src/video/gl/gl_renderer.cpp

   1 //  SuperTux
   2 //  Copyright (C) 2006 Matthias Braun <matze@braunis.de>
   3 //
   4 //  This program is free software: you can redistribute it and/or modify
   5 //  it under the terms of the GNU General Public License as published by
   6 //  the Free Software Foundation, either version 3 of the License, or
   7 //  (at your option) any later version.
   8 //
   9 //  This program is distributed in the hope that it will be useful,
  10 //  but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 //  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 //  GNU General Public License for more details.
  13 //
  14 //  You should have received a copy of the GNU General Public License
  15 //  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 #include "video/gl/gl_renderer.hpp"
  18
  19 #include <iomanip>
  20 #include <iostream>
  21 #include <math.h>
  22 #include <physfs.h>
  23
  24 #include "supertux/gameconfig.hpp"
  25 #include "supertux/globals.hpp"
  26 #include "video/drawing_request.hpp"
  27 #include "video/gl/gl_surface_data.hpp"
  28 #include "video/gl/gl_texture.hpp"
  29 #define LIGHTMAP_DIV 5
  30
  31 #ifdef GL_VERSION_ES_CM_1_0
  32 #  define glOrtho glOrthof
  33 #endif
  34
  35 namespace {
  36
  37 inline void intern_draw(float left, float top, float right, float bottom,
  38                         float uv_left, float uv_top,
  39                         float uv_right, float uv_bottom,
  40                         float angle, float alpha,
  41                         const Color& color,
  42                         const Blend& blend,
  43                         DrawingEffect effect)
  44 {
  45   if(effect & HORIZONTAL_FLIP)
  46     std::swap(uv_left, uv_right);
  47
  48   if(effect & VERTICAL_FLIP)
  49     std::swap(uv_top, uv_bottom);
  50
  51   // unrotated blit
  52   glBlendFunc(blend.sfactor, blend.dfactor);
  53   glColor4f(color.red, color.green, color.blue, color.alpha * alpha);
  54
  55   if (angle == 0.0f) {
  56     float vertices[] = {
  57       left, top,
  58       right, top,
  59       right, bottom,
  60       left, bottom,
  61     };
  62     glVertexPointer(2, GL_FLOAT, 0, vertices);
  63
  64     float uvs[] = {
  65       uv_left, uv_top,
  66       uv_right, uv_top,
  67       uv_right, uv_bottom,
  68       uv_left, uv_bottom,
  69     };
  70     glTexCoordPointer(2, GL_FLOAT, 0, uvs);
  71
  72     glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
  73   } else {
  74     // rotated blit
  75     float center_x = (left + right) / 2;
  76     float center_y = (top + bottom) / 2;
  77
  78     float sa = sinf(angle/180.0f*M_PI);
  79     float ca = cosf(angle/180.0f*M_PI);
  80
  81     left  -= center_x;
  82     right -= center_x;
  83
  84     top    -= center_y;
  85     bottom -= center_y;
  86
  87     float vertices[] = {
  88       left*ca - top*sa + center_x, left*sa + top*ca + center_y,
  89       right*ca - top*sa + center_x, right*sa + top*ca + center_y,
  90       right*ca - bottom*sa + center_x, right*sa + bottom*ca + center_y,
  91       left*ca - bottom*sa + center_x, left*sa + bottom*ca + center_y
  92     };
  93     glVertexPointer(2, GL_FLOAT, 0, vertices);
  94
  95     float uvs[] = {
  96       uv_left, uv_top,
  97       uv_right, uv_top,
  98       uv_right, uv_bottom,
  99       uv_left, uv_bottom,
 100     };
 101     glTexCoordPointer(2, GL_FLOAT, 0, uvs);
 102
 103     glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
 104   }
 105
 106   // FIXME: find a better way to restore the blend mode
 107   glColor4f(1.0f, 1.0f, 1.0f, 1.0f);
 108   glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 109 }
 110
 111 } // namespace
 112
 113 GLRenderer::GLRenderer() :
 114   desktop_size(-1, -1),
 115   screen_size(-1, -1),
 116   fullscreen_active(false)
 117 {
 118   Renderer::instance_ = this;
 119
 120 #if SDL_MAJOR_VERSION > 1 || SDL_MINOR_VERSION > 2 || (SDL_MINOR_VERSION == 2 && SDL_PATCHLEVEL >= 10)
 121   // unfortunately only newer SDLs have these infos.
