Re: [9fans] optimizing graphics

[mirtchov@cpsc.ucalgary.ca]

> It's on sources now.

i ran all the xscreensaver code through it. some of the
improvements are questionable at best :)

example:
			tmpx = xmid + ((       radius1	          /* * * * *            */
			- radius2        )		 /* This algo simulates	*/
			    * cos((      theta 		/* the rotation of a    */
			* M_PI           ) 		/* circular disk inside */
			    / 180           )) 		/* a hollow circular 	*/
			    + (              d 		/* rim. A point on the  */
			* cos((((  radius1 		/* disk dist d from the	*/
			* theta          )		/* centre, traces the 	*/
			    - delta          )		/* path given by this   */
			    / radius2        )  		/* equation.	        */
			    *             M_PI		/* A deviation (error)  */
			/ 180            )            /* of delta needs to be */
			    );           /* given, which greatly */
			/* adds to the beauty   */
			tmpy = ymid + (				/* of the figure.       */
			( radius1 - radius2	/*			*/
			) * sin			/* Imperfection adds to */
			(			/* beauty, symbolically */
			( theta * M_PI     	/* ...			*/
			) / 180		/* Algo deduced by      */
			)			/* Rohit Singh, Jan'00  */
			    ) +                  /* based on a toy he    */
			( d * sin           /* used to play with    */
			(                  /* when he was a kid.  */
			(                 /*            * * * * */

but it's not cb's fault, i'm sure!

there's a bug in cb.c while parsing comments within structure
definitions.  for example the following is parsed incorrectly:

--------snip----------
static double plane_orig[][2][3] = {
	/* X goes into screen, Y goes right, Z goes down(up?) */
	/* {Normal}, {Point} */
	{ {1.0, 0, 0}, {0.01, 0, 0} },
--------/snip---------

rezulting in non-compileable code:

--------snip----------
static double plane_orig[][2][3] = {
	{Normal}
, {
	Point}
*/
{
	{
		1.0, 0, 0},
		{0.01, 0, 0	}
	},
--------/snip---------

here's a diff that fixes this particular problem (and creates a couple
of warnings), it works for me, but i'm not really completely 100%
surely positive that it's the right solution:

--------snip----------
plan9-2% diff cb.c /sys/src/cmd/cb/cb.c
960c960
< 	return(lastplace);
---
> 	return(beg);
plan9-2%
--------/snip---------


CB also doesn't recognize C++-style '//' comments, or at least it
renders them incorrectly if they contain any tokens suck as '}' or
')', try cb on this for example:

	// this is a comment with a smiley at the end :)


andrey