opengl - How to copy CUDA generated PBO to Texture with Mipmapping -

i'm trying copy pbo texture automipmapping enabled, seems top level texture generated (in other words, no mipmapping occuring).

i'm building pbo using

//generate buffer id called pbo (pixel buffer object) glgenbuffers(1, pbo); //make current unpack buffer glbindbuffer(gl_pixel_unpack_buffer, *pbo); //allocate data buffer. 4-channel 8-bit image glbufferdata(gl_pixel_unpack_buffer, size_tex_data, null, gl_dynamic_copy); cudaglregisterbufferobject(*pbo); 

and i'm buildilng texture using

// enable texturing glenable(gl_texture_2d);  // generate texture identifier glgentextures(1,textureid);  // make current texture (remember gl state-based) glbindtexture( gl_texture_2d, *textureid);  // allocate texture memory. last parameter null since // want allocate memory, not initialize glteximage2d(gl_texture_2d, 0, gl_rgba_float32_ati, size_x, size_y, 0, gl_rgba, gl_float, null);  // must set filter mode, gl_linear enables interpolation when scaling gltexparameteri(gl_texture_2d, gl_texture_wrap_s, gl_repeat); gltexparameteri(gl_texture_2d, gl_texture_wrap_t, gl_repeat); gltexparameteri(gl_texture_2d,gl_texture_min_filter,gl_linear_mipmap_linear); gltexparameteri(gl_texture_2d,gl_texture_mag_filter,gl_linear); gltexparameteri(gl_texture_2d, gl_generate_mipmap, gl_true); 

later in kernel modify pbo using like:

float4* aryptr = null; cudaglmapbufferobject((void**)&aryptr, *pbo);  //pixel* gpupixelsrawptr = thrust::raw_pointer_cast(&gpupixels[0]); //... cuda stuff aryptr ...  //if don't unmap pbo opengl won't able use it: cudaglunmapbufferobject(*pbo); 

now, before draw screen using texture generated above call: (note rtmipmaptex = *textureid above , rtresultpbo = *pbo above)

glenable(gl_depth); glenable(gl_texture_2d); glbindtexture(gl_texture_2d, rtmipmaptex); glbindbuffer(gl_pixel_unpack_buffer, rtresultpbo); gltexsubimage2d(gl_texture_2d, 0, 0, 0, canvassize.x, canvassize.y, gl_rgba, gl_float, null); 

this works fine , correctly displays texture. but, if change last line

gltexsubimage2d(gl_texture_2d, 1, 0, 0, canvassize.x, canvassize.y, gl_rgba, gl_float, null); 

which, far understand, should show me first level instead of zeroth level texture in texture pyramid, blank white texture.

how copy texture pbo in such way auto-mipmapping triggered?

thanks.

i being idiot. above code works perfectly, problem

gltexsubimage2d(gl_texture_2d, 1, 0, 0, canvassize.x, canvassize.y, gl_rgba, gl_float, null); 

doesn't select mipmap level texture, selects pbo, not mipmapped. instead can display particular mipmapped level with:

gltexenvi(gl_texture_filter_control,gl_texture_lod_bias, 4);