Using r_drawSunRays 1, r_hdr 0, cg_viewsize 50 caused the sun rays to only draw properly in the bottom right quarter of the world viewport.
The scissor rectangle for the world viewport was applied to the first FBO_FastBlit() in RB_SunRays().
Set glScissor() in FBO_FastBlit() as it's done in FBO_Blit() and FBO_BlitFromTexture(). Sun rays probably worked correctly with r_hdr 1 because the blit for HDR changed the scissor state.
Using r_drawSunRays 1, r_hdr 0, cg_viewsize 50 caused the sun rays to only draw properly in the bottom right quarter of the world viewport.
The scissor rectangle for the world viewport was applied to the first FBO_FastBlit() in RB_SunRays().
Set glScissor() in FBO_FastBlit() as it's done in FBO_Blit() and FBO_BlitFromTexture(). Sun rays probably worked correctly with r_hdr 1 because the blit for HDR changed the scissor state.
Fixes #305.