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 #include <SDL2/SDL.h>
  28 #define GL3_PROTOTYPES 1
  29 #include <GL/glew.h>
  30
  31 static int sdl_initialized = 0;
  32 static int audio_initialized = 0;
  33 static SDL_Window *gl_window = NULL;
  34 static SDL_GLContext gl_context = NULL;
  35 static void (*keyboard_sdl)(int down, SDL_Keycode sym) = NULL;
  36 static void (*audio_sdl)(float *data, int len) = NULL;
  37
  38 static void audio_cb(void __attribute__((unused)) *userdata, Uint8 *stream, int len)
  39 {
  40         float audio_data[len / sizeof(float)];
  41
  42         SDL_memset(stream, 0, len);
  43         audio_sdl(audio_data, len / sizeof(float) / 2);
  44         SDL_MixAudio(stream, (Uint8 *)audio_data, len, SDL_MIX_MAXVOLUME);
  45 }
  46
  47 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), int multisampling)
  48 {
  49         int rc;
  50
  51         keyboard_sdl = keyboard;
  52         audio_sdl = audio;
  53
  54         /* init SDL library */
  55         rc = SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO);
  56         if (rc < 0) {
  57                 print_error("Failed to init SDL\n");
  58                 goto error;
  59         }
  60         sdl_initialized = 1;
  61
  62         if (multisampling) {
  63                 SDL_GL_SetAttribute(SDL_GL_RED_SIZE, 8);
  64                 SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE, 8);
  65                 SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE, 8);
  66                 SDL_GL_SetAttribute(SDL_GL_ALPHA_SIZE, 8);
  67                 SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);
  68                 SDL_GL_SetAttribute(SDL_GL_MULTISAMPLEBUFFERS, 1);
  69                 SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, multisampling);
  70         }
  71
  72         /* open window */
  73         gl_window = SDL_CreateWindow(progname, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, width, height, SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE);
  74         if (!gl_window) {
  75                 print_error("Failed to open SDL window: %s\n", SDL_GetError());
  76                 rc = EIO;
  77                 goto error;
  78         }
  79
  80         /* create GL context */
  81         gl_context = SDL_GL_CreateContext(gl_window);
  82         if (!gl_context) {
  83                 print_error("Failed to create SDL's OpenGL context: %s\n", SDL_GetError());
  84                 rc = EIO;
  85                 goto error;
  86         }
  87
  88         rc = SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
  89         if (rc < 0) {
  90                 print_error("Failed to set SDL's OpenGL context profile\n");
  91                 goto error;
  92         }
  93
  94         rc = SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
  95         if (rc < 0) {
  96                 print_error("Failed to set SDL's OpenGL major version\n");
  97                 goto error;
  98         }
  99         rc = SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 2);
 100         if (rc < 0) {
 101                 print_error("Failed to set SDL's OpenGL minor version\n");
 102                 goto error;
 103         }
 104
 105         rc = SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
 106         if (rc < 0) {
 107                 print_error("Failed to set SDL's OpenGL doublebuffer\n");
 108                 goto error;
 109         }
 110
 111         rc = SDL_GL_SetSwapInterval(1);
 112         if (rc < 0) {
 113                 print_error("Failed to set SDL's OpenGL swap interval to VBLANK\n");
 114                 // continue anyway
 115         }
 116
 117 #ifndef __APPLE__
 118         glewExperimental = GL_TRUE;
 119         if (glewInit() != GLEW_OK) {
 120                 print_error("Failed to init GLEW\n");
 121                 goto error;
 122         }
 123 #endif
 124
 125         /* just in case */
 126         glDisable(GL_DEPTH_TEST);
 127         glDisable(GL_CULL_FACE);
 128         if (multisampling)
 129                 glEnable(GL_MULTISAMPLE);
 130
 131         /* open audio */
 132         SDL_AudioSpec want, have;
 133         SDL_memset(&want, 0, sizeof(want)); /* or SDL_zero(want) */
 134         want.freq = sound_samplerate;
 135         want.format = AUDIO_F32; /* we always use float in this project */
 136         want.channels = 2;
