source/main.c

   1 #define GL_GLEXT_PROTOTYPES
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <string.h>
   5 #include <X11/Xlib.h>
   6 #include <X11/extensions/Xcomposite.h>
   7 #include <X11/extensions/Xdamage.h>
   8 #include <X11/extensions/shape.h>
   9 #include <GL/gl.h>
  10 #include <GL/glx.h>
  11
  12 typedef struct CompositedWindow
  13 {
  14         Window window;
  15         int x;
  16         int y;
  17         unsigned width;
  18         unsigned height;
  19         unsigned border;
  20         int map_state;
  21         Damage damage;
  22         Pixmap pixmap;
  23         GLXPixmap glx_pixmap;
  24         unsigned texture;
  25 } CompositedWindow;
  26
  27 typedef struct CompositedScreen
  28 {
  29         int number;
  30         Window root;
  31         unsigned width;
  32         unsigned height;
  33         Window overlay;
  34         Window render_window;
  35         GLXFBConfig fbconfig;
  36         GLXWindow glx_window;
  37         GLXContext glx_context;
  38         unsigned shaders[2];
  39         unsigned program;
  40         unsigned geometry_loc;
  41         unsigned vertex_buffer;
  42         unsigned vertex_array;
  43         CompositedWindow *windows;
  44         unsigned nwindows;
  45         unsigned windows_capacity;
  46         int dirty;
  47 } CompositedScreen;
  48
  49 typedef struct Compositor
  50 {
  51         Display *display;
  52         CompositedScreen *screens;
  53         unsigned nscreens;
  54         int damage_event;
  55         PFNGLXCREATECONTEXTATTRIBSARBPROC glXCreateContextAttribsARB;
  56         PFNGLXBINDTEXIMAGEEXTPROC glXBindTexImageEXT;
  57         PFNGLXRELEASETEXIMAGEEXTPROC glXReleaseTexImageEXT;
  58         int dirty;
  59 } Compositor;
  60
  61 static const char *vshader =
  62         "#version 150\n"
  63         "uniform vec4 geometry;\n"
  64         "in vec2 vertex;\n"
  65         "out vec2 texcoord;\n"
  66         "void main()\n"
  67         "{\n"
  68         "  gl_Position = vec4((geometry.xy+vertex*geometry.zw)*2.0-1.0, 0.0, 1.0);\n"
  69         "  texcoord = vec2(vertex.x, 1.0-vertex.y);\n"
  70         "}\n";
  71
  72 static const char *fshader =
  73         "#version 150\n"
  74         "uniform sampler2D window;\n"
  75         "in vec2 texcoord;\n"
  76         "out vec4 frag_color;\n"
  77         "void main()\n"
  78         "{\n"
  79         "       frag_color = texture(window, texcoord);\n"
  80         "}\n";
  81
  82 static const float vertices[] =
  83 {
  84         0.0f, 1.0f,
  85         0.0f, 0.0f,
  86         1.0f, 1.0f,
  87         1.0f, 0.0f
  88 };
  89
  90 int x_error_handler(Display *display, XErrorEvent *event)
  91 {
  92         printf("Ignoring X error %d on resource %lx\n", event->error_code, event->resourceid);
  93         (void)display;
  94         return 0;
  95 }
  96
  97 int with_error(const char *message)
  98 {
  99         fprintf(stderr, "%s\n", message);
 100         return 0;
 101 }
 102
 103 int initialize_gl(Compositor *compositor, CompositedScreen *screen)
 104 {
 105         int attribs[9];
 106         unsigned i;
 107         GLXFBConfig *configs;
 108         int nconfigs;
 109         XVisualInfo *vi;
 110         XSetWindowAttributes win_attr;
 111
 112         i = 0;
 113         attribs[i++] = GLX_DRAWABLE_TYPE;
 114         attribs[i++] = GLX_WINDOW_BIT;
 115         attribs[i++] = GLX_RENDER_TYPE;
 116         attribs[i++] = GLX_RGBA_BIT;
 117         attribs[i++] = GLX_DOUBLEBUFFER;
 118         attribs[i++] = True;
 119         attribs[i++] = GLX_BIND_TO_TEXTURE_RGBA_EXT;
 120         attribs[i++] = True;
 121         attribs[i] = None;
 122
 123         configs = glXChooseFBConfig(compositor->display, screen->number, attribs, &nconfigs);
 124         if(!configs || !nconfigs)
 125                 return with_error("Could not find a suitable FBConfig");
 126         screen->fbconfig = configs[0];
 127         XFree(configs);
 128
 129         vi = glXGetVisualFromFBConfig(compositor->display, screen->fbconfig);
 130         win_attr.colormap = XCreateColormap(compositor->display, screen->root, vi->visual, AllocNone);
 131         screen->render_window = XCreateWindow(compositor->display, screen->overlay, 0, 0, screen->width, screen->height, 0, vi->depth, InputOutput, vi->visual, CWColormap, &win_attr);
 132         XMapWindow(compositor->display, screen->render_window);
 133
 134         screen->glx_window = glXCreateWindow(compositor->display, screen->fbconfig, screen->render_window, NULL);
 135
