// ap02.c // cc -o ap02 ap02.c -lgd -lpng -lm // // Apogee skew Keith Lofstrom May 12, 2009 // // FIXED ... apogee skew // at the semiminor points TOWARDS apogee // // Uses the libgd library. For documentation see the file: // /usr/share/doc/gd-*/index.html // or the website: // http://www.libgd.org/Reference #define RMMKDIR "rm -rf ap02dir ; mkdir ap02dir" #define PNGFMT "ap02dir/a%04d.png" #define PNG2SWF "png2swf -o ap02.swf -r 20 ap02dir/*.png" #define XSIZE 1000 #define YSIZE 600 #define YCENTER 360 #define SPACE 60 #define SIZE 20 #define NUM 25 #define NUMX 5 #define NPICS 200 #define ESIZE 90 #define ORBSIZE 90 #define SSIZE 20 #define ZFACTR 0.1 #define LAYER 0.8 #define PSIZE 6 #define TOP 100 #define FNT "DejaVuMonoSans" #define FSZ 40 #define ASCALE 2.0 #include #include #include #include int sun1, white, red, green, blue ; // color indexes int dred, gray, trans, lgray, cyan ; int dgray, yellow, magenta, black ; int dcyan ; int carr[2*NUM]; double xarr[NUM]; double yarr[NUM]; double zarr[NUM]; double xdis[NUM]; // scaled and translated x double wdis[NUM]; // unscaled y double ydis[NUM]; // scaled and translated y double zdis[NUM]; // unscaled z double xcenter = XSIZE / 2 ; double ycenter = YCENTER ; int ex = (int) (1.5*ORBSIZE) ; int ey = (int) (1.5*ORBSIZE) ; int re = ESIZE / 2 ; double pi2 = 6.283185307 ; gdImagePtr im; // Declare the image FILE *pngout; // Declare output file // define colors ----------------------------------------------------------- #define CMAX 240 #define CSTEP 30 #define CCNT 5 void colorstart() { int cp, cq, ix, ired, igreen, iblue ; white =gdImageColorAllocate (im, 255, 255, 255); black =gdImageColorAllocate (im, 0, 0, 0); gray =gdImageColorAllocate (im, 128, 128, 128); dgray =gdImageColorAllocate (im, 96, 96, 96); lgray =gdImageColorAllocate (im, 192, 192, 192); cyan =gdImageColorAllocate (im, 0, 192, 192); dcyan =gdImageColorAllocate (im, 0, 48, 48); red =gdImageColorAllocate (im, 255, 0, 0); dred =gdImageColorAllocate (im, 128, 0, 0); yellow =gdImageColorAllocate (im, 255, 255, 0); green =gdImageColorAllocate (im, 0, 255, 0); blue =gdImageColorAllocate (im, 0, 0, 255); magenta =gdImageColorAllocate (im, 192, 0, 192); trans =gdImageColorAllocate (im, 1, 1, 1); for( cp=0 ; cp < CCNT ; cp++ ) { for( cq=0 ; cq < CCNT ; cq++ ) { ix = CCNT*cp+cq ; ired = CMAX - CSTEP*( cp + cq ) ; igreen = 2*CSTEP * cp ; iblue = 2*CSTEP * cq ; carr[ ix] = gdImageColorAllocate(im, ired , igreen , iblue ); carr[NUM+ix] = gdImageColorAllocate(im, ired/2, igreen/2, iblue/2); } } } // set up array positions --------------------------------------------------- void astart() { int ap, aq, ai ; double n = (double) NUM ; double n2 = sqrt( n ) ; int ni = (int) n2 ; double nm = 0.5*(n2-1.0) ; for( ap=0 ; ap < ni ; ap++ ) { for( aq=0 ; aq < ni ; aq++ ) { ai = ni * ap + aq ; zarr[ai] = ((double) ap ) - nm ; yarr[ai] = ((double) aq ) - nm ; xarr[ai] = 0.0 ; } } carr[NUM-1]=white ; } // draw arrowhead (either degrees or radians ) ----------------------------- void arrowhead( double xp, double yp, double asize, double deg, double rad, int color ) { double angl = rad+pi2*deg/360.0 ; gdPoint arrow[3] ; arrow[0].x = (int)(xp); arrow[0].y = (int)(yp); arrow[1].x = (int)(xp+asize*( -cos(angl)-0.5*sin(angl))); arrow[1].y = (int)(yp+asize*( 0.5*cos(angl)- sin(angl))); arrow[2].x = (int)(xp+asize*( -cos(angl)+0.5*sin(angl))); arrow[2].y = (int)(yp+asize*(-0.5*cos(angl)- sin(angl))); gdImageFilledPolygon( im, arrow, 3, color ); } // draw arrow ------------------------------------------------------------- void arrow( double x0, double y0, double x1, double y1, int color ) { double asize = 0.02*(x1-x0) ; gdImageLine( im, (int)x0, (int)y0, (int)x1, (int)y1, color ) ; arrowhead( x1, y1, 0.02*(x1-x0), 0.0, 0.0, color ) ; } // draw rotating earth and orbiting body and side arrow ------------- void earth( double ang ) { double x, y ; double xs, ys ; int x0, y0 ; int x1, y1 ; double an0 ; int i ; int xcnt ; int orbit = 2*ORBSIZE ; gdImageFilledArc(im, ex, ey, ESIZE, ESIZE, 0, 360, dcyan, gdArc); gdImageFilledArc(im, ex, ey, ESIZE, ESIZE, 90, 270, cyan, gdArc); gdImageArc( im, ex, ey, orbit, orbit, 30, 330, white ); gdImageArc( im, ex, ey, orbit, orbit, 330, 30, dgray ); // draw longitude lines ( 6 = 180/30 degrees ) for( i=0 ; i < 6 ; i++ ) { an0 = (ang/6.0) + pi2*( (double) i ) / 12.0 ; x0 = ex - (int)( ((double)re) * cos(an0 )); x1 = ex + (int)( ((double)re) * cos(an0 )); y0 = ey + (int)( ((double)re) * sin(an0 )); y1 = ey - (int)( ((double)re) * sin(an0 )); gdImageLine( im, x0, y0, x1, y1, black ); } // draw latitude lines for( i=1 ; i < 3 ; i++ ) { an0 = pi2*( (double) i ) / 12.0 ; x0 = (int)( 2.0 * ((double)re) * cos(an0) ); gdImageArc( im, ex, ey, x0, x0, 0, 360, black ); } // draw arrowhead to show side point of view x= -ORBSIZE - 2.0*PSIZE ; y= 0.0 ; xs = x*cos(ang)+y*sin(ang) + (double) ex ; ys = y*cos(ang)-x*sin(ang) + (double) ey ; arrowhead( xs, ys, 2*PSIZE, 0.0, -ang, white ); } // ======================================================================== int main() { double angle ; int i ; int xcnt ; int frame ; char pngfilename[64]; double test ; // depth testing int ox, oy ; int s0 ; double xu, yu ; int xi, yi ; int icol ; double deg ; system( RMMKDIR ); for( frame = 0 ; frame < NPICS ; frame++ ) { im = gdImageCreateTrueColor(XSIZE, YSIZE ); sprintf( pngfilename, PNGFMT, frame ); pngout = fopen( pngfilename, "wb"); angle = frame * pi2 / NPICS ; colorstart() ; astart() ; earth(angle) ; // labels ----------------------------------------------------------- gdImageStringFT( im, NULL, // imagespace, bounding white, FNT, FSZ, // color, font, fontsize 0.0, 0.00*XSIZE, 0.98*YSIZE, // angle, x, y " Side View" ); // the text gdImageStringFT( im, NULL, // imagespace, bounding white, FNT, FSZ/2, // color, font, fontsize 0.0, 0.25*XSIZE, 0.27*YSIZE, // angle, x, y " Top View" ); // the text