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