"A new texture class Texture2DArray derived from
Texture extends the osg to support the new
EXT_texture_array extensions. Texture arrays provides
a feature for people interesting in GPGPU programming.
Faetures and changes:
- Full support for layered 2D textures.
- New uniform types were added (sampler2DArray)
- FrameBufferObject implementation were changed to
support attaching of 2D array textures to the
framebuffer
- StateSet was slightly changed to support texture
arrays. NOTE: array textures can not be used in fixed
function pipeline. Thus using the layered texture as a
statemode for a Drawable produce invalid enumerant
OpenGL errors.
- Image class was extended to support handling of
array textures
Tests:
I have used this class as a new feature of my
application. It works for me without problems (Note:
Texture arrays were introduced only for shading
languages and not for fixed function pipelines!!!).
RTT with Texture2DArray works, as I have tested them
as texture targets for a camera with 6 layers/faces
(i.e. replacement for cube maps). I am using the array
textures in shader programming. Array textures can be
attached to the FBO and used as input and as output."
FrameBufferObject.cpp there is also another fix: when initializing a FBO
attachment from a CameraNode attachment, the renderbuffer's format must be
set to the attachment's internal format, not to the image's pixel format.
Another problem is that attaching a renderbuffer to the FBO through
CameraNode is not simple (if not impossible) if you don't intend to specify
an Image object. Probably CameraNode could be enriched with an
"attach(buffer, width, height, format)" method. For example if you attach a
color buffer as a texture whose size is different than that of the
CameraNode's viewport you also need to attach a depth buffer of the same
size, because the depth buffer that is automatically attached by RenderStage
has the viewport's size. FBOs require that all attachment have the same
dimensions, so said setup will fail if you can't specify a custom depth
renderbuffer"
