Shadow: Add support for Amiga afb4

Add support for Amiga-style bitplanes, with 4 bits per pixel.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Keith Packard <keithp@keithp.com>

3 files changed, 143 insertions, 0 deletions

diff --git a/miext/shadow/Makefile.am b/miext/shadow/Makefile.am
index 882463e58..d2142ad6d 100644
--- a/miext/shadow/Makefile.am
+++ b/miext/shadow/Makefile.am
@@ -9,6 +9,7 @@ endif
 libshadow_la_SOURCES =		\
 	shadow.c		\
 	shadow.h		\
+	shafb4.c		\
 	shalloc.c		\
 	shiplan2p4.c		\
 	shiplan2p8.c		\
diff --git a/miext/shadow/shadow.h b/miext/shadow/shadow.h
index e190cd48f..f9ea6c45e 100644
--- a/miext/shadow/shadow.h
+++ b/miext/shadow/shadow.h
@@ -96,6 +96,9 @@ shadowInit(ScreenPtr pScreen, ShadowUpdateProc update, ShadowWindowProc window);
 extern _X_EXPORT void *shadowAlloc(int width, int height, int bpp);
 
 extern _X_EXPORT void
+ shadowUpdateAfb4(ScreenPtr pScreen, shadowBufPtr pBuf);
+
+extern _X_EXPORT void
  shadowUpdateIplan2p4(ScreenPtr pScreen, shadowBufPtr pBuf);
 
 extern _X_EXPORT void
diff --git a/miext/shadow/shafb4.c b/miext/shadow/shafb4.c
new file mode 100644
index 000000000..07249323a
--- /dev/null
+++ b/miext/shadow/shafb4.c
@@ -0,0 +1,139 @@
+/*
+ *
+ * Copyright © 2013 Geert Uytterhoeven
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that
+ * copyright notice and this permission notice appear in supporting
+ * documentation, and that the name of Geert Uytterhoeven not be used in
+ * advertising or publicity pertaining to distribution of the software without
+ * specific, written prior permission.  Geert Uytterhoeven makes no
+ * representations about the suitability of this software for any purpose.  It
+ * is provided "as is" without express or implied warranty.
+ *
+ * GEERT UYTTERHOEVEN DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+ * EVENT SHALL GEERT UYTTERHOEVEN BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+ * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+ * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ *
+ * Based on shpacked.c, which is Copyright © 2000 Keith Packard
+ */
+
+#ifdef HAVE_DIX_CONFIG_H
+#include <dix-config.h>
+#endif
+
+#include <stdlib.h>
+
+#include    <X11/X.h>
+#include    "scrnintstr.h"
+#include    "windowstr.h"
+#include    <X11/fonts/font.h>
+#include    "dixfontstr.h"
+#include    <X11/fonts/fontstruct.h>
+#include    "mi.h"
+#include    "regionstr.h"
+#include    "globals.h"
+#include    "gcstruct.h"
+#include    "shadow.h"
+#include    "fb.h"
+#include    "c2p_core.h"
+
+
+    /*
+     *  Perform a full C2P step on 32 4-bit pixels, stored in 4 32-bit words
+     *  containing
+     *    - 32 4-bit chunky pixels on input
+     *    - permutated planar data (1 plane per 32-bit word) on output
+     */
+
+static void c2p_32x4(CARD32 d[4])
+{
+    transp4(d, 16, 2);
+    transp4(d, 8, 1);
+    transp4(d, 4, 2);
+    transp4(d, 2, 1);
+    transp4(d, 1, 2);
+}
+
+
+    /*
+     *  Store a full block of permutated planar data after c2p conversion
+     */
+
+static inline void store_afb4(void *dst, unsigned int stride,
+                              const CARD32 d[4])
+{
+    CARD8 *p = dst;
+
+    *(CARD32 *)p = d[3]; p += stride;
+    *(CARD32 *)p = d[1]; p += stride;
+    *(CARD32 *)p = d[2]; p += stride;
+    *(CARD32 *)p = d[0]; p += stride;
+}
+
+
+void
+shadowUpdateAfb4(ScreenPtr pScreen, shadowBufPtr pBuf)
+{
+    RegionPtr damage = shadowDamage(pBuf);
+    PixmapPtr pShadow = pBuf->pPixmap;
+    int nbox = RegionNumRects(damage);
+    BoxPtr pbox = RegionRects(damage);
+    FbBits *shaBase;
+    CARD32 *shaLine, *sha;
+    FbStride shaStride;
+    int scrLine;
+    _X_UNUSED int shaBpp, shaXoff, shaYoff;
+    int x, y, w, h;
+    int i, n;
+    CARD32 *win;
+    CARD32 off, winStride;
+    union {
+        CARD8 bytes[16];
+        CARD32 words[4];
+    } d;
+
+    fbGetDrawable(&pShadow->drawable, shaBase, shaStride, shaBpp, shaXoff,
+                  shaYoff);
+    if (sizeof(FbBits) != sizeof(CARD32))
+        shaStride = shaStride * sizeof(FbBits) / sizeof(CARD32);
+
+    while (nbox--) {
+        x = pbox->x1;
+        y = pbox->y1;
+        w = pbox->x2 - pbox->x1;
+        h = pbox->y2 - pbox->y1;
+
+        scrLine = (x & -32) / 2;
+        shaLine = (CARD32 *)shaBase + y * shaStride + scrLine / sizeof(CARD32);
+
+        off = scrLine / 4;              /* byte offset in bitplane scanline */
+        n = ((x & 31) + w + 31) / 32;   /* number of c2p units in scanline */
+
+        while (h--) {
+            sha = shaLine;
+            win = (CARD32 *) (*pBuf->window) (pScreen,
+                                             y,
+                                             off,
+                                             SHADOW_WINDOW_WRITE,
+                                             &winStride,
+                                             pBuf->closure);
+            if (!win)
+                return;
+            for (i = 0; i < n; i++) {
+                memcpy(d.bytes, sha, sizeof(d.bytes));
+                c2p_32x4(d.words);
+                store_afb4(win++, winStride, d.words);
+                sha += sizeof(d.bytes) / sizeof(*sha);
+            }
+            shaLine += shaStride;
+            y++;
+        }
+        pbox++;
+    }
+}