, GL_DEPTH_COMPONENT32F, GL_DEPTH24_STENCIL8, GL_DEPTH32F_STENCIL8, GL_DEPTH_COMPONENT16

Returns

True if successful, false otherwise.

add_depth_texture()

bool add_depth_texture	(	GLenum	internal_format = GL_DEPTH24_STENCIL8,
		GLenum	filter = GL_NEAREST,
		GLenum	compare_mode = GL_NONE,
		GLenum	compare_func = GL_LEQUAL )

Add a depth texture render buffer.

Parameters

internal_format	The internal format of the texture, e.g., GL_DEPTH_COMPONENT32, GL_DEPTH_COMPONENT32F, GL_DEPTH24_STENCIL8, GL_DEPTH32F_STENCIL8, GL_DEPTH_COMPONENT16
filter	The texture minifying/magnification functions, e.g., GL_NEAREST, GL_LINEAR.
compare_mode	The compare mode for the texture, e.g., GL_NONE, GL_COMPARE_REF_TO_TEXTURE.
compare_func	The compare function for the texture, e.g., GL_GEQUAL, GL_LESS, GL_GREATER, GL_EQUAL, GL_NOTEQUAL, GL_ALWAYS(for 1.0) and GL_NEVER(for 0.0).

Returns

True if successful, false otherwise.

attach_color_texture()

bool attach_color_texture	(	GLenum	target,
		GLuint	texture_id,
		GLenum	attachment )

Attach an existing color texture to the framebuffer.

Parameters

target	The target texture type. GL_TEXTURE_2D, GL_TEXTURE_2D_MULTISAMPLE, GL_TEXTURE_2D_ARRAY
texture_id	The ID of the texture.
attachment	The attachment point. GL_COLOR_ATTACHMENTi

Returns

True if successful, false otherwise.

attach_depth_texture()

bool attach_depth_texture	(	GLenum	target,
		GLuint	texture_id,
		GLenum	attachment )

Attach an existing depth texture to the framebuffer.

Parameters

target	The target texture type. GL_TEXTURE_2D, GL_TEXTURE_2D_MULTISAMPLE, GL_TEXTURE_2D_ARRAY
texture_id	The ID of the texture.
attachment	The attachment point. GL_DEPTH_ATTACHMENT, GL_STENCIL_ATTACHMENT or GL_DEPTH_STENCIL_ATTACHMENT.

Returns

True if successful, false otherwise.

bind()

bool bind

(

GLenum

target = GL_FRAMEBUFFER

)

Bind FBO to FRAMEBUFFER, DRAW_FRAMEBUFFER, or READ_FRAMEBUFFER.

Parameters

target

The target framebuffer.

Returns

True if successful, false otherwise.

Note

bind() and release() should be called in pair.

blit_framebuffer() [1/4]

void blit_framebuffer ( FramebufferObject * target, const FramebufferObject * source, GLbitfield buffers, GLenum filter = GL_NEAREST )

static

Blit the whole sized buffer.

Blits from the source rectangle in the source framebuffer object to the target rectangle in the target framebuffer object. If source or target is 0, the default framebuffer will be used instead of a framebuffer object as source or target respectively. The buffers parameter should be a mask consisting of any combination of GL_COLOR_BUFFER_BIT, GL_DEPTH_BUFFER_BIT, and GL_STENCIL_BUFFER_BIT. Any buffer type that is not present both in the source and target buffers is ignored.

The source and target rectangles may have different sizes; in this case buffers should not contain GL_DEPTH_BUFFER_BIT or GL_STENCIL_BUFFER_BIT. The filter parameter should be set to GL_LINEAR or GL_NEAREST specifying whether linear or nearest interpolation should be used for scaling. For GL_DEPTH_BUFFER_BIT or GL_STENCIL_BUFFER_BIT, the filter parameter must be GL_NEAREST.

If source equals target a copy is performed within the same buffer. Results are undefined if the source and target rectangles overlap and have different sizes. The sizes must also be the same if any of the framebuffer objects are multisample frame buffers.

When multiple render targets are in use, source_color_attachment_index and target_color_attachment_index specify the index of the color attachments in the source and destination frame buffers.

Parameters

target	The target framebuffer object.
source	The source framebuffer object.
buffers	The buffers to blit (e.g., GL_COLOR_BUFFER_BIT, GL_DEPTH_BUFFER_BIT, GL_STENCIL_BUFFER_BIT, or GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT).
filter	The interpolation method (GL_LINEAR or GL_NEAREST).

