Valve Sponsors Work To Greatly Speed-Up Linux OpenGL Game Load Times 202
An anonymous reader writes "Valve Software has sponsored some interesting improvements developed by LunarG for the Mesa OpenGL library on Linux for deferred and threaded GLSL shader compilation. What these changes mean for users of the open-source Linux graphics drivers when running their favorite games is that OpenGL games now load a lot faster. As an example, the time from starting Dota 2 until the time actually being within the game is reduced by about 20 seconds on an Intel system. While Direct3D has offered similar functionality for a while, OpenGL has not, which has given it a bad reputation with regard to game load times until all shaders are compiled and cached — fortunately it's now addressed for OpenGL if using the Mesa Linux graphics drivers on a supported game."
Stop gap (Score:2, Interesting)
OpenGL probably need to move to an IR for shaders. For thost that don't know, shaders are compiled by the driver today. Many games generate shaders with a combinatoric explosion which creates a lot of work for the driver. You can cache the result, which is often done, but you'll end up recompiling when the user change settings, etc.
The solution is off-line compilation to an IR, but of course everyone need to be aboard. The downside is that an IR spec will probably add 'DRM' considerations whereas today OpenGL shaders are shipped in source form.
Re:Stop gap (Score:5, Interesting)
An IR doesn't buy you much. The time taken for clang to compile OpenCL C to SPIR is about 10% of the time required for LLVM to optimise and codegen the resulting SPIR into native code. The driving force behind SPIR comes from developers who don't want their shader source code embedded in their binary source.
Re:Valve competing with Microsoft (Score:5, Interesting)
Even on windows, OpenGL is not that much slower, on the order of 10% for 'normal' 3D game code. With a modern video card that difference almost doesnt matter.
Re:And still linux sucks (Score:4, Interesting)
Comment removed (Score:4, Interesting)
Re:Valve competing with Microsoft (Score:2, Interesting)
In most cases OpenGL is 10 to 20% faster on Windows, just shader compile times were 5 to 10% slower on average.
but once things are running DX11 isn't very competitive, and that's also because it's hard to make proper drivers for it (see Nvidia's late optimizations that made them reach near AMD Mantle performance, that took almost 2 years to reach)
Re:And still linux sucks (Score:3, Interesting)
While a valid excuse, that's another reason why Linux is still "not there" yet. The fact that there were only a couple legit games for it proves it's still in it's fetal stages of becoming a consumer OS. It's got a long way to go. Valve was a huge shot in the arm though. They are the best thing to happen to Linux in awhile.