1 // HUD_ladder.cxx -- HUD Ladder Instrument
3 // Written by Michele America, started September 1997.
5 // Copyright (C) 1997 Michele F. America [micheleamerica#geocities:com]
6 // Copyright (C) 2006 Melchior FRANZ [mfranz#aon:at]
8 // This program is free software; you can redistribute it and/or
9 // modify it under the terms of the GNU General Public License as
10 // published by the Free Software Foundation; either version 2 of the
11 // License, or (at your option) any later version.
13 // This program is distributed in the hope that it will be useful, but
14 // WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 // General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
26 #include <Main/viewer.hxx>
31 float get__heading() { return fgGetFloat("/orientation/heading-deg") * M_PI / 180.0; }
32 float get__throttleval() { return fgGetFloat("/controls/engines/engine/throttle"); }
33 float get__aoa() { return fgGetFloat("/sim/frame-rate"); } // FIXME
34 float get__Vx() { return fgGetFloat("/velocities/uBody-fps"); }
35 float get__Vy() { return fgGetFloat("/velocities/vBody-fps"); }
36 float get__Vz() { return fgGetFloat("/velocities/wBody-fps"); }
37 float get__Ax() { return fgGetFloat("/acclerations/pilot/x-accel-fps_sec"); }
38 float get__Ay() { return fgGetFloat("/acclerations/pilot/y-accel-fps_sec"); }
39 float get__Az() { return fgGetFloat("/acclerations/pilot/z-accel-fps_sec"); }
43 HUD::Ladder::Ladder(HUD *hud, const SGPropertyNode *n, float x, float y) :
45 _pitch(n->getNode("pitch-input", false)),
46 _roll(n->getNode("roll-input", false)),
47 width_units(int(n->getFloatValue("display-span"))),
48 div_units(int(fabs(n->getFloatValue("divisions")))),
49 minor_div(0 /* hud.cxx: static float minor_division = 0 */),
50 label_pos(n->getIntValue("lbl-pos")),
51 _scr_hole(n->getIntValue("screen-hole")),
52 _compression(n->getFloatValue("compression-factor")),
53 _frl(n->getBoolValue("enable-fuselage-ref-line", false)),
54 _target_spot(n->getBoolValue("enable-target-spot", false)),
55 _velocity_vector(n->getBoolValue("enable-velocity-vector", false)),
56 _drift_marker(n->getBoolValue("enable-drift-marker", false)),
57 _alpha_bracket(n->getBoolValue("enable-alpha-bracket", false)),
58 _energy_marker(n->getBoolValue("enable-energy-marker", false)),
59 _climb_dive_marker(n->getBoolValue("enable-climb-dive-marker", false)), // WTF FIXME
60 _glide_slope_marker(n->getBoolValue("enable-glide-slope-marker",false)),
61 _glide_slope(n->getFloatValue("glide-slope", -4.0)),
62 _energy_worm(n->getBoolValue("enable-energy-marker", false)),
63 _waypoint_marker(n->getBoolValue("enable-waypoint-marker", false)),
64 _zenith(n->getIntValue("zenith")),
65 _nadir(n->getIntValue("nadir")),
66 _hat(n->getIntValue("hat"))
68 const char *t = n->getStringValue("type");
69 _type = strcmp(t, "climb-dive") ? PITCH : CLIMB_DIVE;
74 _vmax = width_units / 2;
79 void HUD::Ladder::draw(void)
81 if (!_pitch.isValid() || !_roll.isValid())
88 float cosine, sine, xvvr, yvvr, Vxx = 0.0, Vyy = 0.0, Vzz = 0.0;
