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mutter/clutter/cogl/cogl/cogl-bitmap-fallback.c
Neil Roberts 9750b90f37 cogl-bitmap: Fix converting formats with and without alpha channels 
_cogl_bitmap_convert_format_and_premult was failing when converting
from RGBA to RGB and vice versa. _cogl_bitmap_fallback_convert
converts without altering the premult status so when choosing a new
format it would copy over the premult bit. However, it did this
regardless of whether the new format had an alpha channel so when
converting from RGBA_8888_PRE to RGB_888 it would end up inventing a
new meaningless format which would be RGB_888_PRE. This patch makes it
avoid copying the premult flag if the destination has no alpha. It
doesn't matter if it copies when the source format has no alpha
because it will always be unset.

_cogl_bitmap_convert_format_and_premult was also breaking when
converting from RGBA_8888_PRE to RGB_888 because it would think
RGB_888 is unpremultiplied and try to convert but then
_cogl_bitmap_fallback_premult wouldn't know how to do the conversion.

http://bugzilla.openedhand.com/show_bug.cgi?id=2057
2010-04-21 10:56:21 +01:00

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/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 2007,2008,2009 Intel Corporation.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "cogl.h"
#include "cogl-internal.h"
#include "cogl-bitmap-private.h"
#include <string.h>
/* TO rgba */
inline static void
_cogl_g_to_rgba (const guint8 *src, guint8 *dst)
{
dst[0] = src[0];
dst[1] = src[0];
dst[2] = src[0];
dst[3] = 255;
}
inline static void
_cogl_rgb_to_rgba (const guint8 *src, guint8 *dst)
{
dst[0] = src[0];
dst[1] = src[1];
dst[2] = src[2];
dst[3] = 255;
}
inline static void
_cogl_bgr_to_rgba (const guint8 *src, guint8 *dst)
{
dst[0] = src[2];
dst[1] = src[1];
dst[2] = src[0];
dst[3] = 255;
}
inline static void
_cogl_bgra_to_rgba (const guint8 *src, guint8 *dst)
{
dst[0] = src[2];
dst[1] = src[1];
dst[2] = src[0];
dst[3] = src[3];
}
inline static void
_cogl_argb_to_rgba (const guint8 *src, guint8 *dst)
{
dst[0] = src[1];
dst[1] = src[2];
dst[2] = src[3];
dst[3] = src[0];
}
inline static void
_cogl_abgr_to_rgba (const guint8 *src, guint8 *dst)
{
dst[0] = src[3];
dst[1] = src[2];
dst[2] = src[1];
dst[3] = src[0];
}
inline static void
_cogl_rgba_to_rgba (const guint8 *src, guint8 *dst)
{
dst[0] = src[0];
dst[1] = src[1];
dst[2] = src[2];
dst[3] = src[3];
}
/* FROM rgba */
inline static void
_cogl_rgba_to_g (const guint8 *src, guint8 *dst)
{
dst[0] = (src[0] + src[1] + src[2]) / 3;
}
inline static void
_cogl_rgba_to_rgb (const guint8 *src, guint8 *dst)
{
dst[0] = src[0];
dst[1] = src[1];
dst[2] = src[2];
}
inline static void
_cogl_rgba_to_bgr (const guint8 *src, guint8 *dst)
{
dst[0] = src[2];
dst[1] = src[1];
dst[2] = src[0];
}
inline static void
_cogl_rgba_to_bgra (const guint8 *src, guint8 *dst)
{
dst[0] = src[2];
dst[1] = src[1];
dst[2] = src[0];
dst[3] = src[3];
}
inline static void
_cogl_rgba_to_argb (const guint8 *src, guint8 *dst)
{
dst[0] = src[3];
dst[1] = src[0];
dst[2] = src[1];
dst[3] = src[2];
}
inline static void
_cogl_rgba_to_abgr (const guint8 *src, guint8 *dst)
{
dst[0] = src[3];
dst[1] = src[2];
dst[2] = src[1];
dst[3] = src[0];
}
/* (Un)Premultiplication */
inline static void
_cogl_unpremult_alpha_0 (guint8 *dst)
{
dst[0] = 0;
dst[1] = 0;
dst[2] = 0;
dst[3] = 0;
}
inline static void
_cogl_unpremult_alpha_last (guint8 *dst)
{
guint8 alpha = dst[3];
dst[0] = (dst[0] * 255) / alpha;
dst[1] = (dst[1] * 255) / alpha;
dst[2] = (dst[2] * 255) / alpha;
}
inline static void
_cogl_unpremult_alpha_first (guint8 *dst)
{
guint8 alpha = dst[0];
dst[1] = (dst[1] * 255) / alpha;
dst[2] = (dst[2] * 255) / alpha;
dst[3] = (dst[3] * 255) / alpha;
}
/* No division form of floor((c*a + 128)/255) (I first encountered
* this in the RENDER implementation in the X server.) Being exact
* is important for a == 255 - we want to get exactly c.