Note

The scissor test will restrict the blit area if enabled.

blit_framebuffer() [2/4]

void blit_framebuffer ( FramebufferObject * target, const FramebufferObject * source, int target_color_attachment_index, int source_color_attachment_index, GLbitfield buffers, GLenum filter = GL_NEAREST )

static

Blit the whole sized buffer of a specific color attachment.

Parameters

target	The target framebuffer object.
source	The source framebuffer object.
target_color_attachment_index	The index of the color attachment in the target framebuffer.
source_color_attachment_index	The index of the color attachment in the source framebuffer.
buffers	The buffers to blit (e.g., GL_COLOR_BUFFER_BIT, GL_DEPTH_BUFFER_BIT, GL_STENCIL_BUFFER_BIT, or GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT).
filter	The interpolation method (GL_LINEAR or GL_NEAREST).

blit_framebuffer() [3/4]

void blit_framebuffer ( FramebufferObject * target, int tx0, int ty0, int tx1, int ty1, const FramebufferObject * source, int sx0, int sy0, int sx1, int sy1, GLbitfield buffers, GLenum filter = GL_NEAREST )

static

Blit a specified region.

Parameters

target	The target framebuffer object.
tx0	The x-coordinate of the lower-left corner of the target rectangle.
ty0	The y-coordinate of the lower-left corner of the target rectangle.
tx1	The x-coordinate of the upper-right corner of the target rectangle.
ty1	The y-coordinate of the upper-right corner of the target rectangle.
source	The source framebuffer object.
sx0	The x-coordinate of the lower-left corner of the source rectangle.
sy0	The y-coordinate of the lower-left corner of the source rectangle.
sx1	The x-coordinate of the upper-right corner of the source rectangle.
sy1	The y-coordinate of the upper-right corner of the source rectangle.
buffers	The buffers to blit (e.g., GL_COLOR_BUFFER_BIT, GL_DEPTH_BUFFER_BIT, GL_STENCIL_BUFFER_BIT, , or GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT).
filter	The interpolation method (GL_LINEAR or GL_NEAREST).

blit_framebuffer() [4/4]

void blit_framebuffer ( FramebufferObject * target, int tx0, int ty0, int tx1, int ty1, const FramebufferObject * source, int sx0, int sy0, int sx1, int sy1, int target_color_attachment_index, int source_color_attachment_index, GLbitfield buffers, GLenum filter = GL_NEAREST )

static

Blit a specified region of a specific color attachment.

Parameters

target	The target framebuffer object.
tx0	The x-coordinate of the lower-left corner of the target rectangle.
ty0	The y-coordinate of the lower-left corner of the target rectangle.
tx1	The x-coordinate of the upper-right corner of the target rectangle.
ty1	The y-coordinate of the upper-right corner of the target rectangle.
source	The source framebuffer object.
sx0	The x-coordinate of the lower-left corner of the source rectangle.
sy0	The y-coordinate of the lower-left corner of the source rectangle.
sx1	The x-coordinate of the upper-right corner of the source rectangle.
sy1	The y-coordinate of the upper-right corner of the source rectangle.
target_color_attachment_index	The index of the color attachment in the target framebuffer.
source_color_attachment_index	The index of the color attachment in the source framebuffer.
buffers	The buffers to blit (e.g., GL_COLOR_BUFFER_BIT, GL_DEPTH_BUFFER_BIT, GL_STENCIL_BUFFER_BIT, , or GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT).
filter	The interpolation method (GL_LINEAR or GL_NEAREST).

color_texture()

GLuint color_texture	(	unsigned int	index = 0,
		bool	resolve = true ) const

Returns the texture ID attached to the color attachment at the given index.

Parameters

index	The index of the color attachment.
resolve	If a multisample framebuffer object is used, the function blits and returns the resolved non-multisample texture when resolve is true.

Returns

The texture ID.

copy_color_to_texture()

bool copy_color_to_texture	(	GLuint &	texture_handle,
		unsigned int	index = 0,
		int	internal_format = GL_RGBA8,
		GLenum	format = GL_RGBA,
		GLenum	type = GL_UNSIGNED_BYTE,
		GLenum	filter = GL_NEAREST )

Makes a copy of the current buffer into a texture (regardless the attachments already have textures).

Internally it creates a texture and uses glCopyTexSubImage2D() to directly copy the buffer in it.

