src/flexui/sdlstandalone.pas

   1 (* Copyright (C)  Doom 2D: Forever Developers
   2  *
   3  * This program is free software: you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation, version 3 of the License ONLY.
   6  *
   7  * This program is distributed in the hope that it will be useful,
   8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  * GNU General Public License for more details.
  11  *
  12  * You should have received a copy of the GNU General Public License
  13  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  14  *)
  15 {$INCLUDE ../shared/a_modes.inc}
  16 unit sdlstandalone;
  17
  18   {$IFNDEF USE_SDL2}
  19     {$FATAL SDL2 required for flexui sdlstandalone}
  20   {$ENDIF}
  21
  22 interface
  23
  24 uses
  25   SDL2,
  26   sdlcarcass;
  27
  28
  29 // ////////////////////////////////////////////////////////////////////////// //
  30 // initialize OpenGL; set `gScreenWidth` and `gScreenHeight` before calling this
  31 function glInit (const winTitle: AnsiString='SDL TEST'): Boolean;
  32 procedure glDeinit ();
  33 // call this to show built frame
  34 procedure glSwap ();
  35 // call this to push "quit" event into queue
  36 procedure pushQuitEvent ();
  37 // call this to process queued messages; result is `true` if quit event was received
  38 function processMessages (): Boolean;
  39
  40 // run main loop, call `buildFrameCB()` and `renderFrameCB()`, maintain the given FPS
  41 procedure mainLoop ();
  42
  43
  44 implementation
  45
  46 uses
  47   SysUtils;
  48
  49
  50 var
  51   gWinH: PSDL_Window = nil;
  52   gGLContext: TSDL_GLContext = nil;
  53   lastFrameTime: UInt64 = 0;
  54
  55
  56 // ////////////////////////////////////////////////////////////////////////// //
  57 procedure onExposeFrame ();
  58 begin
  59   glSwap();
  60 end;
  61
  62
  63 // ////////////////////////////////////////////////////////////////////////// //
  64 function sdlInit (): Boolean;
  65 var
  66   sdlflags: LongWord;
  67 begin
  68   result := false;
  69
  70   sdlflags := SDL_INIT_TIMER or SDL_INIT_VIDEO;
  71   if SDL_Init(sdlflags) < 0 then exit; //raise Exception.Create('SDL: Init failed: ' + SDL_GetError());
  72
  73   //SDL_Quit();
  74   result := true;
  75   fuiWinActive := fuiWinActive;
  76   SDL_StartTextInput();
  77 end;
  78
  79
  80 procedure glSwap ();
  81 begin
  82   if (gWinH = nil) then exit;
  83   SDL_GL_SwapWindow(gWinH);
  84 end;
  85
  86
  87 procedure killGLWindow ();
  88 begin
  89   if (gWinH <> nil) then SDL_DestroyWindow(gWinH);
  90   if (gGLContext <> nil) then SDL_GL_DeleteContext(gGLContext);
  91   gWinH := nil;
  92   gGLContext := nil;
  93 end;
  94
  95
  96 procedure pushQuitEvent ();
  97 var
  98   ev: TSDL_Event;
  99 begin
 100   ev.type_ := SDL_QUITEV;
 101   SDL_PushEvent(@ev);
 102 end;
 103
 104
 105 // ////////////////////////////////////////////////////////////////////////// //
 106 // true: quit
 107 function processMessages (): Boolean;
 108 var
 109   ev: TSDL_Event;
 110 begin
 111   result := false;
 112   FillChar(ev, sizeof(ev), 0);
 113   while (SDL_PollEvent(@ev) > 0) do
 114   begin
 115     fuiOnSDLEvent(ev);
 116     //if (ev.type_ = SDL_QUITEV) then exit;
 117   end;
 118   if fuiQuitReceived then result := true;
 119 end;
 120
 121
 122 // ////////////////////////////////////////////////////////////////////////// //
 123 procedure glDeinit ();
 124 begin
 125   if (gWinH <> nil) and assigned(oglDeinitCB) then oglDeinitCB();
 126   killGLWindow();
 127 end;
 128
 129
