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Initialize some variables
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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         Pixmap root_pixmap;
75         GLXPixmap root_glx_pixmap;
76         unsigned root_texture;
77         CompositedWindow *windows;
78         unsigned nwindows;
79         unsigned windows_capacity;
80         CompositedMonitor *monitors;
81         unsigned nmonitors;
82         int dirty;
83 } CompositedScreen;
84
85 typedef struct Compositor
86 {
87         Display *display;
88         CompositedScreen *screens;
89         unsigned nscreens;
90         int damage_event;
91         int shape_event;
92         PFNGLXCREATECONTEXTATTRIBSARBPROC glXCreateContextAttribsARB;
93         PFNGLXBINDTEXIMAGEEXTPROC glXBindTexImageEXT;
94         PFNGLXRELEASETEXIMAGEEXTPROC glXReleaseTexImageEXT;
95         Atom root_pmap_atom;
96         Atom correction_atom;
97         Atom monitors_atom;
98         int dirty;
99 } Compositor;
100
101 static const char *vshader_src =
102         "#version 150\n"
103         "uniform vec4 geometry;\n"
104         "in vec2 vertex;\n"
105         "in vec2 texture_coord;\n"
106         "out vec2 texcoord;\n"
107         "void main()\n"
108         "{\n"
109         "  gl_Position = vec4((geometry.xy+vertex*geometry.zw)*2.0-1.0, 0.0, 1.0);\n"
110         "  texcoord = texture_coord;\n"
111         "}\n";
112
113 static const char *fshader_src =
114         "#version 150\n"
115         "uniform sampler2D image;\n"
116         "in vec2 texcoord;\n"
117         "out vec4 frag_color;\n"
118         "void main()\n"
119         "{\n"
120         "  frag_color = texture(image, texcoord);\n"
121         "}\n";
122
123 static const char *masked_fshader_src =
124         "#version 150\n"
125         "uniform sampler2D image;\n"
126         "uniform sampler2D mask;\n"
127         "in vec2 texcoord;\n"
128         "out vec4 frag_color;\n"
129         "void main()\n"
130         "{\n"
131         "  if(texture(mask, texcoord).r==0.0)\n"
132         "    discard;\n"
133         "  frag_color = texture(image, texcoord);\n"
134         "}\n";
135
136 static const float window_vertices[] =
137 {
138         /* vertex    texcoord */
139         0.0f, 1.0f,  0.0f, 0.0f,
140         0.0f, 0.0f,  0.0f, 1.0f,
141         1.0f, 1.0f,  1.0f, 0.0f,
142         1.0f, 0.0f,  1.0f, 1.0f
143 };
144
145 int terminate_requested = 0;
146
147 int x_error_handler(Display *display, XErrorEvent *event)
148 {
149         printf("Ignoring X error %d on resource %lx\n", event->error_code, event->resourceid);
150         (void)display;
151         return 0;
152 }
153
154 int with_error(const char *message)
155 {
156         fprintf(stderr, "%s\n", message);
157         return 0;
158 }
159
160 int initialize_gl(Compositor *compositor, CompositedScreen *screen)
161 {
162         int attribs[9];
163         unsigned i;
164         GLXFBConfig *configs;
165         int nconfigs;
166         XVisualInfo *vi;
167         XSetWindowAttributes win_attr;
168
169         i = 0;
170         attribs[i++] = GLX_DRAWABLE_TYPE;
171         attribs[i++] = GLX_WINDOW_BIT;
172         attribs[i++] = GLX_RENDER_TYPE;
173         attribs[i++] = GLX_RGBA_BIT;
174         attribs[i++] = GLX_DOUBLEBUFFER;
175         attribs[i++] = True;
176         attribs[i++] = GLX_BIND_TO_TEXTURE_RGBA_EXT;
177         attribs[i++] = True;
178         attribs[i] = None;
179
180         configs = glXChooseFBConfig(compositor->display, screen->number, attribs, &nconfigs);
181         if(!configs || !nconfigs)
182                 return with_error("Could not find a suitable FBConfig");
183         screen->fbconfig = configs[0];
184         XFree(configs);
185
186         vi = glXGetVisualFromFBConfig(compositor->display, screen->fbconfig);
187         win_attr.colormap = XCreateColormap(compositor->display, screen->root, vi->visual, AllocNone);
188         screen->render_window = XCreateWindow(compositor->display, screen->overlay, 0, 0, screen->width, screen->height, 0, vi->depth, InputOutput, vi->visual, CWColormap, &win_attr);
189         XMapWindow(compositor->display, screen->render_window);
190
191         screen->glx_window = glXCreateWindow(compositor->display, screen->fbconfig, screen->render_window, NULL);
192
193         i = 0;
194         attribs[i++] = GLX_CONTEXT_FLAGS_ARB;
195         attribs[i++] = GLX_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB;
196         attribs[i++] = GLX_CONTEXT_MAJOR_VERSION_ARB;
197         attribs[i++] = 3;
198         attribs[i++] = GLX_CONTEXT_MINOR_VERSION_ARB;
199         attribs[i++] = 1;
200         attribs[i] = None;
201
202         screen->glx_context = compositor->glXCreateContextAttribsARB(compositor->display, screen->fbconfig, NULL, True, attribs);
203
204         XFree(vi);
205
206         return 1;
207 }
208
209 void use_gl(Compositor *compositor, CompositedScreen *screen)
210 {
211         glXMakeContextCurrent(compositor->display, screen->glx_window, screen->glx_window, screen->glx_context);
212 }
213
214 unsigned compile_shader(GLenum type, const char *source)
215 {
216         unsigned shader;
217         int status;
218         char info_log[1024];
219         GLsizei length;
220         
221         shader = glCreateShader(type);
222         glShaderSource(shader, 1, &source, NULL);
223         glCompileShader(shader);
224         glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
225         glGetShaderInfoLog(shader, sizeof(info_log), &length, info_log);
226         if(!status)
227         {
228                 fprintf(stderr, "Shader compilation failed:\n%s\n", info_log);
229                 glDeleteShader(shader);
230                 return 0;
231         }
232         else if(length)
233                 printf("Shader info log:\n%s\n", info_log);
234
235         return shader;
236 }
237
238 unsigned link_program(unsigned vshader, unsigned fshader)
239 {
240         unsigned program;
241         int status;
242         char info_log[1024];
243         GLsizei length;
244
245         program = glCreateProgram();
246         glAttachShader(program, vshader);
247         glAttachShader(program, fshader);
248         glBindAttribLocation(program, 0, "vertex");
249         glBindAttribLocation(program, 1, "texture_coord");
