2 * queens - solves n queens problem, displays
3 * i make no claims that this is an optimal solution to the problem,
7 * version 1.0 - May 10, 2002
9 * Copyright (C) 2002 Blair Tennessy (tennessy@cs.ubc.ca)
11 * Permission to use, copy, modify, distribute, and sell this software and its
12 * documentation for any purpose is hereby granted without fee, provided that
13 * the above copyright notice appear in all copies and that both that
14 * copyright notice and this permission notice appear in supporting
15 * documentation. No representations are made about the suitability of this
16 * software for any purpose. It is provided "as is" without express or
20 #include <X11/Intrinsic.h>
23 # define PROGCLASS "Queens"
24 # define HACK_INIT init_queens
25 # define HACK_DRAW draw_queens
26 # define HACK_RESHAPE reshape_queens
27 # define HACK_HANDLE_EVENT queens_handle_event
28 # define EVENT_MASK PointerMotionMask
29 # define queens_opts xlockmore_opts
31 #define DEFAULTS "*delay: 20000 \n" \
32 "*showFPS: False \n" \
33 "*wireframe: False \n" \
35 # include "xlockmore.h"
44 #include "gltrackball.h"
47 #define countof(x) (sizeof((x))/sizeof((*x)))
49 static XrmOptionDescRec opts[] = {
50 {"+rotate", ".queens.rotate", XrmoptionNoArg, "false" },
51 {"-rotate", ".queens.rotate", XrmoptionNoArg, "true" },
52 {"+flat", ".queens.flat", XrmoptionNoArg, "false" },
53 {"-flat", ".queens.flat", XrmoptionNoArg, "true" },
56 int rotate, wire, clearbits, flat;
58 static argtype vars[] = {
59 {&rotate, "rotate", "Rotate", "True", t_Bool},
60 {&flat, "flat", "Flat", "False", t_Bool},
63 ModeSpecOpt queens_opts = {countof(opts), opts, countof(vars), vars, NULL};
66 ModStruct queens_description =
67 {"queens", "init_queens", "draw_queens", "release_queens",
68 "draw_queens", "init_queens", NULL, &queens_opts,
69 1000, 1, 2, 1, 4, 1.0, "",
75 GLXContext *glx_context;
77 trackball_state *trackball;
81 static Queenscreen *qs = NULL;
89 #define M_PI 3.14159265
98 /* definition of white/black colors */
99 GLfloat colors[COLORSETS][2][3] =
101 {{0.43, 0.54, 0.76}, {0.8, 0.8, 0.8}},
102 {{0.5, 0.7, 0.9}, {0.2, 0.3, 0.6}},
103 {{0.53725490196, 0.360784313725, 0.521568627451}, {0.6, 0.6, 0.6}},
104 {{0.15, 0.77, 0.54}, {0.5, 0.5, 0.5}},
105 {{0.9, 0.45, 0.0}, {0.5, 0.5, 0.5}},
108 int board[MAXBOARD][MAXBOARD];
109 int steps = 0, colorset = 0, BOARDSIZE = 8; /* 8 cuz its classic */
113 queens_handle_event (ModeInfo *mi, XEvent *event)
115 Queenscreen *c = &qs[MI_SCREEN(mi)];
117 if (event->xany.type == ButtonPress &&
118 event->xbutton.button & Button1)
120 c->button_down_p = True;
121 gltrackball_start (c->trackball,
122 event->xbutton.x, event->xbutton.y,
123 MI_WIDTH (mi), MI_HEIGHT (mi));
126 else if (event->xany.type == ButtonRelease &&
127 event->xbutton.button & Button1)
129 c->button_down_p = False;
132 else if (event->xany.type == MotionNotify &&
135 gltrackball_track (c->trackball,
136 event->xmotion.x, event->xmotion.y,
137 MI_WIDTH (mi), MI_HEIGHT (mi));
146 /* returns true if placing a queen on column c causes a conflict */
147 int conflictsCols(int c) {
150 for(i = 0; i < BOARDSIZE; ++i)
157 /* returns true if placing a queen on (r,c) causes a diagonal conflict */
