old_tests/linetest.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) 2009-2010 Cyril Hrubis <metan@ucw.cz>                       *
  23  *                                                                           *
  24  *****************************************************************************/
  25
  26 #include <math.h>
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <SDL/SDL.h>
  30
  31 #include "GP.h"
  32
  33 /* The surface used as a display (in fact it is a software surface). */
  34 SDL_Surface *display = NULL;
  35
  36 /* Timer used for refreshing the display */
  37 SDL_TimerID timer;
  38
  39 /* An event used for signaling that the timer was triggered. */
  40 SDL_UserEvent timer_event;
  41
  42 /* Values for color pixels in display format. */
  43 static long colors[GP_BASIC_COLOR_COUNT];
  44
  45 Uint32 timer_callback(__attribute__((unused)) Uint32 interval,
  46                         __attribute__((unused)) void * param)
  47 {
  48         timer_event.type = SDL_USEREVENT;
  49         SDL_PushEvent((SDL_Event *) &timer_event);
  50         return 30;
  51 }
  52
  53 double start_angle = 0.0;
  54
  55 void redraw_screen(void)
  56 {
  57         double angle;
  58         int x, y;
  59         int xcenter = display->w/2;
  60         int ycenter = display->h/2;
  61
  62         SDL_LockSurface(display);
  63
  64         GP_Clear(display, colors[GP_BLACK]);
  65
  66         for (angle = 0.0; angle < 2*M_PI; angle += 0.1) {
  67                 x = (int) (display->w/2 * cos(start_angle + angle));
  68                 y = (int) (display->h/2 * sin(start_angle + angle));
  69
  70                 Uint8 r = 127.0 + 127.0 * cos(start_angle + angle);
  71                 Uint8 g = 127.0 + 127.0 * sin(start_angle + angle);
  72
  73                 Uint32 color = SDL_MapRGB(display->format, r, 0, g);
  74
  75                 /*
  76                  * Draw the line forth and back to detect any pixel change
  77                  * between one direction and the other.
  78                  */
  79                 GP_Line(display, color, xcenter, ycenter, xcenter + x, ycenter + y);
  80                 GP_Line(display, color, xcenter + x, ycenter + y, xcenter, ycenter);
  81         }
  82
  83         /* axes */
  84         GP_HLine(display, colors[GP_WHITE], 0, display->w, ycenter);
  85         GP_VLine(display, colors[GP_WHITE], xcenter, 0, display->h);
  86
  87         SDL_UnlockSurface(display);
  88 }
  89
  90 void event_loop(void)
  91 {
  92         SDL_Event event;
  93
  94         while (SDL_WaitEvent(&event) > 0) {
  95                 switch (event.type) {
  96                         case SDL_USEREVENT:
  97                                 redraw_screen();
  98                                 SDL_Flip(display);
  99                                 start_angle += 0.01;
 100                                 if (start_angle > 2*M_PI) {
 101                                         start_angle = 0.0;
 102                                 }
 103                         break;
 104                         case SDL_KEYDOWN:
 105                         case SDL_QUIT:
 106                                 return;
 107                 }
 108         }
 109 }
 110
 111 int main(void)
 112 {
 113         /* Initialize SDL */
 114         if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER) != 0) {
 115                 fprintf(stderr, "Could not initialize SDL: %s\n", SDL_GetError());
 116                 return 1;
 117         }
 118
 119         /* Create a window with a software back surface */
 120         display = SDL_SetVideoMode(640, 480, 0, SDL_SWSURFACE);
 121         if (display == NULL) {
 122                 fprintf(stderr, "Could not open display: %s\n", SDL_GetError());
 123                 goto fail;
 124         }
 125
 126         /* Print basic information about the surface */
 127         printf("Display surface properties:\n");
 128         printf("    width: %4d, height: %4d, pitch: %4d\n",
 129                display->w, display->h, display->pitch);
 130         printf("    bits per pixel: %2d, bytes per pixel: %2d\n",
 131                display->format->BitsPerPixel, display->format->BytesPerPixel);
 132
 133         /* Get colors */
 134         GP_LoadBasicColors(display, colors);
 135
 136         /* Set up a clipping rectangle to test proper clipping of pixels */
 137         SDL_Rect clip_rect = { 10, 10, 620, 460 };
 138         SDL_SetClipRect(display, &clip_rect);
 139
 140         /* Set up the refresh timer */
 141         timer = SDL_AddTimer(30, timer_callback, NULL);
 142         if (timer == 0) {
 143                 fprintf(stderr, "Could not set up timer: %s\n", SDL_GetError());
 144                 goto fail;
 145         }
 146
 147         /* Enter the event loop */
 148         event_loop();
 149
 150         /* We're done */
 151         SDL_Quit();
 152         return 0;
 153
 154 fail:
 155         SDL_Quit();
 156         return 1;
 157 }
 158