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. Intel Launches The Core i7 5960X, Mighty Powerful Haswell-E CPUs
  2. AMD Radeon R9 290: Gallium3D vs. Catalyst Drivers
  3. AMD Radeon R9 290 Open-Source Driver Works, But Has A Ways To Go
  4. Trying The Configurable 45 Watt TDP With AMD's A10-7800 / A6-7400K
Latest Linux Articles
  1. The Fastest NVIDIA GPUs For Open-Source Nouveau With Steam Linux Gaming
  2. Testing For The Latest Linux Kernel Power Regression
  3. The Most Energy Efficient Radeon GPU For AMD Linux Gaming
  4. 20-Way Radeon Comparison With Open-Source Graphics For Steam On Linux Gaming
Latest Linux News
  1. A New AMD Catalyst Linux Driver Unofficially Surfaces
  2. LibreOffice Ported To 64-bit ARM (AArch64)
  3. Enlightenment E19 RC3 Shows Off The New Wayland Compositor
  4. Metro Redux Is Going To Require OpenGL 4.x On Linux
  5. Jailhouse v0.1 Released As A Basic Hypervisor For Linux
  6. Google's Chromebook "Samus" Now Supported By Coreboot
  7. Chrome 38 Now In Beta With Exciting Advancements
  8. Ubuntu's Utopic Unicorn 14.10 Beta 1 Released
  9. Genode OS 14.08 Has New GUI Architecture, Pluggable VFS
  10. Another Intel Linux Power Regression Is Being Investigated
Latest Forum Discussions
  1. Btrfs Gets Talked Up, Googler Encourages You To Try Btrfs
  2. Catalyst 14.201.1008
  3. Users defect to Linux as OpenBSD removes Lynx from base system
  4. Updated and Optimized Ubuntu Free Graphics Drivers
  5. Canonical Joined The Khronos Group To Help Mir/Wayland Drivers
  6. Radeon HD5670 and Ubuntu 14.04
  7. AMD Releases UVD Video Decode Support For R600 GPUs
  8. Best Radeon for a Power Mac G5?