250         glBindFragDataLocation(program, 0, "frag_color");
251         glLinkProgram(program);
252
253         glGetProgramiv(program, GL_LINK_STATUS, &status);
254         glGetProgramInfoLog(program, sizeof(info_log), &length, info_log);
255         if(!status)
256         {
257                 fprintf(stderr, "Program link failed:\n%s\n", info_log);
258                 glDeleteProgram(program);
259                 return 0;
260         }
261         else if(length)
262                 printf("Program info log:\n%s\n", info_log);
263
264         return program;
265 }
266
267 unsigned create_2d_texture()
268 {
269         unsigned texture;
270         glGenTextures(1, &texture);
271         glBindTexture(GL_TEXTURE_2D, texture);
272         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
273         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
274         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
275         return texture;
276 }
277
278 int create_gl_resources(CompositedScreen *screen)
279 {
280         unsigned stride;
281         int loc;
282
283         screen->shaders[0] = compile_shader(GL_VERTEX_SHADER, vshader_src);
284         screen->shaders[1] = compile_shader(GL_FRAGMENT_SHADER, fshader_src);
285         screen->shaders[2] = compile_shader(GL_FRAGMENT_SHADER, masked_fshader_src);
286         if(!screen->shaders[0] || !screen->shaders[1] || !screen->shaders[2])
287                 return 0;
288
289         screen->program = link_program(screen->shaders[0], screen->shaders[1]);
290         if(!screen->program)
291                 return 0;
292
293         screen->masked_program = link_program(screen->shaders[0], screen->shaders[2]);
294         if(!screen->masked_program)
295                 return 0;
296
297         screen->geometry_loc = glGetUniformLocation(screen->program, "geometry");
298         screen->masked_geometry_loc = glGetUniformLocation(screen->masked_program, "geometry");
299
300         loc = glGetUniformLocation(screen->masked_program, "mask");
301         if(loc>=0)
302         {
303                 glUseProgram(screen->masked_program);
304                 glUniform1i(loc, 1);
305         }
306
307         glGenBuffers(1, &screen->window_vertex_buffer);
308         glBindBuffer(GL_ARRAY_BUFFER, screen->window_vertex_buffer);
309         glBufferData(GL_ARRAY_BUFFER, sizeof(window_vertices), window_vertices, GL_STATIC_DRAW);
310
311         stride = 4*sizeof(float);
312         glGenVertexArrays(1, &screen->window_vertex_array);
313         glBindVertexArray(screen->window_vertex_array);
314         glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, stride, NULL);
315         glEnableVertexAttribArray(0);
316         glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, stride, (void *)(2*sizeof(float)));
317         glEnableVertexAttribArray(1);
318         glBindVertexArray(0);
319
320         glBindBuffer(GL_ARRAY_BUFFER, 0);
321
322         screen->fb_texture = create_2d_texture();
323         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB8, screen->width, screen->height, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
324         glBindTexture(GL_TEXTURE_2D, 0);
325
326         glGenFramebuffers(1, &screen->framebuffer);
327         glBindFramebuffer(GL_DRAW_FRAMEBUFFER, screen->framebuffer);
328         glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, screen->fb_texture, 0);
329         glDepthMask(GL_FALSE);
330         glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
331
332         screen->root_texture = create_2d_texture();
333
334         return 1;
335 }
336
337 CompositedWindow *find_window(CompositedScreen *screen, Window w)
338 {
339         unsigned i;
340
341         for(i=0; i<screen->nwindows; ++i)
342                 if(screen->windows[i].window==w)
343                         return &screen->windows[i];
344
345         return NULL;
346 }
347
348 CompositedWindow *find_window_global(Compositor *compositor, Window w, CompositedScreen **screen)
349 {
350         unsigned i, j;
351
352         for(i=0; i<compositor->nscreens; ++i)
353                 for(j=0; j<compositor->screens[i].nwindows; ++j)
354                         if(compositor->screens[i].windows[j].window==w)
355                         {
356                                 if(screen)
357                                         *screen = &compositor->screens[i];
358                                 return &compositor->screens[i].windows[j];
359                         }
360
361         if(screen)
362                 *screen = NULL;
363         return NULL;
364 }
365
366 GLXPixmap pixmap_to_glx_pixmap(Compositor *compositor, CompositedScreen *screen, Pixmap pixmap)
367 {
368         int attribs[5];
369         unsigned i;
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         return glXCreatePixmap(compositor->display, screen->fbconfig, pixmap, attribs);
379 }
380
381 void create_window_pixmap(Compositor *compositor, CompositedScreen *screen, CompositedWindow *window)
382 {
383         if(window->pixmap)
384         {
385                 glXDestroyPixmap(compositor->display, window->glx_pixmap);
386                 XFreePixmap(compositor->display, window->pixmap);
387         }
388
389         window->pixmap = XCompositeNameWindowPixmap(compositor->display, window->window);
390         window->glx_pixmap = pixmap_to_glx_pixmap(compositor, screen, window->pixmap);
391         window->recreate_pixmap = 0;
392 }
393
394 void update_window_mask(Compositor *compositor, CompositedWindow *window)
395 {
396         Bool bounding_shaped;
397         Bool clip_shaped;
398         int xi, yi;
399         XRectangle *rects;
400         int rect_count;
401         int rect_order;
402         unsigned width;
403         unsigned height;
404         unsigned char *data;
405         int i;
406         unsigned y;
407
408         XShapeQueryExtents(compositor->display, window->window, &bounding_shaped, &xi, &yi, &width, &height, &clip_shaped, &xi, &yi, &width, &height);
409         window->use_mask = bounding_shaped;
410         if(!window->use_mask)
411                 return;
412
413         rects = XShapeGetRectangles(compositor->display, window->window, ShapeBounding, &rect_count, &rect_order);
414
415         width = window->width+2*window->border;
