Quote Originally Posted by WILL
Perhaps you are trying to directly access hardware interupts that don't exist in a Radeon and in doing so just slow down the system's resources handling all these interupt calls? Just an idea... What kind of OpenGL headers or library are you using?
Gosh, no, I don't do any dirty hardware tricks Especially since the game is portable to both Windows and Linux/FreeBSD. Whole graphic is done in plain OpenGL, with some popular (not specific to any particular producer) extensions (like EXT_fog_coord and like --- things that are supported on both Radeon and GeForce).

My OpenGL header was started from old Mike Lischke's OpenGL12 (it was quite modified since then, for FPC, Linux etc.). That's the same source that is used in e.g. GLScene. You can find my unit is castle's sources in file source/units/opengl/openglh.pas

Although most of the base code can be also compiled with USE_GL_GLU_UNITS, and then standard FPC gl, glu, glext headers will be used --- my intention is to drop my OpenGLh unit and switch entirely to using FPC's gl, glu, glext units at some point (but for now I stick to my OpenGLh unit as it's tested). Initially I didn't use OpenGL headers provided with FPC because they had problems, but it's fixed in FPC since a long time now.