Back to library index.

Package pl3d (in pl3d.i) -

Index of documented functions or symbols:

DOCUMENT aim3, xa,ya,za move the current 3D plot to put the point (XA,YA,ZA) in object coordinates at the point (0,0,0) -- the aim point -- in the viewer's coordinates. If any of XA, YA, or ZA is nil, it defaults to zero.

SEE ALSO: mov3, rot3, orient3, setz3, undo3, save3, restore3, light3

DOCUMENT cage3 or cage3, onoff Toggle the cage display. If ONOFF is non-nil and non-zero, turn on the cage. If ONOFF is zero, turn off the cage. The cage draws a rectangular box "behind" the 3D object and attempts to put ticks and labels around the edge of the box.

DOCUMENT draw3 Draw the current 3D display list. (Ordinarily triggered automatically when the drawing changes.)

DOCUMENT get3_centroid(xyz, nxyz) or get3_centroid(xyz) return 3D centroids for polygons with vertices XYZ. If NXYZ is specified, XYZ should be 3-by-sum(nxyz), with NXYZ being the list of numbers of vertices for each polygon (as for the plfp function). If NXYZ is not specified, XYZ should be a quadrilateral mesh, 3-by-ni-by-nj (as for the plf function). In the first case, the return value is 3-by-numberof(NXYZ); in the second case, the return value is 3-by-(ni-1)-by-(nj-1). The centroids are constructed as the mean value of all vertices of each polygon.

SEE ALSO: get3_normal, get3_light

DOCUMENT get3_light(xyz, nxyz) or get3_light(xyz) return 3D lighting for polygons with vertices XYZ. If NXYZ is specified, XYZ should be 3-by-sum(nxyz), with NXYZ being the list of numbers of vertices for each polygon (as for the plfp function). If NXYZ is not specified, XYZ should be a quadrilateral mesh, 3-by-ni-by-nj (as for the plf function). In the first case, the return value is numberof(NXYZ); in the second case, the return value is (ni-1)-by-(nj-1). The parameters of the lighting calculation are set by the light3 function.

SEE ALSO: light3, set3_object, get3_normal, get3_centroid

DOCUMENT get3_normal(xyz, nxyz) or get3_normal(xyz) return 3D normals for polygons with vertices XYZ. If NXYZ is specified, XYZ should be 3-by-sum(nxyz), with NXYZ being the list of numbers of vertices for each polygon (as for the plfp function). If NXYZ is not specified, XYZ should be a quadrilateral mesh, 3-by-ni-by-nj (as for the plf function). In the first case, the return value is 3-by-numberof(NXYZ); in the second case, the return value is 3-by-(ni-1)-by-(nj-1). The normals are constructed from the cross product of the lines joining the midpoints of two edges which as nearly quarter the polygon as possible (the medians for a quadrilateral). No check is made that these not be parallel; the returned "normal" is [0,0,0] in that case. Also, if the polygon vertices are not coplanar, the "normal" has no precisely definable meaning.

SEE ALSO: get3_centroid, get3_light

DOCUMENT get3_xy, xyz, x, y or get3_xy, xyz, x, y, z, 1 Given 3-by-anything coordinates XYZ, return X and Y in viewer's coordinate system (set by rot3, mov3, orient3, etc.). If the fifth argument is present and non-zero, also return Z (for use in sort3d or get3_light, for example). If the camera position has been set to a finite distance with setz3, the returned coordinates will be tangents of angles for a perspective drawing (and Z will be scaled by 1/zc).

SEE ALSO: sort3d, get3_light, rot3, setz3, set3_object

DOCUMENT gnomon or gnomon, onoff Toggle the gnomon display. If ONOFF is non-nil and non-zero, turn on the gnomon. If ONOFF is zero, turn off the gnomon. The gnomon shows the X, Y, and Z axis directions in the object coordinate system. The directions are labeled. The gnomon is always infinitely far behind the object (away from the camera). There is a mirror-through-the-screen-plane ambiguity in the display which is resolved in two ways: (1) The (X,Y,Z) coordinate system is right-handed, and (2) If the tip of an axis projects into the screen, it's label is drawn in opposite polarity to the other text on the screen.

DOCUMENT light3, ambient=a_level, diffuse=d_level, specular=s_level, spower=n, sdir=xyz Sets lighting properties for 3D shading effects. A surface will be shaded according to its to its orientation relative to the viewing direction. The ambient level A_LEVEL is a light level (arbitrary units) that is added to every surface independent of its orientation. The diffuse level D_LEVEL is a light level which is proportional to cos(theta), where theta is the angle between the surface normal and the viewing direction, so that surfaces directly facing the viewer are bright, while surfaces viewed edge on are unlit (and surfaces facing away, if drawn, are shaded as if they faced the viewer). The specular level S_LEVEL is a light level proportional to a high power spower=N of 1+cos(alpha), where alpha is the angle between the specular reflection angle and the viewing direction. The light source for the calculation of alpha lies in the direction XYZ (a 3 element vector) in the viewer's coordinate system at infinite distance. You can have ns light sources by making S_LEVEL, N, and XYZ (or any combination) be vectors of length ns (3-by-ns in the case of XYZ). (See source code for specular_hook function definition if powers of 1+cos(alpha) aren't good enough for you.) With no arguments, return to the default lighting. EXAMPLES: light3, diffuse=.1, specular=1., sdir=[0,0,-1] (dramatic "tail lighting" effect) light3, diffuse=.5, specular=1., sdir=[1,.5,1] (classic "over your right shoulder" lighting) light3, ambient=.1,diffuse=.1,specular=1., sdir=[[0,0,-1],[1,.5,1]],spower=[4,2] (two light sources combining previous effects)

