OpenTissue::gl::FramebufferObject Class Reference

#include <gl_frame_buffer_object.h>

List of all members.

Public Member Functions
	FramebufferObject ()
	~FramebufferObject ()
void	bind ()
void	attach_texture (GLenum attachment, GLenum texture_target, GLuint texture_id, int mip_level=0, int z_slice=0)
void	attach_texture (GLenum attachment, OpenTissue::texture::texture2D_pointer texture)
void	attach_texture (GLenum attachment, OpenTissue::texture::texture3D_pointer texture, int z_slice)
void	attach_render_buffer (GLenum attachment, GLuint buffer_id)
void	attach_render_buffer (GLenum attachment, renderbuffer_pointer buffer)
void	unattach (GLenum attachment)
bool	is_valid (std::ostream &output=std::cerr)
GLenum	get_attached_type (GLenum attachment)
GLuint	get_attached_id (GLenum attachment)
GLint	get_attached_mip_level (GLenum attachment)
GLint	get_attached_cube_face (GLenum attachment)
GLint	get_attached_Z_slice (GLenum attachment)
Static Public Member Functions
static GLint	get_max_color_attachments ()
static void	disable ()
Protected Member Functions
void	guarded_bind ()
void	guarded_unbind ()
Static Protected Member Functions
static GLuint	create_fbo_id ()
Protected Attributes
GLuint	m_fbo_id
	The Frame buffer Identifier of this FBO.
GLuint	m_saved_fbo_id
	The frame buffer identifier of any previously bound FBO. This is used to test whether the FBO is bound before doing anything to it. See guarded_bind and guarded_unbind.

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Detailed Description

Frame Buffer Object. This class encapsulates the frame buffer object (FBO) OpenGL spec. See the official spec at: http://oss.sgi.com/projects/ogl-sample/registry/EXT/framebuffer_object.txt for details.

A frame buffer object (FBO) 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 and are a complete replacement for pbuffers.

Performance Notes:

1) It is more efficient (but not required) to call bind() on an FBO before making multiple method calls.

2) Use FramebufferObject::disable() sparingly.

3) Binding an FBO is usually much faster than enabling/disabling a pbuffer, but is still a costly operation. When switching between multiple FBOs and a visible OpenGL framebuffer.

This implementation was inspired by the ideas in the FBO class from GPUGP by Aaron Lefohn.

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Constructor & Destructor Documentation

OpenTissue::gl::FramebufferObject::FramebufferObject

(

)

[inline]

OpenTissue::gl::FramebufferObject::~FramebufferObject

(

)

[inline]

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Member Function Documentation

void OpenTissue::gl::FramebufferObject::attach_render_buffer	(	GLenum	attachment,
		GLuint	buffer_id
	)			[inline]

Attach Render Buffer. This method binds a render buffer to the spcified "attachment" point of this FBO.

Parameters:

	attachment	The attachment point. For instance the color buffer attachment point: GL_COLOR_ATTACHMENT0_EXT,...,GL_COLOR_ATTACHMENTn_EXT However, this is usually GL_DEPTH_ATTACHMENT_EXT or GL_STENCIL_ATTACHMENT_EXT for depth and stencil buffers.
	buffer_id	The identifier of the render buffer. That is the buffer name generated by calling glGenRenderbuffersEXT(...).

void OpenTissue::gl::FramebufferObject::attach_render_buffer	(	GLenum	attachment,
		renderbuffer_pointer	buffer
	)			[inline]

Attach Render Buffer. This method binds a render buffer to the spcified "attachment" point of this FBO.

Parameters:

	attachment	The attachment point. For instance the color buffer attachment point: GL_COLOR_ATTACHMENT0_EXT,...,GL_COLOR_ATTACHMENTn_EXT. However, this is usually GL_DEPTH_ATTACHMENT_EXT or GL_STENCIL_ATTACHMENT_EXT for depth and stencil buffers.
	buffer	A pointer to a glRenderBuffer.

void OpenTissue::gl::FramebufferObject::attach_texture	(	GLenum	attachment,
		GLenum	texture_target,
		GLuint	texture_id,
		int	mip_level = 0,
		int	z_slice = 0
	)			[inline]

Attach Texture. This method binds a texture to the specified "attachment" point of this FBO.

Parameters:

	attachment	The attachment point. For instance the color buffer attachment point: GL_COLOR_ATTACHMENT0_EXT,...,GL_COLOR_ATTACHMENTn_EXT
	texture_target	The texture target: GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_1D, GL_TEXTURE_2D, GL_TEXTURE_3D etc..
	texture_id	The texture identifier, i.e the texture name as generated by calling the function glGenTextures(...).
	mip_level	The level-of-detail number. Level 0 is the base image level. Level n is the nth mipmap reduction image. Default is zero.
	z_slice	The z slice. This works as a z-offset into a 3D texture. The parameter is only used if texture target is a GL_TEXTURE_3D, the default value is zero.

void OpenTissue::gl::FramebufferObject::attach_texture	(	GLenum	attachment,
		OpenTissue::texture::texture2D_pointer	texture
	)			[inline]

Attach 2D Texture.

