demos/c_simple/koch.c

   1 /*****************************************************************************
   2  * This file is part of gfxprim library.                                     *
   3  *                                                                           *
   4  * Gfxprim is free software; you can redistribute it and/or                  *
   5  * modify it under the terms of the GNU Lesser General Public                *
   6  * License as published by the Free Software Foundation; either              *
   7  * version 2.1 of the License, or (at your option) any later version.        *
   8  *                                                                           *
   9  * Gfxprim is distributed in the hope that it will be useful,                *
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of            *
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU         *
  12  * Lesser General Public License for more details.                           *
  13  *                                                                           *
  14  * You should have received a copy of the GNU Lesser General Public          *
  15  * License along with gfxprim; if not, write to the Free Software            *
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor,                        *
  17  * Boston, MA  02110-1301  USA                                               *
  18  *                                                                           *
  19  * Copyright (C) 2009-2010 Jiri "BlueBear" Dluhos                            *
  20  *                         <jiri.bluebear.dluhos@gmail.com>                  *
  21  *                                                                           *
  22  * Copyright (C) 2009-2013 Cyril Hrubis <metan@ucw.cz>                       *
  23  *                                                                           *
  24  *****************************************************************************/
  25
  26 /*
  27
  28   Simple test for triangle drawing runtime.
  29
  30  */
  31
  32 #include <math.h>
  33
  34 #include <GP.h>
  35
  36 #define TIMER_TICK 10000
  37 #define DISPLAY_W 640
  38 #define DISPLAY_H 480
  39 #define sqr(x) ((x)*(x))
  40 #define sgn(x) ((x)>0 ? 1 : -1)
  41
  42 static GP_Backend *backend;
  43 static GP_Context *context;
  44
  45 static int iter, l, way = 1, draw_edge = 1;
  46 static GP_Pixel black, blue, gray, red;
  47
  48 static void sierpinsky(double x1, double y1, double x4, double y4, int iter)
  49 {
  50         double x2, y2, x3, y3, x5, y5;
  51         GP_Pixel pixel;
  52         pixel = GP_RGBToPixel(0, 0, 255-16*iter, context->pixel_type);
  53
  54         if (iter <= 0) {
  55                 if (draw_edge)
  56                         GP_Line(context, x1, y1, x4, y4, black);
  57                 return;
  58         }
  59
  60         x2 = floor((2*x1 + x4)/3);
  61         y2 = floor((2*y1 + y4)/3);
  62
  63         x3 = floor((2*x4 + x1)/3);
  64         y3 = floor((2*y4 + y1)/3);
  65
  66         x5 = (x1+x4)/2 + (y2 - y3)*sqrt(3.00/4);
  67         y5 = (y1+y4)/2 + (x3 - x2)*sqrt(3.00/4);
  68
  69         GP_FillTriangle(context, x2, y2, x3, y3, x5, y5, pixel);
  70
  71         GP_PutPixel(context, x2, y2, red);
  72         GP_PutPixel(context, x3, y3, red);
  73         GP_PutPixel(context, x5, y5, red);
  74
  75         sierpinsky(x1, y1, x2, y2, iter - 1);
  76         sierpinsky(x2, y2, x5, y5, iter - 1);
  77         sierpinsky(x5, y5, x3, y3, iter - 1);
  78         sierpinsky(x3, y3, x4, y4, iter - 1);
  79 }
  80
  81 static void draw(int x, int y, int l, int iter)
  82 {
  83         double x1, y1, x2, y2, x3, y3;
  84         int w = context->w;
  85         int h = context->h;
  86
  87         l = ((w < h ? w : h) - 20)/(5 - 1.00*iter/120);
  88
  89         x1 = sin(1.00 * iter/57) * l + x;
  90         y1 = cos(1.00 * iter/57) * l + y;
  91
  92         x2 = sin(1.00 * (iter+120)/57) * l + x;
  93         y2 = cos(1.00 * (iter+120)/57) * l + y;
  94
  95         x3 = sin(1.00 * (iter+240)/57) * l + x;
  96         y3 = cos(1.00 * (iter+240)/57) * l + y;
  97
  98         GP_Fill(context, gray);
  99
 100         GP_FillTriangle(context, x1, y1, x2, y2, x3, y3, blue);
 101
 102         sierpinsky(x1, y1, x2, y2, iter/60%6);
 103         sierpinsky(x2, y2, x3, y3, iter/60%6);
 104         sierpinsky(x3, y3, x1, y1, iter/60%6);
 105
 106         GP_BackendFlip(backend);
 107 }
 108
 109 static int paused = 0;
 110
 111 void redraw(void)
 112 {
 113         if (paused)
 114                 return;
 115
 116         iter += 2 * way;
 117
 118         if (iter > 350)
 119                 way *= -1;
 120
 121         if (iter < 0)
 122                 way *= -1;
 123
 124         draw(context->w/2, context->h/2, l, iter);
 125 }
 126
 127 int main(void)
 128 {
 129         const char *backend_opts = "X11";
 130
 131         backend = GP_BackendInit(backend_opts, "Koch", stderr);
 132
 133         if (backend == NULL) {
 134                 fprintf(stderr, "Failed to initalize backend '%s'\n",
 135                         backend_opts);
 136                 return 1;
 137         }
 138
 139         context = backend->context;
 140
 141         black = GP_ColorToContextPixel(GP_COL_BLACK, context);
 142         blue  = GP_ColorToContextPixel(GP_COL_BLUE, context);
 143         gray  = GP_ColorToContextPixel(GP_COL_GRAY_LIGHT, context);
 144         red   = GP_ColorToContextPixel(GP_COL_RED, context);
 145
 146         iter = 0;
 147         draw(context->w/2, context->h/2, l, iter);
 148
 149         for (;;) {
 150                 GP_Event ev;
 151
 152                 redraw();
 153
 154                 GP_BackendPoll(backend);
 155
 156                 while (GP_BackendGetEvent(backend, &ev)) {
 157                         GP_EventDump(&ev);
 158
 159                         switch (ev.type) {
 160                         case GP_EV_KEY:
 161                                 if (ev.code != GP_EV_KEY_DOWN)
 162                                         continue;
 163
 164                                 switch (ev.val.key.key) {
 165                                 case GP_KEY_P:
 166                                         paused = !paused;
 167                                 break;
 168                                 case GP_KEY_E:
 169                                         draw_edge = !draw_edge;
 170                                 break;
 171                                 case GP_KEY_ESC:
 172                                         GP_BackendExit(backend);
 173                                         return 0;
 174                                 break;
 175                                 }
 176                         }
 177                 }
 178                 usleep(TIMER_TICK);
 179         }
 180
 181         return 0;
 182 }