visangle3D: Calculate visual angle given a 3D viewer position, stimulus...

In russmisc: A repository for a variety of useful functions.

Description

This function calculates the visual angle of a stimulus given a viewer position, stimulus size, and stimulus position. Here I make fewer assumptions and calculate the distance between the viewer and the edges of the object in order to use the law of cosines to calculate the associated angle.

Usage

  visangle3D(viewerloc, stimloc, stimdim)

Arguments

viewerloc	The location of the center of the viewer as a numeric vector of length 3 c(X,Y,Z)
stimloc	The location of the center of the stimulus as a numeric vector of length 3 c(X,Y,Z)
stimdim	The stimulus dimensions as a numeric vector of length 2 c(width,height)

Value

Degrees in visual angle for the given stimulus dimentions and positions of viewer and stimuli

Note

The units of measure should be the same for all parameters. Z is assumed to be the depth plane.

See Also

visangle

Examples

#corresponds to an offset of 10 and 10 and a viewer distance of 20
viewerloc <- c(0,0,0)
stimloc<-c(10,10,-20)
stimsize.val <- 10
stimdim <- c(stimsize.val,1)
visangle(stimsize.val,20,pythag(stimloc[1],stimloc[2]))
visangle3D(viewerloc,stimloc,stimdim)
#corresponds to an offset of 10 and 0 and a viewer distance of 20
viewerloc <- c(0,0,0)
stimloc<-c(10,0,-20)
stimsize.val <- 10
stimdim <- c(stimsize.val,1)
visangle(stimsize.val,20,pythag(stimloc[1],stimloc[2]))
visangle3D(viewerloc,stimloc,stimdim)
visangle3D(list(c(1,1),c(1,1),c(1,1)),list(c(2,2),c(2,2),c(2,2)),list(c(3,3),c(3,3)))
visangle3D(list(1,2,3),list(3,4,5),list(2,2))

russmisc documentation built on May 2, 2019, 4:44 p.m.