Parameters

texture_handle	The target texture (will be created if it does not exist).
index	The index of the color attachment.
internal_format	The internal format of the texture.
format	The format of the pixel data.
type	The data type of the pixel data. The internal_format / format / type together define the texture format and hence which and how components of the buffer are copied into the texture. See the glTexImage2D() documentation for details. The typical internal_format/format/type combinations are: For depth: GL_DEPTH_COMPONENT32, GL_DEPTH_COMPONENT24 / GL_DEPTH_COMPONENT / GL_UNSIGNED_BYTE GL_DEPTH_COMPONENT32F / GL_DEPTH_COMPONENT / GL_FLOAT For color: GL_RGBA8 / GL_RGBA / GL_UNSIGNED_BYTE internal_format must be GL_[components][size][type], e.g., GL_RG8, GL_RGBA16, GL_R16F, GL_RG16, GL_RGBA32F ... format must be one of the GL_RED, GL_RG, GL_RGB, GL_BGR, GL_BGRA ... type can be GL_UNSIGNED_BYTE, GL_BYTE, GL_UNSIGNED_SHORT, GL_SHORT, GL_UNSIGNED_INT, GL_INT, GL_FLOAT ... Use GL_LUMINANCE as the internal_format and GL_RED, GL_GREEN or GL_BLUE as format to capture a single color component as a luminance (gray scaled) value.
filter	The texture minifying/magnification functions.

Returns

True if successful, false otherwise.

Note

• GL_STENCIL is not supported as a format.

• The GL_DEPTH_COMPONENT format may not be supported by all hardware. It may sometimes be emulated in software, resulting in poor performances.
• You need to release the texture when you're done.

copy_depth_to_texture()

bool copy_depth_to_texture	(	GLuint &	texture_handle,
		unsigned int	internal_format = GL_DEPTH24_STENCIL8,
		GLenum	filter = GL_NEAREST )

Makes a copy of the current depth buffer into a texture.

Parameters

texture_handle	The target texture (will be created if it does not exist).
internal_format	The internal format of the texture.
filter	The texture minifying/magnification functions.

Returns

True if successful, false otherwise.

Note

• You need to release the texture when you're done.

depth_bits()

int depth_bits

(

)

const

Returns the depth bits.

Returns

The depth bits.

depth_texture()

GLuint depth_texture

(

bool

resolve = true

)

const

Returns the texture ID for the texture attached to the depth attachment.

Parameters

resolve

If a multisample framebuffer object is used, the function blits and returns the resolved non-multisample texture if resolve is true.

Returns

The depth texture ID.

ensure_size()

void ensure_size	(	int	w,
		int	h )

Ensure the size of the buffers is (w, h). If its size matches the required size, i.e, (w, h), it does nothing. Otherwise, it resizes the buffers.

Parameters

w	The width of the buffers.
h	The height of the buffers.

handle()

GLuint handle ( ) const

inline

Returns the OpenGL framebuffer object handle for this framebuffer object. This handle can be used to attach new images or buffers to the framebuffer. If you attach images or buffers, you are responsible for cleaning up and destroying these objects.

Returns

The OpenGL framebuffer object handle.

has_color_attachment()

bool has_color_attachment

(

unsigned int

index

)

const

Checks if the framebuffer object has a color attachment at the given index.

Parameters

index

The index of the color attachment.

Returns

True if the color attachment exists, false otherwise.

has_color_texture()

bool has_color_texture

(

unsigned int

index

)

const

Checks if the framebuffer object has a color texture at the given index.

Parameters

index

The index of the color texture.

Returns

True if the color texture exists, false otherwise.

has_depth_attachment()

bool has_depth_attachment

(

)

const

Checks if the framebuffer object has a depth attachment.

Returns

True if the depth attachment exists, false otherwise.

has_depth_texture()

bool has_depth_texture

(

)

const

Checks if the framebuffer object has a depth texture.

Returns

True if the depth texture exists, false otherwise.

has_stencil()

bool has_stencil

(

)

const

Checks if the framebuffer object has a stencil buffer.

Returns

True if the stencil buffer exists, false otherwise.

height()

int height ( ) const

inline

Returns the height of the render buffers.

Returns

The height of the render buffers.

is_bound()

bool is_bound

(

GLenum

target = GL_FRAMEBUFFER

)

const

Check if the framebuffer object is currently bound to the current context.

Parameters

target

The target framebuffer.

Returns

True if bound, false otherwise.

is_supported()

bool is_supported ( )

static

Queries if FramebufferObject is supported.

Returns

True if supported, false otherwise.

is_valid()

bool is_valid

(

)

const

Returns true if the framebuffer object is valid.

Returns

True if valid, false otherwise.

Returns true if the framebuffer object is valid.

The framebuffer can become invalid if the initialization process fails, the user attaches an invalid buffer to the framebuffer object, or a non-power of two width/height is specified as the texture size if the texture target is {GL_TEXTURE_2D}. The non-power of two limitation does not apply if the OpenGL version is 2.0 or higher, or if the GL_ARB_texture_non_power_of_two extension is present.

