because on some systems (like RPi4 with my experimental GLES3 branch)
the overhead of a FBO is really noticeable, so no reason to pay for it
when it's not needed
Can be disabled with gl3_usefbo 0.
Mostly this adds an underwater warping effect, like the soft-renderer,
and also like the vulkan renderer (the shader is based on the vk one).
When this is enabled, the v_blend effect (for fullscreen overlay with
one color, like when hit or to make the screen white-ish when under
water) is now applied in the shader used for rendering the FBO instead
of rendering a fullscreen quad in blendmode.
This fixes the framecounter in the soft renderer when `viewsize` is set
to something smaller than 100. This requires the renerer to rerender
bigger parts of the borders which has a measurable speed impact. About
5 frames less with the framecounter enabled on my system. No impact with
`viewsize 100`.
The GL renderers require that the borders are redrawn after every
glClear() call, the damage tracking doesn't take that into account.
Since the speedup by the damage tracking is neglibiable in the GL
renderers, don't use it. Just redraw everything when we're running
with everthing which isn't the soft renderer.
I think this looks ugly, I always called it nightmare and it was one of
the first changes I've made to Quake II. But for the sake of peace and
quiet change it to be standard conformant. Closes#809.
both if GL pointparameters are used or not
(though depending on driver and hardware the pointparameters-based
particles *might* be always square or always round, regardless of
gl1_particle_square - that's driver-bugs which we can't fix, disable
pointparameters with `gl1_pointparameters 0` to work around it, or
just use the GL3 renderer)
