Handle SDL windows with BGRA color

The switch to CoreGraphics on OSX (instead of QuickDraw) in SDL 1.2.15
means the SDL-created window now has BGRA color order instead of ARGB.
This change makes the r5g6b5 and xbgr32 format converters handle
whatever channel ordering the main SDL surface has. Skin regions don't
need to change, since we draw them into auxiliary surfaces we created
with ARGB order, and SDL does the conversion when we blit them into
the main window.

Change-Id: I2ae0529c66c11b60b3ade7a7a742368a2ab614bd

2 files changed, 56 insertions, 17 deletions

diff --git a/android/skin/scaler.c b/android/skin/scaler.c
index 5672869..bafd84e 100644
--- a/android/skin/scaler.c
+++ b/android/skin/scaler.c
@@ -150,6 +150,34 @@ skin_scaler_scale( SkinScaler*   scaler,
         else
             scale_generic( &op );
     }
+
+    // The optimized scale functions in argb.h assume the destination is ARGB.
+    // If that's not the case, do a channel reorder now.
+    if (dst_surface->format->Rshift != 16 ||
+        dst_surface->format->Gshift !=  8 ||
+        dst_surface->format->Bshift !=  0)
+    {
+        uint32_t rshift = dst_surface->format->Rshift;
+        uint32_t gshift = dst_surface->format->Gshift;
+        uint32_t bshift = dst_surface->format->Bshift;
+        uint32_t ashift = dst_surface->format->Ashift;
+        uint32_t amask  = dst_surface->format->Amask; // may be 0x00
+        int x, y;
+
+        for (y = 0; y < op.rd.h; y++)
+        {
+            uint32_t* line = (uint32_t*)(op.dst_line + y*op.dst_pitch);
+            for (x = 0; x < op.rd.w; x++) {
+                uint32_t r = (line[x] & 0x00ff0000) >> 16;
+                uint32_t g = (line[x] & 0x0000ff00) >>  8;
+                uint32_t b = (line[x] & 0x000000ff) >>  0;
+                uint32_t a = (line[x] & 0xff000000) >> 24;
+                line[x] = (r << rshift) | (g << gshift) | (b << bshift) |
+                          ((a << ashift) & amask);
+            }
+        }
+    }
+
     SDL_UnlockSurface( dst_surface );
     SDL_UnlockSurface( src_surface );
 
diff --git a/android/skin/window.c b/android/skin/window.c
index 5d8c684..65276ac 100644
--- a/android/skin/window.c
+++ b/android/skin/window.c
@@ -148,22 +148,25 @@ display_init( ADisplay*  disp, SkinDisplay*  sdisp, SkinLocation*  loc, SkinRect
     return (disp->data == NULL) ? -1 : 0;
 }
 
-static __inline__ uint32_t  rgb565_to_argb32( uint32_t  pix )
+static __inline__ uint32_t rgb565_to_rgba32(uint32_t pix,
+        uint32_t rshift, uint32_t gshift, uint32_t bshift, uint32_t amask)
 {
-    uint32_t  r = ((pix & 0xf800) << 8) | ((pix & 0xe000) << 3);
-    uint32_t  g = ((pix & 0x07e0) << 5) | ((pix & 0x0600) >> 1);
-    uint32_t  b = ((pix & 0x001f) << 3) | ((pix & 0x001c) >> 2);
-    return 0xff000000 | r | g | b;
+    uint32_t r8 = ((pix & 0xf800) >>  8) | ((pix & 0xe000) >> 13);
+    uint32_t g8 = ((pix & 0x07e0) >>  3) | ((pix & 0x0600) >>  9);
+    uint32_t b8 = ((pix & 0x001f) <<  3) | ((pix & 0x001c) >>  2);
+    return (r8 << rshift) | (g8 << gshift) | (b8 << bshift) | amask;
 }
 
 /* The framebuffer format is R,G,B,X in framebuffer memory, on a
  * little-endian system, this translates to XBGR after a load.
  */
-static __inline__ uint32_t  xbgr_to_argb32( uint32_t pix )
+static __inline__ uint32_t xbgr_to_rgba32(uint32_t pix,
+        uint32_t rshift, uint32_t gshift, uint32_t bshift, uint32_t amask)
 {
-    uint32_t  g  = (pix & 0x0000ff00);
-    uint32_t  rb = (pix & 0xff00ff);
-    return 0xff000000 | (rb << 16) | g | (rb >> 16);
+    uint32_t r8 = (pix & 0x00ff0000) >> 16;
+    uint32_t g8 = (pix & 0x0000ff00) >>  8;
+    uint32_t b8 = (pix & 0x000000ff) >>  0;
+    return (r8 << rshift) | (g8 << gshift) | (b8 << bshift) | amask;
 }
 