 137         want.samples = sound_chunk; /* must be a power of two */
 138         want.callback = audio_cb;
 139         rc = SDL_OpenAudio(&want, &have);
 140         if (rc < 0) {
 141                 print_error("Failed to open audio! (No speaker connected?)\n");
 142                 goto error;
 143         } else if (have.format != want.format) {
 144                 print_error("Failed to open audio with desired audio format\n");
 145                 SDL_CloseAudio();
 146                 rc = -EIO;
 147                 goto error;
 148         } else if (have.freq != want.freq) {
 149                 print_error("Failed to open audio with desired sample rate\n");
 150                 SDL_CloseAudio();
 151                 rc = -EIO;
 152                 goto error;
 153         } else if (have.channels != want.channels) {
 154                 print_error("Failed to open audio with desired channels (got %d)\n", have.channels);
 155                 SDL_CloseAudio();
 156                 rc = -EIO;
 157                 goto error;
 158         } else {
 159                 SDL_PauseAudio(0);
 160                 audio_initialized = 1;
 161         }
 162
 163         return 0;
 164
 165 error:
 166         exit_sdl();
 167         return rc;
 168 }
 169
 170 static int key_ctrl = 0, fullscreen = 0;
 171
 172 int event_sdl(void)
 173 {
 174         int quit = 0;
 175         SDL_Event event;
 176
 177         while (SDL_PollEvent(&event)) {
 178                 if (event.type == SDL_QUIT)
 179                         quit = 1;
 180                 if (event.type == SDL_WINDOWEVENT) {
 181                         if (event.window.event == SDL_WINDOWEVENT_SIZE_CHANGED)
 182                                 resize_opengl(event.window.data1, event.window.data2);
 183                 }
 184                 if (event.type == SDL_KEYDOWN) {
 185                         switch (event.key.keysym.sym) {
 186                         case SDLK_f:
 187                                 if (key_ctrl) {
 188                                         if (fullscreen) {
 189                                                 fullscreen = 0;
 190                                                 SDL_SetWindowFullscreen(gl_window, 0);
 191                                                 SDL_ShowCursor(SDL_ENABLE);
 192                                         } else {
 193                                                 SDL_SetWindowFullscreen(gl_window, SDL_WINDOW_FULLSCREEN_DESKTOP);
 194                                                 SDL_ShowCursor(SDL_DISABLE);
 195                                                 fullscreen = 1;
 196                                         }
 197                                 }
 198                                 break;
 199                         case SDLK_LCTRL:
 200                         case SDLK_RCTRL:
 201                                 key_ctrl = 1;
 202                                 break;
 203                         }
 204                         keyboard_sdl(1, event.key.keysym.sym);
 205                 }
 206                 if (event.type == SDL_KEYUP) {
 207                         switch (event.key.keysym.sym) {
 208                         case SDLK_LCTRL:
 209                         case SDLK_RCTRL:
 210                                 key_ctrl = 0;
 211                                 break;
 212                         }
 213                         keyboard_sdl(0, event.key.keysym.sym);
 214                 }
 215         }
 216
 217         return quit;
 218 }
 219
 220 void swap_sdl(void)
 221 {
 222         SDL_GL_SwapWindow(gl_window);
 223 }
 224
 225 void exit_sdl(void)
 226 {
 227         /* close window */
 228         if (gl_window) {
 229                 SDL_DestroyWindow(gl_window);
 230                 gl_window = NULL;
 231         }
 232
 233         /* clear OpenGL context */
 234         if (gl_context) {
 235                 SDL_GL_DeleteContext(gl_context);
 236                 gl_context = NULL;
 237         }
 238
 239         /* exit SDL library */
 240         if (audio_initialized) {
 241                 SDL_PauseAudio(1);
 242                 SDL_CloseAudio();
 243                 audio_initialized = 0;
 244         }
 245         if (sdl_initialized) {
 246                 SDL_Quit();
 247                 sdl_initialized = 0;
 248         }
 249 }
 250
 251 uint32_t ticks_sdl(void)
 252 {
 253         return SDL_GetTicks();
 254 }