source/main.c

   1 #define GL_GLEXT_PROTOTYPES
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <string.h>
   5 #include <signal.h>
   6 #include <math.h>
   7 #include <X11/Xlib.h>
   8 #include <X11/Xatom.h>
   9 #include <X11/extensions/Xcomposite.h>
  10 #include <X11/extensions/Xdamage.h>
  11 #include <X11/extensions/shape.h>
  12 #include <X11/extensions/Xrandr.h>
  13 #include <GL/gl.h>
  14 #include <GL/glx.h>
  15
  16 typedef struct CompositedWindow
  17 {
  18         Window window;
  19         int x;
  20         int y;
  21         unsigned width;
  22         unsigned height;
  23         unsigned border;
  24         int map_state;
  25         Damage damage;
  26         Pixmap pixmap;
  27         GLXPixmap glx_pixmap;
  28         int recreate_pixmap;
  29         unsigned texture;
  30         unsigned mask_texture;
  31         int use_mask;
  32         int recreate_mask;
  33 } CompositedWindow;
  34
  35 typedef struct CompositedMonitor
  36 {
  37         char *name;
  38         int enabled;
  39         int x;
  40         int y;
  41         unsigned width;
  42         unsigned height;
  43         float keystone_vertical;
  44         float cylinder_depth;
  45         float vertical_center;
  46         float perspective;
  47         unsigned vertex_buffer;
  48         unsigned index_buffer;
  49         unsigned vertex_array;
  50         unsigned tessellation;
  51         unsigned nelements;
  52 } CompositedMonitor;
  53
  54 typedef struct CompositedScreen
  55 {
  56         int number;
  57         Window root;
  58         unsigned width;
  59         unsigned height;
  60         Window overlay;
  61         Window render_window;
  62         GLXFBConfig fbconfig;
  63         GLXWindow glx_window;
  64         GLXContext glx_context;
  65         unsigned shaders[3];
  66         unsigned program;
  67         int geometry_loc;
  68         unsigned masked_program;
  69         int masked_geometry_loc;
  70         unsigned window_vertex_buffer;
  71         unsigned window_vertex_array;
  72         unsigned framebuffer;
  73         unsigned fb_texture;
  74         CompositedWindow *windows;
  75         unsigned nwindows;
  76         unsigned windows_capacity;
  77         CompositedMonitor *monitors;
  78         unsigned nmonitors;
  79         int dirty;
  80 } CompositedScreen;
  81
  82 typedef struct Compositor
  83 {
  84         Display *display;
  85         CompositedScreen *screens;
  86         unsigned nscreens;
  87         int damage_event;
  88         int shape_event;
  89         PFNGLXCREATECONTEXTATTRIBSARBPROC glXCreateContextAttribsARB;
  90         PFNGLXBINDTEXIMAGEEXTPROC glXBindTexImageEXT;
  91         PFNGLXRELEASETEXIMAGEEXTPROC glXReleaseTexImageEXT;
  92         Atom correction_atom;
  93         Atom monitors_atom;
  94         int dirty;
  95 } Compositor;
  96
  97 static const char *vshader_src =
  98         "#version 150\n"
  99         "uniform vec4 geometry;\n"
 100         "in vec2 vertex;\n"
 101         "in vec2 texture_coord;\n"
 102         "out vec2 texcoord;\n"
 103         "void main()\n"
 104         "{\n"
 105         "  gl_Position = vec4((geometry.xy+vertex*geometry.zw)*2.0-1.0, 0.0, 1.0);\n"
 106         "  texcoord = texture_coord;\n"
 107         "}\n";
 108
 109 static const char *fshader_src =
 110         "#version 150\n"
 111         "uniform sampler2D image;\n"
 112         "in vec2 texcoord;\n"
 113         "out vec4 frag_color;\n"
 114         "void main()\n"
 115         "{\n"
 116         "  frag_color = texture(image, texcoord);\n"
 117         "}\n";
 118
 119 static const char *masked_fshader_src =
 120         "#version 150\n"
 121         "uniform sampler2D image;\n"
 122         "uniform sampler2D mask;\n"
 123         "in vec2 texcoord;\n"
 124         "out vec4 frag_color;\n"
 125         "void main()\n"
 126         "{\n"
 127         "  if(texture(mask, texcoord).r==0.0)\n"
 128         "    discard;\n"
 129         "  frag_color = texture(image, texcoord);\n"
 130         "}\n";
 131
 132 static const float window_vertices[] =
 133 {
 134         /* vertex    texcoord */
 135         0.0f, 1.0f,  0.0f, 0.0f,
 136         0.0f, 0.0f,  0.0f, 1.0f,
 137         1.0f, 1.0f,  1.0f, 0.0f,
 138         1.0f, 0.0f,  1.0f, 1.0f
 139 };
 140
 141 int terminate_requested = 0;
 142
 143 int x_error_handler(Display *display, XErrorEvent *event)
 144 {
 145         printf("Ignoring X error %d on resource %lx\n", event->error_code, event->resourceid);
 146         (void)display;
 147         return 0;
 148 }
 149
 150 int with_error(const char *message)
 151 {
 152         fprintf(stderr, "%s\n", message);
 153         return 0;
 154 }
 155
 156 int initialize_gl(Compositor *compositor, CompositedScreen *screen)
 157 {
 158         int attribs[9];
 159         unsigned i;
 160         GLXFBConfig *configs;
 161         int nconfigs;
 162         XVisualInfo *vi;
 163         XSetWindowAttributes win_attr;
 164
 165         i = 0;
 166         attribs[i++] = GLX_DRAWABLE_TYPE;
 167         attribs[i++] = GLX_WINDOW_BIT;
 168         attribs[i++] = GLX_RENDER_TYPE;
 169         attribs[i++] = GLX_RGBA_BIT;
 170         attribs[i++] = GLX_DOUBLEBUFFER;
 171         attribs[i++] = True;
 172         attribs[i++] = GLX_BIND_TO_TEXTURE_RGBA_EXT;
 173         attribs[i++] = True;
 174         attribs[i] = None;
 175
 176         configs = glXChooseFBConfig(compositor->display, screen->number, attribs, &nconfigs);
 177         if(!configs || !nconfigs)
 178                 return with_error("Could not find a suitable FBConfig");
 179         screen->fbconfig = configs[0];
 180         XFree(configs);
 181
 182         vi = glXGetVisualFromFBConfig(compositor->display, screen->fbconfig);
 183         win_attr.colormap = XCreateColormap(compositor->display, screen->root, vi->visual, AllocNone);
 184         screen->render_window = XCreateWindow(compositor->display, screen->overlay, 0, 0, screen->width, screen->height, 0, vi->depth, InputOutput, vi->visual, CWColormap, &win_attr);
 185         XMapWindow(compositor->display, screen->render_window);
 186
 187         screen->glx_window = glXCreateWindow(compositor->display, screen->fbconfig, screen->render_window, NULL);
 188
 189         i = 0;
 190         attribs[i++] = GLX_CONTEXT_FLAGS_ARB;
 191         attribs[i++] = GLX_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB;