gdImageStringFT( im, NULL, // imagespace, bounding white, FNT, FSZ/2, // color, font, fontsize 0.0, 0.50*XSIZE, 0.27*YSIZE, // angle, x, y " Front View" ); // the text gdImageStringFT( im, NULL, // imagespace, bounding white, FNT, FSZ/2, // color, font, fontsize 0.0, 0.71*XSIZE, 0.27*YSIZE, // angle, x, y " Side View" ); // the text // time code ------------------------------------------------------- double time0 = ( 4.0 * (double) frame ) / ( (double) NPICS ) ; char timestring[64] ; sprintf( timestring, "%3.1f/4.0 hours, 1440x speedup", time0 ); gdImageStringFT( im, NULL, // imagespace, bounding white, FNT, 0.6*FSZ, // color, font, fontsize 0.0, XSIZE-14.0*FSZ, // angle, x 0.98*YSIZE, timestring ); // y, the text // direction arrows ------------------------------------------------ arrow( 0.00*XSIZE, ycenter, 0.96*XSIZE, ycenter, lgray ); arrow( 0.26*XSIZE, 0.25*ycenter, 0.50*XSIZE, 0.25*ycenter, lgray ); arrow( 0.71*XSIZE, 0.25*ycenter, 0.95*XSIZE, 0.25*ycenter, lgray ); // draw main view from top ---------------------------------------- for( i=0 ; i < NUM ; i++ ) { zdis[i] =-cos(angle)*zarr[i]-sin(angle)*yarr[i] ; wdis[i] = cos(angle)*yarr[i]-sin(angle)*zarr[i]; ydis[i] = ycenter - SPACE*wdis[i]; xdis[i] = xcenter + SPACE*(2.0*zdis[i]-0.5*NUMX) ; } for( test = -5.0*LAYER ; test < 5.0*LAYER ; test += LAYER ) { for( i=0 ; i < NUM ; i++ ) { for( xcnt = 0 ; xcnt < NUMX ; xcnt++ ) { if( ( zdis[i] >= test ) && ( zdis[i] < ( test+LAYER ) ) ) { // small top view s0 = (int) ( 0.35*SIZE * (1.00 + ZFACTR * zdis[i] ) ) ; ox = (int) ( 0.26*XSIZE + 0.25*(SPACE*xcnt+xdis[i]) ); oy = (int) ( 0.25*ydis[i] ); gdImageFilledArc(im, ox, oy, s0, s0, 0, 360, carr[i], gdArc); // draw points in top orbit representation xu = -ORBSIZE - ASCALE * wdis[i] ; yu = ASCALE * ( ((double)xcnt) + 2.0*zdis[i]-0.5*NUMX ); xi = ex + (int)( xu*cos(angle)+yu*sin(angle)) ; yi = ey + (int)( yu*cos(angle)-xu*sin(angle)) ; if( ( xi < ex ) ||( yi < ( ey-re ) ) ||( yi > ( ey+re ) ) ) icol = carr[ i]; else icol = carr[NUM+i]; gdImageFilledArc( im, xi, yi, 3, 3, 0, 360, icol, gdArc ); } if( ( wdis[i] >= test ) && ( wdis[i] < ( test+LAYER ) ) ) { // main side view s0 = (int) ( SIZE * (1.00 + ZFACTR * wdis[i] ) ) ; ox = (int) ( SPACE*xcnt+xdis[i]); oy = (int) ( ycenter-SPACE*zdis[i]) ; gdImageFilledArc(im, ox, oy, s0, s0, 0, 360, carr[i], gdArc); // small side view s0 = (int) ( 0.35*SIZE * (1.00 + ZFACTR * wdis[i] ) ) ; ox = (int) ( 0.71*XSIZE + 0.25*(SPACE*xcnt+xdis[i])); oy = (int) ( 0.25*(ycenter-SPACE*zdis[i]) ) ; gdImageFilledArc(im, ox, oy, s0, s0, 0, 360, carr[i], gdArc); } } // small front view - apogee to left, closer s0 = (int) ( 0.35*SIZE * (1.30 + 2.0* ZFACTR * zdis[i] ) ) ; ox = (int) ( 0.60*XSIZE - 0.25*SPACE*wdis[i] ); oy = (int) ( 0.25*( ycenter -SPACE*zdis[i] ) ); gdImageFilledArc(im, ox, oy, s0, s0, 0, 360, carr[i], gdArc); } } /* Output the frame in PNG format. */ gdImagePngEx( im, pngout, 1 ); gdImageDestroy(im); fclose(pngout); } system( PNG2SWF ); }