DOCUMENT limit3, xmin,xmax, ymin,ymax or limit3, xmin,xmax, ymin,ymax, zmin,zmax Set the 3D axis limits for use with the cage. Use keyword aspect=[ax,ay,az] to set the aspect ratios of the cage to ax:ay:az -- that is, the ratios of the lengths of the cage axes will become ax:ay:az.

DOCUMENT mov3, xa,ya,za move the current 3D plot by XA along viewer's x-axis, YA along viewer's y-axis, and ZA along viewer's z-axis.

SEE ALSO: rot3, orient3, setz3, undo3, save3, restore3, light3

DOCUMENT orient3, phi, theta or orient3, phi or orient3, , theta or orient3 Set the "orientation" of the object to (PHI,THETA). "Orientations" are a subset of the possible rotation matrices in which the z-axis of the object appears vertical on the screen (that is, the object z-axis projects onto the viewer y-axis). The THETA angle is the angle from the viewer y-axis to the object z-axis, positive if the object z-axis is tilted toward you (toward viewer +z). PHI is zero when the object x-axis coincides with the viewer x-axis. If neither PHI nor THETA is specified, PHI defaults to -pi/4 and THETA defaults to pi/6. If only one of PHI or THETA is specified, the other remains unchanged, unless the current THETA is near pi/2, in which case THETA returns to pi/6, or unless the current orientation does not have a vertical z-axis, in which case the unspecified value returns to its default. Unlike rot3, orient3 is not a cumulative operation.

DOCUMENT range3, zmin,zmax Set the 3D axis z limits for use with the cage. Use keyword aspect=[ax,ay,az] to set the aspect ratios of the cage to ax:ay:az -- that is, the ratios of the lengths of the cage axes will become ax:ay:az.

DOCUMENT restore3, view Restore a previously saved 3D viewing transformation and lighting. If VIEW is nil, rotate object to viewer's coordinate system.

DOCUMENT rot3, xa,ya,za rotate the current 3D plot by XA about viewer's x-axis, YA about viewer's y-axis, and ZA about viewer's z-axis.

SEE ALSO: orient3, mov3, aim3, setz3, undo3, save3, restore3, light3

DOCUMENT set3_object, drawing_function, _lst(arg1,arg2,...) set up to trigger a call to draw3, adding a call to the 3D display list of the form: DRAWING_FUNCTION, _lst(ARG1, ARG2, ...) When draw3 calls DRAWING_FUNCTION, the external variable _draw3 will be non-zero, so DRAWING_FUNCTION can be written like this: func drawing_function require, "pl3d.i"; if (_draw3) { list= arg1; arg1= _nxt(list); arg2= _nxt(list); ... ...... ... ... return; } ... ... ... ... set3_object, drawing_function, _lst(arg1,arg2,...); }

SEE ALSO: get3_xy, get3_light, sort3d

DOCUMENT setz3, zc Set the camera position to z=ZC (x=y=0) in the viewer's coordinate system. If ZC is nil, set the camera to infinity (default).

DOCUMENT sort3d(z, npolys, &list, &vlist) given Z and NPOLYS, with numberof(Z)==sum(npolys), return LIST and VLIST such that Z(VLIST) and NPOLYS(LIST) are sorted from smallest average Z to largest average Z, where the averages are taken over the clusters of length NPOLYS. Within each cluster (polygon), the cyclic order of Z(VLIST) remains unchanged, but the absolute order may change. This sorting order produces correct or nearly correct order for a plfp command to make a plot involving hidden or partially hidden surfaces in three dimensions. It works best when the polys form a set of disjoint closed, convex surfaces, and when the surface normal changes only very little between neighboring polys. (If the latter condition holds, then even if sort3d mis-orders two neighboring polys, their colors will be very nearly the same, and the mistake won't be noticeable.) A truly correct 3D sorting routine is impossible, since there may be no rendering order which produces correct surface hiding (some polys may need to be split into pieces in order to do that). There are more nearly correct algorithms than this, but they are much slower.

SEE ALSO: get3_xy

DOCUMENT spin3 or spin3, nframes or spin3, nframes, axis Spin the current 3D display list about AXIS over NFRAMES. Keywords tlimit= the total time allowed for the movie in seconds (default 60), dtmin= the minimum allowed interframe time in seconds (default 0.0), bracket_time= (as for movie function in movie.i) The default AXIS is [-1,1,0] and the default NFRAMES is 30.

SEE ALSO: rot3