add Hide border option (#33)

* hide border

src/compat.cpp

@@ -271,6 +271,11 @@ int WinL = NoWinL;
 int WinT = NoWinT;
 int WinB = NoWinB;
 
+int WinRBN=BlWinR;
+int WinLBN=BlWinL;
+int WinTBN=BlWinT;
+int WinBBN=BlWinB;
+
 static int RasterX = 0;
 static int TVW, TVH;
 int TVP;

src/libretro.cpp

@@ -67,7 +67,7 @@ retro_audio_sample_batch_t audio_cb;
 static retro_input_state_t input_state_cb;
 struct retro_perf_callback perf_cb;
 
-extern int WinR, WinL, WinT, WinB, TVP;
+extern int WinR, WinL, WinT, WinB, WinRBN, WinLBN, WinTBN, WinBBN, TVP;
 extern WORD* TVFB;
 extern keybovl_t zx81ovl;
 
@@ -79,6 +79,7 @@ static const struct retro_variable core_vars[] =
 {
   { "81_fast_load",      "Tape Fast Load; enabled|disabled" },
   { "81_8_16_contents",  "8K-16K Contents; auto|ROM shadow|RAM|dK'tronics 4K Graphics ROM + 4K RAM" },
+  { "81_hide_border",    "Hide Video Border; disabled|enabled" },
   { "81_highres",        "High Resolution; auto|none|WRX" },
   { "81_chroma_81",      "Emulate Chroma 81; auto|disabled|enabled" },
   { "81_video_presets",  "Video Presets; clean|tv|noisy" },
@@ -442,8 +443,19 @@ void retro_set_input_poll( retro_input_poll_t cb )
 
 void retro_get_system_av_info( struct retro_system_av_info* info )
 {
-  info->geometry.base_width = WinR - WinL;
-  info->geometry.base_height = WinB - WinT;
+  int hide_border = coreopt(env_cb, core_vars, state.sha1, "81_hide_border", NULL);
+  hide_border += hide_border < 0;
+
+  if (hide_border == 1)
+  {
+    info->geometry.base_width = WinRBN - WinLBN;
+    info->geometry.base_height = WinBBN - WinTBN;
+  }
+  else
+  {
+    info->geometry.base_width = WinR - WinL;
+    info->geometry.base_height = WinB - WinT;
+  }
   info->geometry.max_width = WinR - WinL;
   info->geometry.max_height = WinB - WinT;
   info->geometry.aspect_ratio = 0.0f;
@@ -475,10 +487,21 @@ void retro_run( void )
   input_poll_cb();
   
   uint16_t* fb = TVFB + WinL + WinT * TVP / 2;
-
   eo_tick();
   keybovl_update( input_state_cb, state.devices, fb, TVP / 2, state.transp, state.scaled, state.ms, 20 );
-  video_cb( (void*)fb, WinR - WinL, WinB - WinT, TVP );
+
+  int hide_border = coreopt(env_cb, core_vars, state.sha1, "81_hide_border", NULL);
+  hide_border += hide_border < 0;
+
+  if (hide_border == 1)
+  {    
+    fb = TVFB + WinLBN + WinTBN * TVP / 2; 
+    video_cb( (void*)fb, WinRBN - WinLBN, WinBBN - WinTBN, TVP );  
+  }
+  else
+  {
+    video_cb( (void*)fb, WinR - WinL, WinB - WinT, TVP );  
+  }
 }
 
 void retro_deinit( void )