416         height = window->height+2*window->border;
417         data = (unsigned char *)malloc(width*height);
418         memset(data, 0, width*height);
419         for(i=0; i<rect_count; ++i)
420         {
421                 rects[i].x += window->border;
422                 rects[i].y += window->border;
423                 if(rects[i].x>=(int)width || rects[i].y>=(int)height)
424                         continue;
425
426                 if(rects[i].x<0)
427                 {
428                         if(-rects[i].x>rects[i].width)
429                                 continue;
430                         rects[i].width += rects[i].x;
431                         rects[i].x = 0;
432                 }
433
434                 if(rects[i].y<0)
435                 {
436                         if(-rects[i].y>rects[i].height)
437                                 continue;
438                         rects[i].height += rects[i].y;
439                         rects[i].y = 0;
440                 }
441
442                 if(rects[i].x+rects[i].width>(int)width)
443                         rects[i].width = width-rects[i].x;
444                 if(rects[i].y+rects[i].height>(int)height)
445                         rects[i].height = height-rects[i].y;
446
447                 for(y=0; y<rects[i].height; ++y)
448                 {
449                         unsigned char *row = data+(rects[i].y+y)*width+rects[i].x;
450                         memset(row, 255, rects[i].width);
451                 }
452         }
453
454         XFree(rects);
455
456         glBindTexture(GL_TEXTURE_2D, window->mask_texture);
457         glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
458         glTexImage2D(GL_TEXTURE_2D, 0, GL_R8, width, height, 0, GL_RED, GL_UNSIGNED_BYTE, data);
459
460         free(data);
461
462         window->recreate_mask = 0;
463 }
464
465 CompositedWindow *add_window(Compositor *compositor, CompositedScreen *screen, Window w)
466 {
467         CompositedWindow *window;
468         XWindowAttributes win_attr;
469
470         if(w==screen->root || w==screen->overlay)
471                 return NULL;
472
473         if(!XGetWindowAttributes(compositor->display, w, &win_attr))
474         {
475                 printf("XGetWindowAttributes failed; probably the window was already destroyed\n");
476                 return NULL;
477         }
478         if(win_attr.class==InputOnly)
479                 return NULL;
480
481         if(find_window(screen, w))
482                 return NULL;
483
484         if(screen->nwindows==screen->windows_capacity)
485         {
486                 screen->windows = (CompositedWindow *)realloc(screen->windows, (screen->windows_capacity+1)*sizeof(CompositedWindow));
487                 ++screen->windows_capacity;
488         }
489
490         window = &screen->windows[screen->nwindows++];
491
492         window->window = w;
493         window->x = win_attr.x;
494         window->y = win_attr.y;
495         window->width = win_attr.width;
496         window->height = win_attr.height;
497         window->border = win_attr.border_width;
498         window->map_state = win_attr.map_state;
499
500         window->damage = XDamageCreate(compositor->display, window->window, XDamageReportNonEmpty);
501         window->pixmap = None;
502         window->glx_pixmap = None;
503
504         XCompositeRedirectWindow(compositor->display, window->window, CompositeRedirectManual);
505         window->recreate_pixmap = (window->map_state==IsViewable);
506
507         window->texture = create_2d_texture();
508         window->mask_texture = create_2d_texture();
509         window->use_mask = 0;
510         window->recreate_mask = (window->map_state==IsViewable);
511
512         XShapeSelectInput(compositor->display, window->window, ShapeNotifyMask);
513
514         return window;
515 }
516
517 void remove_window(Compositor *compositor, CompositedScreen *screen, CompositedWindow *window, int destroyed)
518 {
519         unsigned i;
520
521         glDeleteTextures(1, &window->texture);
522         if(!destroyed)
523         {
524                 XDamageDestroy(compositor->display, window->damage);
525                 if(window->pixmap)
526                 {
527                         glXDestroyPixmap(compositor->display, window->glx_pixmap);
528                         XFreePixmap(compositor->display, window->pixmap);
529                 }
530                 XCompositeUnredirectWindow(compositor->display, window->window, CompositeRedirectManual);
531         }
532
533         --screen->nwindows;
534         for(i=window-screen->windows; i<screen->nwindows; ++i)
535                 screen->windows[i] = screen->windows[i+1];
536 }
537
538 CompositedWindow *reorder_window(CompositedScreen *screen, CompositedWindow *window, Window above)
539 {
540         unsigned i, j;
541         CompositedWindow hold;
542
543         i = window-screen->windows;
544         if(above)
545         {
546                 for(j=0; j<screen->nwindows; ++j)
547                         if(screen->windows[j].window==above)
548                                 break;
549
550                 if(j>=screen->nwindows || i==j+1)
551                         return window;
552
553                 if(j<i)
554                         ++j;
555         }
556         else
557                 j = 0;
558
559         hold = *window;
560         if(i<j)
561         {
562                 for(; i<j; ++i)
563                         screen->windows[i] = screen->windows[i+1];
564         }
565         else
566         {
567                 for(; i>j; --i)
568                         screen->windows[i] = screen->windows[i-1];
569         }
570         screen->windows[j] = hold;
571
572         return &screen->windows[j];
573 }
574
575 CompositedScreen *find_screen_by_root(Compositor *compositor, Window root)
576 {
577         unsigned i;
578
579         for(i=0; i<compositor->nscreens; ++i)
580                 if(compositor->screens[i].root==root)
581                         return &compositor->screens[i];
582
583         return NULL;
584 }
585
586 void update_monitor_vertices(CompositedScreen *screen, CompositedMonitor *monitor)
587 {
588         unsigned t;
589         unsigned data_size;
590         float *vertex_data;
591         unsigned short *index_data;
