issue
Hello all,
I have been wondering for a long time that evalglare outputs a position index below line-of-sight which is not concentric, while the Einhorn’s equation below looks to draw concentric rings because it depends on only Radius.
posindex = 1 + fact * Radius / D
fact and D, which are respectively a slope factor and a distance from an eye to an image plane, should be constant.
so I tried to fix this issue. could someone give me feedback?
target
in evalglare.c, these 3 lines calculating Radius might cause this issue.
d = 1 / tan(phi);
s = tan(teta) / tan(phi);
r = sqrt(1 / d * 1 / d + s * s / d / d);
changes
this one line will get a correct Radius.
r = tan(sigma/deg);
then, you won’t need these lines placing a cap on Radius.
/*
if (r > 3) {
fact = 1.2;
r = 3;
}
*/
effects
the left distribution is the position index by the current evalglare. the right one is by the fixed evalglare. the upper half is the same.
- the lower half of the fixed distribution fits the Iwata’s experiment result better.
- and is concentric as the Einhorn’s equation is.
- the fixed distribution has less deviation between the upper half and the lower half at the eye level.