Simple use of vertex arrays in R_DrawTextureChains_Multitexture.

The glBegin(GL_POLYGON), for() loop with GL_MTexCoord2fFunc()/glVertex3fv() calls, and glEnd () per polygon is replaced by a memcpy() and a glDrawArrays() call per poly.

My guess is this only saves function call overhead, but it gives a decent ~20% speedup (36 -> 42fps) on my machine on orl’s map.

Note: glDrawArrays() is in OpenGL 1.1, but the glClientActiveTextureARB function is part of the GL_ARB_multitexture extension but not GL_SGIS_multitexture. Instead of splitting into two code paths, I just dropped support for GL_SGIS_multitexture.

git-svn-id: svn://svn.code.sf.net/p/quakespasm/code/trunk/quakespasm@981 af15c1b1-3010-417e-b628-4374ebc0bcbd
Silence warning about vid_fsaa requiring restart when parsing config.cfg at startup. Add missing newline to warning message.

git-svn-id: svn://svn.code.sf.net/p/quakespasm/code/trunk/quakespasm@982 af15c1b1-3010-417e-b628-4374ebc0bcbd
Revert r981 "Simple use of vertex arrays in R_DrawTextureChains_Multitexture."
It caused a dramatic slowdown on my machine on windows (50% slower)

git-svn-id: svn://svn.code.sf.net/p/quakespasm/code/trunk/quakespasm@983 af15c1b1-3010-417e-b628-4374ebc0bcbd
dropped support for GL_SGIS_multitexture

git-svn-id: svn://svn.code.sf.net/p/quakespasm/code/trunk/quakespasm@984 af15c1b1-3010-417e-b628-4374ebc0bcbd