158 int conflictsDiag(int r, int c) {
162 int n = r < c ? r : c;
163 for(i = 0; i < BOARDSIZE-abs(r-c); ++i)
164 if(board[r-n+i][c-n+i])
168 n = r < BOARDSIZE - (c+1) ? r : BOARDSIZE - (c+1);
169 for(i = 0; i < BOARDSIZE-abs(BOARDSIZE - (1+r+c)); ++i)
170 if(board[r-n+i][c+n-i])
176 /* returns true if placing a queen at (r,c) causes a conflict */
177 int conflicts(int r, int c) {
178 return !conflictsCols(c) ? conflictsDiag(r, c) : 1;
185 for(i = 0; i < MAXBOARD; ++i)
186 for(j = 0; j < MAXBOARD; ++j)
190 /* recursively determine solution */
191 int findSolution(int row, int col) {
195 while(col < BOARDSIZE) {
196 if(!conflicts(row, col)) {
199 if(findSolution(row+1, 0))
211 /** driver for finding solution */
212 void go(void) { while(!findSolution(0, random()%BOARDSIZE)); }
214 /* lighting variables */
215 GLfloat front_shininess[] = {60.0};
216 GLfloat front_specular[] = {0.4, 0.4, 0.4, 1.0};
217 GLfloat ambient[] = {0.3, 0.3, 0.3, 1.0};
218 GLfloat diffuse[] = {0.8, 0.8, 0.8, 1.0};
219 GLfloat position[] = { 0.0, 5.0, 5.0, 1.0 };
220 GLfloat lmodel_ambient[] = {0.6, 0.6, 0.6, 1.0};
221 GLfloat lmodel_twoside[] = {GL_TRUE};
223 /* configure lighting */
224 void setup_lights(void) {
226 /* setup twoside lighting */
227 glLightfv(GL_LIGHT0, GL_AMBIENT, ambient);
228 glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuse);
229 glLightfv(GL_LIGHT0, GL_POSITION, position);
230 glEnable(GL_LIGHTING);
233 /* setup material properties */
234 glMaterialfv(GL_FRONT_AND_BACK, GL_SHININESS, front_shininess);
235 glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, front_specular);
237 glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
240 #define checkImageWidth 8
241 #define checkImageHeight 8
242 GLubyte checkImage[checkImageWidth][checkImageHeight][3];
244 /* return alpha value for fading */
245 GLfloat findAlpha(void) {
246 return steps < 128 ? steps/128.0 : steps < 1024-128 ?1.0:(1024-steps)/128.0;
250 void drawPieces(void) {
253 for(i = 0; i < BOARDSIZE; ++i) {
254 for(j = 0; j < BOARDSIZE; ++j) {
256 glColor3fv(colors[colorset][i%2]);
260 glTranslatef(1.0, 0.0, 0.0);
263 glTranslatef(-1.0*BOARDSIZE, 0.0, 1.0);
267 /** reflectionboard */
268 void draw_reflections(void) {
271 glEnable(GL_STENCIL_TEST);
272 glStencilFunc(GL_ALWAYS, 1, 1);
273 glStencilOp(GL_KEEP, GL_KEEP, GL_REPLACE);
274 glColorMask(0,0,0,0);
275 glDisable(GL_CULL_FACE);
277 glDisable(GL_DEPTH_TEST);
280 /* only draw white squares */
281 for(i = 0; i < BOARDSIZE; ++i) {
282 for(j = (BOARDSIZE+i) % 2; j < BOARDSIZE; j += 2) {
283 glVertex3f(i, 0.0, j + 1.0);
284 glVertex3f(i + 1.0, 0.0, j + 1.0);
285 glVertex3f(i + 1.0, 0.0, j);
286 glVertex3f(i, 0.0, j);
290 glEnable(GL_DEPTH_TEST);
292 glColorMask(1, 1, 1, 1);
293 glStencilFunc(GL_EQUAL, 1, 1);
294 glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
297 glScalef(1.0, -1.0, 1.0);
298 glTranslatef(0.5, 0.001, 0.5);
299 glLightfv(GL_LIGHT0, GL_POSITION, position);
302 glDisable(GL_STENCIL_TEST);
305 glLightfv(GL_LIGHT0, GL_POSITION, position);
307 glEnable(GL_CULL_FACE);
309 glColorMask(1,1,1,1);
313 void drawBoard(void) {
318 for(i = 0; i < BOARDSIZE; ++i)
319 for(j = 0; j < BOARDSIZE; ++j) {