592         unsigned x, y;
593         unsigned i;
594         float aspect;
595         float cyl_radius;
596         float cyl_arc;
597         float sin_ksv;
598         float cos_ksv;
599         float distance;
600         float eye[3];
601         float look[3];
602
603         t = monitor->tessellation;
604
605         data_size = (t+1)*(t+1)*4*sizeof(float);
606         vertex_data = (float *)malloc(data_size);
607
608         aspect = (float)monitor->width/monitor->height;
609
610         if(monitor->cylinder_depth)
611         {
612                 cyl_radius = (monitor->cylinder_depth*monitor->cylinder_depth+0.25f)/(2.0f*monitor->cylinder_depth);
613                 cyl_arc = 2.0f*asin(0.5f/cyl_radius);
614         }
615
616         sin_ksv = monitor->keystone_vertical/sqrt(1.0f+monitor->keystone_vertical*monitor->keystone_vertical);
617         cos_ksv = sqrt(1.0f-sin_ksv*sin_ksv);
618         distance = monitor->perspective+sin_ksv*((sin_ksv>0)-monitor->vertical_center)/aspect;
619
620         eye[0] = 0.0f;
621         eye[1] = (monitor->vertical_center-0.5f)/aspect+sin_ksv*distance;
622         eye[2] = cos_ksv*distance;
623
624         look[0] = 0.0f;
625         look[1] = -sin_ksv;
626         look[2] = -cos_ksv;
627
628         for(y=0; y<=t; ++y)
629                 for(x=0; x<=t; ++x)
630                 {
631                         float *v;
632
633                         v = vertex_data+(y*(t+1)+x)*3;
634                         v[0] = (float)x/t-0.5f;
635                         v[1] = ((float)y/t-0.5f)/aspect;
636                         v[2] = 0;
637                         if(monitor->cylinder_depth)
638                         {
639                                 v[2] = (1.0f-cos(v[0]*cyl_arc))*cyl_radius-monitor->cylinder_depth;
640                                 v[0] = sin(v[0]*cyl_arc)*cyl_radius;
641                         }
642                 }
643
644         for(y=t; y<=t; --y)
645                 for(x=t; x<=t; --x)
646                 {
647                         float *v;
648                         float px, py, pz;
649                         float scale;
650
651                         v = vertex_data+(y*(t+1)+x)*3;
652                         px = v[0]-eye[0];
653                         py = (v[0]-eye[0])*look[0] - (v[1]-eye[1])*look[2] + (v[2]-eye[2])*look[1];
654                         pz = (v[0]-eye[0])*look[0] + (v[1]-eye[1])*look[1] + (v[2]-eye[2])*look[2];
655                         scale = monitor->perspective/pz;
656
657                         v = vertex_data+(y*(t+1)+x)*4;
658                         v[0] = px*scale+0.5f;
659                         v[1] = py*aspect*scale+monitor->vertical_center;
660                         v[2] = (monitor->x+(float)x*monitor->width/t)/screen->width;
661                         v[3] = 1.0f-(monitor->y+(1.0f-(float)y/t)*monitor->height)/screen->height;
662                 }
663
664         glBindBuffer(GL_ARRAY_BUFFER, monitor->vertex_buffer);
665         glBufferData(GL_ARRAY_BUFFER, data_size, vertex_data, GL_STATIC_DRAW);
666         glBindBuffer(GL_ARRAY_BUFFER, 0);
667         free(vertex_data);
668
669         monitor->nelements = t*((t+1)*2+1)-1;
670         data_size = monitor->nelements*sizeof(unsigned short);
671         index_data = (unsigned short *)malloc(data_size);
672         i = 0;
673         for(y=0; y<t; ++y)
674         {
675                 if(y>0)
676                         index_data[i++] = 0xFFFF;
677                 for(x=0; x<=t; ++x)
678                 {
679                         index_data[i++] = (y+1)*(t+1)+x;
680                         index_data[i++] = y*(t+1)+x;
681                 }
682         }
683         glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, monitor->index_buffer);
684         glBufferData(GL_ELEMENT_ARRAY_BUFFER, data_size, index_data, GL_STATIC_DRAW);
685         glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
686         free(index_data);
687 }
688
689 int initialize_monitor(Compositor *compositor, CompositedScreen *screen, XRRScreenResources *xrr_res, unsigned index)
690 {
691         CompositedMonitor *monitor;
692         XRROutputInfo *output;
693         int namelen;
694         XRRCrtcInfo *crtc;
695         unsigned buffers[2];
696         unsigned stride;
697
698         monitor = &screen->monitors[index];
699
700         output = XRRGetOutputInfo(compositor->display, xrr_res, xrr_res->outputs[index]);
701         namelen = strlen(output->name);
702         monitor->name = (char *)malloc(namelen+1);
703         strcpy(monitor->name, output->name);
704         monitor->enabled = !!output->crtc;
705         if(!monitor->enabled)
706         {
707                 XRRFreeOutputInfo(output);
708                 return 1;
709         }
710
711         crtc = XRRGetCrtcInfo(compositor->display, xrr_res, output->crtc);
712         monitor->x = crtc->x;
713         monitor->y = crtc->y;
714         monitor->width = crtc->width;
715         monitor->height = crtc->height;
716         XRRFreeCrtcInfo(crtc);
717         XRRFreeOutputInfo(output);
718
719         monitor->keystone_vertical = 0.0f;
720         monitor->cylinder_depth = 0.0f;
721         monitor->vertical_center = 0.5f;
722         monitor->perspective = 1.0f;
723
724         glGenBuffers(2, buffers);
725         monitor->vertex_buffer = buffers[0];
726         monitor->index_buffer = buffers[1];
727
728         monitor->tessellation = 50;
729         update_monitor_vertices(screen, monitor);
730         stride = 4*sizeof(float);
731
732         glGenVertexArrays(1, &monitor->vertex_array);
733         glBindVertexArray(monitor->vertex_array);
734         glBindBuffer(GL_ARRAY_BUFFER, monitor->vertex_buffer);
735         glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, stride, NULL);
736         glEnableVertexAttribArray(0);
737         glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, stride, (void *)(2*sizeof(float)));
738         glEnableVertexAttribArray(1);
739         glBindBuffer(GL_ARRAY_BUFFER, 0);
740         glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, monitor->index_buffer);
741         glBindVertexArray(0);
742
743         return 1;
744 }
745
746 CompositedMonitor *find_monitor_by_name(CompositedScreen *screen, char *name)
747 {
748         unsigned i;