 122   // This must be called before SDL_SetVideoMode() or it will return
 123   // the window size instead of the desktop size.
 124   const SDL_VideoInfo *info = SDL_GetVideoInfo();
 125   if (info)
 126   {
 127     desktop_size = Size(info->current_w, info->current_h);
 128   }
 129 #endif
 130
 131   if(texture_manager != 0)
 132     texture_manager->save_textures();
 133
 134 #ifdef SDL_GL_SWAP_CONTROL
 135   if(config->try_vsync) {
 136     /* we want vsync for smooth scrolling */
 137     SDL_GL_SetAttribute(SDL_GL_SWAP_CONTROL, 1);
 138   }
 139 #endif
 140
 141   SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
 142
 143   // FIXME: Hu? 16bit rendering?
 144   SDL_GL_SetAttribute(SDL_GL_RED_SIZE,   5);
 145   SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE, 5);
 146   SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE,  5);
 147
 148   if(g_config->use_fullscreen)
 149   {
 150     apply_video_mode(g_config->fullscreen_size, true);
 151   }
 152   else
 153   {
 154     apply_video_mode(g_config->window_size, false);
 155   }
 156
 157   // setup opengl state and transform
 158   glDisable(GL_DEPTH_TEST);
 159   glDisable(GL_CULL_FACE);
 160   glEnable(GL_TEXTURE_2D);
 161   glEnable(GL_BLEND);
 162   glEnableClientState(GL_VERTEX_ARRAY);
 163   glEnableClientState(GL_TEXTURE_COORD_ARRAY);
 164   glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 165
 166   // Init the projection matrix, viewport and stuff
 167   apply_config();
 168
 169   if(texture_manager == 0)
 170     texture_manager = new TextureManager();
 171   else
 172     texture_manager->reload_textures();
 173
 174 #ifndef GL_VERSION_ES_CM_1_0
 175   GLenum err = glewInit();
 176   if (GLEW_OK != err)
 177   {
 178     std::ostringstream out;
 179     out << "GLRenderer: " << glewGetErrorString(err);
 180     throw std::runtime_error(out.str());
 181   }
 182   log_info << "Using GLEW " << glewGetString(GLEW_VERSION) << std::endl;
 183   log_info << "GLEW_ARB_texture_non_power_of_two: " << GLEW_ARB_texture_non_power_of_two << std::endl;
 184 #endif
 185 }
 186
 187 GLRenderer::~GLRenderer()
 188 {
 189 }
 190
 191 void
 192 GLRenderer::draw_surface(const DrawingRequest& request)
 193 {
 194   const Surface* surface = (const Surface*) request.request_data;
 195   GLTexture *gltexture = dynamic_cast<GLTexture *>(surface->get_texture());
 196   GLSurfaceData *surface_data = reinterpret_cast<GLSurfaceData *>(surface->get_surface_data());
 197
 198   glBindTexture(GL_TEXTURE_2D, gltexture->get_handle());
 199   intern_draw(request.pos.x, request.pos.y,
 200               request.pos.x + surface->get_width(),
 201               request.pos.y + surface->get_height(),
 202               surface_data->get_uv_left(),
 203               surface_data->get_uv_top(),
 204               surface_data->get_uv_right(),
 205               surface_data->get_uv_bottom(),
 206               request.angle,
 207               request.alpha,
 208               request.color,
 209               request.blend,
 210               request.drawing_effect);
 211 }
 212
 213 void
 214 GLRenderer::draw_surface_part(const DrawingRequest& request)
 215 {
 216   const SurfacePartRequest* surfacepartrequest
 217     = (SurfacePartRequest*) request.request_data;