 136         i = 0;
 137         attribs[i++] = GLX_CONTEXT_FLAGS_ARB;
 138         attribs[i++] = GLX_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB;
 139         attribs[i++] = GLX_CONTEXT_MAJOR_VERSION_ARB;
 140         attribs[i++] = 3;
 141         attribs[i++] = GLX_CONTEXT_MINOR_VERSION_ARB;
 142         attribs[i++] = 0;
 143         attribs[i] = None;
 144
 145         screen->glx_context = compositor->glXCreateContextAttribsARB(compositor->display, screen->fbconfig, NULL, True, attribs);
 146
 147         XFree(vi);
 148
 149         return 1;
 150 }
 151
 152 void use_gl(Compositor *compositor, CompositedScreen *screen)
 153 {
 154         glXMakeContextCurrent(compositor->display, screen->glx_window, screen->glx_window, screen->glx_context);
 155 }
 156
 157 unsigned compile_shader(GLenum type, const char *source)
 158 {
 159         unsigned shader;
 160         int status;
 161         char info_log[1024];
 162         GLsizei length;
 163
 164         shader = glCreateShader(type);
 165         glShaderSource(shader, 1, &source, NULL);
 166         glCompileShader(shader);
 167         glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
 168         glGetShaderInfoLog(shader, sizeof(info_log), &length, info_log);
 169         if(!status)
 170         {
 171                 fprintf(stderr, "Shader compilation failed:\n%s\n", info_log);
 172                 glDeleteShader(shader);
 173                 return 0;
 174         }
 175         else if(length)
 176                 printf("Shader info log:\n%s\n", info_log);
 177
 178         return shader;
 179 }
 180
 181 int create_gl_resources(Compositor *compositor, CompositedScreen *screen)
 182 {
 183         int status;
 184         char info_log[1024];
 185         GLsizei length;
 186
 187         use_gl(compositor, screen);
 188
 189         screen->shaders[0] = compile_shader(GL_VERTEX_SHADER, vshader);
 190         screen->shaders[1] = compile_shader(GL_FRAGMENT_SHADER, fshader);
 191         if(!screen->shaders[0] || !screen->shaders[1])
 192                 return 0;
 193
 194         screen->program = glCreateProgram();
 195         glAttachShader(screen->program, screen->shaders[0]);
 196         glAttachShader(screen->program, screen->shaders[1]);
 197         glBindAttribLocation(screen->program, 0, "vertex");
 198         glLinkProgram(screen->program);
 199
 200         screen->geometry_loc = glGetUniformLocation(screen->program, "geometry");
 201
 202         glGetProgramiv(screen->program, GL_LINK_STATUS, &status);
 203         glGetProgramInfoLog(screen->program, sizeof(info_log), &length, info_log);
 204         if(!status)
 205         {
 206                 fprintf(stderr, "Program link failed:\n%s\n", info_log);
 207                 glDeleteProgram(screen->program);
 208                 return 0;
 209         }
 210         else if(length)
 211                 printf("Program info log:\n%s\n", info_log);
 212
 213         glGenBuffers(1, &screen->vertex_buffer);
 214         glBindBuffer(GL_ARRAY_BUFFER, screen->vertex_buffer);
 215         glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
 216
 217         glGenVertexArrays(1, &screen->vertex_array);
 218         glBindVertexArray(screen->vertex_array);
 219         glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 0, NULL);
 220         glEnableVertexAttribArray(0);
 221
 222         glBindBuffer(GL_ARRAY_BUFFER, 0);
 223
 224         return 1;
 225 }
 226
 227 CompositedWindow *find_window(CompositedScreen *screen, Window w)
 228 {
 229         unsigned i;
 230
 231         for(i=0; i<screen->nwindows; ++i)
 232                 if(screen->windows[i].window==w)
 233                         return &screen->windows[i];
 234
 235         return NULL;
 236 }
 237
 238 void create_window_pixmap(Compositor *compositor, CompositedScreen *screen, CompositedWindow *window)
 239 {
 240         int attribs[5];
 241         unsigned i;
 242
 243         if(window->pixmap)
 244         {
 245                 glXDestroyPixmap(compositor->display, window->glx_pixmap);
 246                 XFreePixmap(compositor->display, window->pixmap);
 247         }
 248
 249         i = 0;
 250         attribs[i++] = GLX_TEXTURE_TARGET_EXT;
 251         attribs[i++] = GLX_TEXTURE_2D_EXT;
 252         attribs[i++] = GLX_TEXTURE_FORMAT_EXT;
 253         attribs[i++] = GLX_TEXTURE_FORMAT_RGBA_EXT;
 254         attribs[i++] = None;
 255
 256         window->pixmap = XCompositeNameWindowPixmap(compositor->display, window->window);