749
750         for(i=0; i<screen->nmonitors; ++i)
751                 if(!strcmp(screen->monitors[i].name, name))
752                         return &screen->monitors[i];
753
754         return NULL;
755 }
756
757 void update_geometry_correction(Compositor *compositor, CompositedScreen *screen)
758 {
759         Atom prop_type;
760         int prop_format;
761         unsigned long overflow;
762         unsigned long names_length;
763         char *names;
764         unsigned long values_length;
765         short *values;
766         char *name_ptr;
767         unsigned i;
768
769         XGetWindowProperty(compositor->display, screen->root, compositor->monitors_atom, 0, 64, False, XA_STRING,
770                 &prop_type, &prop_format, &names_length, &overflow, (unsigned char **)&names);
771         if(prop_type!=XA_STRING || prop_format!=8)
772                 return;
773
774         XGetWindowProperty(compositor->display, screen->root, compositor->correction_atom, 0, 64, False, XA_INTEGER,
775                 &prop_type, &prop_format, &values_length, &overflow, (unsigned char **)&values);
776         if(prop_type!=XA_INTEGER || prop_format!=16)
777         {
778                 XFree(names);
779                 return;
780         }
781
782         use_gl(compositor, screen);
783
784         name_ptr = names;
785         for(i=0; i*4<values_length; ++i)
786         {
787                 CompositedMonitor *monitor;
788
789                 if(name_ptr>=names+names_length)
790                         break;
791
792                 monitor = find_monitor_by_name(screen, name_ptr);
793                 if(monitor)
794                 {
795                         monitor->keystone_vertical = values[i*4]/10000.0f;
796                         monitor->cylinder_depth = values[i*4+1]/10000.0f;
797                         monitor->vertical_center = values[i*4+2]/10000.0f;
798                         monitor->perspective = values[i*4+3]/10000.0f;
799
800                         if(monitor->enabled)
801                                 update_monitor_vertices(screen, monitor);
802                 }
803
804                 name_ptr += strlen(name_ptr)+1;
805         }
806
807         XFree(names);
808         XFree(values);
809 }
810
811 void update_root_pixmap(Compositor *compositor, CompositedScreen *screen)
812 {
813         Atom prop_type;
814         int prop_format;
815         unsigned long overflow;
816         unsigned long length;
817         long *pixmap;
818
819         XGetWindowProperty(compositor->display, screen->root, compositor->root_pmap_atom, 0, 1, False, XA_PIXMAP,
820                 &prop_type, &prop_format, &length, &overflow, (unsigned char **)&pixmap);
821         if(prop_type!=XA_PIXMAP || prop_format!=32)
822         {
823                 screen->root_pixmap = 0;
824                 if(screen->root_glx_pixmap)
825                 {
826                         glXDestroyPixmap(compositor->display, screen->root_glx_pixmap);
827                         screen->root_glx_pixmap = 0;
828                 }
829                 return;
830         }
831
832         screen->root_pixmap = pixmap[0];
833         screen->root_glx_pixmap = pixmap_to_glx_pixmap(compositor, screen, screen->root_pixmap);
834
835         XFree(pixmap);
836 }
837
838 int initialize_screen(Compositor *compositor, unsigned number)
839 {
840         CompositedScreen *screen;
841         const char *extensions;
842         Window dummy_root;
843         int x, y;
844         unsigned border;
845         unsigned depth;
846         XRRScreenResources *xrr_res;
847         Window dummy_parent;
848         Window *children;
849         unsigned nchildren;
850         unsigned i;
851
852         screen = &compositor->screens[number];
853         screen->number = number;
854
855         extensions = glXQueryExtensionsString(compositor->display, screen->number);
856         if(!strstr(extensions, "GLX_ARB_create_context"))
857                 return with_error("GLX_ARB_create_context is required");
858         if(!strstr(extensions, "GLX_EXT_texture_from_pixmap"))
859                 return with_error("GLX_EXT_texture_from_pixmap is required");
860
861         screen->root = RootWindow(compositor->display, screen->number);
862         XSelectInput(compositor->display, screen->root, SubstructureNotifyMask|PropertyChangeMask);
863         screen->overlay = XCompositeGetOverlayWindow(compositor->display, screen->root);
864         XGetGeometry(compositor->display, screen->overlay, &dummy_root, &x, &y, &screen->width, &screen->height, &border, &depth);
865         XShapeCombineRectangles(compositor->display, screen->overlay, ShapeInput, 0, 0, NULL, 0, ShapeSet, Unsorted);
866
867         if(!initialize_gl(compositor, screen))
868                 return 0;
869
870         use_gl(compositor, screen);
871
872         if(!create_gl_resources(screen))
873                 return 0;
874
875         xrr_res = XRRGetScreenResources(compositor->display, screen->root);
876         screen->nmonitors = xrr_res->noutput;
877         screen->monitors = (CompositedMonitor *)malloc(screen->nmonitors*sizeof(CompositedMonitor));
878         for(i=0; i<screen->nmonitors; ++i)
879                 if(!initialize_monitor(compositor, screen, xrr_res, i))
880                         return 0;
881         XRRFreeScreenResources(xrr_res);
882
883         screen->root_pixmap = 0;
884         screen->root_glx_pixmap = 0;
885
886         update_geometry_correction(compositor, screen);
887         update_root_pixmap(compositor, screen);
888
889         XQueryTree(compositor->display, screen->root, &dummy_root, &dummy_parent, &children, &nchildren);
890
891         screen->windows = (CompositedWindow *)malloc(nchildren*sizeof(CompositedWindow));
892         screen->nwindows = 0;
893         screen->windows_capacity = nchildren;
894
895         for(i=0; i<nchildren; ++i)
896                 add_window(compositor, screen, children[i]);
897
898         XFree(children);
899
900         screen->dirty = 1;
901
902         return 1;
903 }
904
905 int initialize_compositor(Compositor *compositor)
906 {
907         int event_base;
908         int error_base;
909         int major_ver;
910         int minor_ver;
911         unsigned i;
912
913         compositor->display = XOpenDisplay(NULL);
