1. Computers
  2. Display Drivers
  3. Graphics Cards
  4. Memory
  5. Motherboards
  6. Processors
  7. Software
  8. Storage
  9. Operating Systems


Facebook RSS Twitter Twitter Google Plus


Phoronix Test Suite

OpenBenchmarking.org

Marek Works On OpenGL 4.0 Transform Feedback

Mesa

Published on 05 July 2012 07:36 AM EDT
Written by Michael Larabel in Mesa
6 Comments

Marek Olšák, the prolific independent contributor to Mesa/Gallium3D with a special interest in Radeon Gallium3D, has just published his latest patch work. This time around he's been working on the remaining transform feedback extensions from OpenGL 4.0.

OpenGL Transform Feedback has been worked on for months within the Mesa/Gallium3D world with progress having been made. Just a few weeks ago Stream-Out was enabled by default in R600 Gallium3D to allow for this support in the Radeon HD 2000/3000/4000/5000/6000 series open-source driver.

OpenGL Transform Feedback allows for keeping the post-transform rendering state of an object so that it can be submitted again by writing primitives processed by vertex/geometry shaders to buffer objects. Marek's latest work implements the GL_ARB_transform_feedback3 and GL_ARB_transform_feedback_instanced OpenGL extensions as needed by OpenGL 4.0.

GL_ARB_transform_feedback_instanced: "Multiple instances of geometry may be specified to the GL by calling functions such as DrawArraysInstanced and DrawElementsInstanced. Further, the results of a transform feedback operation may be returned to the GL by calling DrawTransformFeedback, or DrawTransformFeedbackStream. However, it is not presently possible to draw multiple instances of data transform feedback without using a query and the resulting round trip from server to client. This extension adds functionality to draw multiple instances of the result of a transform feedback operation."

GL_ARB_transform_feedback3: "This extension further extends the transform feedback capabilities provided by the EXT_transform_feedback, NV_transform_feedback, and NV_transform_feedback2 extensions. Those extensions provided a new transform feedback mode, where selected vertex attributes can be recorded to a buffer object for each primitive processed by the GL. This extension provides increased flexibility in how vertex attributes can be written to buffer objects. Previous extensions allowed applications to record a set of attributes interleaved into a single buffer object (interleaved mode) or to record into multiple objects, but with only a single attribute per buffer (separate mode). This extension extends interleaved mode to write into multiple buffers, with multiple attributes per buffer."

The good news is that for implementing these two transform feedback extensions doesn't require changes to the individual Mesa/Gallium3D drivers assuming they implement the internal interfaces. However, these latest patches from Marek doesn't introduce support for multiple vertex streams. Marek's also contributed matching Piglit regression tests for these new extensions.

Marek's ten patches for this support can be found on the Mesa-dev list and add in over 500 lines of new code.

About The Author
Michael Larabel is the principal author of Phoronix.com and founded the web-site in 2004 with a focus on enriching the Linux hardware experience and being the largest web-site devoted to Linux hardware reviews, particularly for products relevant to Linux gamers and enthusiasts but also commonly reviewing servers/workstations and embedded Linux devices. Michael has written more than 10,000 articles covering the state of Linux hardware support, Linux performance, graphics hardware drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and OpenBenchmarking.org automated testing software. He can be followed via and or contacted via .
Latest Linux Hardware Reviews
  1. NVIDIA GeForce GTX 970 Offers Great Linux Performance
  2. CompuLab Intense-PC2: An Excellent, Fanless, Mini PC Powered By Intel's i7 Haswell
  3. From The Atom 330 To Haswell ULT: Intel Linux Performance Benchmarks
  4. AMD Radeon R9 285 Tonga Performance On Linux
Latest Linux Articles
  1. AMD Moves Forward With Unified Linux Driver Strategy, New Kernel Driver
  2. MSI: Update Your BIOS From The Linux Desktop
  3. NVIDIA vs. AMD 2D Linux Drivers: Catalyst Is Getting Quite Good At 2D
  4. 15-Way GPU Comparison With Mesa 10.3 + Linux 3.17
Latest Linux News
  1. Features Of The Linux 3.18 Kernel
  2. Automatic Feedback Directed Optimizer Merged Into GCC
  3. Debian Now Defaults To Xfce On Non-x86 Desktops
  4. Phoenix Is Trying To Be An Open Version Of Apple's Swift
  5. Linux 3.19 To Have Skylake Graphics, PPGTT Enablement
  6. Ubuntu 16.04 Might Be The Distribution's Last 32-Bit Release
  7. Imagination Releases Full ISA Documentation For PowerVR Rogue GPUs
  8. Features GNOME Developers Want In The Linux Kernel
  9. GTK+ Gains Experimental Overlay Scrollbars
  10. Phoronix Test Suite 5.4 M3 Is Another Hearty Update
Latest Forum Discussions
  1. Users/Developers Threatening Fork Of Debian GNU/Linux
  2. Proof that strlcpy is un-needed
  3. xbox one tv tuner
  4. HOPE: The Ease Of Python With The Speed Of C++
  5. Bye bye BSD, Hello Linux: A Sys Admin's Story
  6. Updated and Optimized Ubuntu Free Graphics Drivers
  7. NVIDIA Presents Its Driver Plans To Support Mir/Wayland & KMS On Linux
  8. AMD Is Restructuring Again, Losing 7% Of Employees