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#include "moon.h"
#include "moondata.h"
#include "tws.h"
#include "phase.h"
#include <stdlib.h>
#include <math.h>
static const unsigned char leftmask[8] = { 0xff, 0x7f, 0x3f, 0x1f, 0x0f, 0x07, 0x03, 0x01 };
static const unsigned char rightmask[8] = { 0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe };
static const unsigned char shades[16][8] =
{
{ 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff },
{ 0x7f,0xff,0xff,0xff,0xff,0xff,0xff,0xff },
{ 0x7f,0xff,0xdf,0xff,0xff,0xff,0xff,0xff },
{ 0x7f,0xff,0xdf,0xff,0xfe,0xff,0xff,0xff },
{ 0x7f,0xff,0xdf,0xff,0xfe,0xff,0xff,0xf7 },
{ 0x7f,0xfd,0xdf,0xff,0xfe,0xff,0xff,0xf7 },
{ 0x7f,0xfd,0xdf,0xfb,0xfe,0xff,0xff,0xf7 },
{ 0x7f,0xfd,0xdf,0xfb,0xfe,0xff,0x7f,0xf7 },
{ 0x7f,0xfd,0xdf,0xfb,0xfe,0xfb,0x7f,0xf7 },
{ 0x7f,0xfd,0xdf,0xfb,0xbe,0xfb,0x7f,0xf7 },
{ 0x7f,0xfd,0xdf,0xfb,0xbe,0xfb,0x5f,0xf7 },
{ 0x7f,0xfd,0xdf,0xfb,0xbe,0xfb,0x5f,0xf5 },
{ 0x7f,0xfd,0x5f,0xfb,0xbe,0xfb,0x5f,0xf5 },
{ 0x7f,0xf5,0x5f,0xfb,0xbe,0xfb,0x5f,0xf5 },
{ 0x7f,0xf5,0x5f,0xfb,0xae,0xfb,0x5f,0xf5 },
{ 0x5f,0xf5,0x5f,0xfb,0xae,0xfb,0x5f,0xf5 }
};
#define PI 3.14159265358979323846 /* assume not near black hole or in
Tennessee */
moon_t *mooncreate()
{
moon_t *moondata;
moondata = (moon_t*)malloc(sizeof( moon_t ));
moondata->bitmap = (png_bytep)moon_bits;
moondata->width = moon_width;
moondata->height = moon_height;
moondata->xbytes = (moon_width + 7) / 8;
return moondata;
}
void moondestroy( moon_t *moon )
{
free( moon );
moon = NULL;
}
void mooncopy(image_t *image, moon_t *moondata, int cx, int cy, int blackflag)
{
double jd, angphase, cphase, aom, cdist, cangdia, csund, csuang;
struct tws* t;
int r = moondata->width/2;
int i;
register int x, y;
int xleft, xright;
int txleft, txright;
double fxleft, fxright;
double fy;
int bytexleft, bitxleft, bytexright, bitxright;
int bytetxleft, bittxleft, bytetxright, bittxright;
int moonoff, imageoff;
double cap, ratio;
int shadeindex;
unsigned char shade;
int xoffset, yoffset;
t = dtwstime();
xoffset = (cx - moondata->width/2);
yoffset = (cy - moondata->height/2);
jd = jtime( t );
angphase = phase( jd, &cphase, &aom, &cdist, &cangdia, &csund, &csuang );
cap = cos( angphase );
/* Hack to figure approximate earthlighting. */
if ( cphase < 0.1 ) cphase = 0.1;
if ( cphase > 0.9 ) cphase = 0.9;
ratio = (1.0 - cphase) / cphase; /* ratio varies from 9.0 to 0.111 */
shadeindex = (int) ( ratio / 9.0 * 15.9999 );
for ( i = 0; i < 2 * r; ++i )
{
y = moondata->height/2 - r + i;
if ( y < 0 || y >= moondata->height )
continue;
fy = i - r;
fxright = r * sqrt( 1.0 - ( fy * fy ) / ( r * r ) );
fxleft = - fxright;
txleft = fxleft + moondata->width/2 + 0.5;
txright = fxright + moondata->width/2 + 0.5;
if ( angphase >= 0.0 && angphase < M_PI )
fxright *= cap;
else
fxleft *= cap;
xleft = fxleft + moondata->width/2 + 0.5;
xright = fxright + moondata->width/2 + 0.5;
bytexleft = xleft / 8;
bitxleft = xleft % 8;
bytexright = (xright-1) / 8;
bitxright = (xright-1) % 8;
bytetxleft = txleft / 8;
bittxleft = txleft % 8;
bytetxright = (txright-1) / 8;
bittxright = (txright-1) % 8;
moonoff = y * ( moondata->width ) / 8;
imageoff = (y + yoffset) * image->xbytes + xoffset / 8;
if ( blackflag )
shade = 0xff;
else
shade = shades[shadeindex][y % 8];
for( x = bytetxleft; x <= bytetxright; x++ )
{
if( bytexleft == x )
{
image->bitmap[x + imageoff] = moondata->bitmap[x + moonoff] & ~(leftmask[bitxleft] & shade);
}
else if( bytexright == x )
{
image->bitmap[x + imageoff] = moondata->bitmap[x + moonoff] & ~(rightmask[bitxright] & shade);
}
else if( (bytexleft < x) && (x < bytexright) )
{
image->bitmap[x + imageoff] = moondata->bitmap[x + moonoff] & ~shade;
}
else
{
image->bitmap[x + imageoff] = moondata->bitmap[x + moonoff];
}
}
}
}
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