914         if(!compositor->display)
915                 return with_error("Could not open X display");
916
917         XSetErrorHandler(&x_error_handler);
918
919         if(!XCompositeQueryExtension(compositor->display, &event_base, &error_base))
920                 return with_error("XComposite is required but was not found");
921         else if(!XCompositeQueryVersion(compositor->display, &major_ver, &minor_ver))
922                 return with_error("Cannot determine XComposite version");
923         else if(major_ver==0 && minor_ver<3)
924                 return with_error("XComposite 0.3 or later is required");
925
926         if(!glXQueryExtension(compositor->display, &event_base, &error_base))
927                 return with_error("GLX is required but was not found");
928         else if(!glXQueryVersion(compositor->display, &major_ver, &minor_ver))
929                 return with_error("Cannot determine GLX version");
930         else if(major_ver<1 || (major_ver==1 && minor_ver<4))
931                 return with_error("GLX 1.4 or later is required");
932
933         if(!XDamageQueryExtension(compositor->display, &compositor->damage_event, &error_base))
934                 return with_error("XDamage is required but was not found");
935         else if(!XDamageQueryVersion(compositor->display, &major_ver, &minor_ver))
936                 return with_error("Cannot determine XDamage version");
937         else if(major_ver<1)
938                 return with_error("XDamage 1.0 or later is required");
939
940         if(!XShapeQueryExtension(compositor->display, &compositor->shape_event, &error_base))
941                 return with_error("XShape is required but was not found");
942         else if(!XShapeQueryVersion(compositor->display, &major_ver, &minor_ver))
943                 return with_error("Cannot determine XShape version");
944         else if(major_ver<1 || (major_ver==1 && minor_ver<1))
945                 return with_error("XShape 1.1 or later is required");
946
947         if(!XRRQueryExtension(compositor->display, &event_base, &error_base))
948                 return with_error("XRandR is required but was not found");
949         else if(!XRRQueryVersion(compositor->display, &major_ver, &minor_ver))
950                 return with_error("Cannot determine XRandR version");
951         else if(major_ver<1 || (major_ver==1 && minor_ver<2))
952                 return with_error("XRandR 1.2 or later is required");
953
954         compositor->glXCreateContextAttribsARB = (PFNGLXCREATECONTEXTATTRIBSARBPROC)glXGetProcAddress((unsigned char *)"glXCreateContextAttribsARB");
955         compositor->glXBindTexImageEXT = (PFNGLXBINDTEXIMAGEEXTPROC)glXGetProcAddress((unsigned char *)"glXBindTexImageEXT");
956         compositor->glXReleaseTexImageEXT = (PFNGLXRELEASETEXIMAGEEXTPROC)glXGetProcAddress((unsigned char *)"glXReleaseTexImageEXT");
957
958         compositor->root_pmap_atom = XInternAtom(compositor->display, "_XROOTPMAP_ID", False);
959         compositor->correction_atom = XInternAtom(compositor->display, "GEOMETRY_CORRECTION", False);
960         compositor->monitors_atom = XInternAtom(compositor->display, "GEOMETRY_CORRECTION_MONITORS", False);
961
962         compositor->nscreens = ScreenCount(compositor->display);
963         compositor->screens = (CompositedScreen *)malloc(compositor->nscreens*sizeof(CompositedScreen));
964         for(i=0; i<compositor->nscreens; ++i)
965                 if(!initialize_screen(compositor, i))
966                         return 0;
967
968         compositor->dirty = 1;
969
970         return 1;
971 }
972
973 void shutdown_screen(Compositor *compositor, CompositedScreen *screen)
974 {
975         unsigned i;
976
977         use_gl(compositor, screen);
978
979         for(i=0; i<screen->nwindows; ++i)
980         {
981                 glDeleteTextures(1, &screen->windows[i].texture);
982                 glDeleteTextures(1, &screen->windows[i].mask_texture);
983                 if(screen->windows[i].pixmap)
984                 {
985                         glXDestroyPixmap(compositor->display, screen->windows[i].glx_pixmap);
986                         XFreePixmap(compositor->display, screen->windows[i].pixmap);
987                         XDamageDestroy(compositor->display, screen->windows[i].damage);
988                 }
989         }
990
991         for(i=0; i<screen->nmonitors; ++i)
992         {
993                 free(screen->monitors[i].name);
994                 if(screen->monitors[i].enabled)
995                 {
996                         glDeleteBuffers(1, &screen->monitors[i].vertex_buffer);
997                         glDeleteBuffers(1, &screen->monitors[i].index_buffer);
998                         glDeleteVertexArrays(1, &screen->monitors[i].vertex_array);
999                 }
1000         }
1001
1002         glDeleteBuffers(1, &screen->window_vertex_buffer);
1003         glDeleteVertexArrays(1, &screen->window_vertex_array);
1004         glDeleteFramebuffers(1, &screen->framebuffer);
1005         glDeleteTextures(1, &screen->fb_texture);
1006         glDeleteProgram(screen->program);
1007         glDeleteProgram(screen->masked_program);
1008         for(i=0; i<3; ++i)
1009                 glDeleteShader(screen->shaders[i]);
1010
1011         glXMakeContextCurrent(compositor->display, 0, 0, NULL);
1012         glXDestroyContext(compositor->display, screen->glx_context);
1013         glXDestroyWindow(compositor->display, screen->glx_window);
1014         XDestroyWindow(compositor->display, screen->render_window);
1015
1016         XCompositeReleaseOverlayWindow(compositor->display, screen->overlay);
1017
1018         free(screen->windows);
1019         free(screen->monitors);
1020 }
1021
1022 void shutdown_compositor(Compositor *compositor)
1023 {
1024         unsigned i;
1025
1026         for(i=0; i<compositor->nscreens; ++i)
1027                 shutdown_screen(compositor, &compositor->screens[i]);
1028         free(compositor->screens);
1029
1030         XCloseDisplay(compositor->display);
1031 }
1032
1033 void mark_dirty(Compositor *compositor, CompositedScreen *screen)
1034 {
1035         compositor->dirty = 1;
1036         screen->dirty = 1;
1037 }
1038
1039 void process_create_window_event(Compositor *compositor, XCreateWindowEvent *event)
