Graphics Reference
In-Depth Information
On some OpenGL ES 3.0 implementations, the first time a framebuffer
object name is bound by calling
glBindFramebuffer
, the framebuffer
object is allocated with the appropriate default state. If the allocation is
successful, this allocated object is bound as the current framebuffer object
for the rendering context.
The following state is associated with a framebuffer object:
• Color attachment point—The attachment point for the color buffer.
• Depth attachment point—The attachment point for the depth buffer.
• Stencil attachment point—The attachment point for the stencil buffer.
• Framebuffer completeness status—Whether the framebuffer is in a
complete state and can be rendered to.
For each attachment point, the following information is specified:
• Object type—Specifies the type of object that is associated with the
attachment point. This can be
GL_RENDERBUFFER
if a renderbuffer
object is attached or
GL_TEXTURE
if a texture object is attached. The
default value is
GL_NONE
.
• Object name—Specifies the name of the object attached. This can be
either the renderbuffer object name or the texture object name. The
default value is 0.
• Texture level—If a texture object is attached, then this specifies the
mip level of the texture associated with the attachment point. The
default value is 0.
• Texture cubemap face—If a texture object is attached and the texture
is a cubemap, then this specifies which one of the six cubemap faces
is to be used as the attachment point. The default value is
GL_TEXTURE_CUBE_MAP_POSITIVE_X
.
• Texture layer—Specifies the 2D slice of the 3D texture to be used as the
attachment point. The default value is 0.
glBindFramebuffer
can also be used to bind to an existing framebuffer
object (i.e., an object that has been assigned and used before and,
therefore, has valid state associated with it). No changes are made to the
state of the newly bound framebuffer object.
Once a framebuffer object has been bound, the color, depth, and stencil
attachments of the currently bound framebuffer object can be set to