89 float up_vel, ground_vel, actslope = 0.0;
90 float Axx = 0.0, Ayy = 0.0, Azz = 0.0, total_vel = 0.0, pot_slope, t1;
91 float t2 = 0.0, psi = 0.0, alpha, pla;
92 float vel_x = 0.0, vel_y = 0.0, drift;
93 bool pitch_ladder = false;
94 bool climb_dive_ladder = false;
95 bool clip_plane = false;
97 GLdouble eqn_top[4] = {0.0, -1.0, 0.0, 0.0};
98 GLdouble eqn_left[4] = {-1.0, 0.0, 0.0, 100.0};
99 GLdouble eqn_right[4] = {1.0, 0.0, 0.0, 100.0};
101 Point centroid = get_centroid();
102 Rect box = get_location();
104 float half_span = box.right / 2.0;
105 float roll_value = _roll.getFloatValue() * SGD_DEGREES_TO_RADIANS; // FIXME rad/deg conversion
107 pla = get__throttleval();
109 #ifdef ENABLE_SP_FMDS
110 int lgear, wown, wowm, ilcanclaw, ihook;
111 ilcanclaw = get__iaux2();
112 lgear = get__iaux3();
115 ihook = get__iaux6();
117 float pitch_value = _pitch.getFloatValue();
119 if (_type == CLIMB_DIVE) {
120 pitch_ladder = false;
121 climb_dive_ladder = true;
124 } else { // _type == PITCH
126 climb_dive_ladder = false;
130 //**************************************************************
132 // define (0, 0) as center of screen
133 glTranslatef(centroid.x, centroid.y, 0);
135 // OBJECT STATIC RETICLE
136 // TYPE FRL (FUSELAGE REFERENCE LINE)
138 // Draw the FRL spot and line
140 #define FRL_DIAMOND_SIZE 2.0
141 glBegin(GL_LINE_LOOP);
142 glVertex2f(-FRL_DIAMOND_SIZE, 0.0);
143 glVertex2f(0.0, FRL_DIAMOND_SIZE);
144 glVertex2f(FRL_DIAMOND_SIZE, 0.0);
145 glVertex2f(0.0, -FRL_DIAMOND_SIZE);
148 glBegin(GL_LINE_STRIP);
149 glVertex2f(0, FRL_DIAMOND_SIZE);
152 #undef FRL_DIAMOND_SIZE
154 // TYPE WATERLINE_MARK (W shaped _ _ )
157 //****************************************************************
159 // Draw the target spot.
161 #define CENTER_DIAMOND_SIZE 6.0
162 glBegin(GL_LINE_LOOP);
163 glVertex2f(-CENTER_DIAMOND_SIZE, 0.0);
164 glVertex2f(0.0, CENTER_DIAMOND_SIZE);
165 glVertex2f(CENTER_DIAMOND_SIZE, 0.0);
166 glVertex2f(0.0, -CENTER_DIAMOND_SIZE);
168 #undef CENTER_DIAMOND_SIZE
171 //****************************************************************
172 //velocity vector reticle - computations
173 if (_velocity_vector) {
180 psi = get__heading();
185 total_vel = sqrt(Vxx * Vxx + Vyy * Vyy + Vzz * Vzz);
186 ground_vel = sqrt(Vxx * Vxx + Vyy * Vyy);
189 if (ground_vel < 2.0) {
190 if (fabs(up_vel) < 2.0)
193 actslope = (up_vel / fabs(up_vel)) * 90.0;
196 actslope = atan(up_vel / ground_vel) * SGD_RADIANS_TO_DEGREES;
199 xvvr = (((atan2(Vyy, Vxx) * SGD_RADIANS_TO_DEGREES) - psi)
200 * (_compression / globals->get_current_view()->get_aspect_ratio()));
201 drift = ((atan2(Vyy, Vxx) * SGD_RADIANS_TO_DEGREES) - psi);
202 yvvr = ((actslope - pitch_value) * _compression);
203 vel_y = ((actslope - pitch_value) * cos(roll_value) + drift * sin(roll_value)) * _compression;
204 vel_x = (-(actslope - pitch_value) * sin(roll_value) + drift * cos(roll_value))
205 * (_compression / globals->get_current_view()->get_aspect_ratio());
206 // printf("%f %f %f %f\n",vel_x, vel_y, drift, psi);
