sdh@joevax.UUCP (The Doctor) (08/06/86)
Posted to net.sources recently was a ray tracing program.
Below is a program to convert the out from the tracer to a picture
suitable for Macpaint.
The program was written in Aztec C version 1.06H, and expects a file
data.dis -the ouput from the ray tracer.
to compile:
cc traceconv.c
ln -m traceconv.o /lib/mixcroot.o -lc
The link statement makes it executable both the finder and the shell.
To use it just run it and sit back and watch. When the picture is drawn,
the Mac waits for a Button press checking events. If the user presses
clover-shift-3, the picture will saved as a MacPaint document.
Bugs:
The dimensions specified by the ray tracer are larger than the mac's screen,
so the picture gets clipped.
The dimensions are hard coded into the program. It assumes a vertical height
(the constant, ylimit) and draws columns of that height until eof. If
ylimit is incorrect the picture gets skewed badly.
/* traceconv.c - a program to convert 256 level gray files to MacPaint
* pictures.
* Written by: Steve Hawley Aztec C V1.06H
*/
#include <quickdraw.h>
#include <window.h>
#include <event.h>
#include <stdio.h>
#include <desk.h>
#define dithsize 7
#define ylimit 451
WindowRecord wRecord;
WindowPtr myWindow;
EventRecord myEvent;
main ()
{
Rect screen;
int x, y;
int level;
FILE *fopen(), *fp;
InitGraf(&thePort); /* do inits */
InitWindows();
FlushEvents(everyEvent,0);
SetCursor(&arrow);
HideCursor();
SetRect(&screen, 4, 40, 508, 340); /*set up window */
myWindow = NewWindow(&wRecord, &screen, ctop("Raytrace"),
1,0,(char*)-1,1,(long)0);
SetPort(myWindow);
ShowWindow(myWindow);
/* put up a new window */
SetOrigin(0,0);
if ( (fp = fopen("data.dis", "r")) == NULL) printf("Can't open file!\n");
else {
x = 0;
y = 0;
while( (level = getc( fp )) != EOF){
if (dither(x, y, level)) PenPat(white);
else PenPat(black);
MoveTo(x,ylimiy - y);
LineTo(x,ylimit - y);
y++;
if (y >= ylimit) {
y = 0;
x++;
}
if (Button()) exit(0); /* abort if button pressed */
}
}
while(!Button()){
GetNextEvent(everyEvent, &myEvent); /* wait for key/btn press */
SystemTask();
}
}
dither (x,y,level) /* dithering function */
register int x, y, level;
{
/* 8 x 8 dithering matrix */
static int matrix[dithsize+1][dithsize+1] = {
{ 0,128, 32,160, 8,136, 40,168},
{192, 64,224, 96,200, 72,232,104},
{ 48,176, 16,144, 56,184, 24,152},
{240,112,208, 80,248,120,216, 88},
{ 12,140, 44,174, 4,132, 36,164},
{204, 76,236,108,196, 68,228,100},
{ 60,188, 28,156, 52,180, 20,148},
{252,124,210, 92,244,116,212, 84}
};
/* dithering by area access to matrix by using
the MOD function on the x and y coordinates */
return(level > matrix[x % dithsize][y % dithsize]);
}