 static void
@@ -392,6 +395,10 @@ display_redraw_rect16( ADisplay* disp, SkinRect* rect, SDL_Surface* surface)
     int           src_pitch = disp->datasize.w*2;
     uint8_t*      src_line  = (uint8_t*)disp->data;
     int           yy, xx;
+    uint32_t      rshift = surface->format->Rshift;
+    uint32_t      gshift = surface->format->Gshift;
+    uint32_t      bshift = surface->format->Bshift;
+    uint32_t      amask  = surface->format->Amask; // may be 0x00 for non-alpha format
 
     switch ( disp->rotation & 3 )
     {
@@ -405,7 +412,7 @@ display_redraw_rect16( ADisplay* disp, SkinRect* rect, SDL_Surface* surface)
 
             xx = 0;
             DUFF4(w, {
-                dst[xx] = rgb565_to_argb32(src[xx]);
+                dst[xx] = rgb565_to_rgba32(src[xx], rshift, gshift, bshift, amask);
                 xx++;
             });
             src_line += src_pitch;
@@ -422,7 +429,7 @@ display_redraw_rect16( ADisplay* disp, SkinRect* rect, SDL_Surface* surface)
             uint8_t*   src = src_line;
 
             DUFF4(w, {
-                dst[0] = rgb565_to_argb32(((uint16_t*)src)[0]);
+                dst[0] = rgb565_to_rgba32(((uint16_t*)src)[0], rshift, gshift, bshift, amask);
                 src -= src_pitch;
                 dst += 1;
             });
@@ -440,7 +447,7 @@ display_redraw_rect16( ADisplay* disp, SkinRect* rect, SDL_Surface* surface)
             uint32_t*  dst = (uint32_t*)dst_line;
 
             DUFF4(w, {
-                dst[0] = rgb565_to_argb32(src[0]);
+                dst[0] = rgb565_to_rgba32(src[0], rshift, gshift, bshift, amask);
                 src -= 1;
                 dst += 1;
             });
@@ -458,7 +465,7 @@ display_redraw_rect16( ADisplay* disp, SkinRect* rect, SDL_Surface* surface)
             uint8_t*   src = src_line;
 
             DUFF4(w, {
-                dst[0] = rgb565_to_argb32(((uint16_t*)src)[0]);
+                dst[0] = rgb565_to_rgba32(((uint16_t*)src)[0], rshift, gshift, bshift, amask);
                 dst   += 1;
                 src   += src_pitch;
             });
@@ -482,6 +489,10 @@ display_redraw_rect32( ADisplay* disp, SkinRect* rect,SDL_Surface* surface)
     int           src_pitch = disp->datasize.w*4;
     uint8_t*      src_line  = (uint8_t*)disp->data;
     int           yy;
+    uint32_t      rshift = surface->format->Rshift;
+    uint32_t      gshift = surface->format->Gshift;
+    uint32_t      bshift = surface->format->Bshift;
+    uint32_t      amask  = surface->format->Amask; // may be 0x00 for non-alpha format
 
     switch ( disp->rotation & 3 )
     {
@@ -493,7 +504,7 @@ display_redraw_rect32( ADisplay* disp, SkinRect* rect,SDL_Surface* surface)
             uint32_t*  dst = (uint32_t*)dst_line;
 
             DUFF4(w, {
-                dst[0] = xbgr_to_argb32(src[0]);
+                dst[0] = xbgr_to_rgba32(src[0], rshift, gshift, bshift, amask);
                 dst++;
                 src++;
             });
@@ -511,7 +522,7 @@ display_redraw_rect32( ADisplay* disp, SkinRect* rect,SDL_Surface* surface)
             uint8_t*   src = src_line;
 
             DUFF4(w, {
-                dst[0] = xbgr_to_argb32(*(uint32_t*)src);
+                dst[0] = xbgr_to_rgba32(*(uint32_t*)src, rshift, gshift, bshift, amask);
                 src -= src_pitch;
                 dst += 1;
             });
@@ -529,7 +540,7 @@ display_redraw_rect32( ADisplay* disp, SkinRect* rect,SDL_Surface* surface)
             uint32_t*  dst = (uint32_t*)dst_line;
 
             DUFF4(w, {
-                dst[0] = xbgr_to_argb32(src[0]);
+                dst[0] = xbgr_to_rgba32(src[0], rshift, gshift, bshift, amask);
                 src -= 1;
                 dst += 1;
             });
@@ -547,7 +558,7 @@ display_redraw_rect32( ADisplay* disp, SkinRect* rect,SDL_Surface* surface)
             uint8_t*   src = src_line;
 
             DUFF4(w, {
-                dst[0] = xbgr_to_argb32(*(uint32_t*)src);
+                dst[0] = xbgr_to_rgba32(*(uint32_t*)src, rshift, gshift, bshift, amask);
                 dst   += 1;
                 src   += src_pitch;
             });