FramebufferObject Class Reference

#include <framebufferObject.h>

List of all members.

Public Member Functions

 FramebufferObject ()
 Ctor/Dtor.
void Bind ()
 Bind this FBO as current render target.
virtual void AttachTexture (GLenum attachment, GLenum texType, GLuint texId, int mipLevel=0, int zSlice=0)
 Bind a texture to the "attachment" point of this FBO.
virtual void AttachRenderBuffer (GLenum attachment, GLuint buffId)
 Bind a render buffer to the "attachment" point of this FBO.
void Unattach (GLenum attachment)
 Free any resource bound to the "attachment" point of this FBO.
bool IsValid (std::ostream &ostr=std::cerr)
GLenum GetAttachedType (GLenum attachment)
 Accessors.
GLuint GetAttachedId (GLenum attachment)
GLint GetAttachedMipLevel (GLenum attachment)
 Which mipmap level is currently attached to "attachement?".
GLint GetAttachedCubeFace (GLenum attachment)
 Which cube face is currently attached to "attachment?".
GLint GetAttachedZSlice (GLenum attachment)
 Which z-slice is currently attached to "attachment?".

Static Public Member Functions

static int GetMaxColorAttachments ()
 END : Accessors.
static void Disable ()

Private Attributes

GLuint m_fboId
 END : Static methods global to all FBOs.


Detailed Description

FramebufferObject Class. This class encapsulates the FramebufferObject (FBO) OpenGL spec. See the official spec at: http://oss.sgi.com/projects/ogl-sample/registry/EXT/framebuffer_object.txt

for details.

A framebuffer 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. For example:

FramebufferObject fbo; fbo.Bind(); fbo.AttachTexture(GL_COLOR_ATTACHMENT0_EXT, texId0); fbo.AttachTexture(GL_COLOR_ATTACHMENT1_EXT, texId1); fbo.IsValid();

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

FramebufferObject fbo; NOTE : No Bind() call fbo.AttachTexture(GL_COLOR_ATTACHMENT0_EXT, texId0); fbo.AttachTexture(GL_COLOR_ATTACHMENT1_EXT, texId1); fbo.IsValid();

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

2) Use FramebufferObject::Disable() sparingly. We have intentionally left out an "Unbind()" method because it is largely unnecessary and encourages rendundant Bind/Unbind coding. 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, the following usage pattern is recommended:

FramebufferObject fbo1, fbo2; fbo1.Bind(); ... Render ... NOTE : No Unbind/Disable here...

fbo2.Bind(); ... Render ...

Disable FBO rendering and return to visible window OpenGL framebuffer. FramebufferObject::Disable();


Member Function Documentation

void FramebufferObject::Disable  )  [static]
 

Disable all FBO rendering and return to traditional, windowing-system controlled framebuffer NOTE: This is NOT an "unbind" for this specific FBO, but rather disables all FBO rendering. This call is intentionally "static" and named "Disable" instead of "Unbind" for this reason. The motivation for this strange semantic is performance. Providing "Unbind" would likely lead to a large number of unnecessary FBO enablings/disabling.

GLuint FramebufferObject::GetAttachedId GLenum  attachment  ) 
 

What is the Id of Renderbuffer/texture currently attached to "attachement?"

GLenum FramebufferObject::GetAttachedType GLenum  attachment  ) 
 

Accessors.

BEGIN : Accessors Is attached type GL_RENDERBUFFER_EXT or GL_TEXTURE?

GLint FramebufferObject::GetMaxColorAttachments  )  [static]
 

END : Accessors.

BEGIN : Static methods global to all FBOs Return number of color attachments permitted

bool FramebufferObject::IsValid std::ostream &  ostr = std::cerr  ) 
 

Is this FBO currently a valid render target?

  • Sends output to std::cerr by default but can be a user-defined C++ stream

NOTE : This function works correctly in debug build mode but always returns "true" if NDEBUG is is defined (optimized builds)


The documentation for this class was generated from the following files:
Generated on Fri Jun 16 08:42:48 2006 for GPU Thesis by  doxygen 1.4.6-NO