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Use ffs to calculate the GL_{UN,}PACK_ALIGNMENT

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Instead of having a series of if-statements this adds an inline
function to calculate the alignment directly using ffs which is
probably slightly faster. Admittedly this is a pointless
micro-optimisation but I think it makes the code looks a bit neater
anyway.

Reviewed-by: Robert Bragg <robert@linux.intel.com>
This commit is contained in:
Neil Roberts 2012-03-22 12:40:38 +00:00
parent c33ce5fc6b
commit d54111795f
1 changed files with 12 additions and 16 deletions
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28
cogl/cogl-texture.c
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@ -256,19 +256,21 @@ _cogl_texture_prepare_for_upload (CoglBitmap *src_bmp,
return dst_bmp;
}
static inline int
calculate_alignment (int rowstride)
{
int alignment = 1 << (_cogl_util_ffs (rowstride) - 1);
return MIN (alignment, 8);
}
void
_cogl_texture_prep_gl_alignment_for_pixels_upload (int pixels_rowstride)
{
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
if (!(pixels_rowstride & 0x7))
GE( ctx, glPixelStorei (GL_UNPACK_ALIGNMENT, 8) );
else if (!(pixels_rowstride & 0x3))
GE( ctx, glPixelStorei (GL_UNPACK_ALIGNMENT, 4) );
else if (!(pixels_rowstride & 0x1))
GE( ctx, glPixelStorei (GL_UNPACK_ALIGNMENT, 2) );
else
GE( ctx, glPixelStorei (GL_UNPACK_ALIGNMENT, 1) );
GE( ctx, glPixelStorei (GL_UNPACK_ALIGNMENT,
calculate_alignment (pixels_rowstride)) );
}
void
@ -276,14 +278,8 @@ _cogl_texture_prep_gl_alignment_for_pixels_download (int pixels_rowstride)
{
_COGL_GET_CONTEXT (ctx, NO_RETVAL);
if (!(pixels_rowstride & 0x7))
GE( ctx, glPixelStorei (GL_PACK_ALIGNMENT, 8) );
else if (!(pixels_rowstride & 0x3))
GE( ctx, glPixelStorei (GL_PACK_ALIGNMENT, 4) );
else if (!(pixels_rowstride & 0x1))
GE( ctx, glPixelStorei (GL_PACK_ALIGNMENT, 2) );
else
GE( ctx, glPixelStorei (GL_PACK_ALIGNMENT, 1) );
GE( ctx, glPixelStorei (GL_PACK_ALIGNMENT,
calculate_alignment (pixels_rowstride)) );
}
/* FIXME: wrap modes should be set on pipelines not textures */