 257         window->glx_pixmap = glXCreatePixmap(compositor->display, screen->fbconfig, window->pixmap, attribs);
 258 }
 259
 260 void add_window(Compositor *compositor, CompositedScreen *screen, Window w)
 261 {
 262         CompositedWindow *window;
 263         XWindowAttributes win_attr;
 264
 265         if(w==screen->root || w==screen->overlay)
 266                 return;
 267
 268         if(!XGetWindowAttributes(compositor->display, w, &win_attr))
 269         {
 270                 printf("XGetWindowAttributes failed; probably the window was already destroyed\n");
 271                 return;
 272         }
 273         if(win_attr.class==InputOnly)
 274                 return;
 275
 276         if(find_window(screen, w))
 277                 return;
 278
 279         if(screen->nwindows==screen->windows_capacity)
 280         {
 281                 screen->windows = (CompositedWindow *)realloc(screen->windows, (screen->windows_capacity+1)*sizeof(CompositedWindow));
 282                 ++screen->windows_capacity;
 283         }
 284
 285         window = &screen->windows[screen->nwindows++];
 286
 287         window->window = w;
 288         window->x = win_attr.x;
 289         window->y = win_attr.y;
 290         window->width = win_attr.width;
 291         window->height = win_attr.height;
 292         window->border = win_attr.border_width;
 293         window->map_state = win_attr.map_state;
 294
 295         window->damage = XDamageCreate(compositor->display, window->window, XDamageReportNonEmpty);
 296         window->pixmap = None;
 297         window->glx_pixmap = None;
 298
 299         XCompositeRedirectWindow(compositor->display, window->window, CompositeRedirectManual);
 300         if(window->map_state==IsViewable)
 301                 create_window_pixmap(compositor, screen, window);
 302
 303         glGenTextures(1, &window->texture);
 304         glBindTexture(GL_TEXTURE_2D, window->texture);
 305         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 306         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 307         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 308 }
 309
 310 CompositedScreen *find_screen_by_root(Compositor *compositor, Window root)
 311 {
 312         unsigned i;
 313
 314         for(i=0; i<compositor->nscreens; ++i)
 315                 if(compositor->screens[i].root==root)
 316                         return &compositor->screens[i];
 317
 318         return NULL;
 319 }
 320
 321 CompositedScreen *find_screen_by_window(Compositor *compositor, Window w)
 322 {
 323         unsigned i, j;
 324
 325         for(i=0; i<compositor->nscreens; ++i)
 326                 for(j=0; j<compositor->screens[i].nwindows; ++j)
 327                         if(compositor->screens[i].windows[j].window==w)
 328                                 return &compositor->screens[i];
 329
 330         return NULL;
 331 }
 332
 333 int initialize_screen(Compositor *compositor, unsigned number)
 334 {
 335         CompositedScreen *screen;
 336         const char *extensions;
 337         Window dummy_root;
 338         int x, y;
 339         unsigned border;
 340         unsigned depth;
 341         Window dummy_parent;
 342         Window *children;
 343         unsigned nchildren;
 344         unsigned i;
 345
 346         screen = &compositor->screens[number];
 347         screen->number = number;
 348
 349         extensions = glXQueryExtensionsString(compositor->display, screen->number);
 350         if(!strstr(extensions, "GLX_ARB_create_context"))
 351                 return with_error("GLX_ARB_create_context is required");
 352         if(!strstr(extensions, "GLX_EXT_texture_from_pixmap"))
 353                 return with_error("GLX_EXT_texture_from_pixmap is required");
 354
 355         screen->root = RootWindow(compositor->display, screen->number);
 356         XSelectInput(compositor->display, screen->root, SubstructureNotifyMask);
 357         screen->overlay = XCompositeGetOverlayWindow(compositor->display, screen->root);
 358         XGetGeometry(compositor->display, screen->overlay, &dummy_root, &x, &y, &screen->width, &screen->height, &border, &depth);
 359         XShapeCombineRectangles(compositor->display, screen->overlay, ShapeInput, 0, 0, NULL, 0, ShapeSet, Unsorted);
 360
 361         if(!initialize_gl(compositor, screen))
 362                 return 0;
 363
 364         if(!create_gl_resources(compositor, screen))
 365                 return 0;
 366
 367         XQueryTree(compositor->display, screen->root, &dummy_root, &dummy_parent, &children, &nchildren);