 192         attribs[i++] = GLX_CONTEXT_MAJOR_VERSION_ARB;
 193         attribs[i++] = 3;
 194         attribs[i++] = GLX_CONTEXT_MINOR_VERSION_ARB;
 195         attribs[i++] = 1;
 196         attribs[i] = None;
 197
 198         screen->glx_context = compositor->glXCreateContextAttribsARB(compositor->display, screen->fbconfig, NULL, True, attribs);
 199
 200         XFree(vi);
 201
 202         return 1;
 203 }
 204
 205 void use_gl(Compositor *compositor, CompositedScreen *screen)
 206 {
 207         glXMakeContextCurrent(compositor->display, screen->glx_window, screen->glx_window, screen->glx_context);
 208 }
 209
 210 unsigned compile_shader(GLenum type, const char *source)
 211 {
 212         unsigned shader;
 213         int status;
 214         char info_log[1024];
 215         GLsizei length;
 216
 217         shader = glCreateShader(type);
 218         glShaderSource(shader, 1, &source, NULL);
 219         glCompileShader(shader);
 220         glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
 221         glGetShaderInfoLog(shader, sizeof(info_log), &length, info_log);
 222         if(!status)
 223         {
 224                 fprintf(stderr, "Shader compilation failed:\n%s\n", info_log);
 225                 glDeleteShader(shader);
 226                 return 0;
 227         }
 228         else if(length)
 229                 printf("Shader info log:\n%s\n", info_log);
 230
 231         return shader;
 232 }
 233
 234 unsigned link_program(unsigned vshader, unsigned fshader)
 235 {
 236         unsigned program;
 237         int status;
 238         char info_log[1024];
 239         GLsizei length;
 240
 241         program = glCreateProgram();
 242         glAttachShader(program, vshader);
 243         glAttachShader(program, fshader);
 244         glBindAttribLocation(program, 0, "vertex");
 245         glBindAttribLocation(program, 1, "texture_coord");
 246         glBindFragDataLocation(program, 0, "frag_color");
 247         glLinkProgram(program);
 248
 249         glGetProgramiv(program, GL_LINK_STATUS, &status);
 250         glGetProgramInfoLog(program, sizeof(info_log), &length, info_log);
 251         if(!status)
 252         {
 253                 fprintf(stderr, "Program link failed:\n%s\n", info_log);
 254                 glDeleteProgram(program);
 255                 return 0;
 256         }
 257         else if(length)
 258                 printf("Program info log:\n%s\n", info_log);
 259
 260         return program;
 261 }
 262
 263 unsigned create_2d_texture()
 264 {
 265         unsigned texture;
 266         glGenTextures(1, &texture);
 267         glBindTexture(GL_TEXTURE_2D, texture);
 268         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 269         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 270         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 271         return texture;
 272 }
 273
 274 int create_gl_resources(CompositedScreen *screen)
 275 {
 276         unsigned stride;
 277         int loc;
 278
 279         screen->shaders[0] = compile_shader(GL_VERTEX_SHADER, vshader_src);
 280         screen->shaders[1] = compile_shader(GL_FRAGMENT_SHADER, fshader_src);
 281         screen->shaders[2] = compile_shader(GL_FRAGMENT_SHADER, masked_fshader_src);
 282         if(!screen->shaders[0] || !screen->shaders[1] || !screen->shaders[2])
 283                 return 0;
 284
 285         screen->program = link_program(screen->shaders[0], screen->shaders[1]);
 286         if(!screen->program)
 287                 return 0;
 288
 289         screen->masked_program = link_program(screen->shaders[0], screen->shaders[2]);
 290         if(!screen->masked_program)
 291                 return 0;
 292
 293         screen->geometry_loc = glGetUniformLocation(screen->program, "geometry");
 294         screen->masked_geometry_loc = glGetUniformLocation(screen->masked_program, "geometry");
 295
 296         loc = glGetUniformLocation(screen->masked_program, "mask");
 297         if(loc>=0)
 298         {
 299                 glUseProgram(screen->masked_program);
 300                 glUniform1i(loc, 1);
 301         }
 302
 303         glGenBuffers(1, &screen->window_vertex_buffer);
 304         glBindBuffer(GL_ARRAY_BUFFER, screen->window_vertex_buffer);
 305         glBufferData(GL_ARRAY_BUFFER, sizeof(window_vertices), window_vertices, GL_STATIC_DRAW);
 306
 307         stride = 4*sizeof(float);
 308         glGenVertexArrays(1, &screen->window_vertex_array);
 309         glBindVertexArray(screen->window_vertex_array);
 310         glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, stride, NULL);
 311         glEnableVertexAttribArray(0);
 312         glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, stride, (void *)(2*sizeof(float)));
 313         glEnableVertexAttribArray(1);
 314         glBindVertexArray(0);
 315
 316         glBindBuffer(GL_ARRAY_BUFFER, 0);
 317
 318         screen->fb_texture = create_2d_texture();
 319         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB8, screen->width, screen->height, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
 320         glBindTexture(GL_TEXTURE_2D, 0);
 321
 322         glGenFramebuffers(1, &screen->framebuffer);
 323         glBindFramebuffer(GL_DRAW_FRAMEBUFFER, screen->framebuffer);
 324         glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, screen->fb_texture, 0);
 325         glDepthMask(GL_FALSE);
 326         glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
 327
 328         return 1;
 329 }
 330
 331 CompositedWindow *find_window(CompositedScreen *screen, Window w)
 332 {
 333         unsigned i;
 334
 335         for(i=0; i<screen->nwindows; ++i)
 336                 if(screen->windows[i].window==w)
 337                         return &screen->windows[i];
 338
 339         return NULL;
 340 }
 341
 342 CompositedWindow *find_window_global(Compositor *compositor, Window w, CompositedScreen **screen)
 343 {
 344         unsigned i, j;
 345
 346         for(i=0; i<compositor->nscreens; ++i)
 347                 for(j=0; j<compositor->screens[i].nwindows; ++j)
 348                         if(compositor->screens[i].windows[j].window==w)
 349                         {
 350                                 if(screen)
 351                                         *screen = &compositor->screens[i];
 352                                 return &compositor->screens[i].windows[j];
