fullscreen_mesh.draw(renderer);
renderer.set_shader_program(&specular_shprog);
for(unsigned i=0; i<specular_fbos.size(); ++i)
{
prefilter_shdata.uniform("roughness", 1.0f-sqrt(1.0f-static_cast<float>(i+1)/specular_fbos.size()));
fullscreen_mesh.draw(renderer);
renderer.set_shader_program(&specular_shprog);
for(unsigned i=0; i<specular_fbos.size(); ++i)
{
prefilter_shdata.uniform("roughness", 1.0f-sqrt(1.0f-static_cast<float>(i+1)/specular_fbos.size()));