*/
#define MULT(d,a,t) \
G_STMT_START { \
t = d * a + 128; \
d = ((t >> 8) + t) >> 8; \
} G_STMT_END
inline static void
_cogl_premult_alpha_last (guint8 *dst)
{
guint8 alpha = dst[3];
/* Using a separate temporary per component has given slightly better
* code generation with GCC in the past; it shouldn't do any worse in
* any case.
*/
unsigned int t1, t2, t3;
MULT(dst[0], alpha, t1);
MULT(dst[1], alpha, t2);
MULT(dst[2], alpha, t3);
}
inline static void
_cogl_premult_alpha_first (guint8 *dst)
{
guint8 alpha = dst[0];
unsigned int t1, t2, t3;
MULT(dst[1], alpha, t1);
MULT(dst[2], alpha, t2);
MULT(dst[3], alpha, t3);
}
#undef MULT
/* Use the SSE optimized version to premult four pixels at once when
it is available. The same assembler code works for x86 and x86-64
because it doesn't refer to any non-SSE registers directly */
#if defined(__SSE2__) && defined(__GNUC__) \
&& (defined(__x86_64) || defined(__i386))
#define COGL_USE_PREMULT_SSE2
#endif
#ifdef COGL_USE_PREMULT_SSE2
inline static void
_cogl_premult_alpha_last_four_pixels_sse2 (guint8 *p)
{
/* 8 copies of 128 used below */
static const gint16 eight_halves[8] __attribute__ ((aligned (16))) =
{ 128, 128, 128, 128, 128, 128, 128, 128 };
/* Mask of the rgb components of the four pixels */
static const gint8 just_rgb[16] __attribute__ ((aligned (16))) =
{ 0xff, 0xff, 0xff, 0x00, 0xff, 0xff, 0xff, 0x00,
0xff, 0xff, 0xff, 0x00, 0xff, 0xff, 0xff, 0x00 };
/* Each SSE register only holds two pixels because we need to work
with 16-bit intermediate values. We still do four pixels by
interleaving two registers in the hope that it will pipeline
better */
asm (/* Load eight_halves into xmm5 for later */
"movdqa (%1), %%xmm5\n"
/* Clear xmm3 */
"pxor %%xmm3, %%xmm3\n"
/* Load two pixels from p into the low half of xmm0 */
"movlps (%0), %%xmm0\n"
/* Load the next set of two pixels from p into the low half of xmm1 */
"movlps 8(%0), %%xmm1\n"
/* Unpack 8 bytes from the low quad-words in each register to 8
16-bit values */
"punpcklbw %%xmm3, %%xmm0\n"
"punpcklbw %%xmm3, %%xmm1\n"
/* Copy alpha values of the first pixel in xmm0 to all
components of the first pixel in xmm2 */
"pshuflw $255, %%xmm0, %%xmm2\n"
/* same for xmm1 and xmm3 */
"pshuflw $255, %%xmm1, %%xmm3\n"
/* The above also copies the second pixel directly so we now
want to replace the RGB components with copies of the alpha
components */
"pshufhw $255, %%xmm2, %%xmm2\n"
"pshufhw $255, %%xmm3, %%xmm3\n"
/* Multiply the rgb components by the alpha */
"pmullw %%xmm2, %%xmm0\n"
"pmullw %%xmm3, %%xmm1\n"
/* Add 128 to each component */
"paddw %%xmm5, %%xmm0\n"
"paddw %%xmm5, %%xmm1\n"
/* Copy the results to temporary registers xmm4 and xmm5 */
"movdqa %%xmm0, %%xmm4\n"
"movdqa %%xmm1, %%xmm5\n"
/* Divide the results by 256 */
"psrlw $8, %%xmm0\n"
"psrlw $8, %%xmm1\n"