 353                         }
 354
 355         if(screen)
 356                 *screen = NULL;
 357         return NULL;
 358 }
 359
 360 void create_window_pixmap(Compositor *compositor, CompositedScreen *screen, CompositedWindow *window)
 361 {
 362         int attribs[5];
 363         unsigned i;
 364
 365         if(window->pixmap)
 366         {
 367                 glXDestroyPixmap(compositor->display, window->glx_pixmap);
 368                 XFreePixmap(compositor->display, window->pixmap);
 369         }
 370
 371         i = 0;
 372         attribs[i++] = GLX_TEXTURE_TARGET_EXT;
 373         attribs[i++] = GLX_TEXTURE_2D_EXT;
 374         attribs[i++] = GLX_TEXTURE_FORMAT_EXT;
 375         attribs[i++] = GLX_TEXTURE_FORMAT_RGBA_EXT;
 376         attribs[i++] = None;
 377
 378         window->pixmap = XCompositeNameWindowPixmap(compositor->display, window->window);
 379         window->glx_pixmap = glXCreatePixmap(compositor->display, screen->fbconfig, window->pixmap, attribs);
 380         window->recreate_pixmap = 0;
 381 }
 382
 383 void update_window_mask(Compositor *compositor, CompositedWindow *window)
 384 {
 385         Bool bounding_shaped;
 386         Bool clip_shaped;
 387         int xi, yi;
 388         XRectangle *rects;
 389         int rect_count;
 390         int rect_order;
 391         unsigned width;
 392         unsigned height;
 393         unsigned char *data;
 394         int i;
 395         unsigned y;
 396
 397         XShapeQueryExtents(compositor->display, window->window, &bounding_shaped, &xi, &yi, &width, &height, &clip_shaped, &xi, &yi, &width, &height);
 398         window->use_mask = bounding_shaped;
 399         if(!window->use_mask)
 400                 return;
 401
 402         rects = XShapeGetRectangles(compositor->display, window->window, ShapeBounding, &rect_count, &rect_order);
 403
 404         width = window->width+2*window->border;
 405         height = window->height+2*window->border;
 406         data = (unsigned char *)malloc(width*height);
 407         memset(data, 0, width*height);
 408         for(i=0; i<rect_count; ++i)
 409         {
 410                 rects[i].x += window->border;
 411                 rects[i].y += window->border;
 412                 if(rects[i].x>=(int)width || rects[i].y>=(int)height)
 413                         continue;
 414
 415                 if(rects[i].x<0)
 416                 {
 417                         if(-rects[i].x>rects[i].width)
 418                                 continue;
 419                         rects[i].width += rects[i].x;
 420                         rects[i].x = 0;
 421                 }
 422
 423                 if(rects[i].y<0)
 424                 {
 425                         if(-rects[i].y>rects[i].height)
 426                                 continue;
 427                         rects[i].height += rects[i].y;
 428                         rects[i].y = 0;
 429                 }
 430
 431                 if(rects[i].x+rects[i].width>(int)width)
 432                         rects[i].width = width-rects[i].x;
 433                 if(rects[i].y+rects[i].height>(int)height)
 434                         rects[i].height = height-rects[i].y;
 435
 436                 for(y=0; y<rects[i].height; ++y)
 437                 {
 438                         unsigned char *row = data+(rects[i].y+y)*width+rects[i].x;
 439                         memset(row, 255, rects[i].width);
 440                 }
 441         }
 442
 443         XFree(rects);
 444
 445         glBindTexture(GL_TEXTURE_2D, window->mask_texture);
 446         glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
 447         glTexImage2D(GL_TEXTURE_2D, 0, GL_R8, width, height, 0, GL_RED, GL_UNSIGNED_BYTE, data);
 448
 449         free(data);
 450
 451         window->recreate_mask = 0;
 452 }
 453
 454 CompositedWindow *add_window(Compositor *compositor, CompositedScreen *screen, Window w)
 455 {
 456         CompositedWindow *window;
 457         XWindowAttributes win_attr;
 458
 459         if(w==screen->root || w==screen->overlay)
 460                 return NULL;
 461
 462         if(!XGetWindowAttributes(compositor->display, w, &win_attr))
 463         {
 464                 printf("XGetWindowAttributes failed; probably the window was already destroyed\n");
 465                 return NULL;
 466         }
 467         if(win_attr.class==InputOnly)
 468                 return NULL;
 469
 470         if(find_window(screen, w))
 471                 return NULL;
 472
 473         if(screen->nwindows==screen->windows_capacity)
 474         {
 475                 screen->windows = (CompositedWindow *)realloc(screen->windows, (screen->windows_capacity+1)*sizeof(CompositedWindow));
 476                 ++screen->windows_capacity;
 477         }
 478
 479         window = &screen->windows[screen->nwindows++];
 480
 481         window->window = w;
 482         window->x = win_attr.x;
 483         window->y = win_attr.y;
 484         window->width = win_attr.width;
 485         window->height = win_attr.height;
 486         window->border = win_attr.border_width;
 487         window->map_state = win_attr.map_state;
 488
 489         window->damage = XDamageCreate(compositor->display, window->window, XDamageReportNonEmpty);
 490         window->pixmap = None;
 491         window->glx_pixmap = None;
 492
 493         XCompositeRedirectWindow(compositor->display, window->window, CompositeRedirectManual);
 494         window->recreate_pixmap = (window->map_state==IsViewable);
 495
 496         window->texture = create_2d_texture();
 497         window->mask_texture = create_2d_texture();
 498         window->recreate_mask = (window->map_state==IsViewable);
 499
 500         XShapeSelectInput(compositor->display, window->window, ShapeNotifyMask);
 501
 502         return window;
 503 }
 504
 505 void remove_window(Compositor *compositor, CompositedScreen *screen, CompositedWindow *window, int destroyed)
 506 {
 507         unsigned i;
 508
 509         glDeleteTextures(1, &window->texture);
 510         if(!destroyed)
 511         {
 512                 XDamageDestroy(compositor->display, window->damage);
 513                 if(window->pixmap)
 514                 {
 515                         glXDestroyPixmap(compositor->display, window->glx_pixmap);
 516                         XFreePixmap(compositor->display, window->pixmap);