208 //****************************************************************
209 // OBJECT MOVING RETICLE
210 // TYPE - DRIFT MARKER
214 glBegin(GL_LINE_STRIP);
215 glVertex2f((xvvr * 25 / 120) - 6, -4);
216 glVertex2f(xvvr * 25 / 120, 8);
217 glVertex2f((xvvr * 25 / 120) + 6, -4);
221 //****************************************************************
222 // Clipping coordinates for ladder to be input from xml file
225 glClipPlane(GL_CLIP_PLANE0, eqn_top);
226 glEnable(GL_CLIP_PLANE0);
227 glClipPlane(GL_CLIP_PLANE1, eqn_left);
228 glEnable(GL_CLIP_PLANE1);
229 glClipPlane(GL_CLIP_PLANE2, eqn_right);
230 glEnable(GL_CLIP_PLANE2);
231 // glScissor(-100,-240, 200, 240);
232 // glEnable(GL_SCISSOR_TEST);
235 //****************************************************************
236 // OBJECT MOVING RETICLE
237 // TYPE VELOCITY VECTOR
240 glBegin(GL_LINE_LOOP); // Use polygon to approximate a circle
241 for (count = 0; count < 50; count++) {
242 cosine = 6 * cos(count * SGD_2PI / 50.0);
243 sine = 6 * sin(count * SGD_2PI / 50.0);
244 glVertex2f(cosine + vel_x, sine + vel_y);
248 //velocity vector reticle orientation lines
249 glBegin(GL_LINE_STRIP);
250 glVertex2f(vel_x - 12, vel_y);
251 glVertex2f(vel_x - 6, vel_y);
253 glBegin(GL_LINE_STRIP);
254 glVertex2f(vel_x + 12, vel_y);
255 glVertex2f(vel_x + 6, vel_y);
257 glBegin(GL_LINE_STRIP);
258 glVertex2f(vel_x, vel_y + 12);
259 glVertex2f(vel_x, vel_y + 6);
262 #ifdef ENABLE_SP_FMDS
263 // OBJECT MOVING RETICLE
265 // ATTRIB - ON CONDITION
267 // undercarriage status
268 glBegin(GL_LINE_STRIP);
269 glVertex2f(vel_x + 8, vel_y);
270 glVertex2f(vel_x + 8, vel_y - 4);
273 // OBJECT MOVING RETICLE
275 // ATTRIB - ON CONDITION
276 glBegin(GL_LINE_STRIP);
277 glVertex2f(vel_x - 8, vel_y);
278 glVertex2f(vel_x - 8, vel_y - 4);
281 // OBJECT MOVING RETICLE
283 // ATTRIB - ON CONDITION
284 glBegin(GL_LINE_STRIP);
285 glVertex2f(vel_x, vel_y - 6);
286 glVertex2f(vel_x, vel_y - 10);
290 // OBJECT MOVING RETICLE
292 // ATTRIB - ON CONDITION
294 // arrestor hook status
295 glBegin(GL_LINE_STRIP);
296 glVertex2f(vel_x - 4, vel_y - 8);
297 glVertex2f(vel_x, vel_y - 10);
298 glVertex2f(vel_x + 4, vel_y - 8);
302 } // if _velocity_vector
305 //***************************************************************
306 // OBJECT MOVING RETICLE
307 // TYPE - SQUARE_BRACKET
308 // ATTRIB - ON CONDITION
310 #ifdef ENABLE_SP_FMDS
311 if (_alpha_bracket && ihook == 1) {
312 glBegin(GL_LINE_STRIP);
313 glVertex2f(vel_x - 20 , vel_y - (16 - alpha) * _compression);
314 glVertex2f(vel_x - 17, vel_y - (16 - alpha) * _compression);
315 glVertex2f(vel_x - 17, vel_y - (14 - alpha) * _compression);
316 glVertex2f(vel_x - 20, vel_y - (14 - alpha) * _compression);
319 glBegin(GL_LINE_STRIP);
320 glVertex2f(vel_x + 20 , vel_y - (16 - alpha) * _compression);
321 glVertex2f(vel_x + 17, vel_y - (16 - alpha) * _compression);
322 glVertex2f(vel_x + 17, vel_y - (14 - alpha) * _compression);
323 glVertex2f(vel_x + 20, vel_y - (14 - alpha) * _compression);
327 //printf("xvr=%f, yvr=%f, Vx=%f, Vy=%f, Vz=%f\n",xvvr, yvvr, Vx, Vy, Vz);