320 int par = (i-j+BOARDSIZE)%2;
321 glColor4f(colors[colorset][par][0],
322 colors[colorset][par][1],
323 colors[colorset][par][2],
325 glNormal3f(0.0, 1.0, 0.0);
326 glVertex3f(i, 0.0, j + 1.0);
327 glVertex3f(i + 1.0, 0.0, j + 1.0);
328 glVertex3f(i + 1.0, 0.0, j);
329 glVertex3f(i, 0.0, j);
335 void display(Queenscreen *c) {
338 glMatrixMode(GL_MODELVIEW);
341 /* setup light attenuation */
342 glEnable(GL_COLOR_MATERIAL);
343 glLightf(GL_LIGHT0, GL_CONSTANT_ATTENUATION, 0.8/(0.01+findAlpha()));
344 glLightf(GL_LIGHT0, GL_LINEAR_ATTENUATION, 0.06);
346 /** setup perspective */
347 glTranslatef(0.0, 0.0, -1.5*BOARDSIZE);
348 glRotatef(30.0, 1.0, 0.0, 0.0);
349 gltrackball_rotate (c->trackball);
350 glRotatef(theta*100, 0.0, 1.0, 0.0);
351 glTranslatef(-0.5*BOARDSIZE, 0.0, -0.5*BOARDSIZE);
353 /* find light positions */
354 position[0] = BOARDSIZE/2.0 + BOARDSIZE/1.4*-sin(theta*100*M_PI/180.0);
355 position[2] = BOARDSIZE/2.0 + BOARDSIZE/1.4*cos(theta*100*M_PI/180.0);
359 glEnable(GL_LIGHTING);
360 glLightfv(GL_LIGHT0, GL_POSITION, position);
364 /* draw reflections */
373 glLightf(GL_LIGHT0, GL_LINEAR_ATTENUATION, 0.1);
375 glTranslatef(0.5, 0.0, 0.5);
379 if(!c->button_down_p)
382 /* zero out board, find new solution of size MINBOARD <= i <= MAXBOARD */
383 if(++steps == 1024) {
386 BOARDSIZE = MINBOARD + (random() % (MAXBOARD - MINBOARD + 1));
387 colorset = (colorset+1)%COLORSETS;
393 GLfloat spidermodel[][3] =
412 #define EPSILON 0.001
414 /** draws cylindermodel */
415 void draw_model(int chunks, GLfloat model[][3], int r) {
417 GLUquadricObj *quadric = gluNewQuadric();
419 glRotatef(-90.0, 1.0, 0.0, 0.0);
421 for(i = 0; i < chunks; ++i) {
422 if(model[i][0] > EPSILON || model[i][1] > EPSILON)
423 gluCylinder(quadric, model[i][0], model[i][1], model[i][2], r, 1);
424 glTranslatef(0.0, 0.0, model[i][2]);
430 void reshape_queens(ModeInfo *mi, int width, int height) {
431 GLfloat h = (GLfloat) height / (GLfloat) width;
432 glViewport(0,0, width, height);
433 glMatrixMode(GL_PROJECTION);
435 gluPerspective(45, 1/h, 2.0, 30.0);
436 glMatrixMode(GL_MODELVIEW);
439 void init_queens(ModeInfo *mi) {
440 int screen = MI_SCREEN(mi);
442 wire = MI_IS_WIREFRAME(mi);
445 !(qs = (Queenscreen *) calloc(MI_NUM_SCREENS(mi), sizeof(Queenscreen))))
449 c->window = MI_WINDOW(mi);
450 c->trackball = gltrackball_init ();
452 if((c->glx_context = init_GL(mi)))
453 reshape_queens(mi, MI_WIDTH(mi), MI_HEIGHT(mi));
457 glClearColor(0.0, 0.0, 0.0, 0.0);
458 glNewList(QUEEN, GL_COMPILE);
459 draw_model(schunks, spidermodel, 24);
463 glShadeModel(GL_FLAT);
465 clearbits = GL_COLOR_BUFFER_BIT;
467 glColorMaterial(GL_FRONT, GL_DIFFUSE);
468 glEnable(GL_COLOR_MATERIAL);
472 glEnable(GL_DEPTH_TEST);
473 clearbits |= GL_DEPTH_BUFFER_BIT;
474 clearbits |= GL_STENCIL_BUFFER_BIT;
475 glEnable(GL_CULL_FACE);
479 glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
481 /* find a solution */
485 void draw_queens(ModeInfo *mi) {
486 Queenscreen *c = &qs[MI_SCREEN(mi)];
487 Window w = MI_WINDOW(mi);
488 Display *disp = MI_DISPLAY(mi);
493 glXMakeCurrent(disp, w, *(c->glx_context));
497 if(mi->fps_p) do_fps(mi);
499 glXSwapBuffers(disp, w);
502 void release_queens(ModeInfo *mi) {