The framebuffer can also become invalid if the OpenGL context that the framebuffer was created within is destroyed and there are no other shared contexts that can take over ownership of the framebuffer.

num_color_attachments()

int num_color_attachments

(

)

const

Returns the number of color attachments.

Returns

The number of color attachments.

read_color() [1/3]

bool read_color	(	unsigned char	rgba[4],
		int	x,
		int	y,
		int	index = 0 ) const

Reads the color at the given pixel coordinates from the color render buffer attached to color attachment at the given index.

Parameters

rgba	The buffer to read into.
x	The x-coordinate of the pixel (in the OpenGL coordinate system).
y	The y-coordinate of the pixel (in the OpenGL coordinate system).
index	The index of the color attachment.

Returns

True if successful, false otherwise (if the color attachment index does not exist).

Note

(x, y) are in the OpenGL coordinate system.

read_color() [2/3]

bool read_color	(	unsigned int	index,
		std::vector< unsigned char > &	buffer,
		unsigned int	format,
		bool	flip_vertically = true ) const

Read the color render buffer attached to color attachment at the given index.

Parameters

index	The index of the color attachment.
buffer	The buffer to read into.
format	The format of the pixel data. Supported formats: GL_RGB, GL_BGR, GL_RGBA, and GL_BGRA.
flip_vertically	If true, flips the buffer vertically.

Returns

True if successful, false otherwise.

read_color() [3/3]

bool read_color	(	unsigned int	index,
		unsigned char *	buffer,
		unsigned int	format,
		bool	flip_vertically = true ) const

Read the color render buffer attached to color attachment at the given index.

Parameters

index	The index of the color attachment.
buffer	The buffer to read into.
format	The format of the pixel data. Supported formats: GL_RGB, GL_BGR, GL_RGBA, and GL_BGRA.
flip_vertically	If true, flips the buffer vertically.

Returns

True if successful, false otherwise.

read_depth() [1/3]

bool read_depth	(	float &	depth,
		int	x,
		int	y ) const

Reads the depth at the given pixel coordinates.

Parameters

depth	The buffer to read into.
x	The x-coordinate of the pixel (in the OpenGL coordinate system).
y	The y-coordinate of the pixel (in the OpenGL coordinate system).

Returns

True if successful, false otherwise (if the depth attachment does not exist).

Note

(x, y) are in the OpenGL coordinate system.

read_depth() [2/3]

bool read_depth	(	float *	buffer,
		bool	flip_vertically = true ) const

Read the depth render buffer into a specified buffer.

Parameters

buffer	The buffer to read into.
flip_vertically	If true, flips the buffer vertically.

Returns

True if successful, false otherwise.

read_depth() [3/3]

bool read_depth	(	std::vector< float > &	buffer,
		bool	flip_vertically = true ) const

Read the depth render buffer into a specified buffer.

Parameters

buffer	The buffer to read into.
flip_vertically	If true, flips the buffer vertically.

Returns

True if successful, false otherwise.

release()

bool release

(

GLenum

target = GL_FRAMEBUFFER

)

Switches rendering back to the default framebuffer.

Parameters

target

The target framebuffer.

Returns

True if successful, false otherwise.

samples()

int samples ( ) const

inline

Returns the number of samples per pixel.

Returns

The number of samples per pixel.

Note

The returned value can be greater than the requested value since the typically supported values are 0, 4, 8, ..., and the requests are mapped to the next supported value.

snapshot_color()

bool snapshot_color	(	unsigned int	index,
		const std::string &	file_name ) const

Snapshots the color render buffer attached to color attachment at the given index into an image file.

Parameters

index	The index of the color attachment.
file_name	The name of the image file.

Returns

True if successful, false otherwise.

Note

Only png, jpg, bmp, tga, ppm are supported. File format is determined by the given extension.

snapshot_depth()

bool snapshot_depth

(

const std::string &

file_name

)

const

Snapshots the depth render buffer into an image file.

Parameters

file_name

The name of the image file.

Returns

True if successful, false otherwise.

Note

Only png, jpg, bmp, tga, ppm are supported. File format is determined by the given extension.

texture_target()

GLenum texture_target

(

)

const

Returns the texture target.

Returns

The texture target, i.e., GL_TEXTURE_2D or GL_TEXTURE_2D_MULTISAMPLE.

width()

int width ( ) const

inline

Returns the width of the render buffers.

Returns

The width of the render buffers.

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

• G:/3_code/Easy3D/easy3d/renderer/framebuffer_object.h
• G:/3_code/Easy3D/easy3d/renderer/framebuffer_object.cpp