src/libsdl/sdl.c

   1 /* SDL handling
   2  *
   3  * (C) 2018 by Andreas Eversberg <jolly@eversberg.eu>
   4  * All Rights Reserved
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <stdio.h>
  21 #include <stdint.h>
  22 #include <errno.h>
  23 #include "sdl.h"
  24 #include "opengl.h"
  25
  26 #define GL3_PROTOTYPES 1
  27 #include <GL/glew.h>
  28
  29 static int sdl_initialized = 0;
  30 static int audio_initialized = 0;
  31 static SDL_Window *gl_window = NULL;
  32 static SDL_GLContext gl_context = NULL;
  33
  34 static void audio_cb(void __attribute__((unused)) *userdata, Uint8 *stream, int len)
  35 {
  36         float audio_data[len / sizeof(float)];
  37
  38         SDL_memset(stream, 0, len);
  39         audio_sdl(audio_data, len / sizeof(float));
  40         SDL_MixAudio(stream, (Uint8 *)audio_data, len, SDL_MIX_MAXVOLUME);
  41 }
  42
  43 int init_sdl(const char *progname, int width, int height, int sound_samplerate, int sound_chunk)
  44 {
  45         int rc;
  46
  47         /* init SDL library */
  48         rc = SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO);
  49         if (rc < 0) {
  50                 fprintf(stderr, "Failed to init SDL\n");
  51                 goto error;
  52         }
  53         sdl_initialized = 1;
  54
  55         /* open window */
  56         gl_window = SDL_CreateWindow(progname, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, width, height, SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE);
  57         if (!gl_window) {
  58                 fprintf(stderr, "Failed to open SDL window: %s\n", SDL_GetError());
  59                 rc = EIO;
  60                 goto error;
  61         }
  62
  63         /* create GL context */
  64         gl_context = SDL_GL_CreateContext(gl_window);
  65         if (!gl_context) {
  66                 fprintf(stderr, "Failed to create SDL's OpenGL context: %s\n", SDL_GetError());
  67                 rc = EIO;
  68                 goto error;
  69         }
  70
  71         rc = SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
  72         if (rc < 0) {
  73                 fprintf(stderr, "Failed to set SDL's OpenGL context profile\n");
  74                 goto error;
  75         }
  76
  77         rc = SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
  78         if (rc < 0) {
  79                 fprintf(stderr, "Failed to set SDL's OpenGL major version\n");
  80                 goto error;
  81         }
  82         rc = SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 2);
  83         if (rc < 0) {
  84                 fprintf(stderr, "Failed to set SDL's OpenGL minor version\n");
  85                 goto error;
  86         }
  87
  88         rc = SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
  89         if (rc < 0) {
  90                 fprintf(stderr, "Failed to set SDL's OpenGL doublebuffer\n");
  91                 goto error;
  92         }
  93
  94         rc = SDL_GL_SetSwapInterval(1);
  95         if (rc < 0) {
  96                 fprintf(stderr, "Failed to set SDL's OpenGL swap interval to VBLANK\n");
  97                 goto error;
  98         }
  99
 100 #ifndef __APPLE__
 101         glewExperimental = GL_TRUE;
 102         if (glewInit() != GLEW_OK) {
 103                 fprintf(stderr, "Failed to init GLEW\n");
 104                 goto error;
 105         }
 106 #endif
 107
 108         /* just in case */
 109         glDisable(GL_DEPTH_TEST);
 110         glDisable(GL_CULL_FACE);
 111
 112         /* open audio */
 113         SDL_AudioSpec want, have;
 114         SDL_memset(&want, 0, sizeof(want)); /* or SDL_zero(want) */
 115         want.freq = sound_samplerate;
 116         want.format = AUDIO_F32; /* we always use float in this project */
 117         want.channels = 1;
 118         want.samples = sound_chunk; /* must be a power of two */
 119         want.callback = audio_cb;
 120         rc = SDL_OpenAudio(&want, &have);
 121         if (rc < 0) {
 122                 fprintf(stderr, "Failed to open audio\n");
 123         } else if (have.format != want.format) {
 124                 fprintf(stderr, "Failed to open audio with desired audio format\n");
 125                 SDL_CloseAudio();
 126         } else {
 127                 SDL_PauseAudio(0);
 128                 audio_initialized = 1;
 129         }
 130
 131         return 0;
 132
 133 error:
 134         exit_sdl();
 135         return rc;
 136 }
 137
 138 static int key_ctrl = 0, fullscreen = 0;
 139
 140 int event_sdl(void)
 141 {
 142         int quit = 0;
 143         SDL_Event event;
 144
 145         while (SDL_PollEvent(&event)) {
 146                 if (event.type == SDL_QUIT)
 147                         quit = 1;
 148                 if (event.type == SDL_WINDOWEVENT) {
 149                         if (event.window.event == SDL_WINDOWEVENT_SIZE_CHANGED)
 150                                 resize_opengl(event.window.data1, event.window.data2);
 151                 }
 152                 if (event.type == SDL_KEYDOWN) {
 153                         switch (event.key.keysym.sym) {
 154                         case SDLK_f:
 155                                 if (key_ctrl) {
 156                                         if (fullscreen) {
 157                                                 fullscreen = 0;
 158                                                 SDL_SetWindowFullscreen(gl_window, 0);
 159                                         } else {
 160                                                 SDL_SetWindowFullscreen(gl_window, SDL_WINDOW_FULLSCREEN_DESKTOP);
 161                                                 fullscreen = 1;
 162                                         }
 163                                 }
 164                                 break;
 165                         case SDLK_LCTRL:
 166                         case SDLK_RCTRL:
 167                                 key_ctrl = 1;
 168                                 break;
 169                         }
 170                         keyboard_sdl(1, event.key.keysym.sym);
 171                 }
 172                 if (event.type == SDL_KEYUP) {
 173                         switch (event.key.keysym.sym) {
 174                         case SDLK_LCTRL:
 175                         case SDLK_RCTRL:
 176                                 key_ctrl = 0;
 177                                 break;
 178                         }
 179                         keyboard_sdl(0, event.key.keysym.sym);
 180                 }
 181         }
 182
 183         return quit;
 184 }
 185
 186 void swap_sdl(void)
 187 {
 188         SDL_GL_SwapWindow(gl_window);
 189 }
 190
 191 void exit_sdl(void)
 192 {
 193         /* close window */
 194         if (gl_window) {
 195                 SDL_DestroyWindow(gl_window);
 196                 gl_window = NULL;
 197         }
 198
 199         /* clear OpenGL context */
 200         if (gl_context) {
 201                 SDL_GL_DeleteContext(gl_context);
 202                 gl_context = NULL;
 203         }
 204
 205         /* exit SDL library */
 206         if (audio_initialized) {
 207                 SDL_PauseAudio(1);
 208                 SDL_CloseAudio();
 209                 audio_initialized = 0;
 210         }
 211         if (sdl_initialized) {
 212                 SDL_Quit();
 213                 sdl_initialized = 0;
 214         }
 215 }
 216