c++ - Changing texture parameters at runtime -

i opengl beginner , have built small engine universitary course. 1 constraint/feature need implement change texture quality (interpolation) @ runtime.

so instead of e.g.:

gltexparameteri(gl_texture_2d, gl_texture_min_filter, gl_linear); 

it should changed mipmaps

gltexparameteri(gl_texture_2d, gl_texture_min_filter, gl_linear_mipmap_linear) 

now have texture class abstracts , loads image , creates id texture etc.

what do: i'd bind textures in game 1 one , set parameters again.

or there more advanced or faster way this, if want effect textures?

in opengl 3.2 , higher, there texture sampler objects, can override sampling parameters in textures themselves. use them here.

it particularly convenient if want of textures use same sampling parameters. create single sampler:

gluint samplerid = 0; glgensamplers(1, &samplerid); glsamplerparameteri(samplerid, gl_texture_min_filter, gl_linear); 

you can bind single sampler object, in addition regular texture binding, when texturing. or keep bound time if have 1 of them, , want use time:

glbindsampler(gl_texture_2d, samplerid); 

then can change sampling attributes single call:

glsamplerparameteri(samplerid, gl_texture_min_filter, gl_linear_mipmap_linear); 

if sampler bound, parameters override corresponding values in bound texture. or in words of spec:

when sampler object bound texture unit, state supersedes of texture object bound texture unit. if sampler name 0 bound texture unit, bound texture’s sampler state becomes active.