328 //printf("Ax=%f, Ay=%f, Az=%f\n",Ax, Ay, Az);
330 //****************************************************************
331 // OBJECT MOVING RETICLE
332 // TYPE ENERGY_MARKERS
334 //energy markers - compute potential slope
335 if (_energy_marker) {
336 if (total_vel < 5.0) {
340 t1 = up_vel / total_vel;
341 t2 = asin((Vxx * Axx + Vyy * Ayy + Vzz * Azz) / (9.81 * total_vel));
343 pot_slope = ((t2 / 3) * SGD_RADIANS_TO_DEGREES) * _compression + vel_y;
344 // if (pot_slope < (vel_y - 45)) pot_slope = vel_y - 45;
345 // if (pot_slope > (vel_y + 45)) pot_slope = vel_y + 45;
348 glBegin(GL_LINE_STRIP);
349 glVertex2f(vel_x - 20, pot_slope - 5);
350 glVertex2f(vel_x - 15, pot_slope);
351 glVertex2f(vel_x - 20, pot_slope + 5);
354 glBegin(GL_LINE_STRIP);
355 glVertex2f(vel_x + 20, pot_slope - 5);
356 glVertex2f(vel_x + 15, pot_slope);
357 glVertex2f(vel_x + 20, pot_slope + 5);
360 if (pla > (105.0 / 131.0)) {
361 glBegin(GL_LINE_STRIP);
362 glVertex2f(vel_x - 24, pot_slope - 5);
363 glVertex2f(vel_x - 19, pot_slope);
364 glVertex2f(vel_x - 24, pot_slope + 5);
367 glBegin(GL_LINE_STRIP);
368 glVertex2f(vel_x + 24, pot_slope - 5);
369 glVertex2f(vel_x + 19, pot_slope);
370 glVertex2f(vel_x + 24, pot_slope + 5);
375 //**********************************************************
377 // OBJECT STATIC RETICLE
379 // ATTRIB - ON CONDITION
380 #ifdef ENABLE_SP_FMDS
381 if (_energy_worm && ilcanclaw == 1) {
382 glBegin(GL_LINE_STRIP);
383 glVertex2f(-15, -134);
384 glVertex2f(15, -134);
387 // OBJECT MOVING RETICLE
389 // ATTRIB - ON CONDITION
390 glBegin(GL_LINE_STRIP);
391 glVertex2f(-6, -134);
392 glVertex2f(-6, t2 * SGD_RADIANS_TO_DEGREES * 4.0 - 134);
393 glVertex2f(+6, t2 * SGD_RADIANS_TO_DEGREES * 4.0 - 134);
397 // OBJECT MOVING RETICLE
399 // ATTRIB - ON CONDITION
400 glBegin(GL_LINE_LOOP);
401 glVertex2f(-6, actslope * 4.0 - 134);
402 glVertex2f(0, actslope * 4.0 -134 + 3);
403 glVertex2f(6, actslope * 4.0 - 134);
404 glVertex2f(0, actslope * 4.0 -134 -3);
409 //*************************************************************
410 // OBJECT MOVING RETICLE
413 // Draw the locked velocity vector.
414 if (_climb_dive_marker) {
415 glBegin(GL_LINE_LOOP);
416 glVertex2f(-3.0, 0.0 + vel_y);
417 glVertex2f(0.0, 6.0 + vel_y);
418 glVertex2f(3.0, 0.0 + vel_y);
419 glVertex2f(0.0, -6.0 + vel_y);
423 //****************************************************************
425 if (climb_dive_ladder) { // CONFORMAL_HUD
426 _vmin = pitch_value - (float)width_units;
427 _vmax = pitch_value + (float)width_units;
428 glTranslatef(vel_x, vel_y, 0);
430 } else { // pitch_ladder - Default Hud
431 _vmin = pitch_value - (float)width_units * 0.5f;
432 _vmax = pitch_value + (float)width_units * 0.5f;
435 glRotatef(roll_value * SGD_RADIANS_TO_DEGREES, 0.0, 0.0, 1.0);
436 // FRL marker not rotated - this line shifted below
439 const int BUFSIZE = 8;
447 float text_offset = 4.0f;
448 float zero_offset = 0.0;
450 if (climb_dive_ladder)
451 zero_offset = 50.0f; // horizon line is wider by this much (hard coded ??)
