graphics - PBRT Spectrum toRGB range -

graphics - PBRT Spectrum toRGB range -

for academic purposes have adapted pbrt writes out info intersections , general path related info (i used path surface integrator).

there difficulty in getting rgb value of spectrum @ intersection. pretty obvious have utilize torgb(float* rgb) on spectrum class generated @ intersection, info observed afterwards bit strange. create sense rgb values reside between 0-1 range. seems case often, @ times see triplets such as

(1.851088, 0.882869, 0.772866)

upon closer inspection, turns out max values rgb set of 400.000 intersections 3.77 2.00 , 1.76. lower bound seem right close zero. question range used pbrt might transform 0.0 - 1.0.

thank you

i haven't read pbrt yet or looked @ source code in detail, don't exclusively believe premise that

it create sense rgb values reside between 0-1 range.

in reality, lite intensity @ point can pretty much arbitrarily large; sun brighter brightest pixel monitor can display. i'm assuming pbrt spectra can arbitrarily intense. in case, map downwards limited lite model, can either downscale values, or clamp them 1.0 (or combination of both).

downscaling analogous decreasing camera's aperture or constricting pupils.

clamping values allows colours "wash out", in same way digital photograph of sun may have many pixels pegged 1.0, 1.0, 1.0.

graphics rendering raytracing