Overscan bordersvogons/overscan-r2569

The old version is not working that well with new render
implementation. Here's completely new approach. It's not
blended border anymore. It is not as universal as the old
version -- currently works only with output=surface, it also
requires forcing fullscreen size to be bigger than video
mode used by game (no such limitation for window mode).
While it is less universal than the old one it does look better.
The controlling option in dosbox.conf is different. Use
overscan=<width> in [sdl] section.
This implementation is much cheaper and simpler than the old
one, near zero performance cost even with frequent border
color changes. For this reason it is compiled
unconditionally - C_OVERSCAN is not used anymore.

Imported-from: https://sourceforge.net/p/dosbox/patches/120/

1 files changed, 49 insertions, 2 deletions

diff --git a/src/gui/sdlmain.cpp b/src/gui/sdlmain.cpp
index ca8618479..38a865ac0 100644
--- a/src/gui/sdlmain.cpp
+++ b/src/gui/sdlmain.cpp
@@ -202,6 +202,8 @@ struct SDL_Block {
 		Bitu sensitivity;
 	} mouse;
 	SDL_Rect updateRects[1024];
+ 	Bitu overscan_color;
+ 	Bitu overscan_width;
 };
 
 static SDL_Block sdl;
@@ -396,6 +398,7 @@ dosurface:
 		sdl.desktop.type=SCREEN_SURFACE;
 		sdl.clip.w=width;
 		sdl.clip.h=height;
+ 		sdl.overscan_color = 0;
 		if (sdl.desktop.fullscreen) {
 			if (sdl.desktop.full.fixed) {
 				sdl.clip.x=(Sint16)((sdl.desktop.full.width-width)/2);
@@ -413,8 +416,8 @@ dosurface:
 					E_Exit("Could not set fullscreen video mode %ix%i-%i: %s",width,height,bpp,SDL_GetError());
 			}
 		} else {
-			sdl.clip.x=0;sdl.clip.y=0;
-			sdl.surface=SDL_SetVideoMode(width,height,bpp,(flags & GFX_CAN_RANDOM) ? SDL_SWSURFACE : SDL_HWSURFACE);
+ 			sdl.clip.x=sdl.overscan_width;sdl.clip.y=sdl.overscan_width;
+ 			sdl.surface=SDL_SetVideoMode(width+2*sdl.overscan_width,height+2*sdl.overscan_width,bpp,(flags & GFX_CAN_RANDOM) ? SDL_SWSURFACE : SDL_HWSURFACE);
 #ifdef WIN32
 			if (sdl.surface == NULL) {
 				LOG_MSG("Failed to create hardware surface.\nRestarting video subsystem with windib enabled.");
@@ -658,6 +661,47 @@ bool GFX_StartUpdate(Bit8u * & pixels,Bitu & pitch) {
 			pixels+=sdl.clip.x*sdl.surface->format->BytesPerPixel;
 			pitch=sdl.surface->pitch;
 		}
+ 
+		if (sdl.overscan_width) {
+ 			Bitu border_color =  GFX_GetRGB(vga.dac.rgb[vga.attr.overscan_color].red<<2,
+ 				vga.dac.rgb[vga.attr.overscan_color].green<<2, vga.dac.rgb[vga.attr.overscan_color].blue<<2);
+ 			if (border_color != sdl.overscan_color) {
+ 				sdl.overscan_color = border_color;
+	 
+ 			// Find four rectangles forming the border
+ 				SDL_Rect *rect = &sdl.updateRects[0];
+ 				rect->x = 0; rect->y = 0; rect->w = sdl.draw.width+2*sdl.clip.x; rect->h = sdl.clip.y; // top
+ 				if (rect->h > sdl.overscan_width) { rect->y += (rect->h-sdl.overscan_width); rect->h = sdl.overscan_width; }
+ 				if (sdl.clip.x > sdl.overscan_width) { rect->x += (sdl.clip.x-sdl.overscan_width); rect->w -= 2*(sdl.clip.x-sdl.overscan_width); }
+ 				rect = &sdl.updateRects[1];
+ 				rect->x = 0; rect->y = sdl.clip.y; rect->w = sdl.clip.x; rect->h = sdl.draw.height; // left
+ 				if (rect->w > sdl.overscan_width) { rect->x += (rect->w-sdl.overscan_width); rect->w = sdl.overscan_width; }
+ 				rect = &sdl.updateRects[2];
+ 				rect->x = sdl.clip.x+sdl.draw.width; rect->y = sdl.clip.y; rect->w = sdl.clip.x; rect->h = sdl.draw.height; // right
+ 				if (rect->w > sdl.overscan_width) { rect->w = sdl.overscan_width; }
+ 				rect = &sdl.updateRects[3];
+ 				rect->x = 0; rect->y = sdl.clip.y+sdl.draw.height; rect->w = sdl.draw.width+2*sdl.clip.x; rect->h = sdl.clip.y; // bottom
+ 				if (rect->h > sdl.overscan_width) { rect->h = sdl.overscan_width; }
+ 				if (sdl.clip.x > sdl.overscan_width) { rect->x += (sdl.clip.x-sdl.overscan_width); rect->w -= 2*(sdl.clip.x-sdl.overscan_width); }
+	 
+ 				if (sdl.surface->format->BitsPerPixel == 8) { // SDL_FillRect seems to have some issues with palettized hw surfaces
+ 					Bit8u* pixelptr = (Bit8u*)sdl.surface->pixels;
+ 					Bitu linepitch = sdl.surface->pitch;
+ 					for (Bits i=0; i<4; i++) {
+ 						rect = &sdl.updateRects[i];
+ 						Bit8u* start = pixelptr + rect->y*linepitch + rect->x;
+ 						for (Bits j=0; j<rect->h; j++) {
+ 							memset(start, vga.attr.overscan_color, rect->w);
+ 							start += linepitch;
+ 						}
+ 					}
+ 				} else {
+ 					for (Bits i=0; i<4; i++)
+ 						SDL_FillRect(sdl.surface, &sdl.updateRects[i], border_color);
+ 					SDL_UpdateRects(sdl.surface, 4, sdl.updateRects);
+ 				}
+ 			}
+		}
 		sdl.updating=true;
 		return true;
 #if (HAVE_DDRAW_H) && defined(WIN32)
@@ -1039,6 +1083,7 @@ static void GUI_StartUp(Section * sec) {
 		LOG_MSG("SDL:Unsupported output device %s, switching back to surface",output);
 		sdl.desktop.want_type=SCREEN_SURFACE;
 	}
+	sdl.overscan_width=section->Get_int("overscan");
 
 	sdl.overlay=0;
 #if C_OPENGL
@@ -1291,6 +1336,7 @@ int main(int argc, char* argv[]) {
 		sdl_sec->Add_string("priority","higher,normal");
 		sdl_sec->Add_string("mapperfile","mapper.txt");
 		sdl_sec->Add_bool("usescancodes",true);
+		sdl_sec->Add_int("overscan",0);
 
 		MSG_Add("SDL_CONFIGFILE_HELP",
 			"fullscreen -- Start dosbox directly in fullscreen.\n"
@@ -1312,6 +1358,7 @@ int main(int argc, char* argv[]) {
 			"            Second entry behind the comma is for when dosbox is not focused/minimized.\n"
 			"mapperfile -- File used to load/save the key/event mappings from.\n"
 			"usescancodes -- Avoid usage of symkeys, might not work on all operating systems.\n"
+			"overscan -- Width of overscan border.\n"
 			);
 		/* Init all the dosbox subsystems */
 		DOSBOX_Init();