1040 {
1041         CompositedScreen *screen;
1042
1043         if((screen = find_screen_by_root(compositor, event->parent)))
1044                 add_window(compositor, screen, event->window);
1045 }
1046
1047 void process_destroy_window_event(Compositor *compositor, XDestroyWindowEvent *event)
1048 {
1049         CompositedScreen *screen;
1050         CompositedWindow *window;
1051
1052         if((screen = find_screen_by_root(compositor, event->event)))
1053                 if((window = find_window(screen, event->window)))
1054                 {
1055                         use_gl(compositor, screen);
1056                         remove_window(compositor, screen, window, 1);
1057                 }
1058 }
1059
1060 void process_map_event(Compositor *compositor, XMapEvent *event)
1061 {
1062         CompositedScreen *screen;
1063         CompositedWindow *window;
1064
1065         screen = find_screen_by_root(compositor, event->event);
1066         if(!screen)
1067                 return;
1068
1069         window = find_window(screen, event->window);
1070         if(!window)
1071                 return;
1072
1073         window->map_state = IsViewable;
1074         window->recreate_pixmap = 1;
1075         window->recreate_mask = 1;
1076
1077         mark_dirty(compositor, screen);
1078 }
1079
1080 void process_unmap_event(Compositor *compositor, XUnmapEvent *event)
1081 {
1082         CompositedScreen *screen;
1083         CompositedWindow *window;
1084
1085         screen = find_screen_by_root(compositor, event->event);
1086         if(!screen)
1087                 return;
1088
1089         window = find_window(screen, event->window);
1090         if(window)
1091                 window->map_state = IsUnviewable;
1092
1093         mark_dirty(compositor, screen);
1094 }
1095
1096 void process_reparent_event(Compositor *compositor, XReparentEvent *event)
1097 {
1098         CompositedScreen *screen;
1099         CompositedWindow *window;
1100
1101         screen = find_screen_by_root(compositor, event->event);
1102         if(!screen)
1103                 return;
1104
1105         if(event->parent==screen->root)
1106                 window = add_window(compositor, screen, event->window);
1107         else
1108         {
1109                 window = find_window(screen, event->window);
1110                 if(!window)
1111                         return;
1112
1113                 remove_window(compositor, screen, window, 0);
1114         }
1115
1116         if(window && window->map_state==IsViewable)
1117                 mark_dirty(compositor, screen);
1118 }
1119
1120 void process_configure_event(Compositor *compositor, XConfigureEvent *event)
1121 {
1122         CompositedScreen *screen;
1123         CompositedWindow *window;
1124
1125         screen = find_screen_by_root(compositor, event->event);
1126         if(!screen)
1127                 return;
1128
1129         window = find_window(screen, event->window);
1130         if(!window)
1131                 return;
1132
1133         window->x = event->x;
1134         window->y = event->y;
1135         if((unsigned)event->width!=window->width || (unsigned)event->height!=window->height || (unsigned)event->border_width!=window->border)
1136         {
1137                 window->width = event->width;
1138                 window->height = event->height;
1139                 window->border = event->border_width;
1140                 window->recreate_pixmap = 1;
1141         }
1142         reorder_window(screen, window, event->above);
1143
1144         if(window->map_state==IsViewable)
1145                 mark_dirty(compositor, screen);
1146 }
1147
1148 void process_property_event(Compositor *compositor, XPropertyEvent *event)
1149 {
1150         CompositedScreen *screen;
1151
1152         if(event->atom!=compositor->correction_atom)
1153                 return;
1154
1155         screen = find_screen_by_root(compositor, event->window);
1156         if(!screen)
1157                 return;
1158
1159         update_geometry_correction(compositor, screen);
1160 }
1161
1162 void process_damage_event(Compositor *compositor, XDamageNotifyEvent *event)
1163 {
1164         CompositedScreen *screen;
1165         CompositedWindow *window;
1166
1167         window = find_window_global(compositor, event->drawable, &screen);
1168         if(window && window->map_state==IsViewable)
1169                 mark_dirty(compositor, screen);
1170 }
1171
1172 void process_shape_event(Compositor *compositor, XShapeEvent *event)
1173 {
1174         CompositedScreen *screen;
1175         CompositedWindow *window;
1176
1177         if(event->kind!=ShapeBounding)
1178                 return;
1179
1180         window = find_window_global(compositor, event->window, &screen);
1181         if(window && window->map_state==IsViewable)
1182         {
1183                 window->recreate_mask = 1;
1184                 mark_dirty(compositor, screen);
1185         }
1186 }
1187
1188 void process_events(Compositor *compositor)
1189 {
1190         int pending;
1191         XEvent event;
1192
1193         pending = 0;
1194         while((pending || !compositor->dirty) && !terminate_requested)
1195         {
1196                 if(!pending)
1197                         pending = XPending(compositor->display);
1198
1199                 XNextEvent(compositor->display, &event);
1200                 if(pending)
1201                         --pending;
1202
1203                 switch(event.type)
1204                 {
1205                 case CreateNotify:
1206                         process_create_window_event(compositor, &event.xcreatewindow);
1207                         break;
1208                 case DestroyNotify:
1209                         process_destroy_window_event(compositor, &event.xdestroywindow);
1210                         break;
1211                 case MapNotify:
1212                         process_map_event(compositor, &event.xmap);
1213                         break;
1214                 case UnmapNotify:
1215                         process_unmap_event(compositor, &event.xunmap);
1216                         break;
1217                 case ReparentNotify:
1218                         process_reparent_event(compositor, &event.xreparent);
1219                         break;
