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> Date: Wed, 21 Mar 2012 12:02:38 +0000
> From: smcv > > On 21/03/12 10:50, Mark Page wrote: > > For the i386 platform the options are: > > A) Disable SSE2 totally > > Option A: > > clanSWRender is not available. > > There will not be any difference to games without sound running OpenGL. > > With sound, the speed difference depends on the CPU speed. > > Is clanSWRender a separate shared library or what? How do ClanLib games > select the software renderer? > All ClanLib components are separate libraries. (This is the same with the old packaged ClanLib 0.8 and ClanLib 1.0) For example: mark@mark-Inferno-Katana:/usr/lib$ ls libcl*.a libclan23App.a libclan23Display.a libclan23MikMod.a libclan23Sqlite.a libclan23Core.a libclan23GL1.a libclan23Network.a libclan23Vorbis.a libclan23CSSLayout.a libclan23GL.a libclan23RegExp.a libclan23Database.a libclan23GUI.a libclan23Sound.a libclan23SWRender.a An application selects which component it requires by calling the setup function and linking in the library For example: #include <ClanLib/swrender.h> CL_SetupSWRender setup_swrender; With clanGL, clanGL1 and clanSWRender, it plugs itself into the clanDisplay interface. So it's easy to change the render target by using a option in the application command line or otherwise. As far as I know, no games use clanSWRender as the default renderer. It usually is clanGL1 (OpenGL 1.3) A game "configure" script can/should detect the presence of clanSWRender, and not use it. > > B) Create 2 versions of the library ( something like /usr/lib and > > /usr/lib/sse2 - http://wiki.debian.org/Multiarch/LibraryPathOverview ) > > Option B: > > This adds extra complexity for little gain > > Application developers have to be aware that SSE2 may or may not be available > > Why would game developers have to be aware of it? Are the only reasons > "the software renderer might not be available, and things might not be > fast enough" or are there others? The only reason is that the software renderer might not be available. Not a real problem though, since the application would only need to catch the "not available" exception on the stub version. > > It's already the case that the software renderer might not be available > (all non-x86 platforms), so game developers have to be aware of that > anyway; it's already the case that things might not be fast enough (slow > CPUs), so users have to be aware of that anyway (don't run it if it's > unplayably slow). > > This solution is only suitable if the versions built with/without SSE2 > have the same ABI. > Yes, I agree> > A non-SSE2 clanSWRender would have to be implemented that throws a "not available" exception > > What do ClanLib games currently do on non-x86 platforms like powerpc, > where SSE2 doesn't exist? They run using OpenGL instead. > > In the future ClanLib 2.4 may contains inline SSE2 intrinsic in the API. > > How does this work on non-x86 platforms like powerpc, where SSE2 doesn't > exist? > That is my mistake. It should not matter. #ifdef SSE2 void func() { ...SSE2_Code... } #else void func() { ... Code ... } #endif |