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 "print.h"
  24 #include "sdl.h"
  25 #include "opengl.h"
  26
  27 #define GL3_PROTOTYPES 1
  28 #include <GL/glew.h>
  29
  30 static int sdl_initialized = 0;
  31 static int audio_initialized = 0;
  32 static SDL_Window *gl_window = NULL;
  33 static SDL_GLContext gl_context = NULL;
  34 static void (*keyboard_sdl)(int down, SDL_Keycode sym) = NULL;
  35 static void (*audio_sdl)(float *data, int len) = NULL;
  36
  37 static void audio_cb(void __attribute__((unused)) *userdata, Uint8 *stream, int len)
  38 {
  39         float audio_data[len / sizeof(float)];
  40
  41         SDL_memset(stream, 0, len);
  42         audio_sdl(audio_data, len / sizeof(float));
  43         SDL_MixAudio(stream, (Uint8 *)audio_data, len, SDL_MIX_MAXVOLUME);
  44 }
  45
  46 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))
  47 {
  48         int rc;
  49
  50         keyboard_sdl = keyboard;
  51         audio_sdl = audio;
  52
  53         /* init SDL library */
  54         rc = SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO);
  55         if (rc < 0) {
  56                 print_error("Failed to init SDL\n");
  57                 goto error;
  58         }
  59         sdl_initialized = 1;
  60
  61         /* open window */
  62         gl_window = SDL_CreateWindow(progname, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, width, height, SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE);
  63         if (!gl_window) {
  64                 print_error("Failed to open SDL window: %s\n", SDL_GetError());
  65                 rc = EIO;
  66                 goto error;
  67         }
  68
  69         /* create GL context */
  70         gl_context = SDL_GL_CreateContext(gl_window);
  71         if (!gl_context) {
  72                 print_error("Failed to create SDL's OpenGL context: %s\n", SDL_GetError());
  73                 rc = EIO;
  74                 goto error;
  75         }
  76
  77         rc = SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
  78         if (rc < 0) {
  79                 print_error("Failed to set SDL's OpenGL context profile\n");
  80                 goto error;
  81         }
  82
  83         rc = SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
  84         if (rc < 0) {
  85                 print_error("Failed to set SDL's OpenGL major version\n");
  86                 goto error;
  87         }
  88         rc = SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 2);
  89         if (rc < 0) {
  90                 print_error("Failed to set SDL's OpenGL minor version\n");
  91                 goto error;
  92         }
  93
  94         rc = SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
  95         if (rc < 0) {
  96                 print_error("Failed to set SDL's OpenGL doublebuffer\n");
  97                 goto error;
  98         }
  99
 100         rc = SDL_GL_SetSwapInterval(1);
 101         if (rc < 0) {
 102                 print_error("Failed to set SDL's OpenGL swap interval to VBLANK\n");
 103                 goto error;
 104         }
 105
 106 #ifndef __APPLE__
 107         glewExperimental = GL_TRUE;
 108         if (glewInit() != GLEW_OK) {
 109                 print_error("Failed to init GLEW\n");
 110                 goto error;
 111         }
 112 #endif
 113
 114         /* just in case */
 115         glDisable(GL_DEPTH_TEST);
 116         glDisable(GL_CULL_FACE);
 117
 118         /* open audio */
 119         SDL_AudioSpec want, have;
 120         SDL_memset(&want, 0, sizeof(want)); /* or SDL_zero(want) */
 121         want.freq = sound_samplerate;
 122         want.format = AUDIO_F32; /* we always use float in this project */
 123         want.channels = 1;
 124         want.samples = sound_chunk; /* must be a power of two */
 125         want.callback = audio_cb;
 126         rc = SDL_OpenAudio(&want, &have);
 127         if (rc < 0) {
 128                 print_error("Failed to open audio\n");
 129                 goto error;
 130         } else if (have.format != want.format) {
 131                 print_error("Failed to open audio with desired audio format\n");
 132                 SDL_CloseAudio();
 133                 rc = -EIO;
 134                 goto error;
 135         } else if (have.freq != want.freq) {
 136                 print_error("Failed to open audio with desired sample rate\n");
 137                 SDL_CloseAudio();
 138                 rc = -EIO;
 139                 goto error;
 140         } else {
 141                 SDL_PauseAudio(0);
 142                 audio_initialized = 1;
 143         }
 144
 145         return 0;
 146
 147 error:
 148         exit_sdl();
 149         return rc;
 150 }
 151
 152 static int key_ctrl = 0, fullscreen = 0;
 153
 154 int event_sdl(void)
 155 {
 156         int quit = 0;
 157         SDL_Event event;
 158
 159         while (SDL_PollEvent(&event)) {
 160                 if (event.type == SDL_QUIT)
 161                         quit = 1;
 162                 if (event.type == SDL_WINDOWEVENT) {
 163                         if (event.window.event == SDL_WINDOWEVENT_SIZE_CHANGED)
 164                                 resize_opengl(event.window.data1, event.window.data2);
 165                 }
 166                 if (event.type == SDL_KEYDOWN) {
 167                         switch (event.key.keysym.sym) {
 168                         case SDLK_f:
 169                                 if (key_ctrl) {
 170                                         if (fullscreen) {
 171                                                 fullscreen = 0;
 172                                                 SDL_SetWindowFullscreen(gl_window, 0);
 173                                         } else {
 174                                                 SDL_SetWindowFullscreen(gl_window, SDL_WINDOW_FULLSCREEN_DESKTOP);
 175                                                 fullscreen = 1;
 176                                         }
 177                                 }
 178                                 break;
 179                         case SDLK_LCTRL:
 180                         case SDLK_RCTRL:
 181                                 key_ctrl = 1;
 182                                 break;
 183                         }
 184                         keyboard_sdl(1, event.key.keysym.sym);
 185                 }
 186                 if (event.type == SDL_KEYUP) {
 187                         switch (event.key.keysym.sym) {
 188                         case SDLK_LCTRL:
 189                         case SDLK_RCTRL:
 190                                 key_ctrl = 0;
 191                                 break;
 192                         }
 193                         keyboard_sdl(0, event.key.keysym.sym);
 194                 }
 195         }
 196
 197         return quit;
 198 }
 199
 200 void swap_sdl(void)
 201 {
 202         SDL_GL_SwapWindow(gl_window);
 203 }
 204
 205 void exit_sdl(void)
 206 {
 207         /* close window */
 208         if (gl_window) {
 209                 SDL_DestroyWindow(gl_window);
 210                 gl_window = NULL;
 211         }
 212
 213         /* clear OpenGL context */
 214         if (gl_context) {
 215                 SDL_GL_DeleteContext(gl_context);
 216                 gl_context = NULL;
 217         }
 218
 219         /* exit SDL library */
 220         if (audio_initialized) {
 221                 SDL_PauseAudio(1);
 222                 SDL_CloseAudio();
 223                 audio_initialized = 0;
 224         }
 225         if (sdl_initialized) {
 226                 SDL_Quit();
 227                 sdl_initialized = 0;
 228         }
 229 }
 230