 368
 369         screen->windows = (CompositedWindow *)malloc(nchildren*sizeof(CompositedWindow));
 370         screen->nwindows = 0;
 371         screen->windows_capacity = nchildren;
 372
 373         for(i=0; i<nchildren; ++i)
 374                 add_window(compositor, screen, children[i]);
 375
 376         XFree(children);
 377
 378         screen->dirty = 1;
 379
 380         return 1;
 381 }
 382
 383 int initialize_compositor(Compositor *compositor)
 384 {
 385         int event_base;
 386         int error_base;
 387         int major_ver;
 388         int minor_ver;
 389         unsigned i;
 390
 391         compositor->display = XOpenDisplay(NULL);
 392         if(!compositor->display)
 393                 return with_error("Could not open X display");
 394
 395         XSetErrorHandler(&x_error_handler);
 396
 397         if(!XCompositeQueryExtension(compositor->display, &event_base, &error_base))
 398                 return with_error("XComposite is required but was not found");
 399         else if(!XCompositeQueryVersion(compositor->display, &major_ver, &minor_ver))
 400                 return with_error("Cannot determine XComposite version");
 401         else if(major_ver==0 && minor_ver<3)
 402                 return with_error("XComposite 0.3 or later is required");
 403
 404         if(!glXQueryExtension(compositor->display, &event_base, &error_base))
 405                 return with_error("GLX is required but was not found");
 406         else if(!glXQueryVersion(compositor->display, &major_ver, &minor_ver))
 407                 return with_error("Cannot determine GLX version");
 408         else if(major_ver<1 || (major_ver==1 && minor_ver<4))
 409                 return with_error("GLX 1.4 or later is required");
 410
 411         if(!XDamageQueryExtension(compositor->display, &compositor->damage_event, &error_base))
 412                 return with_error("XDamage is required but was not found");
 413         else if(!XDamageQueryVersion(compositor->display, &major_ver, &minor_ver))
 414                 return with_error("Cannot determine XDamage version");
 415         else if(major_ver<1)
 416                 return with_error("XDamage 1.0 or later is required");
 417
 418         if(!XShapeQueryExtension(compositor->display, &event_base, &error_base))
 419                 return with_error("XShape is required but was not found");
 420         else if(!XShapeQueryVersion(compositor->display, &major_ver, &minor_ver))
 421                 return with_error("Cannot determine XShape version");
 422         else if(major_ver<1 || (major_ver==1 && minor_ver<1))
 423                 return with_error("XShape 1.1 or later is required");
 424
 425         compositor->glXCreateContextAttribsARB = (PFNGLXCREATECONTEXTATTRIBSARBPROC)glXGetProcAddress((unsigned char *)"glXCreateContextAttribsARB");
 426         compositor->glXBindTexImageEXT = (PFNGLXBINDTEXIMAGEEXTPROC)glXGetProcAddress((unsigned char *)"glXBindTexImageEXT");
 427         compositor->glXReleaseTexImageEXT = (PFNGLXRELEASETEXIMAGEEXTPROC)glXGetProcAddress((unsigned char *)"glXReleaseTexImageEXT");
 428
 429         compositor->nscreens = ScreenCount(compositor->display);
 430         compositor->screens = (CompositedScreen *)malloc(compositor->nscreens*sizeof(CompositedScreen));
 431         for(i=0; i<compositor->nscreens; ++i)
 432                 if(!initialize_screen(compositor, i))
 433                         return 0;
 434
 435         compositor->dirty = 1;
 436
 437         return 1;
 438 }
 439
 440 void shutdown_screen(Compositor *compositor, CompositedScreen *screen)
 441 {
 442         glXDestroyContext(compositor->display, screen->glx_context);
 443         glXDestroyWindow(compositor->display, screen->glx_window);
 444         XDestroyWindow(compositor->display, screen->render_window);
 445
 446         XCompositeReleaseOverlayWindow(compositor->display, screen->overlay);
 447 }
 448
 449 void shutdown_compositor(Compositor *compositor)
 450 {
 451         unsigned i;
 452
 453         glXMakeContextCurrent(compositor->display, 0, 0, NULL);
 454         for(i=0; i<compositor->nscreens; ++i)
 455                 shutdown_screen(compositor, &compositor->screens[i]);
 456 }
 457
 458 void process_create_window_event(Compositor *compositor, XCreateWindowEvent *event)
 459 {
 460         CompositedScreen *screen = find_screen_by_root(compositor, event->parent);
 461         if(!screen)
 462                 return;
 463
 464         add_window(compositor, screen, event->window);