 130 function glInit (const winTitle: AnsiString='SDL TEST'): Boolean;
 131 var
 132   wFlags: LongWord = 0;
 133   v: Byte = 0;
 134 begin
 135   result := false;
 136
 137   wFlags := SDL_WINDOW_OPENGL or SDL_WINDOW_RESIZABLE;
 138   //if gFullscreen then wFlags := wFlags or SDL_WINDOW_FULLSCREEN;
 139   //if gWinMaximized then wFlags := wFlags or SDL_WINDOW_MAXIMIZED;
 140
 141   glDeinit();
 142
 143   //if VSync then v := 1 else v := 0;
 144   SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 2);
 145   SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 1);
 146   SDL_GL_SetAttribute(SDL_GL_RED_SIZE, 8);
 147   SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE, 8);
 148   SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE, 8);
 149   SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 16);
 150   SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
 151   SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 1); // lights; it is enough to have 1-bit stencil buffer for lighting
 152   SDL_GL_SetSwapInterval(v);
 153
 154   {
 155   if gFullscreen then
 156   begin
 157     mode.w := gScreenWidth;
 158     mode.h := gScreenHeight;
 159     mode.format := 0;
 160     mode.refresh_rate := 0;
 161     mode.driverdata := nil;
 162     if SDL_GetClosestDisplayMode(0, @mode, @cmode) = nil then
 163     begin
 164       gScreenWidth := 800;
 165       gScreenHeight := 600;
 166     end
 167     else
 168     begin
 169       gScreenWidth := cmode.w;
 170       gScreenHeight := cmode.h;
 171     end;
 172   end;
 173   }
 174
 175   gWinH := SDL_CreateWindow(PAnsiChar(winTitle), -1, -1, fuiScrWdt, fuiScrHgt, wFlags);
 176   if (gWinH = nil) then exit;
 177
 178   gGLContext := SDL_GL_CreateContext(gWinH);
 179   if (gGLContext = nil) then begin SDL_DestroyWindow(gWinH); gWinH := nil; exit; end;
 180
 181   SDL_GL_MakeCurrent(gWinH, gGLContext);
 182   SDL_ShowCursor(SDL_DISABLE);
 183
 184   if assigned(oglInitCB) then oglInitCB();
 185
 186   result := true;
 187 end;
 188
 189
 190 // run main loop, call `buildFrameCB()` and `renderFrameCB()`, maintain the given FPS
 191 procedure mainLoop ();
 192 var
 193   nft, ctt: UInt64;
 194   wt: Integer;
 195 begin
 196   if assigned(buildFrameCB) then buildFrameCB();
 197   if assigned(prerenderFrameCB) then prerenderFrameCB();
 198   if assigned(renderFrameCB) then renderFrameCB();
 199   if assigned(postrenderFrameCB) then postrenderFrameCB();
 200   glSwap();
 201   lastFrameTime := fuiTimeMilli();
 202   while true do
 203   begin
 204     // calculate time to build and render next frame
 205     nft := lastFrameTime+(1000 div fuiFPS);
 206     ctt := fuiTimeMilli();
 207     if (ctt >= nft) then
 208     begin
 209       // time to build next frame
 210       if assigned(buildFrameCB) then buildFrameCB();
 211       if assigned(prerenderFrameCB) then prerenderFrameCB();
 212       if assigned(renderFrameCB) then renderFrameCB();
 213       if assigned(postrenderFrameCB) then postrenderFrameCB();
 214       glSwap();
 215       lastFrameTime := ctt; // ignore frame processing time
 216     end
 217     else
 218     begin
 219       // has to wait for some time
 220       if (nft-ctt > 1000) then wt := 1000 else wt := Integer(nft-ctt);
 221       SDL_WaitEventTimeout(nil, wt);
 222     end;
 223     if processMessages() then break; // just in case
 224   end;
 225 end;
 226
 227
 228 initialization
 229   exposeFrameCB := onExposeFrame();
 230
 231   if not sdlInit() then raise Exception.Create('cannot initialize SDL');
 232 finalization
 233   glDeinit();
 234   SDL_Quit();
 235 end.