 218   const Surface *surface = surfacepartrequest->surface;
 219   GLTexture *gltexture = dynamic_cast<GLTexture *>(surface->get_texture());
 220   GLSurfaceData *surface_data = reinterpret_cast<GLSurfaceData *>(surface->get_surface_data());
 221
 222   float uv_width = surface_data->get_uv_right() - surface_data->get_uv_left();
 223   float uv_height = surface_data->get_uv_bottom() - surface_data->get_uv_top();
 224
 225   float uv_left = surface_data->get_uv_left() + (uv_width * surfacepartrequest->source.x) / surface->get_width();
 226   float uv_top = surface_data->get_uv_top() + (uv_height * surfacepartrequest->source.y) / surface->get_height();
 227   float uv_right = surface_data->get_uv_left() + (uv_width * (surfacepartrequest->source.x + surfacepartrequest->size.x)) / surface->get_width();
 228   float uv_bottom = surface_data->get_uv_top() + (uv_height * (surfacepartrequest->source.y + surfacepartrequest->size.y)) / surface->get_height();
 229
 230   glBindTexture(GL_TEXTURE_2D, gltexture->get_handle());
 231   intern_draw(request.pos.x, request.pos.y,
 232               request.pos.x + surfacepartrequest->size.x,
 233               request.pos.y + surfacepartrequest->size.y,
 234               uv_left,
 235               uv_top,
 236               uv_right,
 237               uv_bottom,
 238               0.0,
 239               request.alpha,
 240               request.color,
 241               Blend(),
 242               request.drawing_effect);
 243 }
 244
 245 void
 246 GLRenderer::draw_gradient(const DrawingRequest& request)
 247 {
 248   const GradientRequest* gradientrequest
 249     = (GradientRequest*) request.request_data;
 250   const Color& top = gradientrequest->top;
 251   const Color& bottom = gradientrequest->bottom;
 252
 253   glDisable(GL_TEXTURE_2D);
 254   glDisableClientState(GL_TEXTURE_COORD_ARRAY);
 255   glEnableClientState(GL_COLOR_ARRAY);
 256
 257   float vertices[] = {
 258     0, 0,
 259     SCREEN_WIDTH, 0,
 260     SCREEN_WIDTH, SCREEN_HEIGHT,
 261     0, SCREEN_HEIGHT
 262   };
 263   glVertexPointer(2, GL_FLOAT, 0, vertices);
 264
 265   float colors[] = {
 266     top.red, top.green, top.blue, top.alpha,
 267     top.red, top.green, top.blue, top.alpha,
 268     bottom.red, bottom.green, bottom.blue, bottom.alpha,
 269     bottom.red, bottom.green, bottom.blue, bottom.alpha,
 270   };
 271   glColorPointer(4, GL_FLOAT, 0, colors);
 272
 273   glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
 274
 275   glDisableClientState(GL_COLOR_ARRAY);
 276   glEnableClientState(GL_TEXTURE_COORD_ARRAY);
 277
 278   glEnable(GL_TEXTURE_2D);
 279   glColor4f(1, 1, 1, 1);
 280 }
 281
 282 void
 283 GLRenderer::draw_filled_rect(const DrawingRequest& request)
 284 {
 285   const FillRectRequest* fillrectrequest
 286     = (FillRectRequest*) request.request_data;
 287
 288   glDisable(GL_TEXTURE_2D);
 289   glColor4f(fillrectrequest->color.red, fillrectrequest->color.green,
 290             fillrectrequest->color.blue, fillrectrequest->color.alpha);
 291   glDisableClientState(GL_TEXTURE_COORD_ARRAY);
 292
 293   if (fillrectrequest->radius != 0.0f)
 294   {
 295     // draw round rect
 296     // Keep radius in the limits, so that we get a circle instead of
 297     // just graphic junk
 298     float radius = std::min(fillrectrequest->radius,
