src/wx/gl_video_view.cc

   1 /*
   2     Copyright (C) 2018-2021 Carl Hetherington <cth@carlh.net>
   3
   4     This file is part of DCP-o-matic.
   5
   6     DCP-o-matic is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  10
  11     DCP-o-matic is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License
  17     along with DCP-o-matic.  If not, see <http://www.gnu.org/licenses/>.
  18
  19 */
  20
  21
  22 #ifdef DCPOMATIC_WINDOWS
  23 #include <GL/glew.h>
  24 #endif
  25
  26 #include "gl_video_view.h"
  27 #include "film_viewer.h"
  28 #include "wx_util.h"
  29 #include "lib/image.h"
  30 #include "lib/dcpomatic_assert.h"
  31 #include "lib/exceptions.h"
  32 #include "lib/cross.h"
  33 #include "lib/player_video.h"
  34 #include "lib/butler.h"
  35 #include <boost/bind/bind.hpp>
  36 #include <iostream>
  37
  38 #ifdef DCPOMATIC_OSX
  39 #define GL_DO_NOT_WARN_IF_MULTI_GL_VERSION_HEADERS_INCLUDED
  40 #include <OpenGL/OpenGL.h>
  41 #include <OpenGL/gl3.h>
  42 #endif
  43
  44 #ifdef DCPOMATIC_LINUX
  45 #include <GL/glu.h>
  46 #include <GL/glext.h>
  47 #endif
  48
  49 #ifdef DCPOMATIC_WINDOWS
  50 #include <GL/glu.h>
  51 #include <GL/wglext.h>
  52 #endif
  53
  54
  55 using std::cout;
  56 using std::shared_ptr;
  57 using std::string;
  58 using boost::optional;
  59 #if BOOST_VERSION >= 106100
  60 using namespace boost::placeholders;
  61 #endif
  62
  63
  64 static void
  65 check_gl_error (char const * last)
  66 {
  67         GLenum const e = glGetError ();
  68         if (e != GL_NO_ERROR) {
  69                 throw GLError (last, e);
  70         }
  71 }
  72
  73
  74 GLVideoView::GLVideoView (FilmViewer* viewer, wxWindow *parent)
  75         : VideoView (viewer)
  76         , _context (nullptr)
  77         , _have_storage (false)
  78         , _vsync_enabled (false)
  79         , _playing (false)
  80         , _one_shot (false)
  81 {
  82         wxGLAttributes attributes;
  83         /* We don't need a depth buffer, and indeed there is apparently a bug with Windows/Intel HD 630
  84          * which puts green lines over the OpenGL display if you have a non-zero depth buffer size.
  85          * https://community.intel.com/t5/Graphics/Request-for-details-on-Intel-HD-630-green-lines-in-OpenGL-apps/m-p/1202179
  86          */
  87         attributes.PlatformDefaults().MinRGBA(8, 8, 8, 8).DoubleBuffer().Depth(0).EndList();
  88         _canvas = new wxGLCanvas (
  89                 parent, attributes, wxID_ANY, wxDefaultPosition, wxDefaultSize, wxFULL_REPAINT_ON_RESIZE
  90         );
  91         _canvas->Bind (wxEVT_PAINT, boost::bind(&GLVideoView::update, this));
  92         _canvas->Bind (wxEVT_SIZE, boost::bind(&GLVideoView::size_changed, this, _1));
  93
  94         _canvas->Bind (wxEVT_TIMER, boost::bind(&GLVideoView::check_for_butler_errors, this));
  95         _timer.reset (new wxTimer(_canvas));
  96         _timer->Start (2000);
  97 }
  98
  99
 100 void
 101 GLVideoView::size_changed (wxSizeEvent const& ev)
 102 {
 103         _canvas_size = ev.GetSize ();
 104         Sized ();
 105 }
 106
 107
 108
 109 GLVideoView::~GLVideoView ()
 110 {
 111         boost::this_thread::disable_interruption dis;
 112
 113         try {
 114                 _thread.interrupt ();
 115                 _thread.join ();
 116         } catch (...) {}
 117
 118         glDeleteTextures (1, &_texture);
 119 }
 120
 121 void
 122 GLVideoView::check_for_butler_errors ()
 123 {
 124         if (!_viewer->butler()) {
 125                 return;
 126         }
 127
 128         try {
 129                 _viewer->butler()->rethrow ();
 130         } catch (DecodeError& e) {
 131                 error_dialog (get(), e.what());
 132         } catch (dcp::ReadError& e) {
 133                 error_dialog (get(), wxString::Format(_("Could not read DCP: %s"), std_to_wx(e.what())));
 134         }
 135 }
 136
 137
 138 /** Called from the UI thread */
 139 void
 140 GLVideoView::update ()
 141 {
 142         if (!_canvas->IsShownOnScreen()) {
 143                 return;
 144         }
 145
 146         /* It appears important to do this from the GUI thread; if we do it from the GL thread
 147          * on Linux we get strange failures to create the context for any version of GL higher
 148          * than 3.2.
