Texture2DMultismaple as name suggests provides means to directly access subsamples of rendered FBO target. (GLSL 1.5 texelFetch call).
Recently I was working on deferred renderer with OSG, during that I noticed there is no support for multisampled textures (GL_ARB_texture_multisample extension). After consultations with Paul Martz and Wojtek Lewandowski I added Texture2DMultisample class and made few necessary changes around osg::FrameBufferObject, osg::Texture and osgUtil::RenderStage classes."
and from follow email:
"Fixed. According to ARB_texture_multisample extension specification multisample textures don't need TexParameters since they can only be fetched with texelFetch."
I create a compositeviewer with two views that share a context. One view is deleted. Texture::TextureObjectSet::discardAllTextureObjects is called, but this does not reset _tail. Now the texture object is again created and addToBack is called from Texture::TextureObjectSet::takeOrGenerate. In addToBack (line 612) _tail is now not 0 (although the list should be empty) and a loop is created from the texture object to itself. Then when the second view is deleted, Texture::TextureObjectSet::deleteAllTextureObjects loops forever. Setting _tail to 0 fixes it for me (see attached)."
was able to follow the problem until following addition to Texture.cpp:
// GLES doesn't cope with internal formats of 1,2,3 and 4 so map them to
the appropriate equivilants.
if (_internalFormat==1) _internalFormat = GL_ALPHA;
if (_internalFormat==2) _internalFormat = GL_LUMINANCE_ALPHA;
if (_internalFormat==3) _internalFormat = GL_RGB;
if (_internalFormat==4) _internalFormat = GL_RGBA;
The problem is that internal format "1" corresponds to GL_LUMINANCE, not
GL_ALPHA. I double checked this from the Red Book. Fixed version is
attached to the email."
Fixed to osg::Texture for GLES support.
Added automatic GLenum mode mappings in osg::PrimitiveSet to provide a fallback for non support glDrawArray/glDrawElement modes.
Added finer gained error checking during StateSet::compile().
Removed EXT postfix of FrameBufferObject functions, and added support for checking non EXT versions frame buffer object GL functions.
Introduced usage of OSG_GL*_FEATURES to avoid some #if #else #endif code blocks.
Using a submissions from Paul Martz as a guide added perliminary GL3 support to a range of OSG classes
The Texture Pool can be enabled by setting the env var OSG_TEXTURE_POOL_SIZE=size_in_bytes.
Note, setting a size of 1 will result in the TexturePool allocating the minimum number of
textures it can without having to reuse TextureObjects from within the same frame.
- osg::Texture sets GL_MAX_TEXTURE_LEVEL if image uses fewer mipmaps than
number from computeNumberOfMipmaps (and it works!)
- DDS fix to read only available mipmaps
- DDS fixes to read / save 3D textures with mipmaps ( packing == 1 is
required)
- Few cosmetic DDS modifications and comments to make code cleaner (I hope)
Added _isTextureMaxLevelSupported variable to texture extensions. It
could be removed if OSG requires OpenGL version 1.2 by default.
Added simple ComputeImageSizeInBytes function in DDSReaderWrites. In
my opinion it would be better if similar static method was defined for
Image. Then it could be used not only in DDS but other modules as well (I
noticed that Texture/Texture2D do similar computations).
Also attached is an example test.osg model with DDS without last mipmaps to
demonstrate the problem. When loaded into Viewer with current code and moved
far away, so that cube occupies 4 pixels, cube becomes red due to the issue
I described in earlier post. When you patch DDS reader writer with attched
code but no osg::Texture yet, cube becomes blank (at least on my
Windows/NVidia) When you also merge osg::Texture patch cube will look right
and mipmaps will be correct."
returns true if (the extension string is supported or GL version is greater than or equal to a specified version) and
non extension disable is used. This makes it possible to disable extensions that are now
available as parts of the core OpenGL spec.
Updated Texture.cpp is use this method.
nvidia 6 months ago and the issue is still "in progress". I've given up
waiting for them!
Platform - various Intel Windows XP SP2 PCs with various nvidia cards
including GeForce 8800 GTS and Quadro FX 4500, and various driver
versions including the latest WHQL 175.16.
I investigated your concerns about glGenerateMipmapEXT being slower than
GL_GENERATE_MIPMAP_SGIS, and for power-of-two textures, to my surprise
it is. For a 512*512 texture, glGenerateMipmapEXT takes on average 10ms,
while GL_GENERATE_MIPMAP_SGIS takes on average 6ms. Therefore I have
modified the code to only use glGenerateMipmapEXT if the texture has a
non-power-of-two width or height. I am resubmitting all the files
previously submitted (only "Texture.cpp" has significant changes since
my previous submission, I've also replaced tabs with spaces in
"Texture").
"
GL_GENERATE_MIPMAP_SGIS is very slow (over half a second for a 720*576
texture). However, glGenerateMipmapEXT() performs well (16ms for the
same texture), so I have modified the attached files to use
Texture::generateMipmap() if glGenerateMipmapEXT is supported, instead
of enabling & disabling GL_GENERATE_MIPMAP_SGIS."
Notes, from Robert Osfield, I've tested the out of the previous path using
GL_GENERATE_MIPMAP_SGIS and non power of two textures on NVidia 7800GT and
Nvidia linux drivers with the image size 720x576 and only get compile times
of 56ms, so the above half second speed looks to be a driver bug. With
Muchael's changes the cost goes done to less than 5ms, so it's certainly
an effective change, even given that Michael's poor expereiences with
GL_GENERATE_MIP_SGIS do look to be a driver bug.
- Implementation of integer textures as in EXT_texture_integer
- setBorderColor(Vec4) changed to setBorderColor(Vec4d) to pass double values
as border color. (Probably we have to provide an overloading function to
still support Vec4f ?)
- new method Texture::getInternalFormatType() added. Gives information if the
internal format normalized, float, signed integer or unsigned integer. Can
help people to write better code ;-)
"
Futher changes to this submission by Robert Osfield, changed the dirty mipmap
flag into a buffer_value<> vector to ensure safe handling of multiple contexts.
local function pointer to avoid compiler warnings related to case void*.
Moved various OSG classes across to using setGLExtensions instead of getGLExtensions,
and changed them to use typedef declarations in the headers rather than casts in
the .cpp.
Updated wrappers