 517                 }
 518                 XCompositeUnredirectWindow(compositor->display, window->window, CompositeRedirectManual);
 519         }
 520
 521         --screen->nwindows;
 522         for(i=window-screen->windows; i<screen->nwindows; ++i)
 523                 screen->windows[i] = screen->windows[i+1];
 524 }
 525
 526 CompositedWindow *reorder_window(CompositedScreen *screen, CompositedWindow *window, Window above)
 527 {
 528         unsigned i, j;
 529         CompositedWindow hold;
 530
 531         i = window-screen->windows;
 532         if(above)
 533         {
 534                 for(j=0; j<screen->nwindows; ++j)
 535                         if(screen->windows[j].window==above)
 536                                 break;
 537
 538                 if(j>=screen->nwindows || i==j+1)
 539                         return window;
 540
 541                 if(j<i)
 542                         ++j;
 543         }
 544         else
 545                 j = 0;
 546
 547         hold = *window;
 548         if(i<j)
 549         {
 550                 for(; i<j; ++i)
 551                         screen->windows[i] = screen->windows[i+1];
 552         }
 553         else
 554         {
 555                 for(; i>j; --i)
 556                         screen->windows[i] = screen->windows[i-1];
 557         }
 558         screen->windows[j] = hold;
 559
 560         return &screen->windows[j];
 561 }
 562
 563 CompositedScreen *find_screen_by_root(Compositor *compositor, Window root)
 564 {
 565         unsigned i;
 566
 567         for(i=0; i<compositor->nscreens; ++i)
 568                 if(compositor->screens[i].root==root)
 569                         return &compositor->screens[i];
 570
 571         return NULL;
 572 }
 573
 574 void update_monitor_vertices(CompositedScreen *screen, CompositedMonitor *monitor)
 575 {
 576         unsigned t;
 577         unsigned data_size;
 578         float *vertex_data;
 579         unsigned short *index_data;
 580         unsigned x, y;
 581         unsigned i;
 582         float aspect;
 583         float cyl_radius;
 584         float cyl_arc;
 585         float sin_ksv;
 586         float cos_ksv;
 587         float distance;
 588         float eye[3];
 589         float look[3];
 590
 591         t = monitor->tessellation;
 592
 593         data_size = (t+1)*(t+1)*4*sizeof(float);
 594         vertex_data = (float *)malloc(data_size);
 595
 596         aspect = (float)monitor->width/monitor->height;
 597
 598         if(monitor->cylinder_depth)
 599         {
 600                 cyl_radius = (monitor->cylinder_depth*monitor->cylinder_depth+0.25f)/(2.0f*monitor->cylinder_depth);
 601                 cyl_arc = 2.0f*asin(0.5f/cyl_radius);
 602         }
 603
 604         sin_ksv = monitor->keystone_vertical/sqrt(1.0f+monitor->keystone_vertical*monitor->keystone_vertical);
 605         cos_ksv = sqrt(1.0f-sin_ksv*sin_ksv);
 606         distance = monitor->perspective+sin_ksv*((sin_ksv>0)-monitor->vertical_center)/aspect;
 607
 608         eye[0] = 0.0f;
 609         eye[1] = (monitor->vertical_center-0.5f)/aspect+sin_ksv*distance;
 610         eye[2] = cos_ksv*distance;
 611
 612         look[0] = 0.0f;
 613         look[1] = -sin_ksv;
 614         look[2] = -cos_ksv;
 615
 616         for(y=0; y<=t; ++y)
 617                 for(x=0; x<=t; ++x)
 618                 {
 619                         float *v;
 620
 621                         v = vertex_data+(y*(t+1)+x)*3;
 622                         v[0] = (float)x/t-0.5f;
 623                         v[1] = ((float)y/t-0.5f)/aspect;
 624                         v[2] = 0;
 625                         if(monitor->cylinder_depth)
 626                         {
 627                                 v[2] = (1.0f-cos(v[0]*cyl_arc))*cyl_radius-monitor->cylinder_depth;
 628                                 v[0] = sin(v[0]*cyl_arc)*cyl_radius;
 629                         }
 630                 }
 631
 632         for(y=t; y<=t; --y)
 633                 for(x=t; x<=t; --x)
 634                 {
 635                         float *v;
 636                         float px, py, pz;
 637                         float scale;
 638
 639                         v = vertex_data+(y*(t+1)+x)*3;
 640                         px = v[0]-eye[0];
 641                         py = (v[0]-eye[0])*look[0] - (v[1]-eye[1])*look[2] + (v[2]-eye[2])*look[1];
 642                         pz = (v[0]-eye[0])*look[0] + (v[1]-eye[1])*look[1] + (v[2]-eye[2])*look[2];
 643                         scale = monitor->perspective/pz;
 644
 645                         v = vertex_data+(y*(t+1)+x)*4;
 646                         v[0] = px*scale+0.5f;
 647                         v[1] = py*aspect*scale+monitor->vertical_center;
 648                         v[2] = (monitor->x+(float)x*monitor->width/t)/screen->width;
 649                         v[3] = 1.0f-(monitor->y+(1.0f-(float)y/t)*monitor->height)/screen->height;
 650                 }
 651
 652         glBindBuffer(GL_ARRAY_BUFFER, monitor->vertex_buffer);
 653         glBufferData(GL_ARRAY_BUFFER, data_size, vertex_data, GL_STATIC_DRAW);
 654         glBindBuffer(GL_ARRAY_BUFFER, 0);
 655         free(vertex_data);
 656
 657         monitor->nelements = t*((t+1)*2+1)-1;
 658         data_size = monitor->nelements*sizeof(unsigned short);
 659         index_data = (unsigned short *)malloc(data_size);
 660         i = 0;
 661         for(y=0; y<t; ++y)
 662         {
 663                 if(y>0)
 664                         index_data[i++] = 0xFFFF;
 665                 for(x=0; x<=t; ++x)
 666                 {
 667                         index_data[i++] = (y+1)*(t+1)+x;
 668                         index_data[i++] = y*(t+1)+x;
 669                 }
 670         }
 671         glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, monitor->index_buffer);
 672         glBufferData(GL_ELEMENT_ARRAY_BUFFER, data_size, index_data, GL_STATIC_DRAW);
 673         glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
 674         free(index_data);
 675 }
 676
 677 int initialize_monitor(Compositor *compositor, CompositedScreen *screen, XRRScreenResources *xrr_res, unsigned index)
 678 {
 679         CompositedMonitor *monitor;
 680         XRROutputInfo *output;
 681         int namelen;
 682         XRRCrtcInfo *crtc;
 683         unsigned buffers[2];
 684         unsigned stride;
 685