 149          */
 150         ensure_context ();
 151
 152 #ifdef DCPOMATIC_OSX
 153         /* macOS gives errors if we don't do this (and therefore [NSOpenGLContext setView:]) from the main thread */
 154         if (!_setup_shaders_done) {
 155                 setup_shaders ();
 156                 _setup_shaders_done = true;
 157         }
 158 #endif
 159
 160         if (!_thread.joinable()) {
 161                 _thread = boost::thread (boost::bind(&GLVideoView::thread, this));
 162         }
 163
 164         request_one_shot ();
 165
 166         rethrow ();
 167 }
 168
 169
 170 static constexpr char vertex_source[] =
 171 "#version 330 core\n"
 172 "\n"
 173 "layout (location = 0) in vec3 in_pos;\n"
 174 "layout (location = 1) in vec2 in_tex_coord;\n"
 175 "\n"
 176 "out vec2 TexCoord;\n"
 177 "\n"
 178 "void main()\n"
 179 "{\n"
 180 "       gl_Position = vec4(in_pos, 1.0);\n"
 181 "       TexCoord = in_tex_coord;\n"
 182 "}\n";
 183
 184
 185 /* Bicubic interpolation stolen from https://stackoverflow.com/questions/13501081/efficient-bicubic-filtering-code-in-glsl */
 186 static constexpr char fragment_source[] =
 187 "#version 330 core\n"
 188 "\n"
 189 "in vec2 TexCoord;\n"
 190 "\n"
 191 "uniform sampler2D texture_sampler;\n"
 192 "uniform int draw_border;\n"
 193 "uniform vec4 border_colour;\n"
 194 "\n"
 195 "out vec4 FragColor;\n"
 196 "\n"
 197 "vec4 cubic(float x)\n"
 198 "{\n"
 199 "    float x2 = x * x;\n"
 200 "    float x3 = x2 * x;\n"
 201 "    vec4 w;\n"
 202 "    w.x =     -x3 + 3 * x2 - 3 * x + 1;\n"
 203 "    w.y =  3 * x3 - 6 * x2         + 4;\n"
 204 "    w.z = -3 * x3 + 3 * x2 + 3 * x + 1;\n"
 205 "    w.w =  x3;\n"
 206 "    return w / 6.f;\n"
 207 "}\n"
 208 "\n"
 209 "vec4 texture_bicubic(sampler2D sampler, vec2 tex_coords)\n"
 210 "{\n"
 211 "   vec2 tex_size = textureSize(sampler, 0);\n"
 212 "   vec2 inv_tex_size = 1.0 / tex_size;\n"
 213 "\n"
 214 "   tex_coords = tex_coords * tex_size - 0.5;\n"
 215 "\n"
 216 "   vec2 fxy = fract(tex_coords);\n"
 217 "   tex_coords -= fxy;\n"
 218 "\n"
 219 "   vec4 xcubic = cubic(fxy.x);\n"
 220 "   vec4 ycubic = cubic(fxy.y);\n"
 221 "\n"
 222 "   vec4 c = tex_coords.xxyy + vec2 (-0.5, +1.5).xyxy;\n"
 223 "\n"
 224 "   vec4 s = vec4(xcubic.xz + xcubic.yw, ycubic.xz + ycubic.yw);\n"
 225 "   vec4 offset = c + vec4 (xcubic.yw, ycubic.yw) / s;\n"
 226 "\n"
 227 "   offset *= inv_tex_size.xxyy;\n"
 228 "\n"
 229 "   vec4 sample0 = texture(sampler, offset.xz);\n"
 230 "   vec4 sample1 = texture(sampler, offset.yz);\n"
 231 "   vec4 sample2 = texture(sampler, offset.xw);\n"
 232 "   vec4 sample3 = texture(sampler, offset.yw);\n"
 233 "\n"
 234 "   float sx = s.x / (s.x + s.y);\n"
 235 "   float sy = s.z / (s.z + s.w);\n"
 236 "\n"
 237 "   return mix(\n"
 238 "          mix(sample3, sample2, sx), mix(sample1, sample0, sx)\n"
 239 "          , sy);\n"
 240 "}\n"
 241 "\n"
 242 "void main()\n"
 243 "{\n"
 244 "       if (draw_border == 1) {\n"
 245 "               FragColor = border_colour;\n"
 246 "       } else {\n"
 247 "               FragColor = texture_bicubic(texture_sampler, TexCoord);\n"
 248 "       }\n"
 249 "}\n";
 250
 251
 252 void
 253 GLVideoView::ensure_context ()
 254 {
 255         if (!_context) {
 256                 wxGLContextAttrs attrs;
 257                 attrs.PlatformDefaults().CoreProfile().OGLVersion(4, 1).EndList();
 258                 _context = new wxGLContext (_canvas, nullptr, &attrs);
 259                 if (!_context->IsOK()) {
 260                         throw GLError ("Making GL context", -1);
 261                 }
 262         }
 263 }
 264
 265 void
 266 GLVideoView::setup_shaders ()
 267 {
 268         DCPOMATIC_ASSERT (_canvas);
 269         DCPOMATIC_ASSERT (_context);
 270         auto r = _canvas->SetCurrent (*_context);
 271         DCPOMATIC_ASSERT (r);
 272