455 fntFont *font = _hud->_font_renderer->getFont(); // FIXME
456 float pointsize = _hud->_font_renderer->getPointSize();
457 float italic = _hud->_font_renderer->getSlant();
459 _locTextList.setFont(_hud->_font_renderer);
460 _locTextList.erase();
461 _locLineList.erase();
462 _locStippleLineList.erase();
464 int last = int(_vmax) + 1;
470 for (; i<last; i++) {
471 y = (((float)(i - pitch_value) * _compression) + .5f);
473 if (!(i % div_units)) { // At integral multiple of div
474 snprintf(buf, BUFSIZE, "%d", i);
475 font->getBBox(buf, pointsize, italic, &left, &right, &bot, &top);
476 label_length = right - left;
477 label_length += text_offset;
478 label_height = (top - bot) / 2.0f;
483 // Make zero point wider on left
485 x_ini -= zero_offset;
487 // Zero or above draw solid lines
488 draw_line(x_ini, y, x_end, y);
490 if (i == 90 && _zenith == 1)
491 draw_zenith(x_ini, x_end, y);
493 // Below zero draw dashed lines.
494 draw_stipple_line(x_ini, y, x_end, y);
496 if (i == -90 && _nadir ==1)
497 draw_nadir(x_ini, x_end, y);
500 // Calculate the position of the left text and write it.
501 draw_text(x_ini - label_length, y - label_height, buf);
502 draw_text(x_end + text_offset, y - label_height, buf);
506 } else { // if (_scr_hole)
507 // Draw ladder with space in the middle of the lines
508 float hole = (float)((_scr_hole) / 2.0f);
510 x_end = -half_span + hole;
511 x_ini2 = half_span - hole;
513 for (; i < last; i++) {
515 y = (((float)(i - pitch_value) * _compression) + .5);
516 else // _type == CLIMB_DIVE
517 y = (((float)(i - actslope) * _compression) + .5);
519 if (!(i % div_units)) { // At integral multiple of div
520 snprintf(buf, BUFSIZE, "%d", i);
521 font->getBBox(buf, pointsize, italic, &left, &right, &bot, &top);
522 label_length = right - left;
523 label_length += text_offset;
524 label_height = (top - bot) / 2.0f;
525 // printf("l %f r %f b %f t %f\n",left, right, bot, top);
527 // Start by calculating the points and drawing the
533 // Make zero point wider on left
535 x_ini -= zero_offset;
536 x_end2 += zero_offset;
538 //draw climb bar vertical lines
539 if (climb_dive_ladder) {
540 // Zero or above draw solid lines
541 draw_line(x_end, y - 5.0, x_end, y);
542 draw_line(x_ini2, y - 5.0, x_ini2, y);
544 // draw pitch / climb bar
545 draw_line(x_ini, y, x_end, y);
546 draw_line(x_ini2, y, x_end2, y);
548 if (i == 90 && _zenith == 1)
549 draw_zenith(x_ini2, x_end, y);
552 // draw dive bar vertical lines
553 if (climb_dive_ladder) {
554 draw_line(x_end, y + 5.0, x_end, y);
555 draw_line(x_ini2, y + 5.0, x_ini2, y);
558 // draw pitch / dive bars
559 draw_stipple_line(x_ini, y, x_end, y);
560 draw_stipple_line(x_ini2, y, x_end2, y);
562 if (i == -90 && _nadir == 1)
563 draw_nadir(x_ini2, x_end, y);
566 // Now calculate the location of the left side label using
567 draw_text(x_ini - label_length, y - label_height, buf);
568 draw_text(x_end2 + text_offset, y - label_height, buf);
572 // OBJECT LADDER MARK
574 // ATTRIB - ON CONDITION
