9 s=`"${0%-soft.sh}" "$i" "$o" "$f"`
12 # we want to map so that:
16 realscale=`echo "$s" | grep ^Scale: | cut -d ' ' -f 2`
17 realmedian=`echo "$s" | grep ^Scaled-Med: | cut -d ' ' -f 2`
19 # we have to undo realscale, and apply sca instead
20 # assume we had an input range of 0 .. 1
21 # then this tool will scale by 2, stretching it to 1..255
22 # so, scale 2 means a 254/255 scale from DP's view!
23 extrascale=`echo "$sca / ($realscale * (127.0 / 255.0))" | bc -l`
25 # we want to make $realmedian + $ofs neutral
26 # note: ofs is in pre-scale units
27 extraoffset=`echo "($realmedian + $ofs / $realscale)" | bc -l`
29 # note: this tool maps -1 to 1 neutral, and +1 to 255 neutral
30 # darkplaces maps 1 to 0 neutral, and 0 to 255 neutral
34 # -> p_t(x) = 128 + 127 * x
37 # -> p_d(x) = 255 * (1 - x)
38 # -> p_d^-1(x) = 1 - x / 255
40 # we need p_d^-1(p_t(x)) = 1 - (128 + 127 * x) / 255
42 extraoffset="match8 "`echo "128 + 127 * $extraoffset" | bc -l`
44 echo " dpoffsetmapping - $extrascale $extraoffset"