 273 #ifdef DCPOMATIC_WINDOWS
 274         r = glewInit();
 275         if (r != GLEW_OK) {
 276                 throw GLError(reinterpret_cast<char const*>(glewGetErrorString(r)));
 277         }
 278 #endif
 279
 280         unsigned int indices[] = {
 281                 0, 1, 3, // texture triangle #1
 282                 1, 2, 3, // texture triangle #2
 283                 4, 5,    // border line #1
 284                 5, 6,    // border line #2
 285                 6, 7,    // border line #3
 286                 7, 4,    // border line #4
 287         };
 288
 289         glGenVertexArrays(1, &_vao);
 290         check_gl_error ("glGenVertexArrays");
 291         GLuint vbo;
 292         glGenBuffers(1, &vbo);
 293         check_gl_error ("glGenBuffers");
 294         GLuint ebo;
 295         glGenBuffers(1, &ebo);
 296         check_gl_error ("glGenBuffers");
 297
 298         glBindVertexArray(_vao);
 299         check_gl_error ("glBindVertexArray");
 300
 301         glBindBuffer(GL_ARRAY_BUFFER, vbo);
 302         check_gl_error ("glBindBuffer");
 303
 304         glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);
 305         check_gl_error ("glBindBuffer");
 306         glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
 307         check_gl_error ("glBufferData");
 308
 309         /* position attribute to vertex shader (location = 0) */
 310         glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), nullptr);
 311         glEnableVertexAttribArray(0);
 312         /* texture coord attribute to vertex shader (location = 1) */
 313         glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), reinterpret_cast<void*>(3 * sizeof(float)));
 314         glEnableVertexAttribArray(1);
 315         check_gl_error ("glEnableVertexAttribArray");
 316
 317         auto compile = [](GLenum type, char const* source) -> GLuint {
 318                 auto shader = glCreateShader(type);
 319                 DCPOMATIC_ASSERT (shader);
 320                 GLchar const * src[] = { static_cast<GLchar const *>(source) };
 321                 glShaderSource(shader, 1, src, nullptr);
 322                 check_gl_error ("glShaderSource");
 323                 glCompileShader(shader);
 324                 check_gl_error ("glCompileShader");
 325                 GLint ok;
 326                 glGetShaderiv(shader, GL_COMPILE_STATUS, &ok);
 327                 if (!ok) {
 328                         GLint log_length;
 329                         glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &log_length);
 330                         string log;
 331                         if (log_length > 0) {
 332                                 char* log_char = new char[log_length];
 333                                 glGetShaderInfoLog(shader, log_length, nullptr, log_char);
 334                                 log = string(log_char);
 335                                 delete[] log_char;
 336                         }
 337                         glDeleteShader(shader);
 338                         throw GLError(String::compose("Could not compile shader (%1)", log).c_str(), -1);
 339                 }
 340                 return shader;
 341         };
 342
 343         auto vertex_shader = compile (GL_VERTEX_SHADER, vertex_source);
 344         auto fragment_shader = compile (GL_FRAGMENT_SHADER, fragment_source);
 345
 346         auto program = glCreateProgram();
 347         check_gl_error ("glCreateProgram");
 348         glAttachShader (program, vertex_shader);
 349         check_gl_error ("glAttachShader");
 350         glAttachShader (program, fragment_shader);
 351         check_gl_error ("glAttachShader");
 352         glLinkProgram (program);
 353         check_gl_error ("glLinkProgram");
 354         GLint ok;
 355         glGetProgramiv (program, GL_LINK_STATUS, &ok);
