we know that at present the clutter's clipping is
implemented in clip plane/stencil buffer/Scissor. but now ,we have a new demand to implement the clipping
without stencil buffer . because in our target the clipping based on stencil
buffer is very slow, unacceptable. we consider two ways. i hope other guys can give me some
suggestion or new idear. 1. if only rect clipping is considered,can
i clip the actor in fragment shader? the clip arear is in object
coordinates, can i in fragment shader , convert the fragment coord point from
clip coordinates to object coordiantes ,then using rect including algorthim
to discard those not in the area? vec4 obj = inverse_mvp*gl_FragCoord
to compute the fragment's object coordiate , then to discard those not
in the clip area can it be possible? 2. if the arbitrarily ploygonous clipping is required, can texture-based
clipping be one good option? i may use one offscreen texture to render
the clipping area, then in the later fragment shader, to discard those
outise of the cliping texture . it is just my idear, i still don't know how
to implement it in the shaders. except the aboves, can i have other way to do the clipping
?can someone give me good idear or comment some detail info on how to implement
? i also see some clipping using depth buffer test, this is also
not one good way in our target, in our target ,the depth test is also slow. thanks.
using stencil buffer, we
can implement arbitrarily ploygonous clipping. it is one very common way
to do the clipping in gles.