 299                             std::min(fillrectrequest->size.x/2,
 300                                      fillrectrequest->size.y/2));
 301
 302     // inner rectangle
 303     Rectf irect(request.pos.x    + radius,
 304                request.pos.y    + radius,
 305                request.pos.x + fillrectrequest->size.x - radius,
 306                request.pos.y + fillrectrequest->size.y - radius);
 307
 308     int n = 8;
 309     int p = 0;
 310     std::vector<float> vertices((n+1) * 4 * 2);
 311
 312     for(int i = 0; i <= n; ++i)
 313     {
 314       float x = sinf(i * (M_PI/2) / n) * radius;
 315       float y = cosf(i * (M_PI/2) / n) * radius;
 316
 317       vertices[p++] = irect.get_left() - x;
 318       vertices[p++] = irect.get_top()  - y;
 319
 320       vertices[p++] = irect.get_right() + x;
 321       vertices[p++] = irect.get_top()   - y;
 322     }
 323
 324     for(int i = 0; i <= n; ++i)
 325     {
 326       float x = cosf(i * (M_PI/2) / n) * radius;
 327       float y = sinf(i * (M_PI/2) / n) * radius;
 328
 329       vertices[p++] = irect.get_left()   - x;
 330       vertices[p++] = irect.get_bottom() + y;
 331
 332       vertices[p++] = irect.get_right()  + x;
 333       vertices[p++] = irect.get_bottom() + y;
 334     }
 335
 336     glVertexPointer(2, GL_FLOAT, 0, &*vertices.begin());
 337     glDrawArrays(GL_TRIANGLE_STRIP, 0,  vertices.size()/2);
 338   }
 339   else
 340   {
 341     float x = request.pos.x;
 342     float y = request.pos.y;
 343     float w = fillrectrequest->size.x;
 344     float h = fillrectrequest->size.y;
 345
 346     float vertices[] = {
 347       x,   y,
 348       x+w, y,
 349       x+w, y+h,
 350       x,   y+h
 351     };
 352     glVertexPointer(2, GL_FLOAT, 0, vertices);
 353
 354     glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
 355   }
 356
 357   glEnableClientState(GL_TEXTURE_COORD_ARRAY);
 358   glEnable(GL_TEXTURE_2D);
 359   glColor4f(1, 1, 1, 1);
 360 }
 361
 362 void
 363 GLRenderer::draw_inverse_ellipse(const DrawingRequest& request)
 364 {
 365   const InverseEllipseRequest* ellipse = (InverseEllipseRequest*)request.request_data;
 366
 367   glDisable(GL_TEXTURE_2D);
 368   glColor4f(ellipse->color.red,  ellipse->color.green,
 369             ellipse->color.blue, ellipse->color.alpha);
 370
 371   float x = request.pos.x;
 372   float y = request.pos.y;
 373   float w = ellipse->size.x/2.0f;
 374   float h = ellipse->size.y/2.0f;
 375
 376   static const int slices = 16;
 377   static const int points = (slices+1) * 12;
 378
 379   float vertices[points * 2];
 380   int   p = 0;
 381
 382   // Bottom
 383   vertices[p++] = SCREEN_WIDTH; vertices[p++] = SCREEN_HEIGHT;
 384   vertices[p++] = 0;            vertices[p++] = SCREEN_HEIGHT;
 385   vertices[p++] = x;            vertices[p++] = y+h;
 386
 387   // Top
 388   vertices[p++] = SCREEN_WIDTH; vertices[p++] = 0;
 389   vertices[p++] = 0;            vertices[p++] = 0;
 390   vertices[p++] = x;            vertices[p++] = y-h;
 391
 392   // Left
 393   vertices[p++] = SCREEN_WIDTH; vertices[p++] = 0;
 394   vertices[p++] = SCREEN_WIDTH; vertices[p++] = SCREEN_HEIGHT;
 395   vertices[p++] = x+w;          vertices[p++] = y;
 396
 397   // Right
 398   vertices[p++] = 0;            vertices[p++] = 0;