 356         if (!ok) {
 357                 GLint log_length;
 358                 glGetProgramiv(program, GL_INFO_LOG_LENGTH, &log_length);
 359                 string log;
 360                 if (log_length > 0) {
 361                         char* log_char = new char[log_length];
 362                         glGetProgramInfoLog(program, log_length, nullptr, log_char);
 363                         log = string(log_char);
 364                         delete[] log_char;
 365                 }
 366                 glDeleteProgram (program);
 367                 throw GLError(String::compose("Could not link shader (%1)", log).c_str(), -1);
 368         }
 369         glDeleteShader (vertex_shader);
 370         glDeleteShader (fragment_shader);
 371
 372         glUseProgram (program);
 373
 374         _draw_border = glGetUniformLocation (program, "draw_border");
 375         check_gl_error ("glGetUniformLocation");
 376         set_border_colour (program);
 377
 378         glLineWidth (2.0f);
 379 }
 380
 381
 382 void
 383 GLVideoView::set_border_colour (GLuint program)
 384 {
 385         auto uniform = glGetUniformLocation (program, "border_colour");
 386         check_gl_error ("glGetUniformLocation");
 387         auto colour = outline_content_colour ();
 388         glUniform4f (uniform, colour.Red() / 255.0f, colour.Green() / 255.0f, colour.Blue() / 255.0f, 1.0f);
 389         check_gl_error ("glUniform4f");
 390 }
 391
 392
 393 void
 394 GLVideoView::draw (Position<int>, dcp::Size)
 395 {
 396         auto pad = pad_colour();
 397         glClearColor(pad.Red() / 255.0, pad.Green() / 255.0, pad.Blue() / 255.0, 1.0);
 398         glClear (GL_COLOR_BUFFER_BIT);
 399         check_gl_error ("glClear");
 400
 401         auto const size = _canvas_size.load();
 402         int const width = size.GetWidth();
 403         int const height = size.GetHeight();
 404
 405         if (width < 64 || height < 0) {
 406                 return;
 407         }
 408
 409         glViewport (0, 0, width, height);
 410         check_gl_error ("glViewport");
 411
 412         glBindTexture(GL_TEXTURE_2D, _texture);
 413         glBindVertexArray(_vao);
 414         check_gl_error ("glBindVertexArray");
 415         glUniform1i(_draw_border, 0);
 416         glDrawElements (GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
 417         if (_viewer->outline_content()) {
 418                 glUniform1i(_draw_border, 1);
 419                 glDrawElements (GL_LINES, 8, GL_UNSIGNED_INT, reinterpret_cast<void*>(6 * sizeof(int)));
 420                 check_gl_error ("glDrawElements");
 421         }
 422
 423         glFlush();
 424         check_gl_error ("glFlush");
 425
 426         _canvas->SwapBuffers();
 427 }
 428
 429
 430 void
 431 GLVideoView::set_image (shared_ptr<const Image> image)
 432 {
 433         if (!image) {
 434                 _size = optional<dcp::Size>();
 435                 return;
 436         }
 437
 438
 439         DCPOMATIC_ASSERT (image->pixel_format() == AV_PIX_FMT_RGB24);
 440         DCPOMATIC_ASSERT (!image->aligned());
 441
 442         if (image->size() != _size) {
 443                 _have_storage = false;
 444         }
 445
 446         _size = image->size ();
 447         glPixelStorei (GL_UNPACK_ALIGNMENT, 1);
 448         check_gl_error ("glPixelStorei");
 449
 450         if (_have_storage) {
 451                 glTexSubImage2D (GL_TEXTURE_2D, 0, 0, 0, _size->width, _size->height, GL_RGB, GL_UNSIGNED_BYTE, image->data()[0]);
 452                 check_gl_error ("glTexSubImage2D");
 453         } else {
 454                 glTexImage2D (GL_TEXTURE_2D, 0, GL_RGBA8, _size->width, _size->height, 0, GL_RGB, GL_UNSIGNED_BYTE, image->data()[0]);
 455                 check_gl_error ("glTexImage2D");
 456
 457                 auto const canvas_size = _canvas_size.load();
