Scripting Guide - SAS

464 Three-Dimensional Scenes Chapter 13
Using the mouse
/* after one of the 3 Click2d functions figures out which axis of the model is
represented by the screen X, Y, pass in to this common code */
dragfunc = Function( {x, y, m, ix, iy}, /* ix, iy are the index of the X, Y, or
Z part of the coord in the points matrix */
If( CurrentPoint > 0,
points[CurrentPoint, ix] = (x / boxwide) * (orthoright - ortholeft) +
ortholeft;
points[CurrentPoint, iy] = (y / boxhigh) * (orthotop - orthobottom) +
orthobottom;
makepatch();
)
);
When a 2-D function is called, the arguments are X, Y, M, K.
• X and Y are the coordinates of the mouse.
• M shows the state of the mouse and button. M=0 says that the mouse button is up. M=1 says that the
button was just pressed. M=2 says that the button is down and the mouse is moving. M=3 says that the
button was just released.
• K is related to the keys Shift, Alt, and control. K=1 for the Shift key, K=2 for the Control (command) key,
and K=3 for the Alt (Option) key.
The 3-D function is called similarly. The arguments are X, Y, M, K, hitlist, where hitlist is a list of
matrices
[znear, zfar, id1, id2, id3, ...]
znear, zfar is the Z distance from the camera of the near and far edge of the object. The matrices are
sorted from near to far by the midpoint of znear, zfar. The ids in the list are the pushname, loadname,
and popname values you just put in the display list.
The drag functions use a return value to tell if mouse processing should continue. That is the trailing “1”
you see in the functions. Anything else stops the mouse tracking. This is needed because the 2-D and 3-D
functions do not run in parallel. You might want the 2-D to return 0 and the 3-D to return 1 so the tracking
would happen in 3-D rather than 2-D.
Pick Commands
This SceneBox callback gets the 2-D mouse coordinates, and then uses pick to determine the “named”
object under the mouse. For example, hitlist is a 5x5 pixel pick box around x,y; up to 1000 items
returned, but just the leaf names. The format of the return is determined by the last parameter (1 returns a
simple array, 0 returns a sorted (by depth) list of arrays).
Track2d=function({x, y, m, k},
hitlist = theSceneBox