 399   vertices[p++] = 0;            vertices[p++] = SCREEN_HEIGHT;
 400   vertices[p++] = x-w;          vertices[p++] = y;
 401
 402   for(int i = 0; i < slices; ++i)
 403   {
 404     float ex1 = sinf(M_PI/2 / slices * i) * w;
 405     float ey1 = cosf(M_PI/2 / slices * i) * h;
 406
 407     float ex2 = sinf(M_PI/2 / slices * (i+1)) * w;
 408     float ey2 = cosf(M_PI/2 / slices * (i+1)) * h;
 409
 410     // Bottom/Right
 411     vertices[p++] = SCREEN_WIDTH; vertices[p++] = SCREEN_HEIGHT;
 412     vertices[p++] = x + ex1;      vertices[p++] = y + ey1;
 413     vertices[p++] = x + ex2;      vertices[p++] = y + ey2;
 414
 415     // Top/Left
 416     vertices[p++] = 0;            vertices[p++] = 0;
 417     vertices[p++] = x - ex1;      vertices[p++] = y - ey1;
 418     vertices[p++] = x - ex2;      vertices[p++] = y - ey2;
 419
 420     // Top/Right
 421     vertices[p++] = SCREEN_WIDTH; vertices[p++] = 0;
 422     vertices[p++] = x + ex1;      vertices[p++] = y - ey1;
 423     vertices[p++] = x + ex2;      vertices[p++] = y - ey2;
 424
 425     // Bottom/Left
 426     vertices[p++] = 0;            vertices[p++] = SCREEN_HEIGHT;
 427     vertices[p++] = x - ex1;      vertices[p++] = y + ey1;
 428     vertices[p++] = x - ex2;      vertices[p++] = y + ey2;
 429   }
 430
 431   glDisableClientState(GL_TEXTURE_COORD_ARRAY);
 432   glVertexPointer(2, GL_FLOAT, 0, vertices);
 433
 434   glDrawArrays(GL_TRIANGLES, 0, points);
 435
 436   glEnableClientState(GL_TEXTURE_COORD_ARRAY);
 437
 438   glEnable(GL_TEXTURE_2D);
 439   glColor4f(1, 1, 1, 1);
 440 }
 441
 442 void
 443 GLRenderer::do_take_screenshot()
 444 {
 445   // [Christoph] TODO: Yes, this method also takes care of the actual disk I/O. Split it?
 446
 447   SDL_Surface *shot_surf;
 448   // create surface to hold screenshot
 449 #if SDL_BYTEORDER == SDL_BIG_ENDIAN
 450   shot_surf = SDL_CreateRGBSurface(SDL_SWSURFACE, SCREEN_WIDTH, SCREEN_HEIGHT, 24, 0x00FF0000, 0x0000FF00, 0x000000FF, 0);
 451 #else
 452   shot_surf = SDL_CreateRGBSurface(SDL_SWSURFACE, SCREEN_WIDTH, SCREEN_HEIGHT, 24, 0x000000FF, 0x0000FF00, 0x00FF0000, 0);
 453 #endif
 454   if (!shot_surf) {
 455     log_warning << "Could not create RGB Surface to contain screenshot" << std::endl;
 456     return;
 457   }
 458
 459   // read pixels into array
 460   char* pixels = new char[3 * SCREEN_WIDTH * SCREEN_HEIGHT];
 461   if (!pixels) {
 462     log_warning << "Could not allocate memory to store screenshot" << std::endl;
 463     SDL_FreeSurface(shot_surf);
 464     return;
 465   }
 466   glPixelStorei(GL_PACK_ALIGNMENT, 1);
 467   glReadPixels(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT, GL_RGB, GL_UNSIGNED_BYTE, pixels);
 468
 469   // copy array line-by-line
 470   for (int i = 0; i < SCREEN_HEIGHT; i++) {
 471     char* src = pixels + (3 * SCREEN_WIDTH * (SCREEN_HEIGHT - i - 1));
 472     if(SDL_MUSTLOCK(shot_surf))
 473     {
 474       SDL_LockSurface(shot_surf);
 475     }
 476     char* dst = ((char*)shot_surf->pixels) + i * shot_surf->pitch;
 477     memcpy(dst, src, 3 * SCREEN_WIDTH);
 478     if(SDL_MUSTLOCK(shot_surf))
 479     {
 480       SDL_UnlockSurface(shot_surf);
 481     }
 482   }
 483
 484   // free array
 485   delete[](pixels);
 486
 487   // save screenshot
 488   static const std::string writeDir = PHYSFS_getWriteDir();