1220                 case ConfigureNotify:
1221                         process_configure_event(compositor, &event.xconfigure);
1222                         break;
1223                 case PropertyNotify:
1224                         process_property_event(compositor, &event.xproperty);
1225                         break;
1226                 default:
1227                         if(event.type==compositor->damage_event+XDamageNotify)
1228                                 process_damage_event(compositor, (XDamageNotifyEvent *)&event);
1229                         else if(event.type==compositor->shape_event+ShapeNotify)
1230                                 process_shape_event(compositor, (XShapeEvent *)&event);
1231                         else
1232                                 printf("Event %d\n", event.type);
1233                 }
1234         }
1235 }
1236
1237 void refresh_screen(Compositor *compositor, CompositedScreen *screen)
1238 {
1239         unsigned i;
1240         int use_mask;
1241
1242         for(i=0; i<screen->nwindows; ++i)
1243                 if(screen->windows[i].map_state==IsViewable)
1244                         XDamageSubtract(compositor->display, screen->windows[i].damage, None, None);
1245         glXWaitX();
1246
1247         use_gl(compositor, screen);
1248
1249         glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
1250         glBindFramebuffer(GL_DRAW_FRAMEBUFFER, screen->framebuffer);
1251
1252         use_mask = -1;
1253         glBindVertexArray(screen->window_vertex_array);
1254
1255         if(screen->root_pixmap)
1256         {
1257                 use_mask = 0;
1258                 glUseProgram(screen->program);
1259                 glBindTexture(GL_TEXTURE_2D, screen->root_texture);
1260                 compositor->glXBindTexImageEXT(compositor->display, screen->root_glx_pixmap, GLX_FRONT_LEFT_EXT, NULL);
1261                 glUniform4f(screen->geometry_loc, 0.0f, 0.0f, 1.0f, 1.0f);
1262                 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
1263                 compositor->glXReleaseTexImageEXT(compositor->display, screen->root_glx_pixmap, GLX_FRONT_LEFT_EXT);
1264         }
1265         else
1266                 glClear(GL_COLOR_BUFFER_BIT);
1267
1268         for(i=0; i<screen->nwindows; ++i)
1269         {
1270                 CompositedWindow *window;
1271
1272                 window = &screen->windows[i];
1273                 if(window->map_state!=IsViewable)
1274                         continue;
1275
1276                 if(window->use_mask!=use_mask)
1277                 {
1278                         use_mask = window->use_mask;
1279                         glUseProgram(use_mask ? screen->masked_program : screen->program);
1280                 }
1281
1282                 if(window->use_mask)
1283                 {
1284                         glActiveTexture(GL_TEXTURE1);
1285                         glBindTexture(GL_TEXTURE_2D, window->mask_texture);
1286                         glActiveTexture(GL_TEXTURE0);
1287                 }
1288
1289                 if(window->recreate_pixmap)
1290                         create_window_pixmap(compositor, screen, window);
1291                 if(window->recreate_mask)
1292                         update_window_mask(compositor, window);
1293
1294                 glBindTexture(GL_TEXTURE_2D, window->texture);
1295                 compositor->glXBindTexImageEXT(compositor->display, window->glx_pixmap, GLX_FRONT_LEFT_EXT, NULL);
1296                 glUniform4f((use_mask ? screen->masked_geometry_loc : screen->geometry_loc),
1297                         (float)window->x/screen->width, 1.0f-(float)(window->y+window->height)/screen->height,
1298                         (float)(window->width+2*window->border)/screen->width, (float)(window->height+2*window->border)/screen->height);
1299                 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
1300                 compositor->glXReleaseTexImageEXT(compositor->display, window->glx_pixmap, GLX_FRONT_LEFT_EXT);
1301         }
1302
1303         glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
1304         glClear(GL_COLOR_BUFFER_BIT);
1305         glBindTexture(GL_TEXTURE_2D, screen->fb_texture);
1306         glEnable(GL_PRIMITIVE_RESTART);
1307         glPrimitiveRestartIndex(0xFFFF);
1308         if(use_mask)
1309                 glUseProgram(screen->program);
1310
1311         for(i=0; i<screen->nmonitors; ++i)
1312         {
1313                 CompositedMonitor *monitor = &screen->monitors[i];
1314                 if(!monitor->enabled)
1315                         continue;
1316
1317                 glUniform4f(screen->geometry_loc,
1318                         (float)monitor->x/screen->width, 1.0f-(float)(monitor->y+monitor->height)/screen->height,
1319                         (float)monitor->width/screen->width, (float)monitor->height/screen->height);
1320
1321                 glBindVertexArray(monitor->vertex_array);
1322                 glDrawElements(GL_TRIANGLE_STRIP, monitor->nelements, GL_UNSIGNED_SHORT, NULL);
1323         }
1324
1325         glBindVertexArray(0);
1326
1327         glXSwapBuffers(compositor->display, screen->glx_window);
1328
1329         screen->dirty = 0;
1330 }
1331
1332 void refresh_all_screens(Compositor *compositor)
1333 {
1334         unsigned i;
1335
1336         for(i=0; i<compositor->nscreens; ++i)
1337         {
1338                 CompositedScreen *screen = &compositor->screens[i];
1339                 if(screen->dirty)
1340                         refresh_screen(compositor, screen);
1341         }
1342
1343         compositor->dirty = 0;
1344 }
1345
1346 void sighandler(int sig)
1347 {
1348         terminate_requested = 1;
1349         (void)sig;
1350 }
1351
1352 int main()
1353 {
1354         Compositor compositor;
1355
1356         signal(SIGINT, &sighandler);
1357         signal(SIGTERM, &sighandler);
1358
1359         if(!initialize_compositor(&compositor))
1360                 return 1;
1361
1362         while(!terminate_requested)
1363         {
1364                 process_events(&compositor);
1365                 if(compositor.dirty && !terminate_requested)
1366                         refresh_all_screens(&compositor);
1367         }
1368
1369         shutdown_compositor(&compositor);
1370
1371         return 0;
1372 }