Parameters:

	attachment	The attachment point. For instance the color buffer attachment point: GL_COLOR_ATTACHMENT0_EXT,...,GL_COLOR_ATTACHMENTn_EXT
	texture	A pointer to Texture2D containing the texture that should be attached.

void OpenTissue::gl::FramebufferObject::attach_texture	(	GLenum	attachment,
		OpenTissue::texture::texture3D_pointer	texture,
		int	z_slice
	)			[inline]

Attach 3D Texture.

Parameters:

	attachment	The attachment point. For instance the color buffer attachment point: GL_COLOR_ATTACHMENT0_EXT,...,GL_COLOR_ATTACHMENTn_EXT
	texture	A pointer to Texture3D containing the texture that should be attached.

void OpenTissue::gl::FramebufferObject::bind

(

)

[inline]

Bind FBO. This method binds this FBO as current render target.

static GLuint OpenTissue::gl::FramebufferObject::create_fbo_id

(

)

[inline, static, protected]

Create Frame Buffer Object Identifier.

Returns:

A new unused identifier for a frame buffer object.

static void OpenTissue::gl::FramebufferObject::disable

(

)

[inline, static]

Disable FBO. Disable all FBO rendering and return to traditional, windowing-system controlled framebuffer. This is NOT an "unbind" for this specific FBO, but rather disables all FBO rendering.

GLint OpenTissue::gl::FramebufferObject::get_attached_cube_face

(

GLenum

attachment

)

[inline]

Get Cube Face.

Parameters:

attachment

The attachment point. For instance the color buffer attachment point: GL_COLOR_ATTACHMENT0_EXT,...,GL_COLOR_ATTACHMENTn_EXT

Returns:

The cube face that is currently attached to specified attachment point.

GLuint OpenTissue::gl::FramebufferObject::get_attached_id

(

GLenum

attachment

)

[inline]

Get Attachment Identifier.

Parameters:

attachment

The attachment point. For instance the color buffer attachment point: GL_COLOR_ATTACHMENT0_EXT,...,GL_COLOR_ATTACHMENTn_EXT

Returns:

The identifier of the of the render buffer/texture currently attached to specified attachement point.

GLint OpenTissue::gl::FramebufferObject::get_attached_mip_level

(

GLenum

attachment

)

[inline]

Get MipMap Level.

Parameters:

attachment

The attachment point. For instance the color buffer attachment point: GL_COLOR_ATTACHMENT0_EXT,...,GL_COLOR_ATTACHMENTn_EXT

Returns:

The mipmap level that is currently attached to specified attachement point.

GLenum OpenTissue::gl::FramebufferObject::get_attached_type

(

GLenum

attachment

)

[inline]

Get Attachment Type.

Parameters:

attachment

The attachment point. For instance the color buffer attachment point: GL_COLOR_ATTACHMENT0_EXT,...,GL_COLOR_ATTACHMENTn_EXT

Returns:

Returns the attached type, that is GL_RENDERBUFFER_EXT or GL_TEXTURE?

GLint OpenTissue::gl::FramebufferObject::get_attached_Z_slice

(

GLenum

attachment

)

[inline]

Get Z Slice.

Parameters:

attachment

The attachment point. For instance the color buffer attachment point: GL_COLOR_ATTACHMENT0_EXT,...,GL_COLOR_ATTACHMENTn_EXT

Returns:

The z-slice that is currently attached to specified attachment point.

static GLint OpenTissue::gl::FramebufferObject::get_max_color_attachments

(

)

[inline, static]

Get Maximum Color Attachments That is if GL_COLOR_ATTACHMENT0_EXT,...,GL_COLOR_ATTACHMENT(n-1)_EXT are valid attachment points then the number n is returned.

Returns:

The number of color buffer attachments permitted.

void OpenTissue::gl::FramebufferObject::guarded_bind

(

)

[inline, protected]

Guarded Bind. This method tests whether this FBO is already bound. If not it will save the currently bound FBO before binding this FBO.

void OpenTissue::gl::FramebufferObject::guarded_unbind

(

)

[inline, protected]

Guarded Unbind. In case another FBO was bound prior to invoking guarded_bind(), this method will restore that FBO.

bool OpenTissue::gl::FramebufferObject::is_valid

(

std::ostream &

output = std::cerr

)

[inline]

Test if Frame Buffer Object is valid.

Parameters:

output

An output stream where error messages (if any) should be written. Default value is the std::cerr stream.

Returns:

If the FBO is valid render target then the return value is true otherwise it is false. Notice that in non-debug build mode this function always return true.

void OpenTissue::gl::FramebufferObject::unattach

(

GLenum

attachment

)

[inline]

Unattach Resources. This method frees any resource bound to the specified "attachment" point of this FBO.

Parameters:

attachment

The attachment point. For instance the color buffer attachment point: GL_COLOR_ATTACHMENT0_EXT,...,GL_COLOR_ATTACHMENTn_EXT

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Member Data Documentation

GLuint OpenTissue::gl::FramebufferObject::m_fbo_id [protected]

The Frame buffer Identifier of this FBO.

GLuint OpenTissue::gl::FramebufferObject::m_saved_fbo_id [protected]

The frame buffer identifier of any previously bound FBO. This is used to test whether the FBO is bound before doing anything to it. See guarded_bind and guarded_unbind.

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

• /home/hauberg/Dokumenter/Capture/humim-tracker-0.1/src/OpenTissue/OpenTissue/utility/gl/gl_frame_buffer_object.h