575 // draw appraoch glide slope marker
576 #ifdef ENABLE_SP_FMDS
577 if (_glide_slope_marker && ihook) {
578 draw_line(-half_span + 15, (_glide_slope - actslope) * _compression,
579 -half_span + hole, (_glide_slope - actslope) * _compression);
580 draw_line(half_span - 15, (_glide_slope - actslope) * _compression,
581 half_span - hole, (_glide_slope - actslope) * _compression);
591 glEnable(GL_LINE_STIPPLE);
592 glLineStipple(1, 0x00FF);
593 _locStippleLineList.draw();
594 glDisable(GL_LINE_STIPPLE);
596 glDisable(GL_CLIP_PLANE0);
597 glDisable(GL_CLIP_PLANE1);
598 glDisable(GL_CLIP_PLANE2);
599 // glDisable(GL_SCISSOR_TEST);
601 //*************************************************************
603 //*************************************************************
604 #ifdef ENABLE_SP_FMDS
605 if (_waypoint_marker) {
606 //waypoint marker computation
607 float fromwp_lat, towp_lat, fromwp_lon, towp_lon, dist, delx, dely, hyp, theta, brg;
609 fromwp_lon = get__longitude() * SGD_DEGREES_TO_RADIANS;
610 fromwp_lat = get__latitude() * SGD_DEGREES_TO_RADIANS;
611 towp_lon = get__aux2() * SGD_DEGREES_TO_RADIANS;
612 towp_lat = get__aux1() * SGD_DEGREES_TO_RADIANS;
614 dist = acos(sin(fromwp_lat) * sin(towp_lat) + cos(fromwp_lat)
615 * cos(towp_lat) * cos(fabs(fromwp_lon - towp_lon)));
616 delx= towp_lat - fromwp_lat;
617 dely = towp_lon - fromwp_lon;
618 hyp = sqrt(pow(delx, 2) + pow(dely, 2));
621 theta = asin(dely / hyp);
625 brg = theta * SGD_RADIANS_TO_DEGREES;
631 // {Brg = asin(cos(towp_lat)*sin(fabs(fromwp_lon-towp_lon))/ sin(dist));
632 // Brg = Brg * SGD_RADIANS_TO_DEGREES; }
634 dist *= SGD_RADIANS_TO_DEGREES * 60.0 * 1852.0; //rad->deg->nm->m
635 // end waypoint marker computation
637 //*********************************************************
638 // OBJECT MOVING RETICLE
641 if (fabs(brg-psi) > 10.0) {
643 glTranslatef(centroid.x, centroid.y, 0);
644 glTranslatef(vel_x, vel_y, 0);
645 glRotatef(brg - psi, 0.0, 0.0, -1.0);
646 glBegin(GL_LINE_LOOP);
647 glVertex2f(-2.5, 20.0);
648 glVertex2f(-2.5, 30.0);
649 glVertex2f(-5.0, 30.0);
650 glVertex2f(0.0, 35.0);
651 glVertex2f(5.0, 30.0);
652 glVertex2f(2.5, 30.0);
653 glVertex2f(2.5, 20.0);
658 // waypoint marker on heading scale
659 if (fabs(brg-psi) < 12.0) {
661 glBegin(GL_LINE_LOOP);
662 glVertex2f(((brg - psi) * 60 / 25) + 320, 240.0);
663 glVertex2f(((brg - psi) * 60 / 25) + 326, 240.0 - 4);
664 glVertex2f(((brg - psi) * 60 / 25) + 323, 240.0 - 4);
665 glVertex2f(((brg - psi) * 60 / 25) + 323, 240.0 - 8);
666 glVertex2f(((brg - psi) * 60 / 25) + 317, 240.0 - 8);
667 glVertex2f(((brg - psi) * 60 / 25) + 317, 240.0 - 4);
668 glVertex2f(((brg - psi) * 60 / 25) + 314, 240.0 - 4);
672 float x = (brg - psi) * 60 / 25 + 320, y = 240.0, r = 5.0;
675 glEnable(GL_POINT_SMOOTH);
678 for (int count = 0; count <= 200; count++) {
679 float temp = count * 3.142 * 3 / (200.0 * 2.0);
680 float temp1 = temp - (45.0 * SGD_DEGREES_TO_RADIANS);
681 x1 = x + r * cos(temp1);
682 y1 = y + r * sin(temp1);
687 glDisable(GL_POINT_SMOOTH);
691 } // if _waypoint_marker
