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