shithub: choc

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textscreen: Init screen at native bit depth.

Always call SDL_SetVideoMode with bpp=0 to use the desktop's native
bit depth, and instead draw into an intermediate 8-bit screenbuffer
surface. This ensures that we do not encounter any palette mess-ups
as on some systems true 8-bit screen modes are poorly supported.

--- a/textscreen/txt_sdl.c

+++ b/textscreen/txt_sdl.c

@@ -58,6 +58,7 @@

 #define BLINK_PERIOD 250

 static SDL_Surface *screen;

+static SDL_Surface *screenbuffer;

 static unsigned char *screendata;

 static int key_mapping = 1;

@@ -246,24 +247,29 @@

 int TXT_Init(void)

 {

-    int flags;

-

     if (SDL_InitSubSystem(SDL_INIT_VIDEO) < 0)

     {

         return 0;

     }

-    flags = SDL_SWSURFACE | SDL_HWPALETTE | SDL_DOUBLEBUF;

-

     ChooseFont();

+    // Always create the screen at the native screen depth (bpp=0);

+    // some systems nowadays don't seem to support true 8-bit palettized

+    // screen modes very well and we end up with screwed up colors.

     screen = SDL_SetVideoMode(TXT_SCREEN_W * font->w,

-                              TXT_SCREEN_H * font->h, 8, flags);

+                              TXT_SCREEN_H * font->h, 0, 0);

     if (screen == NULL)

         return 0;

-    SDL_SetColors(screen, ega_colors, 0, 16);

+    // Instead, we draw everything into an intermediate 8-bit surface

+    // the same dimensions as the screen. SDL then takes care of all the

+    // 8->32 bit (or whatever depth) color conversions for us.

+    screenbuffer = SDL_CreateRGBSurface(0, TXT_SCREEN_W * font->w,

+                                        TXT_SCREEN_H * font->h,

+                                        8, 0, 0, 0, 0);

+    SDL_SetColors(screenbuffer, ega_colors, 0, 16);

     SDL_EnableUNICODE(1);

     screendata = malloc(TXT_SCREEN_W * TXT_SCREEN_H * 2);

@@ -285,6 +291,8 @@

 {

     free(screendata);

     screendata = NULL;

+    SDL_FreeSurface(screenbuffer);

+    screenbuffer = NULL;

     SDL_QuitSubSystem(SDL_INIT_VIDEO);

 }

@@ -324,8 +332,8 @@

     bytes = (font->w + 7) / 8;

     p = &font->data[character * font->h * bytes];

-    s = ((unsigned char *) screen->pixels)

-      + (y * font->h * screen->pitch)

+    s = ((unsigned char *) screenbuffer->pixels)

+      + (y * font->h * screenbuffer->pitch)

       + (x * font->w);

     for (y1=0; y1<font->h; ++y1)

@@ -357,7 +365,7 @@

             ++p;

         }

-        s += screen->pitch;

+        s += screenbuffer->pitch;

     }

 }

@@ -379,6 +387,7 @@

 void TXT_UpdateScreenArea(int x, int y, int w, int h)

 {

+    SDL_Rect rect;

     int x1, y1;

     int x_end;

     int y_end;

@@ -396,9 +405,13 @@

         }

     }

-    SDL_UpdateRect(screen,

-                   x * font->w, y * font->h,

-                   (x_end - x) * font->w, (y_end - y) * font->h);

+    rect.x = x * font->w;

+    rect.y = y * font->h;

+    rect.w = (x_end - x) * font->w;

+    rect.h = (y_end - y) * font->h;

+

+    SDL_BlitSurface(screenbuffer, &rect, screen, &rect);

+    SDL_UpdateRects(screen, 1, &rect);

 }

 void TXT_UpdateScreen(void)