 686         monitor = &screen->monitors[index];
 687
 688         output = XRRGetOutputInfo(compositor->display, xrr_res, xrr_res->outputs[index]);
 689         namelen = strlen(output->name);
 690         monitor->name = (char *)malloc(namelen+1);
 691         strcpy(monitor->name, output->name);
 692         monitor->enabled = !!output->crtc;
 693         if(!monitor->enabled)
 694         {
 695                 XRRFreeOutputInfo(output);
 696                 return 1;
 697         }
 698
 699         crtc = XRRGetCrtcInfo(compositor->display, xrr_res, output->crtc);
 700         monitor->x = crtc->x;
 701         monitor->y = crtc->y;
 702         monitor->width = crtc->width;
 703         monitor->height = crtc->height;
 704         XRRFreeCrtcInfo(crtc);
 705         XRRFreeOutputInfo(output);
 706
 707         monitor->keystone_vertical = 0.0f;
 708         monitor->cylinder_depth = 0.0f;
 709         monitor->vertical_center = 0.5f;
 710         monitor->perspective = 1.0f;
 711
 712         glGenBuffers(2, buffers);
 713         monitor->vertex_buffer = buffers[0];
 714         monitor->index_buffer = buffers[1];
 715
 716         monitor->tessellation = 50;
 717         update_monitor_vertices(screen, monitor);
 718         stride = 4*sizeof(float);
 719
 720         glGenVertexArrays(1, &monitor->vertex_array);
 721         glBindVertexArray(monitor->vertex_array);
 722         glBindBuffer(GL_ARRAY_BUFFER, monitor->vertex_buffer);
 723         glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, stride, NULL);
 724         glEnableVertexAttribArray(0);
 725         glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, stride, (void *)(2*sizeof(float)));
 726         glEnableVertexAttribArray(1);
 727         glBindBuffer(GL_ARRAY_BUFFER, 0);
 728         glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, monitor->index_buffer);
 729         glBindVertexArray(0);
 730
 731         return 1;
 732 }
 733
 734 CompositedMonitor *find_monitor_by_name(CompositedScreen *screen, char *name)
 735 {
 736         unsigned i;
 737
 738         for(i=0; i<screen->nmonitors; ++i)
 739                 if(!strcmp(screen->monitors[i].name, name))
 740                         return &screen->monitors[i];
 741
 742         return NULL;
 743 }
 744
 745 void update_geometry_correction(Compositor *compositor, CompositedScreen *screen)
 746 {
 747         Atom prop_type;
 748         int prop_format;
 749         unsigned long overflow;
 750         unsigned long names_length;
 751         char *names;
 752         unsigned long values_length;
 753         short *values;
 754         char *name_ptr;
 755         unsigned i;
 756
 757         XGetWindowProperty(compositor->display, screen->root, compositor->monitors_atom, 0, 64, False, XA_STRING,
 758                 &prop_type, &prop_format, &names_length, &overflow, (unsigned char **)&names);
 759         if(prop_type!=XA_STRING || prop_format!=8)
 760                 return;
 761
 762         XGetWindowProperty(compositor->display, screen->root, compositor->correction_atom, 0, 64, False, XA_INTEGER,
 763                 &prop_type, &prop_format, &values_length, &overflow, (unsigned char **)&values);
 764         if(prop_type!=XA_INTEGER || prop_format!=16)
 765         {
 766                 XFree(names);
 767                 return;
 768         }
 769
 770         use_gl(compositor, screen);
 771
 772         name_ptr = names;
 773         for(i=0; i*4<values_length; ++i)
 774         {
 775                 CompositedMonitor *monitor;
 776
 777                 if(name_ptr>=names+names_length)
 778                         break;
 779
 780                 monitor = find_monitor_by_name(screen, name_ptr);
 781                 if(monitor)
 782                 {
 783                         monitor->keystone_vertical = values[i*4]/10000.0f;
 784                         monitor->cylinder_depth = values[i*4+1]/10000.0f;
 785                         monitor->vertical_center = values[i*4+2]/10000.0f;
 786                         monitor->perspective = values[i*4+3]/10000.0f;
 787
 788                         if(monitor->enabled)
 789                                 update_monitor_vertices(screen, monitor);
 790                 }
 791
 792                 name_ptr += strlen(name_ptr)+1;
 793         }
 794
 795         XFree(names);
 796         XFree(values);
 797 }
 798
 799 int initialize_screen(Compositor *compositor, unsigned number)
 800 {
 801         CompositedScreen *screen;
 802         const char *extensions;
 803         Window dummy_root;
 804         int x, y;
 805         unsigned border;
 806         unsigned depth;
 807         XRRScreenResources *xrr_res;
 808         Window dummy_parent;
 809         Window *children;
 810         unsigned nchildren;
 811         unsigned i;
 812
 813         screen = &compositor->screens[number];
 814         screen->number = number;
 815
 816         extensions = glXQueryExtensionsString(compositor->display, screen->number);
 817         if(!strstr(extensions, "GLX_ARB_create_context"))
 818                 return with_error("GLX_ARB_create_context is required");
 819         if(!strstr(extensions, "GLX_EXT_texture_from_pixmap"))
 820                 return with_error("GLX_EXT_texture_from_pixmap is required");
 821
 822         screen->root = RootWindow(compositor->display, screen->number);
 823         XSelectInput(compositor->display, screen->root, SubstructureNotifyMask|PropertyChangeMask);
 824         screen->overlay = XCompositeGetOverlayWindow(compositor->display, screen->root);
 825         XGetGeometry(compositor->display, screen->overlay, &dummy_root, &x, &y, &screen->width, &screen->height, &border, &depth);
 826         XShapeCombineRectangles(compositor->display, screen->overlay, ShapeInput, 0, 0, NULL, 0, ShapeSet, Unsorted);
 827
 828         if(!initialize_gl(compositor, screen))
 829                 return 0;
 830
 831         use_gl(compositor, screen);
 832
 833         if(!create_gl_resources(screen))
 834                 return 0;
 835
 836         xrr_res = XRRGetScreenResources(compositor->display, screen->root);
 837         screen->nmonitors = xrr_res->noutput;
 838         screen->monitors = (CompositedMonitor *)malloc(screen->nmonitors*sizeof(CompositedMonitor));
 839         for(i=0; i<screen->nmonitors; ++i)
 840                 if(!initialize_monitor(compositor, screen, xrr_res, i))
