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diff --git a/man/man3/qball.html b/man/man3/qball.html new file mode 100644 index 00000000..b1403336 --- /dev/null +++ b/man/man3/qball.html @@ -0,0 +1,111 @@ +<head> +<title>qball(3) - Plan 9 from User Space</title> +<meta content="text/html; charset=utf-8" http-equiv=Content-Type> +</head> +<body bgcolor=#ffffff> +<table border=0 cellpadding=0 cellspacing=0 width=100%> +<tr height=10><td> +<tr><td width=20><td> +<tr><td width=20><td><b>QBALL(3)</b><td align=right><b>QBALL(3)</b> +<tr><td width=20><td colspan=2> + <br> +<p><font size=+1><b>NAME </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + qball – 3-d rotation controller<br> + +</table> +<p><font size=+1><b>SYNOPSIS </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + <tt><font size=+1>#include <draw.h> + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + </font></tt> + <tt><font size=+1>#include <geometry.h> + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + </font></tt> + <tt><font size=+1>void qball(Rectangle r, Mouse *mousep,<br> + + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + Quaternion *orientation,<br> + void (*redraw)(void), Quaternion *ap)<br> + + </table> + </font></tt> +</table> +<p><font size=+1><b>DESCRIPTION </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + <i>Qball</i> is an interactive controller that allows arbitrary 3-space + rotations to be specified with the mouse. Imagine a sphere with + its center at the midpoint of rectangle <i>r</i>, and diameter the smaller + of <i>r</i>’s dimensions. Dragging from one point on the sphere to another + specifies the endpoints of a great-circle arc. (Mouse + points outside the sphere are projected to the nearest point on + the sphere.) The axis of rotation is normal to the plane of the + arc, and the angle of rotation is twice the angle of the arc. + + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + Argument <i>mousep</i> is a pointer to the mouse event that triggered + the interaction. It should have some button set. <i>Qball</i> will read + more events into <i>mousep</i>, and return when no buttons are down. + + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + While <i>qball</i> is reading mouse events, it calls out to the caller-supplied + routine <i>redraw</i>, which is expected to update the screen to reflect + the changing orientation. Argument <i>orientation</i> is the orientation + that <i>redraw</i> should examine, represented as a unit Quaternion (see + <i>quaternion(9.2)).</i> The caller may set it to any + orientation. It will be updated before each call to <i>redraw</i> (and + on return) by multiplying by the rotation specified with the mouse. + + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + It is possible to restrict <i>qball’s</i> attention to rotations about + a particular axis. If <i>ap</i> is null, the rotation is unconstrained. + Otherwise, the rotation will be about the same axis as <i>*ap</i>. This + is accomplished by projecting points on the sphere to the nearest + point also on the plane through the sphere’s center and normal + to + the axis.<br> + +</table> +<p><font size=+1><b>SOURCE </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + <tt><font size=+1>/usr/local/plan9/src/libgeometry/qball.c<br> + </font></tt> +</table> +<p><font size=+1><b>SEE ALSO </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + <a href="../man3/quaternion.html"><i>quaternion</i>(3)</a><br> + Ken Shoemake, “Animating Rotation with Quaternion Curves”, <i>SIGGRAPH + ’85 Conference Proceedings.<br> + </i> +</table> + +<td width=20> +<tr height=20><td> +</table> +<!-- TRAILER --> +<table border=0 cellpadding=0 cellspacing=0 width=100%> +<tr height=15><td width=10><td><td width=10> +<tr><td><td> +<center> +<a href="../../"><img src="../../dist/spaceglenda100.png" alt="Space Glenda" border=1></a> +</center> +</table> +<!-- TRAILER --> +</body></html> |