 465 }
 466
 467 void process_map_event(Compositor *compositor, XMapEvent *event)
 468 {
 469         CompositedScreen *screen = find_screen_by_root(compositor, event->event);
 470         if(!screen)
 471                 return;
 472
 473         CompositedWindow *window = find_window(screen, event->window);
 474         if(window)
 475         {
 476                 window->map_state = IsViewable;
 477                 create_window_pixmap(compositor, screen, window);
 478         }
 479 }
 480
 481 void process_unmap_event(Compositor *compositor, XUnmapEvent *event)
 482 {
 483         CompositedScreen *screen = find_screen_by_root(compositor, event->event);
 484         if(!screen)
 485                 return;
 486
 487         CompositedWindow *window = find_window(screen, event->window);
 488         if(window)
 489                 window->map_state = IsUnviewable;
 490 }
 491
 492 void process_damage_event(Compositor *compositor, XDamageNotifyEvent *event)
 493 {
 494         CompositedScreen *screen = find_screen_by_window(compositor, event->drawable);
 495         if(!screen)
 496                 return;
 497
 498         screen->dirty = 1;
 499         compositor->dirty = 1;
 500 }
 501
 502 int process_event(Compositor *compositor)
 503 {
 504         XEvent event;
 505         if(compositor->dirty)
 506         {
 507                 if(!XCheckMaskEvent(compositor->display, -1, &event))
 508                         return 0;
 509         }
 510         else
 511                 XNextEvent(compositor->display, &event);
 512
 513         switch(event.type)
 514         {
 515         case CreateNotify:
 516                 process_create_window_event(compositor, &event.xcreatewindow);
 517                 break;
 518         case MapNotify:
 519                 process_map_event(compositor, &event.xmap);
 520                 break;
 521         case UnmapNotify:
 522                 process_unmap_event(compositor, &event.xunmap);
 523                 break;
 524         default:
 525                 if(event.type==compositor->damage_event+XDamageNotify)
 526                         process_damage_event(compositor, (XDamageNotifyEvent *)&event);
 527                 else
 528                         printf("Event %d\n", event.type);
 529         }
 530
 531         return 1;
 532 }
 533
 534 void refresh_screens(Compositor *compositor)
 535 {
 536         unsigned i, j;
 537
 538         for(i=0; i<compositor->nscreens; ++i)
 539         {
 540                 CompositedScreen *screen = &compositor->screens[i];
 541                 use_gl(compositor, screen);
 542
 543                 glClearColor(0.5f, 0.5f, 0.5f, 0.0f);
 544                 glClear(GL_COLOR_BUFFER_BIT);
 545
 546                 glUseProgram(screen->program);
 547                 glBindVertexArray(screen->vertex_array);
 548                 for(j=0; j<screen->nwindows; ++j)
 549                 {
 550                         CompositedWindow *window = &screen->windows[j];
 551                         if(window->map_state==IsViewable)
 552                         {
 553                                 glBindTexture(GL_TEXTURE_2D, window->texture);
 554                                 compositor->glXBindTexImageEXT(compositor->display, window->glx_pixmap, GLX_FRONT_LEFT_EXT, NULL);
 555                                 glUniform4f(screen->geometry_loc, (float)window->x/screen->width, (float)(screen->height-window->y-window->height)/screen->height, (float)(window->width+2*window->border)/screen->width, (float)(window->height+2*window->border)/screen->height);
 556                                 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
 557                                 compositor->glXReleaseTexImageEXT(compositor->display, window->glx_pixmap, GLX_FRONT_LEFT_EXT);
 558                                 XDamageSubtract(compositor->display, window->damage, None, None);
 559                         }
 560                 }
 561                 glXSwapBuffers(compositor->display, screen->glx_window);
 562
 563                 screen->dirty = 0;
 564         }
 565
 566         compositor->dirty = 0;
 567 }
 568
 569 int main()
 570 {
 571         Compositor compositor;
 572
 573         if(!initialize_compositor(&compositor))
 574                 return 1;
 575
 576         while(1)
 577         {
 578                 if(!process_event(&compositor))
 579                         refresh_screens(&compositor);
 580         }
 581
 582         shutdown_compositor(&compositor);
 583
 584         return 0;
 585 }