 841                         return 0;
 842         XRRFreeScreenResources(xrr_res);
 843
 844         update_geometry_correction(compositor, screen);
 845
 846         XQueryTree(compositor->display, screen->root, &dummy_root, &dummy_parent, &children, &nchildren);
 847
 848         screen->windows = (CompositedWindow *)malloc(nchildren*sizeof(CompositedWindow));
 849         screen->nwindows = 0;
 850         screen->windows_capacity = nchildren;
 851
 852         for(i=0; i<nchildren; ++i)
 853                 add_window(compositor, screen, children[i]);
 854
 855         XFree(children);
 856
 857         screen->dirty = 1;
 858
 859         return 1;
 860 }
 861
 862 int initialize_compositor(Compositor *compositor)
 863 {
 864         int event_base;
 865         int error_base;
 866         int major_ver;
 867         int minor_ver;
 868         unsigned i;
 869
 870         compositor->display = XOpenDisplay(NULL);
 871         if(!compositor->display)
 872                 return with_error("Could not open X display");
 873
 874         XSetErrorHandler(&x_error_handler);
 875
 876         if(!XCompositeQueryExtension(compositor->display, &event_base, &error_base))
 877                 return with_error("XComposite is required but was not found");
 878         else if(!XCompositeQueryVersion(compositor->display, &major_ver, &minor_ver))
 879                 return with_error("Cannot determine XComposite version");
 880         else if(major_ver==0 && minor_ver<3)
 881                 return with_error("XComposite 0.3 or later is required");
 882
 883         if(!glXQueryExtension(compositor->display, &event_base, &error_base))
 884                 return with_error("GLX is required but was not found");
 885         else if(!glXQueryVersion(compositor->display, &major_ver, &minor_ver))
 886                 return with_error("Cannot determine GLX version");
 887         else if(major_ver<1 || (major_ver==1 && minor_ver<4))
 888                 return with_error("GLX 1.4 or later is required");
 889
 890         if(!XDamageQueryExtension(compositor->display, &compositor->damage_event, &error_base))
 891                 return with_error("XDamage is required but was not found");
 892         else if(!XDamageQueryVersion(compositor->display, &major_ver, &minor_ver))
 893                 return with_error("Cannot determine XDamage version");
 894         else if(major_ver<1)
 895                 return with_error("XDamage 1.0 or later is required");
 896
 897         if(!XShapeQueryExtension(compositor->display, &compositor->shape_event, &error_base))
 898                 return with_error("XShape is required but was not found");
 899         else if(!XShapeQueryVersion(compositor->display, &major_ver, &minor_ver))
 900                 return with_error("Cannot determine XShape version");
 901         else if(major_ver<1 || (major_ver==1 && minor_ver<1))
 902                 return with_error("XShape 1.1 or later is required");
 903
 904         if(!XRRQueryExtension(compositor->display, &event_base, &error_base))
 905                 return with_error("XRandR is required but was not found");
 906         else if(!XRRQueryVersion(compositor->display, &major_ver, &minor_ver))
 907                 return with_error("Cannot determine XRandR version");
 908         else if(major_ver<1 || (major_ver==1 && minor_ver<2))
 909                 return with_error("XRandR 1.2 or later is required");
 910
 911         compositor->glXCreateContextAttribsARB = (PFNGLXCREATECONTEXTATTRIBSARBPROC)glXGetProcAddress((unsigned char *)"glXCreateContextAttribsARB");
 912         compositor->glXBindTexImageEXT = (PFNGLXBINDTEXIMAGEEXTPROC)glXGetProcAddress((unsigned char *)"glXBindTexImageEXT");
 913         compositor->glXReleaseTexImageEXT = (PFNGLXRELEASETEXIMAGEEXTPROC)glXGetProcAddress((unsigned char *)"glXReleaseTexImageEXT");
 914
 915         compositor->correction_atom = XInternAtom(compositor->display, "GEOMETRY_CORRECTION", False);
 916         compositor->monitors_atom = XInternAtom(compositor->display, "GEOMETRY_CORRECTION_MONITORS", False);
 917
 918         compositor->nscreens = ScreenCount(compositor->display);
 919         compositor->screens = (CompositedScreen *)malloc(compositor->nscreens*sizeof(CompositedScreen));
 920         for(i=0; i<compositor->nscreens; ++i)
 921                 if(!initialize_screen(compositor, i))
 922                         return 0;
 923
 924         compositor->dirty = 1;
 925
 926         return 1;
 927 }
 928
 929 void shutdown_screen(Compositor *compositor, CompositedScreen *screen)
 930 {
 931         unsigned i;
 932
 933         use_gl(compositor, screen);
 934
 935         for(i=0; i<screen->nwindows; ++i)
 936         {
 937                 glDeleteTextures(1, &screen->windows[i].texture);
 938                 glDeleteTextures(1, &screen->windows[i].mask_texture);
 939                 if(screen->windows[i].pixmap)
 940                 {
 941                         glXDestroyPixmap(compositor->display, screen->windows[i].glx_pixmap);
 942                         XFreePixmap(compositor->display, screen->windows[i].pixmap);
 943                         XDamageDestroy(compositor->display, screen->windows[i].damage);
 944                 }
 945         }
 946
 947         for(i=0; i<screen->nmonitors; ++i)
 948         {
 949                 free(screen->monitors[i].name);
 950                 if(screen->monitors[i].enabled)
 951                 {
 952                         glDeleteBuffers(1, &screen->monitors[i].vertex_buffer);
 953                         glDeleteBuffers(1, &screen->monitors[i].index_buffer);
 954                         glDeleteVertexArrays(1, &screen->monitors[i].vertex_array);
 955                 }
 956         }
 957
 958         glDeleteBuffers(1, &screen->window_vertex_buffer);
 959         glDeleteVertexArrays(1, &screen->window_vertex_array);
 960         glDeleteFramebuffers(1, &screen->framebuffer);
 961         glDeleteTextures(1, &screen->fb_texture);
 962         glDeleteProgram(screen->program);
 963         glDeleteProgram(screen->masked_program);
 964         for(i=0; i<3; ++i)
 965                 glDeleteShader(screen->shaders[i]);
 966
 967         glXMakeContextCurrent(compositor->display, 0, 0, NULL);
 968         glXDestroyContext(compositor->display, screen->glx_context);
 969         glXDestroyWindow(compositor->display, screen->glx_window);