 458                 int const canvas_width = canvas_size.GetWidth();
 459                 int const canvas_height = canvas_size.GetHeight();
 460
 461                 float const image_x = float(_size->width) / canvas_width;
 462                 float const image_y = float(_size->height) / canvas_height;
 463
 464                 auto x_pixels_to_gl = [canvas_width](int x) {
 465                         return (x * 2.0f / canvas_width) - 1.0f;
 466                 };
 467
 468                 auto y_pixels_to_gl = [canvas_height](int y) {
 469                         return (y * 2.0f / canvas_height) - 1.0f;
 470                 };
 471
 472                 auto inter_position = player_video().first->inter_position();
 473                 auto inter_size = player_video().first->inter_size();
 474
 475                 float const border_x1 = x_pixels_to_gl (inter_position.x) + 1.0f - image_x;
 476                 float const border_y1 = y_pixels_to_gl (inter_position.y) + 1.0f - image_y;
 477                 float const border_x2 = x_pixels_to_gl (inter_position.x + inter_size.width) + 1.0f - image_x;
 478                 float const border_y2 = y_pixels_to_gl (inter_position.y + inter_size.height) + 1.0f - image_y;
 479
 480                 float vertices[] = {
 481                         // positions                  // texture coords
 482                          image_x,   image_y,   0.0f,  1.0f, 0.0f,   // top right           (index 0)
 483                          image_x,  -image_y,   0.0f,  1.0f, 1.0f,   // bottom right        (index 1)
 484                         -image_x,  -image_y,   0.0f,  0.0f, 1.0f,   // bottom left         (index 2)
 485                         -image_x,   image_y,   0.0f,  0.0f, 0.0f,   // top left            (index 3)
 486                          border_x1, border_y1, 0.0f,  0.0f, 0.0f,   // border bottom left  (index 4)
 487                          border_x1, border_y2, 0.0f,  0.0f, 0.0f,   // border top left     (index 5)
 488                          border_x2, border_y2, 0.0f,  0.0f, 0.0f,   // border top right    (index 6)
 489                          border_x2, border_y1, 0.0f,  0.0f, 0.0f,   // border bottom right (index 7)
 490                 };
 491
 492                 /* Set the vertex shader's input data (GL_ARRAY_BUFFER) */
 493                 glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
 494                 check_gl_error ("glBufferData");
 495
 496                 _have_storage = true;
 497         }
 498
 499         glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 500         glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 501         check_gl_error ("glTexParameteri");
 502
 503         glTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 504         glTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 505         check_gl_error ("glTexParameterf");
 506 }
 507
 508 void
 509 GLVideoView::start ()
 510 {
 511         VideoView::start ();
 512
 513         boost::mutex::scoped_lock lm (_playing_mutex);
 514         _playing = true;
 515         _thread_work_condition.notify_all ();
 516 }
 517
 518 void
 519 GLVideoView::stop ()
 520 {
 521         boost::mutex::scoped_lock lm (_playing_mutex);
 522         _playing = false;
 523 }
 524
 525
 526 void
 527 GLVideoView::thread_playing ()
 528 {
 529         if (length() != dcpomatic::DCPTime()) {
 530                 auto const next = position() + one_video_frame();
 531
 532                 if (next >= length()) {
 533                         _viewer->finished ();
 534                         return;
 535                 }
 536
 537                 get_next_frame (false);
 538                 set_image_and_draw ();
 539         }
 540
 541         while (true) {
 542                 optional<int> n = time_until_next_frame();