696 /******************************************************************/
697 // draws the zenith symbol for highest possible climb angle (i.e. 90 degree climb angle)
699 void HUD::Ladder::draw_zenith(float xfirst, float xlast, float yvalue)
701 float xcentre = (xfirst + xlast) / 2.0;
702 float ycentre = yvalue;
704 draw_line(xcentre - 9.0, ycentre, xcentre - 3.0, ycentre + 1.3);
705 draw_line(xcentre - 9.0, ycentre, xcentre - 3.0, ycentre - 1.3);
707 draw_line(xcentre + 9.0, ycentre, xcentre + 3.0, ycentre + 1.3);
708 draw_line(xcentre + 9.0, ycentre, xcentre + 3.0, ycentre - 1.3);
710 draw_line(xcentre, ycentre + 9.0, xcentre - 1.3, ycentre + 3.0);
711 draw_line(xcentre, ycentre + 9.0, xcentre + 1.3, ycentre + 3.0);
713 draw_line(xcentre - 3.9, ycentre + 3.9, xcentre - 3.0, ycentre + 1.3);
714 draw_line(xcentre - 3.9, ycentre + 3.9, xcentre - 1.3, ycentre + 3.0);
716 draw_line(xcentre + 3.9, ycentre + 3.9, xcentre + 1.3, ycentre+3.0);
717 draw_line(xcentre + 3.9, ycentre + 3.9, xcentre + 3.0, ycentre+1.3);
719 draw_line(xcentre - 3.9, ycentre - 3.9, xcentre - 3.0, ycentre-1.3);
720 draw_line(xcentre - 3.9, ycentre - 3.9, xcentre - 1.3, ycentre-2.6);
722 draw_line(xcentre + 3.9, ycentre - 3.9, xcentre + 3.0, ycentre-1.3);
723 draw_line(xcentre + 3.9, ycentre - 3.9, xcentre + 1.3, ycentre-2.6);
725 draw_line(xcentre - 1.3, ycentre - 2.6, xcentre, ycentre - 27.0);
726 draw_line(xcentre + 1.3, ycentre - 2.6, xcentre, ycentre - 27.0);
730 // draws the nadir symbol for lowest possible dive angle (i.e. 90 degree dive angle)
732 void HUD::Ladder::draw_nadir(float xfirst, float xlast, float yvalue)
734 float xcentre = (xfirst + xlast) / 2.0;
735 float ycentre = yvalue;
738 float x1, y1, x2, y2;
741 float xcent1, xcent2, ycent1, ycent2;
742 xcent1 = xcentre + r;
745 for (int count = 1; count <= 400; count++) {
746 float temp = count * 2 * 3.142 / 400.0;
747 xcent2 = xcentre + r * cos(temp);
748 ycent2 = ycentre + r * sin(temp);
750 draw_line(xcent1, ycent1, xcent2, ycent2);
756 xcent2 = xcentre + r;
759 Item::draw_line(xcent1, ycent1, xcent2, ycent2); //to connect last point to first point
762 //to draw a line above the circle
763 draw_line(xcentre, ycentre + 7.5, xcentre, ycentre + 22.5);
765 //line in the middle of circle
766 draw_line(xcentre - 7.5, ycentre, xcentre + 7.5, ycentre);
768 float theta = asin (2.5 / 7.5);
769 float theta1 = asin(5.0 / 7.5);
771 x1 = xcentre + r * cos(theta);
773 x2 = xcentre + r * cos((180.0 * SGD_DEGREES_TO_RADIANS) - theta);
775 draw_line(x1, y1, x2, y2);
777 x1 = xcentre + r * cos(theta1);
779 x2 = xcentre + r * cos((180.0 * SGD_DEGREES_TO_RADIANS) - theta1);
781 draw_line(x1, y1, x2, y2);
783 x1 = xcentre + r * cos((180.0 * SGD_DEGREES_TO_RADIANS) + theta);
785 x2 = xcentre + r * cos((360.0 * SGD_DEGREES_TO_RADIANS) - theta);
787 draw_line(x1, y1, x2, y2);
789 x1 = xcentre + r * cos((180.0 * SGD_DEGREES_TO_RADIANS) + theta1);
791 x2 = xcentre + r * cos((360.0 * SGD_DEGREES_TO_RADIANS) - theta1);
793 draw_line(x1, y1, x2, y2);