 970         XDestroyWindow(compositor->display, screen->render_window);
 971
 972         XCompositeReleaseOverlayWindow(compositor->display, screen->overlay);
 973
 974         free(screen->windows);
 975         free(screen->monitors);
 976 }
 977
 978 void shutdown_compositor(Compositor *compositor)
 979 {
 980         unsigned i;
 981
 982         for(i=0; i<compositor->nscreens; ++i)
 983                 shutdown_screen(compositor, &compositor->screens[i]);
 984         free(compositor->screens);
 985
 986         XCloseDisplay(compositor->display);
 987 }
 988
 989 void mark_dirty(Compositor *compositor, CompositedScreen *screen)
 990 {
 991         compositor->dirty = 1;
 992         screen->dirty = 1;
 993 }
 994
 995 void process_create_window_event(Compositor *compositor, XCreateWindowEvent *event)
 996 {
 997         CompositedScreen *screen;
 998
 999         if((screen = find_screen_by_root(compositor, event->parent)))
1000                 add_window(compositor, screen, event->window);
1001 }
1002
1003 void process_destroy_window_event(Compositor *compositor, XDestroyWindowEvent *event)
1004 {
1005         CompositedScreen *screen;
1006         CompositedWindow *window;
1007
1008         if((screen = find_screen_by_root(compositor, event->event)))
1009                 if((window = find_window(screen, event->window)))
1010                 {
1011                         use_gl(compositor, screen);
1012                         remove_window(compositor, screen, window, 1);
1013                 }
1014 }
1015
1016 void process_map_event(Compositor *compositor, XMapEvent *event)
1017 {
1018         CompositedScreen *screen;
1019         CompositedWindow *window;
1020
1021         screen = find_screen_by_root(compositor, event->event);
1022         if(!screen)
1023                 return;
1024
1025         window = find_window(screen, event->window);
1026         if(!window)
1027                 return;
1028
1029         window->map_state = IsViewable;
1030         window->recreate_pixmap = 1;
1031         window->recreate_mask = 1;
1032
1033         mark_dirty(compositor, screen);
1034 }
1035
1036 void process_unmap_event(Compositor *compositor, XUnmapEvent *event)
1037 {
1038         CompositedScreen *screen;
1039         CompositedWindow *window;
1040
1041         screen = find_screen_by_root(compositor, event->event);
1042         if(!screen)
1043                 return;
1044
1045         window = find_window(screen, event->window);
1046         if(window)
1047                 window->map_state = IsUnviewable;
1048
1049         mark_dirty(compositor, screen);
1050 }
1051
1052 void process_reparent_event(Compositor *compositor, XReparentEvent *event)
1053 {
1054         CompositedScreen *screen;
1055         CompositedWindow *window;
1056
1057         screen = find_screen_by_root(compositor, event->event);
1058         if(!screen)
1059                 return;
1060
1061         if(event->parent==screen->root)
1062                 window = add_window(compositor, screen, event->window);
1063         else
1064         {
1065                 window = find_window(screen, event->window);
1066                 if(!window)
1067                         return;
1068
1069                 remove_window(compositor, screen, window, 0);
1070         }
1071
1072         if(window && window->map_state==IsViewable)
1073                 mark_dirty(compositor, screen);
1074 }
1075
1076 void process_configure_event(Compositor *compositor, XConfigureEvent *event)
1077 {
1078         CompositedScreen *screen;
1079         CompositedWindow *window;
1080
1081         screen = find_screen_by_root(compositor, event->event);
1082         if(!screen)
1083                 return;
1084
1085         window = find_window(screen, event->window);
1086         if(!window)
1087                 return;
1088
1089         window->x = event->x;
1090         window->y = event->y;
1091         if((unsigned)event->width!=window->width || (unsigned)event->height!=window->height || (unsigned)event->border_width!=window->border)
1092         {
1093                 window->width = event->width;
1094                 window->height = event->height;
1095                 window->border = event->border_width;
1096                 window->recreate_pixmap = 1;
1097         }
1098         reorder_window(screen, window, event->above);
1099
1100         if(window->map_state==IsViewable)
1101                 mark_dirty(compositor, screen);
1102 }
1103
1104 void process_property_event(Compositor *compositor, XPropertyEvent *event)
1105 {
1106         CompositedScreen *screen;
1107
1108         if(event->atom!=compositor->correction_atom)
1109                 return;
1110
1111         screen = find_screen_by_root(compositor, event->window);
1112         if(!screen)
1113                 return;
1114
1115         update_geometry_correction(compositor, screen);
1116 }
1117
1118 void process_damage_event(Compositor *compositor, XDamageNotifyEvent *event)
1119 {
1120         CompositedScreen *screen;
1121         CompositedWindow *window;
1122
1123         window = find_window_global(compositor, event->drawable, &screen);
1124         if(window && window->map_state==IsViewable)
1125                 mark_dirty(compositor, screen);
1126 }
1127
1128 void process_shape_event(Compositor *compositor, XShapeEvent *event)
1129 {
1130         CompositedScreen *screen;
1131         CompositedWindow *window;
1132
1133         if(event->kind!=ShapeBounding)
1134                 return;
1135
1136         window = find_window_global(compositor, event->window, &screen);
1137         if(window && window->map_state==IsViewable)
1138         {
1139                 window->recreate_mask = 1;
1140                 mark_dirty(compositor, screen);
1141         }
1142 }
1143
1144 void process_events(Compositor *compositor)
1145 {
1146         int pending;
1147         XEvent event;
1148
1149         pending = 0;
1150         while((pending || !compositor->dirty) && !terminate_requested)
1151         {
1152                 if(!pending)
1153                         pending = XPending(compositor->display);
1154
1155                 XNextEvent(compositor->display, &event);
1156                 if(pending)
1157                         --pending;
1158
1159                 switch(event.type)
1160                 {
1161                 case CreateNotify:
1162                         process_create_window_event(compositor, &event.xcreatewindow);