 543                 if (!n || *n > 5) {
 544                         break;
 545                 }
 546                 get_next_frame (true);
 547                 add_dropped ();
 548         }
 549 }
 550
 551
 552 void
 553 GLVideoView::set_image_and_draw ()
 554 {
 555         auto pv = player_video().first;
 556         if (pv) {
 557                 set_image (pv->image(bind(&PlayerVideo::force, _1, AV_PIX_FMT_RGB24), VideoRange::FULL, false, true));
 558                 draw (pv->inter_position(), pv->inter_size());
 559                 _viewer->image_changed (pv);
 560         }
 561 }
 562
 563
 564 void
 565 GLVideoView::thread ()
 566 try
 567 {
 568         start_of_thread ("GLVideoView");
 569
 570 #if defined(DCPOMATIC_OSX)
 571         /* Without this we see errors like
 572          * ../src/osx/cocoa/glcanvas.mm(194): assert ""context"" failed in SwapBuffers(): should have current context [in thread 700006970000]
 573          */
 574         WXGLSetCurrentContext (_context->GetWXGLContext());
 575 #else
 576         if (!_setup_shaders_done) {
 577                 setup_shaders ();
 578                 _setup_shaders_done = true;
 579         }
 580 #endif
 581
 582 #if defined(DCPOMATIC_LINUX) && defined(DCPOMATIC_HAVE_GLX_SWAP_INTERVAL_EXT)
 583         if (_canvas->IsExtensionSupported("GLX_EXT_swap_control")) {
 584                 /* Enable vsync */
 585                 Display* dpy = wxGetX11Display();
 586                 glXSwapIntervalEXT (dpy, DefaultScreen(dpy), 1);
 587                 _vsync_enabled = true;
 588         }
 589 #endif
 590
 591 #ifdef DCPOMATIC_WINDOWS
 592         if (_canvas->IsExtensionSupported("WGL_EXT_swap_control")) {
 593                 /* Enable vsync */
 594                 PFNWGLSWAPINTERVALEXTPROC swap = (PFNWGLSWAPINTERVALEXTPROC) wglGetProcAddress("wglSwapIntervalEXT");
 595                 if (swap) {
 596                         swap (1);
 597                         _vsync_enabled = true;
 598                 }
 599         }
 600
 601 #endif
 602
 603 #ifdef DCPOMATIC_OSX
 604         /* Enable vsync */
 605         GLint swapInterval = 1;
 606         CGLSetParameter (CGLGetCurrentContext(), kCGLCPSwapInterval, &swapInterval);
 607         _vsync_enabled = true;
 608 #endif
 609
 610         glGenTextures (1, &_texture);
 611         check_gl_error ("glGenTextures");
 612         glBindTexture (GL_TEXTURE_2D, _texture);
 613         check_gl_error ("glBindTexture");
 614
 615         while (true) {
 616                 boost::mutex::scoped_lock lm (_playing_mutex);
 617                 while (!_playing && !_one_shot) {
 618                         _thread_work_condition.wait (lm);
 619                 }
 620                 lm.unlock ();
 621
 622                 if (_playing) {
 623                         thread_playing ();
 624                 } else if (_one_shot) {
 625                         _one_shot = false;
 626                         set_image_and_draw ();
 627                 }
 628
 629                 boost::this_thread::interruption_point ();
 630                 dcpomatic_sleep_milliseconds (time_until_next_frame().get_value_or(0));
 631         }
 632
 633         /* XXX: leaks _context, but that seems preferable to deleting it here
 634          * without also deleting the wxGLCanvas.
 635          */
 636 }
 637 catch (...)
 638 {
 639         store_current ();
 640 }
 641
 642
 643 VideoView::NextFrameResult
 644 GLVideoView::display_next_frame (bool non_blocking)
 645 {
 646         NextFrameResult const r = get_next_frame (non_blocking);
 647         request_one_shot ();
 648         return r;
 649 }
 650
 651
 652 void
 653 GLVideoView::request_one_shot ()
 654 {
 655         boost::mutex::scoped_lock lm (_playing_mutex);
 656         _one_shot = true;
 657         _thread_work_condition.notify_all ();
 658 }
 659