 489   static const std::string dirSep = PHYSFS_getDirSeparator();
 490   static const std::string baseName = "screenshot";
 491   static const std::string fileExt = ".bmp";
 492   std::string fullFilename;
 493   for (int num = 0; num < 1000; num++) {
 494     std::ostringstream oss;
 495     oss << baseName;
 496     oss << std::setw(3) << std::setfill('0') << num;
 497     oss << fileExt;
 498     std::string fileName = oss.str();
 499     fullFilename = writeDir + dirSep + fileName;
 500     if (!PHYSFS_exists(fileName.c_str())) {
 501       SDL_SaveBMP(shot_surf, fullFilename.c_str());
 502       log_debug << "Wrote screenshot to \"" << fullFilename << "\"" << std::endl;
 503       SDL_FreeSurface(shot_surf);
 504       return;
 505     }
 506   }
 507   log_warning << "Did not save screenshot, because all files up to \"" << fullFilename << "\" already existed" << std::endl;
 508   SDL_FreeSurface(shot_surf);
 509 }
 510
 511 void
 512 GLRenderer::flip()
 513 {
 514   assert_gl("drawing");
 515   SDL_GL_SwapBuffers();
 516 }
 517
 518 void
 519 GLRenderer::resize(int w, int h)
 520 {
 521   // This causes the screen to go black, which is annoying, but seems
 522   // unavoidable with SDL at the moment
 523   SDL_SetVideoMode(w, h, 0, SDL_OPENGL /*| SDL_RESIZABLE*/);
 524
 525   g_config->window_size = Size(w, h);
 526
 527   apply_config();
 528 }
 529
 530 void
 531 GLRenderer::apply_config()
 532 {
 533   if (false)
 534   {
 535     log_info << "Applying Config:"
 536              << "\n  Desktop: " << desktop_size.width << "x" << desktop_size.height
 537              << "\n  Window:  " << g_config->window_size
 538              << "\n  FullRes: " << g_config->fullscreen_size
 539              << "\n  Aspect:  " << g_config->aspect_size
 540              << "\n  Magnif:  " << g_config->magnification
 541              << std::endl;
 542   }
 543
 544   float target_aspect = static_cast<float>(desktop_size.width) / static_cast<float>(desktop_size.height);
 545   if (g_config->aspect_size != Size(0, 0))
 546   {
 547     target_aspect = float(g_config->aspect_size.width) / float(g_config->aspect_size.height);
 548   }
 549
 550   float desktop_aspect = 4.0f / 3.0f; // random default fallback guess
 551   if (desktop_size.width != -1 && desktop_size.height != -1)
 552   {
 553     desktop_aspect = float(desktop_size.width) / float(desktop_size.height);
 554   }
 555
 556   Size screen_size;
 557
 558   // Get the screen width
 559   if (g_config->use_fullscreen)
 560   {
 561     screen_size = g_config->fullscreen_size;
 562     desktop_aspect = float(screen_size.width) / float(screen_size.height);
 563   }
 564   else
 565   {
 566     screen_size = g_config->window_size;
 567   }
 568
 569   apply_video_mode(screen_size, g_config->use_fullscreen);
 570
 571   if (target_aspect > 1.0f)
 572   {
 573     SCREEN_WIDTH  = static_cast<int>(screen_size.width * (target_aspect / desktop_aspect));
 574     SCREEN_HEIGHT = static_cast<int>(screen_size.height);
 575   }
 576   else
 577   {
 578     SCREEN_WIDTH  = static_cast<int>(screen_size.width);
 579     SCREEN_HEIGHT = static_cast<int>(screen_size.height  * (target_aspect / desktop_aspect));
 580   }
 581
 582   Size max_size(1600, 1200); // FIXME: Maybe 1920 is ok too