1163                         break;
1164                 case DestroyNotify:
1165                         process_destroy_window_event(compositor, &event.xdestroywindow);
1166                         break;
1167                 case MapNotify:
1168                         process_map_event(compositor, &event.xmap);
1169                         break;
1170                 case UnmapNotify:
1171                         process_unmap_event(compositor, &event.xunmap);
1172                         break;
1173                 case ReparentNotify:
1174                         process_reparent_event(compositor, &event.xreparent);
1175                         break;
1176                 case ConfigureNotify:
1177                         process_configure_event(compositor, &event.xconfigure);
1178                         break;
1179                 case PropertyNotify:
1180                         process_property_event(compositor, &event.xproperty);
1181                         break;
1182                 default:
1183                         if(event.type==compositor->damage_event+XDamageNotify)
1184                                 process_damage_event(compositor, (XDamageNotifyEvent *)&event);
1185                         else if(event.type==compositor->shape_event+ShapeNotify)
1186                                 process_shape_event(compositor, (XShapeEvent *)&event);
1187                         else
1188                                 printf("Event %d\n", event.type);
1189                 }
1190         }
1191 }
1192
1193 void refresh_screen(Compositor *compositor, CompositedScreen *screen)
1194 {
1195         unsigned i;
1196         int use_mask;
1197
1198         for(i=0; i<screen->nwindows; ++i)
1199                 if(screen->windows[i].map_state==IsViewable)
1200                         XDamageSubtract(compositor->display, screen->windows[i].damage, None, None);
1201         glXWaitX();
1202
1203         use_gl(compositor, screen);
1204
1205         glBindFramebuffer(GL_DRAW_FRAMEBUFFER, screen->framebuffer);
1206
1207         glClearColor(0.5f, 0.5f, 0.5f, 0.0f);
1208         glClear(GL_COLOR_BUFFER_BIT);
1209
1210         use_mask = -1;
1211         glBindVertexArray(screen->window_vertex_array);
1212         for(i=0; i<screen->nwindows; ++i)
1213         {
1214                 CompositedWindow *window;
1215
1216                 window = &screen->windows[i];
1217                 if(window->map_state!=IsViewable)
1218                         continue;
1219
1220                 if(window->use_mask!=use_mask)
1221                 {
1222                         use_mask = window->use_mask;
1223                         glUseProgram(use_mask ? screen->masked_program : screen->program);
1224                 }
1225
1226                 if(window->use_mask)
1227                 {
1228                         glActiveTexture(GL_TEXTURE1);
1229                         glBindTexture(GL_TEXTURE_2D, window->mask_texture);
1230                         glActiveTexture(GL_TEXTURE0);
1231                 }
1232
1233                 if(window->recreate_pixmap)
1234                         create_window_pixmap(compositor, screen, window);
1235                 if(window->recreate_mask)
1236                         update_window_mask(compositor, window);
1237
1238                 glBindTexture(GL_TEXTURE_2D, window->texture);
1239                 compositor->glXBindTexImageEXT(compositor->display, window->glx_pixmap, GLX_FRONT_LEFT_EXT, NULL);
1240                 glUniform4f((use_mask ? screen->masked_geometry_loc : screen->geometry_loc),
1241                         (float)window->x/screen->width, 1.0f-(float)(window->y+window->height)/screen->height,
1242                         (float)(window->width+2*window->border)/screen->width, (float)(window->height+2*window->border)/screen->height);
1243                 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
1244                 compositor->glXReleaseTexImageEXT(compositor->display, window->glx_pixmap, GLX_FRONT_LEFT_EXT);
1245         }
1246
1247         glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
1248         glClearColor(0.5f, 0.0f, 0.5f, 0.0f);
1249         glClear(GL_COLOR_BUFFER_BIT);
1250         glBindTexture(GL_TEXTURE_2D, screen->fb_texture);
1251         glEnable(GL_PRIMITIVE_RESTART);
1252         glPrimitiveRestartIndex(0xFFFF);
1253         if(use_mask)
1254                 glUseProgram(screen->program);
1255
1256         for(i=0; i<screen->nmonitors; ++i)
1257         {
1258                 CompositedMonitor *monitor = &screen->monitors[i];
1259                 if(!monitor->enabled)
1260                         continue;
1261
1262                 glUniform4f(screen->geometry_loc,
1263                         (float)monitor->x/screen->width, 1.0f-(float)(monitor->y+monitor->height)/screen->height,
1264                         (float)monitor->width/screen->width, (float)monitor->height/screen->height);
1265
1266                 glBindVertexArray(monitor->vertex_array);
1267                 glDrawElements(GL_TRIANGLE_STRIP, monitor->nelements, GL_UNSIGNED_SHORT, NULL);
1268         }
1269
1270         glBindVertexArray(0);
1271
1272         glXSwapBuffers(compositor->display, screen->glx_window);
1273
1274         screen->dirty = 0;
1275 }
1276
1277 void refresh_all_screens(Compositor *compositor)
1278 {
1279         unsigned i;
1280
1281         for(i=0; i<compositor->nscreens; ++i)
1282         {
1283                 CompositedScreen *screen = &compositor->screens[i];
1284                 if(screen->dirty)
1285                         refresh_screen(compositor, screen);
1286         }
1287
1288         compositor->dirty = 0;
1289 }
1290
1291 void sighandler(int sig)
1292 {
1293         terminate_requested = 1;
1294         (void)sig;
1295 }
1296
1297 int main()
1298 {
1299         Compositor compositor;
1300
1301         signal(SIGINT, &sighandler);
1302         signal(SIGTERM, &sighandler);
1303
1304         if(!initialize_compositor(&compositor))
1305                 return 1;
1306
1307         while(!terminate_requested)
1308         {
1309                 process_events(&compositor);
1310                 if(compositor.dirty && !terminate_requested)
1311                         refresh_all_screens(&compositor);
1312         }
1313
1314         shutdown_compositor(&compositor);
1315
1316         return 0;
1317 }