/* Add the temporaries back in */
"paddw %%xmm4, %%xmm0\n"
"paddw %%xmm5, %%xmm1\n"
/* Divide again */
"psrlw $8, %%xmm0\n"
"psrlw $8, %%xmm1\n"
/* Pack the results back as bytes */
"packuswb %%xmm1, %%xmm0\n"
/* Load just_rgb into xmm3 for later */
"movdqa (%2), %%xmm3\n"
/* Reload all four pixels into xmm2 */
"movups (%0), %%xmm2\n"
/* Mask out the alpha from the results */
"andps %%xmm3, %%xmm0\n"
/* Mask out the RGB from the original four pixels */
"andnps %%xmm2, %%xmm3\n"
/* Combine the two to get the right alpha values */
"orps %%xmm3, %%xmm0\n"
/* Write to memory */
"movdqu %%xmm0, (%0)\n"
: /* no outputs */
: "r" (p), "r" (eight_halves), "r" (just_rgb)
: "xmm0", "xmm1", "xmm2", "xmm3", "xmm4", "xmm5");
}
#endif /* COGL_USE_PREMULT_SSE2 */
gboolean
_cogl_bitmap_fallback_can_convert (CoglPixelFormat src, CoglPixelFormat dst)
{
if (src == dst)
return FALSE;
switch (src & COGL_UNORDERED_MASK)
{
case COGL_PIXEL_FORMAT_G_8:
case COGL_PIXEL_FORMAT_24:
case COGL_PIXEL_FORMAT_32:
if ((dst & COGL_UNORDERED_MASK) != COGL_PIXEL_FORMAT_24 &&
(dst & COGL_UNORDERED_MASK) != COGL_PIXEL_FORMAT_32 &&
(dst & COGL_UNORDERED_MASK) != COGL_PIXEL_FORMAT_G_8)
return FALSE;
break;
default:
return FALSE;
}
return TRUE;
}
gboolean
_cogl_bitmap_fallback_can_unpremult (CoglPixelFormat format)
{
return ((format & COGL_UNORDERED_MASK) == COGL_PIXEL_FORMAT_32);
}
gboolean
_cogl_bitmap_fallback_can_premult (CoglPixelFormat format)
{
return ((format & COGL_UNORDERED_MASK) == COGL_PIXEL_FORMAT_32);
}
gboolean
_cogl_bitmap_fallback_convert (const CoglBitmap *bmp,
CoglBitmap *dst_bmp,
CoglPixelFormat dst_format)
{
guint8 *src;
guint8 *dst;
int src_bpp;
int dst_bpp;
int x,y;
guint8 temp_rgba[4] = {0,0,0,0};
/* Make sure conversion supported */
if (!_cogl_bitmap_fallback_can_convert (bmp->format, dst_format))
return FALSE;
src_bpp = _cogl_get_format_bpp (bmp->format);
dst_bpp = _cogl_get_format_bpp (dst_format);
/* Initialize destination bitmap */
*dst_bmp = *bmp;
dst_bmp->rowstride = sizeof(guint8) * dst_bpp * dst_bmp->width;
/* Copy the premult bit if the new format has an alpha channel */
if ((dst_format & COGL_A_BIT))
dst_bmp->format = ((bmp->format & COGL_PREMULT_BIT) |
(dst_format & COGL_UNPREMULT_MASK));
else
dst_bmp->format = dst_format;
/* Allocate a new buffer to hold converted data */
dst_bmp->data = g_malloc (sizeof(guint8)
* dst_bmp->height
* dst_bmp->rowstride);
/* FIXME: Optimize */
for (y = 0; y < bmp->height; y++)
{
src = (guint8*)bmp->data + y * bmp->rowstride;
dst = (guint8*)dst_bmp->data + y * dst_bmp->rowstride;
for (x = 0; x < bmp->width; x++)
{
/* FIXME: Would be nice to at least remove this inner
* branching, but not sure it can be done without
* rewriting of the whole loop */
switch (bmp->format & COGL_UNPREMULT_MASK)
{
case COGL_PIXEL_FORMAT_G_8:
