Slides From Valve's OpenGL BOF Talk at SIGGRAPH

G'day all

Copies of the slides from Rich Geldreich's talk at last week's SIGGRAPH OpenGL BOF are now available on the Khronos.org website.

They touch on the progress of the Linux OpenGL port of Left 4 Dead 2, the hurdles they faced, and the tools they used. The slides also make mention of OpenGL 3.0 being a future target, and say that they'l be putting up blog posts with lots of further technical details over the next few months.

Quote

• Linux Team started with little practical OpenGL experience, so we needed help
• We shared builds and invited all vendors to our offices
• Focused on why the D3D9 vs. OpenGL builds had such vastly different performance on the same hardware
• Process: Devise/conduct experiment, test results with known workload,
  refine/update mental model of system’s behavior, repeat
• Goal was to account for every microsecond spent in our D3D->GL translation layer and render thread
• Interpreting experimental results can be challenging:
  
  • Game is multithreaded – bottlenecks can shift around in unintuitive ways
  • Driver’s server thread is mostly invisible to our profiling tools
  • Source Engine is extremely configurable/scalable – easily misconfigured
  
  
• Primary profiling/debugging tools used:
  
  • Telemetry: Profiling/visualization system from RAD Game Tools
  • Custom batch trace recording mode in our D3D and D3D->GL translation layers
  • AMD’s GPU PerfStudio for GL state debugging/API call tracing
  
  

http://www.khronos.org/assets/uploads/developers/library/2012-siggraph-opengl-bof/Valve-Left-4-Dead-2-Linux-SIGGRAPH_Aug12.pdf Article taken from GamingOnLinux.com.