 583
 584   if (g_config->magnification == 0.0f) // Magic value that means 'minfill'
 585   {
 586     // This scales SCREEN_WIDTH/SCREEN_HEIGHT so that they never excede
 587     // max_size.width/max_size.height
 588     if (SCREEN_WIDTH > max_size.width || SCREEN_HEIGHT > max_size.height)
 589     {
 590       float scale1  = float(max_size.width)/SCREEN_WIDTH;
 591       float scale2  = float(max_size.height)/SCREEN_HEIGHT;
 592       float scale   = (scale1 < scale2) ? scale1 : scale2;
 593       SCREEN_WIDTH  = static_cast<int>(SCREEN_WIDTH  * scale);
 594       SCREEN_HEIGHT = static_cast<int>(SCREEN_HEIGHT * scale);
 595     }
 596
 597     glViewport(0, 0, screen_size.width, screen_size.height);
 598   }
 599   else
 600   {
 601     SCREEN_WIDTH  = static_cast<int>(SCREEN_WIDTH  / g_config->magnification);
 602     SCREEN_HEIGHT = static_cast<int>(SCREEN_HEIGHT / g_config->magnification);
 603
 604     // This works by adding black borders around the screen to limit
 605     // SCREEN_WIDTH/SCREEN_HEIGHT to max_size.width/max_size.height
 606     Size new_size = screen_size;
 607
 608     if (SCREEN_WIDTH > max_size.width)
 609     {
 610       new_size.width = static_cast<int>((float) new_size.width * float(max_size.width)/SCREEN_WIDTH);
 611       SCREEN_WIDTH = static_cast<int>(max_size.width);
 612     }
 613
 614     if (SCREEN_HEIGHT > max_size.height)
 615     {
 616       new_size.height = static_cast<int>((float) new_size.height * float(max_size.height)/SCREEN_HEIGHT);
 617       SCREEN_HEIGHT = static_cast<int>(max_size.height);
 618     }
 619
 620     // Clear both buffers so that we get a clean black border without junk
 621     glClear(GL_COLOR_BUFFER_BIT);
 622     SDL_GL_SwapBuffers();
 623     glClear(GL_COLOR_BUFFER_BIT);
 624     SDL_GL_SwapBuffers();
 625
 626     glViewport(std::max(0, (screen_size.width  - new_size.width)  / 2),
 627                std::max(0, (screen_size.height - new_size.height) / 2),
 628                std::min(new_size.width,  screen_size.width),
 629                std::min(new_size.height, screen_size.height));
 630   }
 631
 632   glMatrixMode(GL_PROJECTION);
 633   glLoadIdentity();
 634
 635   glOrtho(0, SCREEN_WIDTH, SCREEN_HEIGHT, 0, -1, 1);
 636
 637   glMatrixMode(GL_MODELVIEW);
 638   glLoadIdentity();
 639   glTranslatef(0, 0, 0);
 640   check_gl_error("Setting up view matrices");
 641 }
 642
 643 void
 644 GLRenderer::apply_video_mode(const Size& size, bool fullscreen)
 645 {
 646   // Only change video mode when its different from the current one
 647   if (screen_size != size || fullscreen_active != fullscreen)
 648   {
 649     int flags = SDL_OPENGL;
 650
 651     if (fullscreen)
 652     {
 653       flags |= SDL_FULLSCREEN;
 654     }
 655     else
 656     {
 657       flags |= SDL_RESIZABLE;
 658     }
 659
 660     if (SDL_Surface *screen = SDL_SetVideoMode(size.width, size.height, 0, flags))
 661     {
 662       screen_size = Size(screen->w, screen->h);
 663       fullscreen_active = fullscreen;
 664     }
 665     else
 666     {
 667       std::ostringstream msg;
 668       msg << "Couldn't set video mode " << size.width << "x" << size.height << ": " << SDL_GetError();
 669       throw std::runtime_error(msg.str());
 670     }
 671   }
 672 }
 673
 674 /* EOF */