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 static void (*keyboard_sdl)(int down, SDL_Keycode sym) = NULL;
  34 static void (*audio_sdl)(float *data, int len) = NULL;
  35
  36 static void audio_cb(void __attribute__((unused)) *userdata, Uint8 *stream, int len)
  37 {
  38         float audio_data[len / sizeof(float)];
  39
  40         SDL_memset(stream, 0, len);
  41         audio_sdl(audio_data, len / sizeof(float));
  42         SDL_MixAudio(stream, (Uint8 *)audio_data, len, SDL_MIX_MAXVOLUME);
  43 }
  44
  45 int init_sdl(const char *progname, int width, int height, int sound_samplerate, int sound_chunk, void (*keyboard)(int down, SDL_Keycode sym), void (*audio)(float *data, int len))
  46 {
  47         int rc;
  48
  49         keyboard_sdl = keyboard;
  50         audio_sdl = audio;
  51
  52         /* init SDL library */
  53         rc = SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO);
  54         if (rc < 0) {
  55                 fprintf(stderr, "Failed to init SDL\n");
  56                 goto error;
  57         }
  58         sdl_initialized = 1;
  59
  60         /* open window */
  61         gl_window = SDL_CreateWindow(progname, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, width, height, SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE);
  62         if (!gl_window) {
  63                 fprintf(stderr, "Failed to open SDL window: %s\n", SDL_GetError());
  64                 rc = EIO;
  65                 goto error;
  66         }
  67
  68         /* create GL context */
  69         gl_context = SDL_GL_CreateContext(gl_window);
  70         if (!gl_context) {
  71                 fprintf(stderr, "Failed to create SDL's OpenGL context: %s\n", SDL_GetError());
  72                 rc = EIO;
  73                 goto error;
  74         }
  75
  76         rc = SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
  77         if (rc < 0) {
  78                 fprintf(stderr, "Failed to set SDL's OpenGL context profile\n");
  79                 goto error;
  80         }
  81
  82         rc = SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
  83         if (rc < 0) {
  84                 fprintf(stderr, "Failed to set SDL's OpenGL major version\n");
  85                 goto error;
  86         }
  87         rc = SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 2);
  88         if (rc < 0) {
  89                 fprintf(stderr, "Failed to set SDL's OpenGL minor version\n");
  90                 goto error;
  91         }
  92
  93         rc = SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
  94         if (rc < 0) {
  95                 fprintf(stderr, "Failed to set SDL's OpenGL doublebuffer\n");
  96                 goto error;
  97         }
  98
  99         rc = SDL_GL_SetSwapInterval(1);
 100         if (rc < 0) {
 101                 fprintf(stderr, "Failed to set SDL's OpenGL swap interval to VBLANK\n");
 102                 goto error;
 103         }
 104
 105 #ifndef __APPLE__
 106         glewExperimental = GL_TRUE;
 107         if (glewInit() != GLEW_OK) {
 108                 fprintf(stderr, "Failed to init GLEW\n");
 109                 goto error;
 110         }
 111 #endif
 112
 113         /* just in case */
 114         glDisable(GL_DEPTH_TEST);
 115         glDisable(GL_CULL_FACE);
 116
 117         /* open audio */
 118         SDL_AudioSpec want, have;
 119         SDL_memset(&want, 0, sizeof(want)); /* or SDL_zero(want) */
 120         want.freq = sound_samplerate;
 121         want.format = AUDIO_F32; /* we always use float in this project */
 122         want.channels = 1;
 123         want.samples = sound_chunk; /* must be a power of two */
 124         want.callback = audio_cb;
 125         rc = SDL_OpenAudio(&want, &have);
 126         if (rc < 0) {
 127                 fprintf(stderr, "Failed to open audio\n");
 128                 goto error;
 129         } else if (have.format != want.format) {
 130                 fprintf(stderr, "Failed to open audio with desired audio format\n");
 131                 SDL_CloseAudio();
 132                 rc = -EIO;
 133                 goto error;
 134         } else if (have.freq != want.freq) {
 135                 fprintf(stderr, "Failed to open audio with desired sample rate\n");
 136                 SDL_CloseAudio();
 137                 rc = -EIO;
 138                 goto error;
 139         } else {
 140                 SDL_PauseAudio(0);
 141                 audio_initialized = 1;
 142         }
 143
 144         return 0;
 145
 146 error:
 147         exit_sdl();
 148         return rc;
 149 }
 150
 151 static int key_ctrl = 0, fullscreen = 0;
 152
 153 int event_sdl(void)
 154 {
 155         int quit = 0;
 156         SDL_Event event;
 157
 158         while (SDL_PollEvent(&event)) {
 159                 if (event.type == SDL_QUIT)
 160                         quit = 1;
 161                 if (event.type == SDL_WINDOWEVENT) {
 162                         if (event.window.event == SDL_WINDOWEVENT_SIZE_CHANGED)
 163                                 resize_opengl(event.window.data1, event.window.data2);
 164                 }
 165                 if (event.type == SDL_KEYDOWN) {
 166                         switch (event.key.keysym.sym) {
 167                         case SDLK_f:
 168                                 if (key_ctrl) {
 169                                         if (fullscreen) {
 170                                                 fullscreen = 0;
 171                                                 SDL_SetWindowFullscreen(gl_window, 0);
 172                                         } else {
 173                                                 SDL_SetWindowFullscreen(gl_window, SDL_WINDOW_FULLSCREEN_DESKTOP);
 174                                                 fullscreen = 1;
 175                                         }
 176                                 }
 177                                 break;
 178                         case SDLK_LCTRL:
 179                         case SDLK_RCTRL:
 180                                 key_ctrl = 1;
 181                                 break;
 182                         }
 183                         keyboard_sdl(1, event.key.keysym.sym);
 184                 }
 185                 if (event.type == SDL_KEYUP) {
 186                         switch (event.key.keysym.sym) {
 187                         case SDLK_LCTRL:
 188                         case SDLK_RCTRL:
 189                                 key_ctrl = 0;
 190                                 break;
 191                         }
 192                         keyboard_sdl(0, event.key.keysym.sym);
 193                 }
 194         }
 195
 196         return quit;
 197 }
 198
 199 void swap_sdl(void)
 200 {
 201         SDL_GL_SwapWindow(gl_window);
 202 }
 203
 204 void exit_sdl(void)
 205 {
 206         /* close window */
 207         if (gl_window) {
 208                 SDL_DestroyWindow(gl_window);
 209                 gl_window = NULL;
 210         }
 211
 212         /* clear OpenGL context */
 213         if (gl_context) {
 214                 SDL_GL_DeleteContext(gl_context);
 215                 gl_context = NULL;
 216         }
 217
 218         /* exit SDL library */
 219         if (audio_initialized) {
 220                 SDL_PauseAudio(1);
 221                 SDL_CloseAudio();
 222                 audio_initialized = 0;
 223         }
 224         if (sdl_initialized) {
 225                 SDL_Quit();
 226                 sdl_initialized = 0;
 227         }
 228 }
 229