_cogl_g_to_rgba (src, temp_rgba); break;
case COGL_PIXEL_FORMAT_RGB_888:
_cogl_rgb_to_rgba (src, temp_rgba); break;
case COGL_PIXEL_FORMAT_BGR_888:
_cogl_bgr_to_rgba (src, temp_rgba); break;
case COGL_PIXEL_FORMAT_RGBA_8888:
_cogl_rgba_to_rgba (src, temp_rgba); break;
case COGL_PIXEL_FORMAT_BGRA_8888:
_cogl_bgra_to_rgba (src, temp_rgba); break;
case COGL_PIXEL_FORMAT_ARGB_8888:
_cogl_argb_to_rgba (src, temp_rgba); break;
case COGL_PIXEL_FORMAT_ABGR_8888:
_cogl_abgr_to_rgba (src, temp_rgba); break;
default:
break;
}
switch (dst_format & COGL_UNPREMULT_MASK)
{
case COGL_PIXEL_FORMAT_G_8:
_cogl_rgba_to_g (temp_rgba, dst); break;
case COGL_PIXEL_FORMAT_RGB_888:
_cogl_rgba_to_rgb (temp_rgba, dst); break;
case COGL_PIXEL_FORMAT_BGR_888:
_cogl_rgba_to_bgr (temp_rgba, dst); break;
case COGL_PIXEL_FORMAT_RGBA_8888:
_cogl_rgba_to_rgba (temp_rgba, dst); break;
case COGL_PIXEL_FORMAT_BGRA_8888:
_cogl_rgba_to_bgra (temp_rgba, dst); break;
case COGL_PIXEL_FORMAT_ARGB_8888:
_cogl_rgba_to_argb (temp_rgba, dst); break;
case COGL_PIXEL_FORMAT_ABGR_8888:
_cogl_rgba_to_abgr (temp_rgba, dst); break;
default:
break;
}
src += src_bpp;
dst += dst_bpp;
}
}
return TRUE;
}
gboolean
_cogl_bitmap_fallback_unpremult (CoglBitmap *bmp)
{
guint8 *p;
int x,y;
/* Make sure format supported for un-premultiplication */
if (!_cogl_bitmap_fallback_can_unpremult (bmp->format))
return FALSE;
for (y = 0; y < bmp->height; y++)
{
p = (guint8*) bmp->data + y * bmp->rowstride;
if (bmp->format & COGL_AFIRST_BIT)
{
for (x = 0; x < bmp->width; x++)
{
if (p[0] == 0)
_cogl_unpremult_alpha_0 (p);
else
_cogl_unpremult_alpha_first (p);
p += 4;
}
}
else
{
for (x = 0; x < bmp->width; x++)
{
if (p[3] == 0)
_cogl_unpremult_alpha_0 (p);
else
_cogl_unpremult_alpha_last (p);
p += 4;
}
}
}
bmp->format &= ~COGL_PREMULT_BIT;
return TRUE;
}
gboolean
_cogl_bitmap_fallback_premult (CoglBitmap *bmp)
{
guint8 *p;
int x,y;
/* Make sure format supported for un-premultiplication */
if (!_cogl_bitmap_fallback_can_premult (bmp->format))
return FALSE;
for (y = 0; y < bmp->height; y++)
{
p = (guint8*) bmp->data + y * bmp->rowstride;
if (bmp->format & COGL_AFIRST_BIT)
{
for (x = 0; x < bmp->width; x++)
{
_cogl_premult_alpha_first (p);
p += 4;
}
}
else
{
x = bmp->width;
#ifdef COGL_USE_PREMULT_SSE2
/* Process 4 pixels at a time */
while (x >= 4)
{
_cogl_premult_alpha_last_four_pixels_sse2 (p);
p += 4 * 4;
x -= 4;
}
/* If there are any pixels left we will fall through and
handle them below */
#endif /* COGL_USE_PREMULT_SSE2 */
while (x-- > 0)
{
_cogl_premult_alpha_last (p);
p += 4;
}
}
}
bmp->format |= COGL_PREMULT_BIT;
return TRUE;
}
gboolean
_cogl_bitmap_fallback_from_file (CoglBitmap *bmp,
const char *filename)
{
/* FIXME: use jpeglib, libpng, etc. manually maybe */
return FALSE;
}
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